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Volume XLIII
Dicembre 2017
Memorie della Società Italiana di Scienze Naturali
e del Museo Civico di Storia Naturale di Milano
Filippo Bertozzo, Cristiano Dal Sasso, Matteo Fabbri,
Fabio Manucci & Simone Maganuco
Redescription of a remarkably large Gryposaurus notabilis
(Dinosauria: Hadrosauridae) from Alberta, Canada
Per ricevere le Memorie: info@scienzenaturali.org
© 2017 Società Italiana di Scienze Naturali
Museo Civico di Storia Naturale di Milano
Corso Venezia, 55 - 20121 Milano
In copertina: ricostruzione di Gryposaurus basata sull’esemplare MSNM V345. /
Reconstruction of Gryposaurus based on specimen MSNM V345.
(Disegno/drawing: Marco Auditore).
Registrato al Tribunale di Milano al n. 6694
Direttore responsabile : Anna Alessandrello
Graca editoriale: Michela Mura
Stampa: Litograa Solari, Peschiera Borromeo - Dicembre 2017 ISSN 0376-2726
INDICE
INTRODUCTION Pag. 4
Fossil location and history Pag. 4
Geological setting Pag. 8
Palaeobiogeography of Gryposaurus Pag. 8
MATERIALS Pag. 8
METHODS Pag. 11
SYSTEMATIC PALAEONTOLOGY Pag. 12
TAXONOMY Pag. 12
OSTEOLOGY Pag. 13
Skull and lower jaw Pag. 13
Axial skeleton Pag. 22
Appendicular skeleton Pag. 35
Histology and ontogenetic assessment Pag. 44
Pathological bones Pag. 46
SKELETAL AND LIFE
RECONSTRUCTION OF GRYPOSAURUS
Pag. 48
Reconstruction history Pag. 48
Review of skin impressions Pag. 51
A revised reconstruction based on MSNM
V345
Pag. 52
CONCLUSIONS Pag. 52
Acknowledgements Pag. 53
REFERENCES Pag. 54
Filippo Bertozzo, Cristiano Dal Sasso, Matteo Fabbri,
Fabio Manucci & Simone Maganuco
Redescription of a remarkably large Gryposaurus notabilis
(Dinosauria: Hadrosauridae) from Alberta, Canada
Abstract - MSNM V345 is a partial skeleton of the North American hadrosaur species Gryposaurus notabilis, Lambe 1914, dis-
covered in 1922 in the Dinosaur Park Formation of Dinosaur Provincial Park, Alberta, Canada. It was shipped in several crates to the
Museo di Storia Naturale di Milano (MSNM), Italy, where it arrived in October 1958. Careless transportation during its long journey
to Milan meant that the skeleton arrived extremely damaged and required heavy restoration work by MSNM staff.
A preliminary study of the specimen was conducted by Vittorio Vialli in 1960 while part of it was still under preparation. That
study was followed by a more detailed, although still partial, osteological description by Giovanni Pinna in 1979. On the centennial
of the species’ discovery, we decided to examine the specimen in even greater detail in order to improve knowledge on the dinosaur’s
skeletal anatomy and help clarify the taxonomy of the genus.
Here, we redescribe the dinosaur’s osteology, focusing on unpublished elements, such as metapodials, phalanges, sacral vertebrae,
and some caudal vertebrae, recently discovered to be located at the MSNM. Isolated appendicular elements found at the same quarry
and tentatively referable to other individuals of the same taxon or to other dinosaur species are also briey mentioned. Histological
analysis of a core obtained from the femur revealed that it was made of brolamellar bone with a high number of Haversian systems.
The presence of an external fundamental system indicates that the individual was fully adult at the moment of death.
Of note, the skeletal remains present with traces of at least four pathological conditions: a cavity in the predentary is speculated
to be the result of osteomyelitis; the fth dorsal vertebra is fused to the left rib through a overgrowth of bone, and is interpreted as
osteosclerosis subsequent to a fracture; the neural spine of the 26th caudal vertebra is fractured and healed, and the centrum has a strap
of bone growing up to the side of the preceding centrum, explainable as idiopathic skeletal hyperostosis.
A review of the skeletal reconstructions of the genus is also presented, followed by a summary of the skin remains and remarks on
other anatomical traits. Altogether, the new data obtained on MSNM V345 have allowed us to present a more accurate and up-to-date
skeletal reconstruction and in vivo restoration of G. notabilis.
Keywords: Hadrosauridae, Cretaceous, osteology, palaeopathology, anatomical illustration.
Riassunto - Ridescrizione di un esemplare particolarmente grande di Gryposaurus notabilis (Dinosauria: Hadrosauridae) rinve-
nuto in Alberta, Canada.
MSNM V345 è uno scheletro parziale di Gryposaurus notabilis Lambe 1914 (Dinosauria, Hadrosauridae), visibile al pubblico del
Museo di Storia Naturale di Milano (MSNM) all’interno di un diorama che ne riproduce lo scavo. L’esemplare fu scoperto nel 1922
nella Dinosaur Park Formation (Dinosaur Provincial Park, Alberta, Canada), e successivamente spedito al MSNM nell’Ottobre 1958.
All’arrivo in museo le ossa versavano in cattive condizioni a causa del lungo viaggio, pertanto necessitarono di lunghe ore di restauro
e consolidamento da parte dello staff museale.
Un primo studio, preliminare, fu pubblicato da Vittorio Vialli nel 1960, benché parte dello scheletro fosse ancora in preparazione.
Il lavoro di Vialli fu successivamente ripreso e ampliato da un’analisi osteologica più dettagliata, ma ancora incompleta, a cura di
Giovanni Pinna nel 1979. Nel centenario della scoperta della specie, abbiamo pertanto deciso di riesaminare lo scheletro in maggior
dettaglio per approfondire la conoscenza di anatomia, tassonomia e biologia della specie, valorizzandone l’importanza anche dal punto
di vista museologico.
In questo studio rivisitiamo l’osteologia di MSNM V345 con particolare attenzione agli elementi scheletrici nora non pubblicati,
tra cui ossa metapodiali, falangi, vertebre sacrali e alcune vertebre caudali, recentemente identicate nelle collezioni del museo. Ele-
menti isolati dello scheletro appendicolare trovati nel sito di scavo originale, assegnati ad altri esemplari della stessa specie e/o ad altre
specie, sono brevemente menzionati.
L’analisi istologica effettuata sul femore di G. notabilis rivela una struttura brolamellare dell’osso con un’elevata densità di
canali haversiani. Inoltre, la presenza del sistema fondamentale esterno (EFS) indica che, al momento della morte, l’esemplare aveva
raggiunto l’età adulta e la maturità.
Di particolare interesse sono alcune ossa che presentano tracce di almeno quattro patologie fossilizzate: una profonda cavità nel
predentale è probabilmente conseguenza di una osteomielite; la quinta vertebra dorsale è fusa con la costola sinistra, tramite un accre-
scimento osseo anomalo, interpretato qui come osteosclerosi indotta da frattura; la spina neurale della 26esima vertebra caudale ha
subito una frattura poi risaldatasi e il centro vertebrale presenta un accrescimento osseo che invade lateralmente il centro vertebrale
della vertebra precedente, interpretato qui come iperostosi scheletrica idiopatica diffusa.
Inne proponiamo una revisione delle illustrazioni anatomiche e paleoartistiche del genere Gryposaurus pubblicate dalla scoperta
del taxon a oggi, accompagnata da un compendio dei reperti di pelle fossilizzata e della loro morfologia. La combinazione di tutti
questi nuovi dati ci permette di presentare una ricostruzione più precisa dello scheletro di G. notabilis, accompagnata da un’illustra-
zione accurata dell’aspetto in vita del dinosauro.
Parole chiave: Adrosauridi, Cretaceo, osteologia, paleopatologia, illustrazione anatomica.
4FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
INTRODUCTION
Fossil location and history
MSNM V345 is a partial skeleton of a hadrosaurid di-
nosaur referable to Gryposaurus notabilis, Lambe 1914.
Its whole history is reviewed here, from its excavation in
1922 to its depiction in the diorama on display today at the
Museo di Storia Naturale di Milano (MSNM) in Italy.
According to Vialli (1960), the skeleton was collected
by J. B. Abbott during the Chicago Field Museum’s 1922
palaeontological expedition to the area now known as
Dinosaur Park Formation (Belly River Group, Red Deer
River, Alberta, Canada) led by George F. Sternberg. Pinna
(1979) simply reported that the specimen was collected
not far from Steveville, a village, now extinct, formerly
located in the NW corner of today’s Dinosaur Provincial
Fig. 1 - Photographs taken in 1922 (A) and 2003 (B) of the quarry where MSNM V345 was found. Courtesy of Darren Tanke (Royal
Tyrrell Museum of Palaeontology) and Federico Fanti (Università di Bologna). / Confronto tra una foto scattata nel 1922 (A) e nel 2003
(B), esattamente nello stesso luogo in cui venne scoperto MSNM V345, ora conservato al Museo di Storia Naturale di Milano. Foto per
gentile concessione di Darren Tanke (Royal Tyrrell Museum of Palaeontology) e Federico Fanti (Università di Bologna).
Park. Apart from these scanty details, the expedition has
remained practically undocumented until recently (Brin-
kman, 2013). Darren Tanke of the Royal Tyrrell Museum
of Palaeontology (TMP), Drumheller, Canada has been
relocating lost dinosaur quarry sites in the Park since 1997
and discovered objects (i.e. fragments of glass, pieces of
newspaper, tools) abandoned at the eld during previous
palaeontological digs. Thanks to these objects and to old
eld photographs, over thirty lost or mystery quarries
have been identied (Tanke, 2001, 2005, 2006; Tanke &
Evans, 2014). Among them is the site where Gryposau-
rus notabilis MSNM V345 was discovered, now staked
as “Quarry 137, 1922 Chicago Field Museum expedition
to Dinosaur Provincial Park” (Currie and Russell, 2005;
Mallon, 2012) (Fig. 1).
5
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
MSNM V345 was found embedded in a greyish-to-
brownish sandstone matrix. The residual sediment encru-
sting the fossil was described as more or less cemented
and containing clays, small carbonaceous lenses, and so-
me rounded cobbles (Pinna, 1979). The unearthed skele-
tal elements were consolidated with 68 jackets of burlap
sacking dipped in plaster of Paris. Wood splint reinforce-
ments were used for the bigger bones. The jackets were
divided among 12 crates, for a total weight of 1,900 kg.
Several pages of the Chicago Sunday Tribune dated 1922
and partially impregnated with plaster of Paris were re-
cently found at the MSNM in a box containing most of
the undescribed fragments of the skeleton (Fig. 2). These
pages of newspaper were likely used to ll among the ja-
ckets during the transportation of the bones from the eld
to Chicago, and were shipped 36 years later with the spe-
cimen to Milan. The original jackets containing the un-
prepared specimen arrived in Italy in October 1958, and
were exchanged for a collection of fossil shes from the
Eocene of Monte Bolca (Vialli, 1960; Pinna, 1979; Brink-
man, 2013). Pinna (1979) reported that part of the material
Fig. 2 - Pages of the Chicago Sunday Tribune (dated August 6, 1922) stained with plaster after being used to protect the bones of
MSNM V345. They are kept at the MSNM palaeontological collections as historical proof of the Chicago Field Museum’s 1922 expe-
dition. Photo by CDS. / Una copia del “Chicago Sunday Tribune” datato 6 agosto 1922, sporco di gesso poiché utilizzato per imballare
le ossa del griposauro e ora conservato nelle collezioni di paleontologia del MSNM come prova storica degli scavi condotti dal Field
Museum di Chicago. Foto di CDS.
received by the MSNM (possibly the jacket containing
the ilia and sacrum) was accidentally and severely dama-
ged during loading onto a boat at the port of New York.
Preparation of the fossil started in November 1958 and
was carried out by Vittorio Vialli with the help of a labo-
ratory technician, Renato Pozzi. It was a very slow and
difcult process because of the fragility of the bones. The
specimen was probably nearly complete, but some bones
were extracted almost totally crushed from the jackets. As
Vialli (1960) wrote, “The majority of bones are broken in-
to tens, if not hundreds, of fragments; unfortunately, some
bones have been pulverised into dust or broken into very
small, detached elements. For these bones, restoration is
a real problem” (translated from Italian). Based on Vialli
(1960), the quality of preservation of the specimen was
already compromised at the beginning. Furthermore, no-
wadays the plaster reconstruction work looks quite crude
and some of the bones appear to have had the cortical bo-
ne ground off to the point that trabecular bone underneath
is visible. These severely impact the usefulness of some
elements for interpretation.
6FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 3 - MSNM V345 during restoration work carried out in the 1950s (A). The same specimen as it was displayed at the MSNM
before the making of the diorama (B). Photos from MSNM archive. / L’esemplare MSNM V345 fotografato durante le fasi di restauro
avvenute negli anni 50 del ‘900 (A). Lo stesso esemplare come venne esposto nelle sale del Museo di Storia Naturale di Milano prima
del moderno diorama (B). Foto archivio MSNM.
After preparation, the unmounted bones were displa-
yed for several years on a panel in the dinosaur hall at the
MSNM (Pinna, 1979) (Fig. 3). At the beginning of the
new millennium, the bones were moulded and cast for a
diorama depicting Quarry 137, and now are permanently
housed in the fossil vertebrate collection of the MSNM.
The diorama (Fig. 4) was curated in any detail, thanks to
the talented artwork of Valter Fogato, but also to the fact
7
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 4 - Top, the diorama reproducing the partially unearthed specimen MSNM V345. Casts of the original fossils were made and
put on display. The surrounding environment was replicated in detail on the basis of old and modern photographs of the site. Bottom,
a close-up of the life-size model of George F. Sternberg, added to the diorama at the end of 2017. Photos by Gabriele Bindellini. /
In alto, il diorama che riproduce fedelmente lo scavo dell’esemplare MSNM V345 nelle “badlands” canadesi, documentato da foto
storiche e recenti. Le ossa esposte sono calchi dei fossili originali. In basso, particolare del modello di George F. Sternberg, aggiunto
al diorama alla ne del 2017. Fotograe di Gabriele Bindellini.
8FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
that in 1998 Darren Tanke (TMP) relocated the Gryposau-
rus site at the Dinosaur Park (Tanke, 2001), providing ac-
tual rock samples from different layers cropping out in the
quarry and surrounding area. This, together with black and
white historical photos and new images of Quarry 137 at
high resolution (Tanke, pers. comm. to CDS, 2001-2002),
allowed to replicate rock texture and colours in the dio-
rama to a hyperrealistic level. Even the erosion occurred
in the meantime to the hoodoos and hills was taken into
account, in order to remake the landscape as it appeared to
George F. Sternberg in 1922. A life-size model of him in
the act of digging Gryposaurus was added to the scenery
in 2017 (Fig. 4). The face was modeled by Fabio Fogliazza
(MSNM) thanks to information provided by Darren Tanke
(TMP) and Clive Coy (University of Alberta) (pers. comm.
to CDS, 2002, 2016). Clive Coy also provided a cast of a
chisel with engraved initials GFS (George F. Sternberg),
found by him in 2010 at the University of Alberta, in the
Vertebrate Paleontology preparation lab.
When Darren Tanke relocated Quarry 137, he anno-
tated the following additional information (Tanke, pers.
comm. to FB, 2017): “A dorsal rib head and a proximal
caudal vertebra were still on the site of the Gryposaurus.
They were badly eroded and not worth collecting. Nothing
is left of them now. It is likely that the disarticulated ske-
leton was thought to be all collected (in 1922), but some
bones were still in the ground, completely buried and sim-
ply overlooked. Decades of erosion later, they came to the
surface and their signicance was not recognised”.
Geological setting
The Dinosaur Park Formation (DPF, Belly River
Group, Campanian, southeastern Alberta, Canada) is a 70-
m-thick formation characterised by thick grey sandstones,
red-brown ironstones and siltstones, green-to-brown clay-
stones, and thin coals that form layers of rock containing
the remains of articulated dinosaurs as well as monospe-
cic (mainly ceratopsian) and multigeneric bone beds
(Currie & Koppelhus, 2005). The DPF is largely made of
sediments deposited by deep, meandering rivers that origi-
nated in the north and central Canadian Cordillera and
that owed southeastwards, subparallel to the axis of the
Alberta Basin 76.5 to 74.5 million years ago (Eberth &
Hamblin, 1993). The DPF is subdivided into two assem-
blage zones: MAZ-1 and MAZ-2 (Ryan & Evans, 2005;
Mallon et al., 2012). Gryposaurus notabilis appears only
in the MAZ-1a sub-zone, along with Corythosaurus cas-
uarius and Dyoplosaurus acutosquameus (both of which
are also restricted to this sub-zone), and Euoplocephalus
tutus, Panoplosaurus mirus, Centrosaurus apertus, and
Parasaurolophus sp., which extend upwards beyond the
bounds of MAZ-1a to the overlying sub-zone, MAZ-1b.
As reported above, the specimen MSNM V345 was found
close to the ghost town of Steveville, in the Dinosaur
Provincial Park, southern Alberta, Canada (Vialli, 1960;
Pinna, 1979). Mallon (2012, p. 76, Appendix 2.1) reported
that MSNM V345 was found in Quarry Q137, 2.0 m above
the Oldman/Dinosaur Park limit (geographic coordinates:
50.74323 -111.51398; Currie & Koppelhus, 2005), which
falls within the MAZ-1a subunit of the Dinosaur Park For-
mation (Fig. 5).
Palaeobiogeography of Gryposaurus
Although basal Kritosaurini, such as Naashoibitosaurus
ostromi, appeared in southern Laramidia (Prieto-Márquez,
2014), the most recent common ancestor of the species of
Gryposaurus moved towards northern Laramidia no later
than early Campanian, speciating in G. latidens and G. no-
tabilis + G. monumentensis in two vicariant events (Prieto-
Márquez, 2014). G. latidens is found in the Lower Two
Medicine Formation of Montana, USA (Prieto-Márquez,
2012), more southern than the specimens of G. notabilis,
recovered from the different sites in the Dinosaur Provin-
cial Park (Alberta, Canada) (Prieto-Márquez, 2010b). G.
monumentensis, instead, is found in the late Campanian
Kaiparowits Formation of Southern Utah, USA (Gates &
Sampson, 2007). This species migrated back to southern
Laramidia after the split with G. notabilis (Prieto-Már-
quez, 2014; Xing et al., 2017) (Fig. 5C).
Another hadrosaur closely related to the gryposaur tri-
be is Rhinorex condrupus. It was discovered in the Book
Cliffs of central Utah, within estuarine sediments deposi-
ted by a river on the margin of the Western Interior Seaway
(Gates & Scheetz, 2014). Considered initially as a basal
kritosaurine, recently Xing et al. (2017) placed it as sister
taxon to G. latidens. Rhinorex condrupus is thought coeval
with G. monumentensis, but, as pointed out by Gates &
Scheetz (2014), the absence of accurate dating of the se-
diments might have falsied the contemporaneity of these
two closely related species and renders premature any pa-
laeobiogeographic discussion including the former.
Recently, Lehman et al. (2016) described a new spe-
cies, ?Gryposaurus alsatei, based on fragmentary mate-
rial recovered from the Big Bend National Park (Texas,
USA). As they point out, if the attribution of this species
to Gryposaurus is conrmed by future ndings, it would
indicate survival of the genus into middle or late Maa-
strichtian times (69 to 66 ma), a range over 10 to 13 mil-
lion years in duration (Lehman et al., 2016). New material
is also necessary to establish the position of ?G. alsatei
within the genus. This species might represent the last
migration further south or the last descendant of a long-
living lineage of Gryposaurus that rst appeared in sou-
thern Laramidia.
MATERIALS
In his preliminary study of MSNM V345, Vialli (1960)
provided a list of the skeletal elements he identied at that
time, which included the skull, the predentary and one
dentary, 28 vertebrae, ve haemal arches, three ribs, the
left (L) sternal plate, the two humeri, the two ulnae, the L
pubis and ?postpubis, the two ischia, the two femora, one
tibia, the right (R) metatarsal (mt) III, one pedal phalanx
(III-1), and some ossied tendons.
Pinna (1979) reported a new list of the elements be-
longing to MSNM V345: skull (left side) + L dentary, R
dentary, predentary, R quadrate (incomplete), eight cervical
vertebrae (identied as n. 3, 4, 5 or 6, 7, 8, 10, 11, 12), eight
9
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 5 - Hypothetical cranial growth series for G. notabilis, based on known specimens (A), size-comparison between the smallest and
the largest individuals referred to this species (B), and time-calibrated phylogenetic relationships with palaeogeographic distribution
of species belonging to the genus Gryposaurus (C). Scale bars = 1 m. Drawings by FM. / Ipotetica serie di crescita del cranio di G.
notabilis, basata sugli esemplari noti (A); confronto dimensionale tra l’esemplare più piccolo e quello più grande riferiti a questa specie
(B); relazioni logenetiche calibrate temporalmente e distribuzione paleogeograca delle specie riferite al genere Gryposaurus (C).
Scale metriche = 1 m. Disegni di FM.
dorsal vertebrae (tentatively identied as n. 1, 2, 5, 6, 8 or
9, plus three indeterminate vertebrae), 40 caudal vertebrae
(missing n. 1, 3, 6, 7, 43, 45, 47, and from 48 to the tip of
the tail), ve haemal arches, fragments of dorsal ribs, two
scapulae, L sternal plate, two humeri, two ulnae, two radii,
L metacarpal (mc) II, six phalanges of the R manus (II-1,
II-2, II-3; III-1, III-2, ?IV-2), L pubis, a fragment of R pu-
bis, two ischia, two femora, two tibiae, L bula, R astraga-
lus, L mt III, R mt IV, ve L pedal phalanges (III-1, III-3;
IV-1, IV-4, IV-5), three right pedal phalanges (II-1, II-2;
IV-5), and some indeterminate fragments. New work on the
MSNM collection (this study) permitted us to comment on
the interpretations of Vialli (1960) and Pinna (1979) and
to identify additional bones referable with condence to
MSNM V345 based on their anatomy, size, and state of
preservation. These bones were neither mentioned nor il-
lustrated by Pinna (1979), despite his claim that his paper
was published after having completed the preparation of
the specimen. It is possible that he was not able to identify
some of these bones due to their fragmentary nature and/
or to the scarcity of comparative material available at that
time. However, it cannot be excluded that some elements
were never removed from the original box, where they ha-
ve remained together with the old newspaper pages mentio-
ned above until our recent work on the MSNM collection.
The list of bones provided by Vialli (1960) can be
included in the list later provided by Pinna (1979), with
only minor differences (Table 1). Vialli interpreted mt III
as a right element, whereas Pinna interpreted it as a left
element; we agree with Pinna’s interpretation because of
the orientation of the proximal articular surface. Vialli
mentioned three ribs, whereas Pinna generically reported
some fragments; however, we have identied six dorsal
ribs, of which two almost complete, one missing the pro-
ximal part, one preserved only in its proximal third, and
two completely covered by plaster. Because Vialli repor-
ted the need to preserve some extremely fragile bones by
covering them entirely, we think that the ribs were proba-
bly among those bones.
Furthermore, Vialli mentioned a pubis and a postpu-
bis, probably meaning the prepubis and pubis typical of
derived ornithischians. He also mentioned some ossied
tendons not listed by Pinna, which we have been unable
to nd among the material housed at the MSNM. All other
bones of MSNM V345 listed by Pinna have been found,
including a well-preserved tooth on display at the MSNM
in Hall IV (see Dentary). The bone that Pinna interpreted
as a bula can be more likely interpreted as a radius be-
longing to an even larger individual; therefore, it has been
catalogued under a different inventory number (MSNM
V6123). Contrary to Pinna, we identify caudal vertebra
“14” (as written on the bone) as caudal 8 or 9, mainly
because of the size and orientation of the neural spine.
Moreover, contrary to Vialli (1960) and Pinna (1979), the
preserved sternal plate is here interpreted as the right side
element. A second, previously unidentied portion of the
10 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
right quadrate found among the indeterminate fragments
perfectly conjoins with the known portion. This bone is
now complete dorsoventrally.
The other bones identied here for the rst time and
referred to MSNM V345 are: the L mc III, preserved for
two-thirds of its length; the R mt II; a proximal-mid por-
tion of the diaphysis of the ?R bula; two ungual phalan-
ges, probably belonging to the manus, congruent in size
with the rest of the skeleton; fragments of the R ischium,
later successfully reconnected to the caudal ramus of the
bone; fragments of the L pubis that match the main body
of the bone; two vertebral centra, heavily eroded on one
side, referred to position ?19 and ?28 along the caudal
series; two fused sacral vertebrae, 138 mm long and pre-
serving only the ventral halves of the centra, identied
as hadrosaurid sacrals 4 and 5 and compatible with the
size of MSNM V345 (see specimen AMNH FARB 5350
in Lull & Wright, 1942); and six fragments of vertebral
processes probably belonging to the neural arches of ver-
tebrae from MSNM V345.
Tab. 1 - Inventories of material referred to MSNM V345 as reported by Vialli (1960), Pinna (1979), and our
new analysis. * Estimated completeness of the skeleton; in square brackets, values obtained after adding the
inaccessible cranial bones (i.e., palatal bones and braincase) and after duplicating preserved R or L elements.
Vialli, 1960 Pinna, 1979 This study
skull skull, L side and isolated R quadrate skull, L side and isolated R quadrate
L dentary and predentary R and L dentaries and predentary R and L dentaries and predentary
28 vertebrae 56 vertebrae, including 8 cervicals (n.
3, 4, 5 or 6, 7, 8, 10, 11, 12), 8 dorsals
(hypothetically assigned to positions
1, 2, 5, 6, 8 or 9, and 3 indeterminate
vertebrae) and 40 caudals
60 vertebrae, including 8 cervicals (n. 3,
4, 5, 7, 8, 10, 11, 12), 8 dorsals (n. 1, 2, 5,
6, 7, 8, 9, 10), 2 incomplete sacrals and 42
caudals
5 chevrons 5 chevrons 5 chevrons (n. 6, 7, 11, 12, 23)
3 ribs several R fragmentary ribs Cervicals: 1 L rib (c8); dorsals: 4 L ribs and
2 R ribs.
2 scapulae 2 scapulae
L sternal plate L sternal plate R sternal plate
2 humeri 2 humeri 2 humeri
2 ulnae 2 ulnae 2 ulnae
2 radii 2 radii
L mc II L mc II, L mc III
6 R manual phalanges: II-1, II-2, II-3;
III-1, III-2; ?IV-2
4 manual phalanges: L III-1; L IV-1; 2 indet.
unguals (likely II and IV)
L pubis and ?postpubis L pubis L pubis
fragmentary R pubis fragmentary R pubis
2 ischia 2 ischia 2 ischia
2 femora 2 femora 2 femora
1 tibia 2 tibiae 2 tibiae
L bula fragmentary ?R bula
R astragalus R astragalus
R mt III L mt III, R mt IV R mt II, L mt III, R mt IV
1 pedal phalanx: III-1 5 L pedal phalanges: III-1, III-3, IV-1,
IV-4, IV-5
7 pedal phalanges: L II-2; L III-1, R III-3;
?L IV-1, R IV-3; 2 indet. unguals (likely II
and IV)
3 R pedal phalanges: II-1, II-2; IV-5
ossied tendons several indeterminate fragments several indeterminate fragments
18.50% [25.25%; 29.25%]* 31.25% [38.00%; 46.00%]* 32.68% [39.54%; 48.37]*
11
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Several fragments mostly belonging to the right side
of the skull and to the ilia of MSNM V345 (according to
the labels) are also present but are too fragmentary and
eroded to be informative; therefore, we do not describe or
illustrate them here.
Uncertainty remains on the distinction between R and L
phalanges as well as between some pedal and manual ele-
ments. In particular, the phalanx identied by Pinna (1979)
as the rst one of the third digit of the manus (III-1) proba-
bly belongs to the pes, as well as the second phalanx of the
fourth digit of the manus (which is a IV-3 of the pes). It al-
so turned out that there are two pedal phalanges L II-2 with
the same shape and morphology; the large one is consist-
ent in size with most other pedal bones referred to MSNM
V345; the smaller one belongs to a younger G. notabilis
individual. Furthermore, a manual phalanx and a pedal
phalanx, previously attributed to MSNM V345, are here
attribuited to Ceratopsia indet., following Fujiwara (2009).
During the re-examination of the material from the
Field Museum carried out in 1958, several extra bones
referable to other hadrosaurid individuals or to other di-
nosaur taxa were found. They include: a partial ?mc II,
preserved for two-thirds of its length and possibly belong-
ing to a hadrosaur larger than MSNM V345; the large ra-
dius MSNM V6123 mentioned above; two fragments of
tibiae and a quadrate of an individual smaller than MSNM
V345; a neural arch with diapophysis from a caudal verte-
bra of an indeterminate ornithischian; and ve postcranial
bones from different dinosaurs found at the Dinosaur Pro-
vincial Park in Alberta (Maganuco, 2004), which include
two ceratopsian tibiae (MSNM V5175; MSNM V5176),
the radius of a juvenile hadrosaurid (MSNM V5177), an
ornithomimid pubis (MSNM V5178), and an ankylosau-
rid ischium (MSNM V5179). The isolated partial ?mc II
and radius MSNM V6123 might be tentatively referred
to an adult individual of Corythosaurus casuarius, based
on their size and proportions: according to Brown (1916),
this large lambeosaurine hadrosaurid, which was sym-
patric with G. notabilis, has a radius considerably longer
than the humerus.
METHODS
MSNM V345 and the extra bones mentioned above
are part of the palaeontological collection housed at the
MSNM. The history of the specimen was reconstructed
from Vialli (1960) and Pinna (1979), together with more
recent information from Tanke (2001, 2005) and from the
1922 American newspaper used to pack the specimen. At
present, the bones are kept in a large new cabinet, sorted
by dimensions and anatomical position. We took photo-
graphs of each skeletal element following standardised
procedures in cranial/rostral, caudal, dorsal, ventral, late-
ral, and medial views using a Panasonic DMC-LZ3 digi-
tal camera. The photographs were processed using Adobe
Photoshop. Measurements were taken with a tape or with
digital callipers.
We refer to the margins and surfaces of the bones ac-
cording to their orientation in vivo. Following Weisham-
pel et al. (2004), we adopted the following terminology
of the Nomina Anatomica Veterinaria (Bryden & Halnan,
2009) and the Nomina Anatomica Avium (Baumel et al.,
1993): ventral (towards the belly), dorsal (towards the
back), rostral (in describing head elements towards the
tip, or rostrum, of the head), cranial (towards the head),
caudal (towards the tail), medial (towards the midline),
and lateral (away from the midline); proximal (towards
the mass of the body) and distal (away from the mass of
the body) are used to designate appendages, like segments
or elements of a limb, and also regions (proximal, midd-
le, distal) of the tail. The cervicodorsal transition in the
vertebral column was identify by the position of the pa-
rapophysis for the capitulum of the rib head, and using
previous descriptions of hadrosaurs as comparison (Parks,
1920; Lull & Wright, 1942; Horner et al., 2004). Moreo-
ver, following Norman (1980), we considered as proximal
any caudal vertebrae with pleurapophyses; as middle any
caudals lacking pleurapophyses but having haemapophy-
ses; and as distal any caudals lacking pleurapophyses and
haemapophyses.
We also performed histological analysis to dene the
ontogenetic stage of the individual. Histology is the only
reliable method for ontogenetic assessment and absolu-
te estimation of the age of an individual (e.g., Chinsamy,
2005; Erickson et al., 2004; Erickson, 2005). Indeed,
other common characters used to assess the ontogenetic
stage of fossil tetrapods, such as surface texture of bones,
degree of fusion of the elements, and obliteration of the
sutures in skulls and vertebrae, have been recently found
to be ambiguous (e.g., Brochu, 1996; Werning, 2012;
Bailleul et al., 2016). To this end, we sampled the right
femur, given its completeness, preservation, and absen-
ce of reconstruction artefacts. Areas lacking evident su-
percial erosion and surface cracks were selected, and a
core sample was taken following the method described
in Stein & Sander (2009), using a Timbertech Kebo01
electric drill press with a cylindrical diamond drill bit (16
mm in diameter, 80 mm in height, and with a 2 mm-thick
wall). The diaphysis of the femur was sampled laterally
(see Fig. 27A). Samples were mounted on glass slides,
polished down to a thickness of ~70 μm, and analysed
under a Nikon Eclipse E600 POL microscope. The type
of microstructure, the density and type of vascular canals,
the amount of remodelling, the number of lines of arre-
sted growth (LAGs), and the presence or absence of an
external fundamental system (EFS) were the proxies used
in this study to evaluate ontogenetic stage. LAGs are he-
re considered as continuous lines delimiting zones within
the compacta that represent stop in the deposition of new
layers of bone on the outer surface of the bone through
ontogeny (sensu Chinsamy, 2005). They were identied
and counted when the arrest in bone deposition was visi-
ble at different magnications and when the interruption
was continuous along the slide. An EFS is here conside-
red as a microstructural complex including lamellar bo-
ne constituting the microstructure, absence of vascular
canals, and tightly spaced LAGs placed in the outermost
compacta (as per Chinsamy, 2005). Terminology used for
describing the microstructure and the vascularization fol-
lows Francillon-Vieillot et al. (1990).
Bones presumably presenting signs of pathology (the
predentary, the fth dorsal vertebra, and a caudal verte-
bra) were subjected to X-ray computed tomography (CT)
12 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
at the Servizio di Radiologia, Fondazione IRCCS Ca’
Granda Ospedale Maggiore Policlinico, Milano, using a
Siemens Somatom Denition Dual Source CT Scanner.
The CT imaging was obtained with bone and mediasti-
num algorithms on transverse (axial) slices, with scan pa-
rameters 140 kV, 204 mA, and slice thickness of 0.4 mm.
Raw data were exported in DICOM format and processed
using Sante DICOM Viewer 3D FREE (64-bit). For the
predentary, we also drilled a core sample following the
above-described procedure, piercing through to the ab-
normal cavity to assess if it was caused by pathology.
Institutional abbreviations - AEHM, Palaeontologi-
cal Museum of the Institute of Geology and Nature Mana-
gement, Far East Branch, Russian Academy of Sciences,
Blagoveschensk, Russia; AMNH FARB, American Mu-
seum of Natural History, Fossil Amphibians, Reptiles, and
Birds collection, New York City, New York, USA; BYU,
Brigham Young University, Museum of Paleontology,
Provo, Utah, USA; CMN, Canadian Museum of Nature,
Ottawa, Ontario, Canada; IGM, Instituto de Geología de
la Universidad Nacional Autónoma de México, Mexico;
JRF, Judith River Foundation/Great Plains Dinosaur Mu-
seum, Malta, Montana, USA; MSNM V, Museo di Storia
Naturale di Milano, fossil Vertebrates collection, Milan,
Italy; MOR, Museum of the Rockies, Bozeman, Monta-
na, USA; RAM, Raymond M. Alf Museum, Claremont,
California, USA; ROM, Royal Ontario Museum, Toron-
to, Ontario, Canada; SMF, Senckenberg Gesellschaft für
Naturforschung, Senckenberg Naturmuseum Frankfurt,
Germany; TMP, Royal Tyrrell Museum of Palaeontology,
Drumheller, Alberta, Canada; UAL VP, University of Al-
berta, Laboratory for Vertebrate Palaeontology, Edmonton,
Canada; UMNH VP, Utah Museum of Natural History,
composed, constituted forse? Salt Lake City, Utah, USA.
Anatomical abbreviations - ac, acetabulum; af, angu-
lar facet; art, articular; BS, basement scales; c, centrum;
caf, chevron articular surface; cap, capitulum; cf, cora-
coid facet; clp, caudolateral process; cmp, craniomedial
plate; cnc, cnemial crest; cp, coronoid process; d, denta-
ry; db, dental battery; dbl, distal blade; df, deltoid fossa;
dia, diapophysis; dpc, deltopectoral crest; d(p), denticles
(papillae); dt, predentary denticles; ec, erosional cavities;
EFS, External Fundamental System; f, frontal; fh, femoral
head; fr, fused rib; FS, feature scales; ftr, fourth trochan-
ter; gl, glenoid; gtr, greater trochanter; hh, humeral head;
hs, humeral shaft; ilp, iliac peduncle; ilr, iliac ramus; is,
ischial shaft; iscp, ischial peduncle; L, left; la, lacrimal;
LAGs, lines of arrested growth; lcd, lateral condyle; l,
lateral ange; Mc, Meckelian canal; mc, metacarpal; mac,
mandibular condyle; med, medial condyle; mf, median
foramen; m, medial ange; MFS, midline feature scales;
ms, mandibular symphysis; mt, metatarsal; mx, maxilla;
n, nasal; nc, neural canal; nf, nutritive foramen; ns, neural
spine; obn, obturator notch; obp, obturator process; ol,
oleocranon process; om, oral margin; pa, parietal; pam,
proximal articular margin; pap, pseudoacromion process;
par, parapophysis; pem, proximal edentulous margin; pf,
prefrontal; pmx, premaxilla; po, postorbital; poz, post-
zygapophysis; pp, proximal constriction of the prepubic
process; ppb, postpubic process; ppr, pubic process; prp,
prepubic process; prz, prezygapophysis; ptw, pterygoidal
wing; q, quadrate; qh, quadrate head; qj, quadratojugal;
qjn, quadratojugal notch; qs, quadrate shelf; R, right; rc,
radial condyle; so, secondary osteons; sq, squamosal; sur,
surangular; tp, transverse process; tub, tuberculum; uc,
ulnar condyle; var, vertical accessory ridge; vk, ventral
keel; vmr, vertical median ridge; vp, ventral process; wf,
wear facet.
SYSTEMATIC PALAEONTOLOGY
Dinosauria Owen, 1842
Ornithischia Seeley, 1887
Ornithopoda Marsh, 1881
Hadrosauroidea Sereno, 1986
Hadrosauridae Cope, 1869
Hadrosaurinae Lambe 1918 (sensu Xing et al., 2017)
Kritosaurini Brett-Surman, 1989
Gryposaurus notabilis Lambe, 1914
TAXONOMY
Gryposaurus notabilis was erected by Lambe in 1914
based on a nearly complete skeleton found by C. H. Ster-
nberg at the Belly River Formation, along the Red Deer
River (Alberta, Canada). The diagnosis was based on se-
veral features: very deep skull with highly arched nasals,
lower rostral border of the premaxillae expanded laterally,
orbit smaller than the infratemporal fenestra, high qua-
drate, small quadratojugal, predentary expanded laterally,
ischia not expanded distally, neural spines of the cranial
dorsal vertebrae long. G. notabilis resembled Kritosau-
rus navajovius, a hadrosaur found near Ojo Alamo (New
Mexico, USA) and described earlier by Barnum Brown
(1910).
In 1920, Parks described a new skeleton that was
morphologically and stratigraphically similar to Lambe’s
Gryposaurus, but he gave priority to the earlier-establi-
shed genus Kritosaurus, naming his specimen Kritosau-
rus (Gryposaurus) incurvimanus. Later, Lull & Wright
(1942) regarded Gryposaurus as a junior synonym of
Kritosaurus, an assumption that was accepted for a long
time (Prieto-Márquez, 2014, and references therein). It
was only in 1992 that Horner erected Gryposaurus lati-
dens, claiming the validity of Gryposaurus because they
were different taxa on the basis of diagnostic differences
in the fronto-nasal suture morphology. Some features
used by Lull & Wright (1942) to synonymize Grypo-
13
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
saurus with Kritosaurus, such as the size of the infra-
temporal openings, are not fully diagnostic as they vary
among conspecic individuals (Horner, 1992). In the end,
Prieto-Márquez (2010b) considered G. incurvimanus as
a junior synonym of G. notabilis, and in his revision of
the Kritosaurini (Prieto-Márquez, 2014) he re-evaluated
the material of Kritosaurus, clarifying the phylogenetic
relationships among these hadrosaurs. G. latidens, G. no-
tabilis, and G. monumentensis were included within the
hadrosaurine Kritosaurini, along with K. horneri, K. nava-
jovius, Secernosaurus koerneri, Willinaqake salitralensis,
and Naashoibitosaurus ostromi (Prieto-Márquez, 2014:
g. 26). The most recent additions to the Kritosaurini are
Rhinorex condrupus, placed at the base of the gryposaur
node in the Kritosaurini phylogeny by Gates & Scheetz
(2014), and ?Gryposaurus alsatei, placed within the ge-
nus Gryposaurus in an analysis by Lehman et al. (2016),
pending more complete material.
Vialli (1960) referred MSNM V345 to Kritosaurus no-
tabilis on the basis of the cranial osteology. On August 17,
1959, before the ofcial date of publication, J. T. Gregory,
from the University of California at Berkeley, sent a letter
to Vialli conrming his attribution, writing “So far as I
can determine from the photographs which you sent, the-
re is no reason why the dinosaur should not be identied
as Kritosaurus notabilis (Lambe). About the only feature
that seems to differ from the published illustrations is the
front part of the lower jaw, which seems to be shallower
than in the gured species of Kritosaurus. Is it possible
that the pre-dentary bone has shipped forward a bit with
relation to the dentary?” Later, Pinna (1979) referred the
specimen to Kritosaurus notabilis, whereas Currie & Rus-
sell (2005) claimed it was G. incurvimanus. Here, we con-
rm Vialli’s diagnosis and specic assignment, supported
by Prieto-Márquez (2010b): MSNM V345 bears several
characters ascribed to the species G. notabilis, such as the
nasal highly arched; the lower branch of the premaxilla
that does not reach the prefrontal; the lacrimal irregular-
ly pentagonal, long, and narrow, overlapping the maxilla;
and the highly denticulate predentary.
OSTEOLOGY
According to our revision, MSNM V345 consists of
about 40% of the bones that should be present in a com-
plete Gryposaurus skeleton. Skeletal completeness is
greatly compromised by the absence of the vast majority
of the ribs and chevrons (Fig. 6). However, because most
of the appendicular skeleton is represented by either a
left or right element, duplication allows up to about 50%
(48.37%) of this individual to be reconstructed. The skull
and mandible are well represented (Figs. 7-11). The left
side of the skull is well preserved (Fig. 7), whereas the
right side is strictly glued to a chalk base and is impos-
sible to examine. Likely, in situ the skull was laying left
side down and was thus more complete than the right,
cradled in the soft sediment. Consequently, the postcrani-
al skeleton may have been left side down too. Numerous
elements of the axial (Figs. 6, 11-19) and appendicular
(Figs. 6, 20-26) skeleton are preserved. In the shoulder
girdle and forelimbs, both left and right scapulae, hu-
meri, ulnae, and radii are present (Figs. 20, 21), as well
as metacarpals II and III, and four phalanges (Fig. 22). In
the pelvic girdle and hindlimbs, the left pubis and a frag-
mentary right pubis are preserved (Fig. 23), along with
both ischia, femora, tibia, the left bula, the right astra-
galus, metatarsals III and IV, and seven pedal phalanges
(Figs. 24-26).
Here, we also describe the following new material that
has not been reported before: left metacarpal III, right
metatarsal II, two unguals, fragments from the right is-
chium, six partial vertebral processes, two caudal centra,
the ventral halves of two fused sacral centra, and a frag-
ment of the right quadrate.
Overall, the material clearly indicates that this is one
of the biggest and stoutest specimens of G. notabilis ever
found. Vialli (1960) reported that the whole specimen
was estimated in the eld notes to be more than 7.50 m in
length and 2.50 m in height at the hip: “ […] Dr. Clifford
C. Gregg offered an original, unprepared skeleton of Kri-
tosaurus. Based on the eld notes, it should be complete,
together with the skull. Additional notes indicated that:
the specimen should measure around 7.50 [m] long, and
2.50 [m] high at the hip; the preparation should not be that
hard, because the bones are preserved in a soft sandstone;
the Kritosaurus (which species is not being identied yet)
should be easily mounted on the wall, a common proce-
dure with similar skeletons; nally, the only known skel-
eton of Kritosaurus is that of Parks, 1920.”
Pinna (1979) took new measurements after specimen
preparation and after having compared MSNM V345 with
other specimens of the genus Gryposaurus known at that
time, such as ROM 764 (“Gryposaurus incurvimanus”),
estimating a total length of 789 cm (neck, 110 cm; dorsal
region, 167 cm; sacrum, 80 cm; tail, 337 cm) and a height
at the hip of 270 cm. For our new skeletal reconstruction
(Fig. 6), we took into account the intervertebral spaces
that separate the vertebrae along the vertebral column in
SMF-R-4050, the beautifully preserved specimen of Ed-
montosaurus annectens nicknamed “Dakota” (Manning,
2008), and the large cartilaginous epiphyses that were
undoubtedly present on the limb bones (Lull & Wright,
1942) just as in extant archosaurs (Bonnan et al., 2010;
Holliday et al., 2010). We obtained an estimated maxi-
mum length (i.e., with the neck and tail stretched horizon-
tally) from the tip of the snout to the tip of the tail of 873
cm (neck, 118 cm; dorsal region, 175 cm; sacrum, 90 cm;
and tail, consisting of 70 vertebrae, 400 cm), an estimated
length in a more natural pose (as in Fig. 6) of 800 cm, and
a height at the hip of 315 cm.
Skull and lower jaw
Most of the description of the skull is based on the left
side seen in lateral view (Fig. 7). The skull is mounted on
a plate and is lying on its right side, which –consequen-
tly- has never been fully prepared and restored. Nume-
rous small indeterminate fragments of bones that cannot
be positioned in any way are still stored in a box with the
preparator’s hand-written label.
The skull suffered post-mortem deformation due to
diagenetic compression of the sediment, and so is com-
14 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 6 - The skeleton of MSNM V345 (A). The bones are placed in articulation based on a new skeletal reconstruction of Gryposaurus
(B). Elements such as the right quadrate, right dentary, ribs, the fragmentary pubis, metacarpals, metatarsals, and phalanges of the
manus and pes are not represented in A. The right tibia is digitally modied to follow a more natural twisting of its shaft. In B, missing
bones are in white, and the elements known from one side only (e.g., the right astragalus) have been duplicated on the other side. Scale
bars = 1 m. Drawing by Marco Auditore. / Scheletro di MSNM V345 (A). Le ossa sono articolate tra di loro in base ad un’aggiornata
ricostruzione scheletrica di Gryposaurus (B). In A elementi come il quadrato e il dentale destri, le costole, il pube frammentario, i
metacarpi, i metatarsi e le falangi della mano e del piede non sono posizionati. La tibia destra è stata modicata digitalmente a causa
della sua distorsione innaturale. Le ossa in bianco corrispondono agli elementi mancanti in MSNM V345. Le ossa che sono conservate
solo su un lato (ad esempio, l’astragalo destro) sono segnate come presenti in entrambi i lati. Scale metriche = 1 m. Disegno di Marco
Auditore.
pressed mediolaterally. The preserved interorbital di-
stance is 20 cm; Vialli (1960) estimated this distance in
life to be between 44 cm and 46 cm. The rostral and
ventral portions of the left premaxilla and the right side
of the skull roof (i.e., the left rostralmost corner and the
right caudalmost corner) are the areas most affected by
deformation. As a consequence, at rst glance the pre-
maxilla looks slightly deeper, the narial fenestra seems
to be shallower, and part of the dorsal surface of the skull
roof along with some fragments of the bones of the right
side are exposed in left lateral view (Fig. 7). Among the
bones of the right side, the quadrate is fully accessible,
it being not mounted on the plate (Fig. 8). The left lo-
wer jaw is mounted on the plate, still articulated with the
skull, whereas the right dentary and the unpaired pre-
dentary are respectively unmounted and mounted but re-
movable, so can be studied in detail (Figs. 9, 10). Vialli
(1960) and Pinna (1979) hypothesised that the diagene-
tic compression forces generated a 20-mm shift rostrally
of the left cranial bones with respect to the lower jaw,
causing a misalignment of the maxillary and dentary
tooth rows (with the former starting slightly rostral to
the latter), a displacement of the jugal – now comple-
tely covering the coronoid process – and a stretching
of the ventral portion of the infraorbital fossa, which is
elongated rostrocaudally. Most of the skulls illustrated
in Gates & Sampson (2007, g. 5) have the two tooth
rows almost perfectly aligned and the coronoid process
15
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 7 - Skull of MSNM V345 in lateral view (A) and after reconstruction (B), with dotted lines corresponding to uncertain bone limits.
C) Ventral view of the orbit (the exact position is determined by the red dot in B), showing the zigzagging margin (indicated by the
red line) between prefrontal and frontal. For abbreviations, see text. Scale bar = 10 cm. Photos by Gabriele Bindellini and drawing by
FB & SM. / Cranio di MSNM V345 in norma laterale (A) e sua ricostruzione schematica (B). Le linee tratteggiate corrispondono ai
margini incerti tra le ossa. C), supercie ventrale del tetto dell’orbita (la posizione precisa è indicata dal punto rosso in B). La linea
rossa indica il margine dentellato tra prefrontale e frontale. Le abbreviazioni sono riportate nel testo. Scala metrica = 10 cm. Foto di
Gabriele Bindellini, disegno di FB & SM.
16 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 8 - Right quadrate in caudal (A1), medial (A2), lateral (A3), proximal (A5), and distal (A6) views. A4) Drawing in lateral view,
showing the areas covered by plaster (grey) and the hypothetical extension of the pterygoidal wing (dotted line). For abbreviations, see
text. Scale bars = 10 cm. Photos and drawing by FB. / Quadrato destro in norma caudale (A1), mediale (A2), laterale (A3), prossimale
(A5), e distale (A6). Disegno schematico del quadrato destro in norma laterale, dove le parti in grigio corrispondono alle aree ricoperte
di gesso, mentre la linea tratteggiata delinea l’ipotetica estensione dell’ala pterigoidea (A4). Le abbreviazioni sono riportate nel testo.
Scale metriche = 10 cm. Foto e disegno di FB.
not so largely covered by the caudoventral ange of the
jugal. Interestingly, however, the skull of G. monumen-
tensis described in 2007 shows the same features seen in
MSNM V345, suggesting that the shift might be more
illusory than real.
Most of the length of the skull is provided by a deep
snout, which has a nasal crest or hump just in front of
the orbits and above the caudal portion of the apertura
nasi ossea. Most bones are articulated, and for this rea-
son some cranial sutures are not easily discernible (Fig.
7). Some bones (e.g., surangular and articular) are part-
ly covered by others, making it difcult to check their
contacts. The bones, restored with chalk and polish, as
well as the few bones entirely modelled in plaster, have
been identied by their colour and texture: for example,
the comma-like paroccipital process is restored in plaster.
The braincase and palatal bones are inaccessible but are
probably preserved in the matrix. There is no trace of the
sclerotic ring, which possibly was lost in the eld or du-
ring specimen preparation.
The skull of MSNM V345 is among the largest and
more robust of the known skulls of Gryposaurus (Fig. 5).
Pinna (1979) reported a length of 980 mm from the tip
of the premaxillae to the caudal-most margin of the part-
ly reconstructed paraoccipital processes, and a height of
500 mm from the ventral margin of the mandible to the
17
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 9 - Predentary in dorsal (A), ventral (B), caudal (C), rostral (D), left lateral (E), and right lateral (F) views. G) CT image of the
predentary, showing the genuinity of the denticles (image not to scale). For abbreviations, see text. Scale bar for A-F = 10 cm. Photos
by FB and CDS. / Predentale in norma dorsale (E), ventrale (F), caudale (G), rostrale (H), laterale sinistra (I) e laterale destra (L). G)
immagine ottenuta tramite TAC del predentale, che mostra l’autenticità dei denticoli (immagine non in scala). Le abbreviazioni sono
riportate nel testo. Scala metrica per A-F = 10 cm. Foto di FB e CDS.
top of the squamosal. In turn, the length measured from
the caudal margin of the caudodorsal corner of the qua-
drate to the rostralmost margin of the premaxillary lip is
900 mm. The ratio of this length to the maximum leng-
th of the quadrate is 2.35, second only to ROM 783, but
higher than the other Gryposaurus species. It is also hi-
gher than in BYU 13528 (Rhinorex condrupus) and TMP
1990.104.0001 (Brachylophosaurus canadensis), but it
is similar the value of another B. canadensis specimen,
NMC 8893 (Table 2).
Tab. 2 - Ratio of skull length (s) to quadrate length (q) in
selected specimens of North American kritosaurini taxa.
Species and specimen s/q
Gryposaurus notabilis MSNM V345 2.35
Gryposaurus notabilis ROM 873 2.49
Gryposaurus monumentensis RAM 6797 1.80
“Gryposaurus incurvimanus” TMP
1980.022.0001
1.97
Gryposaurus latidens AMNH FARB 5465 2.18
Brachylophosaurus canadensis NMC 8893 2.30
Brachylophosaurus canadensis TMP
1990.104.0001
2.20
Rhinorex condrupus BYU 13528 1.72
Cranial openings - The narial fenestra is rostrocaudally
expanded, as in other gryposaurs (Gates & Sampson, 2007),
but it is dorsoventrally narrower than in G. monumentensis
(Gates & Sampson, 2007). It is bordered by the premaxil-
la rostroventrally and by the nasal caudodorsally (Fig. 7).
18 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 10 - Right lower jaw in lateral (A), caudal (B), ventral (C), dorsal (D), rostral (E), and medial (lingual, F) views. For abbreviations,
see text. Scale bar = 10 cm. Photos by FB. / Ramo mandibolare destro in norma laterale (A), caudale (B), ventrale (C), dorsale (D),
rostrale (E) e mediale (linguale, F). Le abbreviazioni sono riportate nel testo. Scala metrica = 10 cm. Foto di FB.
margin deeply embayed and the opening of the lacrimal
canal (lacrimal foramen) lying within the emargination.
The upper rim of the orbit is rugose and formed exclusi-
vely by the prefrontal and postorbital.
The supratemporal fenestra is triangular, 13 cm long,
and 9 cm wide. Its rostrocaudal length matches that of
the orbit. The infratemporal fenestra is reniform, with the
As reported by Lull & Wright (1942), the nasal forms ne-
arly four-fths of the superior border and nearly one-third
of the lower border of the narial fenestra. However, be-
cause the skull has been compressed, the real shape of this
opening might have been different.
The orbit is smaller than the infratemporal fossa and
is vaguely D-shaped, with the upper part of the rostral
19
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
ventral portion wider than the dorsal one. It is more than
twice as high as it is wide, a diagnostic feature of Grypo-
saurus notabilis according to Lull & Wright (1942). It is
slightly bigger than the orbit, but with a similar rostrocau-
dal width.
Premaxilla - The left premaxilla is U-shaped in lateral
view and bifurcates caudally into two rami: the caudodor-
sal ramus tapers caudally; the caudolateral ramus has an
outline that is not well dened due to poor preservation
(Fig. 7). The premaxilla forms the rostral and ventral bor-
ders of the narial fenestra and the surrounding circum-
narial fossa. The rostral portion is squared with rounded
margins, closely resembling those of the G. notabilis
specimens NMC 2278 and ROM 873. However, it seems
more enlarged in its rostral portion than in other G. nota-
bilis (ROM 873, NMC 2278, see Kirkland et al., 2006), a
difference partly due to deformation of the bone that has
caused also part of the dorsal surfaces in the lateral view
of the skull to be exposed. By contrast, G. latidens has a
pointed rostral portion (Prieto-Márquez, 2010b) and G.
monumentensis has a more squared form (Gates & Sam-
pson, 2007). The caudolateral ramus is slightly deformed
due to lateral compression caused by taphonomic pro-
cesses, with its dorsal surface exposed within the narial
fenestra. The dorsal ramus contacts the nasal at the begin-
ning of the nasal crest. The oral margin of the premaxilla
is edentulous, smooth, and rounded and lacks the rugose
rostral limit of the interpremaxillary contact seen in G.
monumentensis (Gates & Sampson, 2007). The premaxil-
lary lip is large, upturned, and caudally less folded than
in G. monumentensis (Gates & Sampson, 2007), with a
rough external texture. It is subdivided into a wider upper
portion and a thinner lower portion. The premaxillary lip
borders the shallow circumnarial fossa rostrally, while the
premaxillary shelf borders it ventrally. The premaxillary
foramen (Gates & Sampson, 2007; Prieto-Márquez, 2012)
is present, but seems deformed by taphonomic processes.
In the middle of the caudolateral process, the premaxil-
lary shelf originates caudal to the postoral constriction.
It is squared in shape, with a crenulated caudal margin.
In our reconstruction (Fig. 7), the caudal portion of the
caudolateral process contacts the nasal dorsally and the
lacrimal caudally, as reported by Lull & Wright (1942).
However, due to the poor preservation, we cannot conrm
its exact shape.
Nasal - The nasal of MSNM V345 (Fig. 7) is axe-
shaped and represents the most diagnostic element for
the genus Gryposaurus (Gates & Sampson, 2007; Prieto-
Márquez, 2010b). The nasal rostral process is at lateral-
ly, and tapers rostrally where it contacts the caudodorsal
ramus of the premaxilla, and forms the dorsal margin of
the narial fenestra. The nasal arch rises just in front of
the orbits and dorsal to the narial fenestra. The highest
point is at the level of the rostral tip of the lacrimal (Pinna,
1979; Lull & Wright, 1942). It is well developed, resul-
ting remarkably taller than the skull roof at the level of the
frontal, similar to AMNH FARB 5465 but different from
MOR 478-7-2-7-3 (Prieto-Márquez, 2012). Based on the
skeletal reconstructions of G. notabilis (Kirkland et al.,
2006), G. monumentensis, and G. latidens (Gates & Sam-
pson, 2007), the dorsal arch of MSNM V345 more closely
resembles AMNH FARB 5465, the holotype of G. mo-
numentensis, than any other Gryposaurus specimen (Fig.
5). The well-developed nasal arch or hump is therefore
more pronounced than in other G. notabilis specimens,
and this does not seem to be related to any post-mortem
deformation: the crest is naturally tall and laterally com-
pressed, and it lies correctly on the sagittal medial plane.
We compared the height of the nasal crest (i.e., the distan-
ce between the dorsocaudal margin of the narial opening
and the dorsalmost margin of the crest) also with the ma-
ximum length of the quadrate in MSNM V345 and other
kritosaurines: MSNM V345 bears the tallest nasal crest,
alongside ROM 873 (G. notabilis). These values exceed
those of the other kritosaurines, Rhinorex included (Table
3). The nasal contacts the frontal in the caudal ange. The
ventral process of the nasal contacts the premaxilla and is
a nearly squared process forming the caudoventral portion
of the narial fenestra, although its original shape might be
difcult to determine due to taphonomical distortion.
Tab. 3 - Ratio of nasal crest height (nc) to quadrate length
(q) in selected North American kritosaurine species.
Species and specimen nc/q
Gryposaurus notabilis MSNM V345 0.27
Gryposaurus notabilis ROM 873 0.27
Gryposaurus monumentensis RAM 6797 0.18
“Gryposaurus incurvimanus” TMP
1980.022.0001
0.13
Gryposaurus latidens AMNH FARB 5465 0.16
Rhinorex condrupus BYU 13528 0.10
Maxilla - Only the left maxilla in lateral view can
be examined (Fig. 7). This element is trapezoidal, with a
broad base formed by a tooth row that is almost straight
and not as sinusoidal as in G. monumentensis (Gates &
Sampson, 2007). Although the dentition is eroded, the
number of tooth positions can be counted, resulting in
10.5–11 per 10 cm (Pinna, 1979; FB & SM, pers. obs.,
2016), like in the holotype of G. notabilis. The estima-
ted tooth count on the lateral side of the maxillary tooth
row is 30–32 (the uncertainty is due to the poorly pre-
served rostral teeth). The apex of the main body of the
maxilla is formed from the dorsal process arising from
the central region of the maxilla, as in G. monumenten-
sis (Gates & Sampson, 2007), and contacts the lacrimal
dorsally, the premaxilla dorsorostrally along an oblique
margin, and the jagged jugal caudoventrally. Here, the
articular margin continues caudal to the dorsal process,
forming an angle of about 90° with the rostral process of
the jugal. Rostral to the dorsal process, a rostral portion
can be identied, clearly shorter in length than the cau-
dal portion, as in G. monumentensis (RAM 6797) and G.
notabilis (CMN 2278). The relative length of the rostral
region of the maxilla is likely intraspecically variable
in Gryposaurus, as suggested by Prieto-Márquez (2012).
The dorsal margin of the rostral maxillary region forms a
47° angle with the rostral segment of the alveolar margin.
In G. latidens, this angle is 42° (Prieto-Márquez, 2012).
The rostrodorsal process is covered by the ventral bor-
20 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
der of the premaxilla, and its lateral surface cannot be
seen through the narial fenestra in our specimen. Gates
& Sampson (2007) recognize the latter feature as auta-
pomorphic for G. monumentensis, so it is likely absent
in MSNM V345. At least four maxillary foramina can
be seen on the middle shelf, although their detection is
problematic because of the restoration work.
Prefrontal - The comma-shaped prefrontal forms the
rostral portion of the orbit (Fig. 7). It is connected to the
lacrimal ventrally, and the caudal portion of the nasal ro-
strodorsally. The prefrontal does not contact the premaxil-
la, contrary to other gryposaurs (Gates & Sampson, 2007).
The angle between the ventral and caudal rami is about
137°. In caudal view, the prefrontal contacts the frontal. In
its caudoventral side (orbital roof), the prefrontal shows
an interdigitated margin with a rostrolateral pointed end
of the frontal (Fig. 7C).
Lacrimal - The elongate left lacrimal is visible in la-
teral view (Fig. 7). As reported by Lull & Wright (1942),
it is nearly pentagonal, long, and narrow. It participates
to the rostral border of the orbit for about 2.5 cm. The
dorsal region is in articulation with the ventral ramus of
the prefrontal, and it seems to touch the nasal (as reported
by Vialli, 1960, g. 7), as in G. monumentensis (Gates &
Sampson, 2007) and G. notabilis ROM 873. The jugal-
lacrimal articulation, similar to that of the holotype of G.
notabilis (Lambe, 1914), is sinusoidal, with dorsal and
rostral triangular-shaped processes. The rostral portion
of the lacrimal is compressed between the rostral portion
of the jugal caudally and the caudolateral ramus of the
premaxilla rostrally. It becomes wider along the articular
surface of the maxilla. The maxilla-lacrimal articulation
is nearly straight (it is arched in ROM 873).
Frontal - The frontal contacts the prefrontal rostro-
medially, the caudal rami of prefrontal and nasal rostrally,
and the rostral process of the postorbital and the parietal
caudally (Fig. 7). Contrary to Pinna (1979), the frontal
of MSNM V345 participates in the dorsal orbital rim.
Moreover, unlike most Gryposaurus species (Gates &
Sampson, 2007, g.5), this participation is conspicuous,
consisting of an expanded triangular process. The medial
sagittal suture with the right frontal is still visible in dor-
sal view, as well as the nasofrontal and the frontoparietal
sutures.
Parietal - The parietal forms the median section of
the caudodorsal region of the skull roof, and it borders
the supratemporal fenestral. In MSNM V345, it is visi-
ble in lateral and dorsal views, although the central and
caudal portions have been heavily reconstructed (Fig. 7).
The margin with the squamosal is not dened because of
restoration work. The sagittal crest is missing. The con-
tacts with the laterosphenoid, the prootic, the opisthotic-
exoccipital, and the supraoccipital are not visible.
Jugal - Only the left jugal is preserved (Fig. 7). The
rostral process is long and dorsoventrally developed, with
irregular margins. Dorsally, it ascends to contact the la-
crimal in an indented suture; caudally, it forms the ro-
stroventral corner of the orbit. The rostral process is not
regularly pointed as in RAM 6797, ROM 873, and TMP
1980.022.0001, but it resembles that of the holotype of G.
notabilis (Lambe, 1914) and G. latidens (Gates & Sam-
pson, 2007; Prieto-Márquez, 2012). The rostroventral
margin of the jugal borders the rostrocaudal portion of
the maxilla, having an indented margin resembling that
in the holotype of G. notabilis (Lambe, 1914). In con-
trast, the ventral embayment is wide and irregular, and
therefore different from those of the other gryposaur spe-
cimens (Gates & Sampson, 2007). The postorbital pro-
cess ascends at an angle close to 95° (92° when measuring
the angle formed by the process and the plane from the
rostral process to the ventral process; 98° when conside-
ring the caudoventral ange), as in the other Gryposaurus
species (Prieto-Márquez, 2012; Gates & Sampson, 2007).
It meets the caudal surface of the jugal process of the
postorbital obliquely, the two bones separating the orbit
from the infratemporal fenestra. The quadratojugal ange
(sensu Prieto-Márquez, 2012) contacts the quadratojugal
and overlaps the quadrate laterally, excluding the quadra-
tojugal from the margin of the infratemporal fenestra. The
quadratojugal ange is long and narrow rather than squa-
red as in G. monumentensis (Gates & Sampson, 2007) or
large and wide as in G. latidens (Prieto-Márquez, 2012).
It is caudally inclined, ascending parallel to the postor-
bital process as in G. latidens (Gates & Sampson, 2007)
and forming the caudoventral margin of the infratemporal
fenestra. Ventrally, this fenestra is wider than the orbit and
similar in size and shape to those of G. notabilis and TMP
80.22.1 (Gates & Sampson, 2007, g. 5). MSNM V345
differs from G. latidens MOR 478-6-10-87-2 (Prieto-
Márquez, 2012) in that the latter has a smaller orbit and a
longer infratemporal margin that is not as arched as in our
specimen. Moreover, in MOR 478-6-10-87-2 the lower
portion of the infratemporal margin is placed at the same
level as the lower portion of the orbital margin, whereas in
MSNM V345 the former is lower than the latter. The ove-
rall morphology of the dorsal portion of the jugal (infra-
temporal fenestra wider than the orbit; postorbital process
and quadratojugal ange ascending parallel, both close to
90° to the sagittal plane of the shaft) resembles that of Rhi-
norex (Gates & Scheetz, 2014). A prominent caudoventral
ange immediately ventral to the infratemporal fenestra
covers the coronoid process of the dentary. This large pro-
cess, somewhat squared in MSNM V345, is also found
in the holotype of G. notabilis (Lambe, 1914), as well as
in all other species of Gryposaurus, Rhinorex condrupus
(Gates & Scheetz, 2014), Anazisaurus horneri (Lucas et
al., 2006), Maiasaura peeblesorum (Horner, 1983), and
Brachylophosaurus canadensis (Prieto-Márquez, 2005).
It has been hypothesised that this process might have at-
tached to the powerful M. pterygoideus ventralis (Holli-
day, 2009). However, bone texture is not preserved well
in MSNM V345, making it difcult to correctly identify
the rugose and striated areas where the tendons were at-
tached.
Postorbital - The T-shaped postorbital forms the cau-
dodorsal corner of the rim of the orbital fenestra (Fig. 7).
The rostrodorsal process is shorter than the ventral (ju-
gal) and caudodorsal (squamosal) processes, and in lateral
view it contacts the small lateral portion of the frontal.
The narrow ventral ramus forms a 90° angle with the ro-
strodorsal margin. It borders the rostrodorsal portion of
the infratemporal fenestra. The dorsal margin of the in-
fratemporal fenestra is placed above the dorsal margin of
the orbital rim, where the caudodorsal margin of the po-
storbital ascends obliquely at an angle of 140° to meet the
squamosal above the reconstructed precondyloid fossa of
the quadrate. The ventral and caudodorsal rami are the
same length.
21
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Squamosal - Although most of this element is heavily
reconstructed, the original shape is maintained (Fig. 7). The
squamosal meets the postorbital rostrally, bifurcating into
ventral and dorsal rami. Dorsocaudally, it borders the orbit
rim and participates in the caudolateral margin of the upper
temporal fenestra. The quadrate is connected to the squa-
mosal via the precotyloid process. The precotyloid fossa
is reconstructed probably quite accurately, as is the area
caudal to the precotyle. No diagnostic features are visible.
Quadrate - Both quadrates are preserved: the left is
rmly articulated with the skull (Fig. 7), whereas the right
is disarticulated from the rest of the skeleton, so may be
assessed in all views despite it being heavily restored (Fig.
8). The quadrate articulates rostrally with the squamosal,
jugal, and quadratojugal and ventrally with the surangular
and articular. Proximally, the quadrate buttress present in
the other Gryposaurus species (G. notabilis CMN 2278,
G. monumentensis RAM 6797, “G. incurvimanus” TMP
1980.022.0001; Gates & Sampson, 2007) is missing. In
lateral view, the pterygoid wing (sensu Gates & Sampson,
2007) is broken and the central part is missing. The dotted
line in gure 8 reconstructs the outline based on the qua-
drate of RAM 6797 (after Gates & Sampson, 2007). The
dorsal articular surface of the right quadrate is triangular
in cross section, with the apex of the tringle articulating
with the squamosal cotyle. A shallow embayment – pro-
bably the quadratojugal notch, homologous to the para-
quadrate foramen (Sues & Averianov, 2009) – is visible
on the shaft of the left quadrate in caudal view, in corre-
spondence with the quadratojugal. The margin of the bone
seems to be unaltered here for a few centimetres. The late-
ral condyle of the distal articular surface is visible on both
the right and left quadrates, whereas the poorly preserved
medial condyle is visible only on the right element.
Quadratojugal - The small trapezoidal quadratojugal
contacts the jugal rostrally and the quadrate caudally, as
in other hadrosaurs, overlapping the quadratojugal notch
of the quadrate (Fig. 7). As reported by Lull & Wright
(1942), it does not completely separate the quadrate from
the jugal. It is shorter and broader than that of G. monu-
mentensis (Gates & Sampson, 2007). In the holotype of
G. notabilis (Lambe, 1914) and in ROM 764 (Gates &
Sampson, 2007), the pointed dorsal process of the qua-
dratojugal inserts into the quadratojugal ange of the ju-
gal without participating to the caudoventral border of the
lower temporal fenestra. This condition is visible also in
MSNM V345, but the caudodorsal portion of the jugal
process is wider than in G. monumentensis (RAM 6797)
or in G. latidens (Gates & Sampson, 2007).
Predentary - The predentary is disarticulated from
the skull, and so can be analysed in all views (Fig. 9). It
is a scoop-shaped, at, and robust bone with a gently ar-
ched outline. Both inner and outer sides have a smooth
surface. A peculiarity of this bone is the presence of nine
well-developed, thick, pointed, and triangular denticles
(12–20 mm high; up to 27 mm wide) lying on the hori-
zontal plane and rostrally oriented. They are placed on the
rostral margin rather than on the lateral rami as in other
hadrosaurids (Prieto-Márquez, 2010a; 2014). It is possible
that some of them have been emphasised during prepara-
tion, as suggested by parallel striae on some margins and
by little portions of spongy bone emerging at the base of
some denticles. Nevertheless, the cortical bone is conti-
nuous and well-preserved along the whole denticle row,
and their authenticity is proved by CT-scan analysis (Fig.
9G). The arrangement of the denticles is asymmetrical,
with ve on the left and four on the right side, separated
by a low medial keel. Two small knobs on both sides of
the predentary delimit the denticle row. A central denticle
on the sagittal medial plane that divides the denticles into
left and right groups of equal size, as seen in Bactrosaurus
(Prieto-Márquez, 2011), is not present. The predentary is
missing in G. latidens (Prieto-Márquez, 2012), so we can-
not conrm the presence of such structures in this taxon.
The predentary of G. monumentensis bears denticles, but
they are more dorsally oriented, rostrocaudally compres-
sed, and clover-shaped (Gates & Sampson, 2007). TMP
1981.27.50, a predentary from an indeterminate hadrosau-
rid, bears 13 rostrocaudally compressed denticles, but they
are not as pointed as in MSNM V345. Well-developed pre-
dentary denticles are present also in other ornithopods, like
Bactrosaurus johnsoni (Prieto-Márquez, 2011), Tethysha-
dros insularis (Dalla Vecchia, 2009), and Mantellisaurus
artheeldensis (Norman, 1986), but they have different
shapes from those of MSNM V345. The presence of denti-
cles may suggest the presence of a rhamphoteca (Norman,
1986; Horner et al., 2004), but a more comprehensive
analysis is needed to understand the evolutionary pathway
of the number, shape, and position of the denticles. Two
lateral wedge-shaped rami run caudally, connecting the
predentary to the lateral margins of the dentaries. Vialli
(1960) estimated that both caudal ends are incomplete,
with at least 5 cm of bone missing, giving the idea that
the predentary articulated only with the ventral part of the
tips of the dentaries. The left ramus is vertically oriented,
whereas the right one is horizontally oriented. The shape
of the latter has likely been diagenetically deformed, an as-
sumption supported by the morphology of other dentaries,
such as TMP 1991.036.0311. The left ramus is slightly da-
maged, but it clearly shows the vertical orientation of the
caudalmost end of the process. Two large and deep forami-
na open on the caudodorsal surface of the predentary, just
ventral to the base of the second and eighth denticles (Fig.
9A) and align with the lateral processes of the predentary
that form thick dorsal margins. Based on their symmetrical
position, smooth margins, and uninterrupted bone surface,
it is unlikely that these foramina are articial. On the outer
surface of the bone, a third, smaller (nutrient?) foramen is
present below the rst denticle. A central keel is present on
the inner side, between the fth and sixth denticles, but it
does not project caudally beyond the caudal margin as a
narrow process as in TMP 1991.036.0311. A large cavity is
present on the caudoventral margin, in front of the dentary
articular surface (Fig. 9A-C). To our knowledge, such a
structure is hitherto undescribed in any other Gryposaurus
specimen or hadrosaurid. We hypothesize that this structu-
re represents a pathological condition (see section on pa-
thological bones below).
Dentary - Both dentaries are preserved: the left is r-
mly articulated with the skull, so only its lateral side can
be seen (Fig. 7), whereas the right is separated and can be
studied in lateral and medial views (Fig. 10). The proxi-
mal edentulous margin (sensu Prieto-Márquez, 2012) is
slightly shorter than in G. latidens (see Prieto-Márquez,
2012), and the ratio of its length to the distance between
the rst tooth position and the caudal margin of the coro-
noid process is 0.40. This ratio is 0.35 in G. latidens AM-
NH FARB 5465 (Prieto-Márquez, 2012) and 0.25 in G.
22 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
notabilis AMNH FARB 5350. The proximal edentulous
margin forms a 135° angle with the alveolar border of the
tooth row. This is less than in G. latidens (154° in AMNH
FARB 5465; Prieto-Márquez, 2012), other G. notabilis
specimens (e.g., 146° in AMNH FARB 5350), and in G.
monumentensis (see Gates & Sampson, 2007). The ven-
tral deection of the dentary that can be seen also in other
Gryposaurus specimens originates from beneath the rst
tooth position, as in AMNH FARB 5350. This is more
rostral than in G. latidens, but similar to G. monumenten-
sis, although the rostral margin caudal to the deection
is slightly more convex in MSNM V345 than in AMNH
FARB 5350 or RAM 6797. The coronoid process of the
disarticulated right dentary is well visible, whereas in the
articulated left dentary the process is partly covered by
the jugal, as it extends into the adductor chamber medial
to the jugal. The coronoid process forms an angle of about
90° with the dentary shaft, in contrast with AMNH FARB
5350 (80°) and G. latidens AMNH FARB 5465 (70°). The
distal portion of the coronoid process is suboval in sha-
pe, with the caudal portion higher than the rostral one.
A large Meckelian canal is visible on the medial side of
the dentary, ventral to the caudalmost extent of the den-
tal battery, and attenuates rostrally, similarly to in AMNH
FARB 5350. There are 13 dentary foramina on the lateral
side of the lower right jaw: eight below the tooth row and
ve closely appressed on the symphysis. The ratio of the
labiolingual extension of the symphyseal region to the
maximum labiolingual width of the dentary is 1.27. The
angle formed by the dentary symphysis with the lateral
side of the rostral half of the dentary is 17°.
Surangular - The left surangular is preserved and
forms the lateral portion of the broad, dorsally oriented
mandibular glenoid that accommodates the more ventral
and larger of the two quadrate condyles, namely the late-
ral condyle (Fig. 7). The surangular and the quadrate are
still articulated, as clearly seen in Figure 7, not allowing
a description of the medial features and the contacts of
the former bone. Rostrally, the surangular is covered by
the jugal, so it is difcult to determine its participation to
the coronoid process. The surangular forms the rostral and
ventral margins of the mandibular foramen, which is bor-
dered by the jugal dorsally and by the quadrate caudally.
Articular - The left articular is preserved, rmly sutu-
red with the surangular and articulated with the quadrate.
Thus, it is not possible to describe any of its anatomical
features (Fig. 7).
Dentition - Vialli (1960) and Pinna (1979) illustrated
an incomplete but well-preserved tooth from the right lo-
wer jaw, reporting an estimated crown height of 35 mm
and maximum crown width of 14 mm (Fig. 11). This to-
oth is now on display in Hall IV of the MSNM. We me-
asured the crown height to be 37 mm (i.e., 2 mm more)
– taking into account that the tooth is broken obliquely
in the labiolingual direction and is more complete on the
lingual side – the maximum mesiodistal crown width to
be 15 mm (i.e., 1 mm more), and the maximum labio-
lingual crown width to be 18 mm. Although the root is
absent, the crown can be considered nearly complete be-
cause the lower half of the preserved crown tapers to a
narrower diameter. The resulting ratio of height to width
(2.46) is almost identical to previous calculations (i.e.,
2.5). In lingual view, the crown is oblanceolate, with a
nely rugose enamel surface divided into two equal hal-
ves by a prominent vertical median ridge. There are no
accessory ridges. Marginal denticles consist of tiny, irre-
gularly spaced papillae that are oriented apically on both
margins of the tooth but that are larger on the mesial edge
(Fig. 11B, C). The mesial margin probably overlapped the
distal margin of the adjacent crown. In labial view, the
crown is divided into two halves by another median ridge
that disappears towards the apex and becomes increasin-
gly prominent towards the base. A pair of less prominent
vertical accessory ridges divides each half of the crown
equally along the labial side; these were illustrated but not
described by Vialli (1960, tab. IX, g. 6). In distal view,
the crown is gently curved labially. In occlusal view, the
apex of the tooth has a feebly concave wear facet inclined
lingually about 50° with respect to the horizontal plane.
Vialli (1960) also described the typical mosaic-like pat-
tern of the teeth implanted in the lingual side of the right
dentary, the base of each crown being covered by the tip
of the underlying tooth. The grinding surface is inclined
outwards and widened mediolaterally, as seen in Edmon-
tosaurus sp. USNM 22102 (FB, pers. obs., 2014). It is
impossible to count the tooth rows precisely, but we iden-
tied 30 (?32) and 28 (?29) rows in the maxilla and denta-
ry respectively, with ve teeth per column. Lull & Wright
(1942) have indicated 35 maxillary and 32 dentary tooth
rows as diagnostic for the species, thus the differences in
number might be due either to the poor preservation of
the specimen, which presents with damaged alveoli and
broken teeth (Figs. 7, 10), or to intraspecic variation.
Axial skeleton
The axial skeleton of hadrosaurs consists of 12 to 15
cervical, 16 to 20 dorsal, 9 to 12 sacral, and 50 to 70 cau-
dal vertebrae (Horner et al., 2004). In MSNM V345, an
incomplete vertebral series of 60 vertebrae is preserved
(contra Pinna, 1979, who identied 56 elements), inclu-
ding eight cervicals, eight dorsals, two partial sacrals, and
42 caudals with ve chevrons (Figs. 11-19). Pinna (1979)
estimated for MSNM V345 a vertebral series composed
of 13 cervicals, 16 dorsals, 9 sacrals, and 47 caudals, ba-
sing this on “G. incurvimanus” (Parks, 1920) and other
hadrosaurid specimens (Lull & Wright, 1942). In the
neck, the axis and the atlas are missing. In the dorsal seri-
es, only the cranial-most vertebrae are preserved. The cer-
vicals and the dorsals are heavily deformed by diagenetic
compression. Most of the ribs are missing. Dorsal 5 and
caudals 25 and 26 show pathologies, which we describe
below. The distal-most preserved caudal is quite squared
in lateral view and resembles the middle caudals rather
than the usual distalmost tail vertebrae, indicating that the
distal end of the tail is likely missing. As a result, we have
reconstructed the tail with 70 vertebrae (Fig. 6).
Cervical vertebrae - Eight cervical vertebrae are pre-
served, here identied as c3, c4, c5, c7, c8, c10, c11, and
c12 (Figs. 11-13; Table 4). Pinna (1979) reached the same
conclusion, but with a margin of uncertainty on whether
one was either c5 or c6. Cervical 3 has an opisthocoelous
centrum, but the caudal part is highly deformed and shif-
ted upwards so that its real shape is not discernible (Fig.
12A). Its prezygaphophyses are asymmetrical due to de-
formation, the right one more complete than the left. The
postzygapophyses have undergone the same deformation.
23
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Cervical 4 is even more eroded than c3 (Fig. 12B): the
cranial surface of the vertebra is completely deformed,
whereas in caudal view it still shows some anatomical
features. The neural canal is deformed and completely
lled with matrix. The left diapophysis is still recogni-
zable and does not differ from that of the previous verte-
bra. The right postzygapophysis is complete and projects
caudodorsally; the articular surface faces ventrally. The
right proximal portions of the rib processes are present.
In lateral view, the right side of the centrum is uplifted in
the caudal part, a diagenetic deformation that has affected
other vertebrae as well. Such dorsal displacement of the
caudal part of the centrum has increased the opisthoco-
elic condition. Cervical 5 has only the right side preser-
ved (Fig. 12C). Its centrum is squared, slightly taller than
long, and opisthocoelic; the caudal portion is set off due
to diagenetic distortion, making the centrum thinner than
the other cervicals in lateral view. The neural canal is l-
led with sediment and its identication is difcult. The
bases of the prezygapophyses and postzygapophyses are
covered by plaster, making identication of the articular
facets impossible. Ventral to the lateral process is a small
subtriangular knob. The ventral side of the centrum is sub-
circular, with no keel present in the medial region. Only
the proximal part of the cervical rib is present, which ar-
ticulates with the lateral process of the vertebra. Cervical
Fig. 11 - Dentary tooth in lingual (A), distal (B), labial (C), and occlusal (D) views. Cervical vertebra n. 7 in cranial (E) and lateral
(F) views. For abbreviations, see text. Scale bars = 1 cm (A-D) and 10 cm (E,F). Photos by FB and Giovanni Bindellini. / Dente man-
dibolare in norma linguale (A), distale (B), labiale (C) e occlusale (D). Vertebra cervicale 7 in norma craniale (E) e laterale (F). Le
abbreviazioni sono riportate nel testo. Scale metriche = 1 cm (A-D), 10 cm (E-F). Foto di FB e Giovanni Bindellini.
24 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 12 - Cervical vertebra n. 3 in cranial (A1), caudal (A2), right lateral (A3), left lateral (A4), ventral (A5), and dorsal (A6) views;
cervical vertebra n. 4 in cranial (B1), caudal (B2), right lateral (B3), left lateral (B4), ventral (B5), and dorsal (B6) views; cervical
vertebra n. 5 in cranial (C1), caudal (C2), right lateral (C3), left lateral (C4), ventral (C5), and dorsal (C6) views; cervical vertebra n.7
in cranial (D1), caudal (D2), right lateral (D3), left lateral (D4), ventral (D5), and dorsal (D6) views. Scale bar = 10 cm. Photos by FB.
Vertebra cervicale n. 3 in norma craniale (A1), caudale (A2), laterale destra (A3), laterale sinistra (A4), ventrale (A5), e dorsale (A6);
vertebra cervicale n. 4 in norma craniale (B1), caudale (B2), laterale destra (B3), laterale sinistra (B4), ventrale (B5), e dorsale (B6);
vertebra cervicale n. 5 in norma craniale (C1), caudale (C2), laterale destra (C3), laterale sinistra (C4), ventrale (C5), e dorsale (C6);
vertebra cervicale n. 7 in norma craniale (D1), caudale (D2), laterale destra (D3), laterale sinistra (D4), ventrale (D5), e dorsale (D6).
Scala metrica = 10 cm. Foto di FB.
25
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
7 is one of the most complete elements of the neck (Figs.
11E-F, 12D). It is a stout bone, and all the processes are
preserved. The centrum is opisthocoelous, just like the
other cervical centra, and longer than tall. In caudal view,
the cotyle of the centrum is very deep and heart shaped.
The prezygapophyseal pedicels are as long as those of the
postzygapophyses, and they diverge from the centrum
along the sagittal plane at 180°. The articular facets of
the prezygapophyses are squared and can be recognised
by their smooth surfaces. On both sides, a stout lamina
connects the pre- to the post-zygapophyseal pedicels. The
prezygapophyses converge towards the dorsal side of the
centrum, forming a cranially directed process. The angle
between this process and the two pedicels is 100°. The
left parapophysis is better preserved than the right one.
Similar to the preceding cervicals, the ventral side of the
centrum is semicircular, without any keel. In c8, only the
centrum and the base of the neural arch with the left prezy-
gapophysis are preserved, but overall this element is qui-
te modied by previous restoration (Fig. 13A). In caudal
view, the deep cotyle of the centrum is still recognizable,
but there are two openings in its dorsal side: the largest is
the neural canal; the other might be the result of collapse
of the neural canal. The left side of the neural canal is
highly deformed, and the overall shape of the bone is dif-
cult to describe. The entire left cervical rib is preserved
and still articulated to the vertebra, but it is deformed by
diagenesis and, as a result, is directed dorsally. Cervical
10 has a preserved centrum, neural canal, right diapophy-
sis, and left diapophyseal base (Fig. 13B). The centrum is
strongly opisthocoelous and has an elliptical cranial con-
dyle that is wider than tall. The caudal articular surface is
mostly crushed, but it retains its spherical shape. The right
parapophysis is present as a small spur-like lateral process
on the side of the centrum, ventral to the right diapophy-
sis. The articular surface of the prezygapophysis is well
visible in cranial view. The dorsal margin of the diapo-
physis is offset from the dorsal margin of the lateral pro-
cess housing the tubercular rib facet. The ventral margin
of the lateral process is mostly covered by plaster, as is the
distalmost region. Likely, the tuberculum of the cervical
rib is still fused with it, as in the previous vertebrae. The
neural canal is visible, well preserved, and subcircular in
outline. Dorsal to it, the two postzygapophyseal pedicels
diverge from each other at an angle of 123°. As a result
of diagenetic deformation, the ventral side of the centrum
points downwards more strongly than in other cervicals
in lateral view. In ventral view, the ventral side of c10 is
subrectangular. Cervical 11 is poorly preserved. It has an
opisthocoelic centrum that is heart-shaped in cranial view,
with a triangular cranial condyle and a deeply concave
caudal cotyle (Fig. 13C). The caudal articular surface of
the centrum has been dorsally displaced during diagene-
sis, so that it completely lls the neural canal. The parapo-
physes are preserved as small, slightly developed lateral
processes on the two sides of the centrum. Only the base
of the left transverse process is preserved. In ventral view,
the caudal region appears eroded away, and the general
shape of the centrum is not recognizable. The nal cervi-
cal vertebra we can identify is c12 (Fig. 13D). It is a stout,
strongly opisthocoelic bone. The cranial articular surface
of the centrum is roughly spherical in shape, whereas the
caudal surface is deeply concave. In caudal view, a small
parapophysis can be seen pointing laterally on the right
side of the centrum; the left one is not preserved. The lar-
ge neural canal is subtriangular. The prezygapophyses are
present only in their proximal-most portion, and the neural
arch is triangular, without any processes other than those
described, due to erosion. The ventral side of the cen-
trum is subrectangular in ventral view, without any keel.
According to Pinna (1979), the cervical vertebrae of
MSNM V345 seem shorter (more compressed?) cranio-
caudally and more inclined ventrally than those of “G. in-
curvimanus” (Parks, 1920). Evaluation on the morpholo-
gical trends in the cervical series cannot be assessed with
certainty due to the heavy diagenetic deformation of the
bones. However, the vertebrae become taller and narro-
wer moving caudally, as expected (Fig. 13). Furthermore,
the diapophyses are short and stout in the rst vertebrae,
becoming more elongated and craniocaudally thinner mo-
ving caudally, as reported by Pinna (1979).
Tab. 4 - Dimensions of the cervical vertebral centra in
MSNM V345.
Element Height
(mm)
Width
(mm)
Length
(mm)
c3 60 69 56
c4 63 102 80
c5 n/a 93 62
c7 71 85 79
c8 70.5 79 63
c10 66 100 73
c11 65 85 59
c12 92 95 85
Dorsal vertebrae - The eight preserved dorsal ver-
tebrae are identied as d1, d2, d5, d6, d7, d8, d9, and
d10 based on their preserved anatomical features (Figs.
14-16; Table 5). The rst dorsal is still opisthocoelic
(Fig. 15A). The cranial articular surface of the centrum
is roughly circular in outline, whereas the caudal one is
heart-shaped. The transverse processes are dorsolateral-
ly directed. The circular neural canal is lled by bone on
account of post-mortem deformation, visible especially
in lateral view. The compression has produced a lateral
edge clearly dividing the cranial portion from the caudal
region of the vertebral body. The articular surfaces of
the prezygapophyses are still at the level of the diapo-
physes. The right diapophysis is the only one preserved
in this vertebra. With respect to the cervicals, the neural
spine is taller and the postzygapophyseal pedicels di-
verge from each other at a more acute angle (i.e., 99°).
The ventral side of the centrum is subrectangular, with
a central depression (i.e., spool-shaped). Dorsal 2 has
only the centrum and the base of the neural arch preser-
ved; all other processes are lost (Fig. 15B). The centrum
is higher than long and still retains the opisthocoelic
condition encountered in the cervical and cervicodorsal
regions. A medial constriction is present on the sides
of the centrum, between the cranial and the caudal arti-
cular surfaces, giving this vertebra an hourglass shape
in ventral view. A ventral keel is preserved, originating
26 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 13 - Cervical vertebra n.8 in cranial (A1), caudal (A2), right lateral (A3), left lateral (A4), dorsal (A5), and ventral (A6) views;
cervical vertebra n.10 in cranial (B1), caudal (B2), right lateral (B3), left lateral (B4), dorsal (B5), and ventral (B6) views; cervical ver-
tebra n. 11 in cranial (C1), caudal (C2), right lateral (C3), left lateral (C4), dorsal (C5), and ventral (C6) views; cervical vertebra n.12
in cranial (D1), caudal (D2), right lateral (D3), left lateral (D4), dorsal (D5), and ventral (D6) views. Scale bar = 10 cm. Photos by FB .
Vertebra cervicale n. 8 in norma craniale (A1), caudale (A2), laterale destra (A3), laterale sinistra (A4), dorsale (A5), e ventrale (A6);
vertebra cervicale n. 10 in norma craniale (B1), caudale (B2), laterale destra (B3), laterale sinistra (B4), dorsale (B5), e ventrale (B6);
Vertebra cervicale n. 11 in norma craniale (C1), caudale (C2), laterale destra (C3), laterale sinistra (C4), dorsale (C5), e ventrale (C6);
vertebra cervicale n. 12 in norma craniale (D1), caudale (D2), laterale destra (D3), laterale sinistra (D4), dorsale (D5), e ventrale (D6).
Scala metrica = 10 cm. Foto di FB.
27
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
gradually from the ventral surface. Dorsal 5 is comple-
te, together with its left rib, and presents with a patho-
logical condition (Fig. 15C; see section on pathological
bones). This vertebra is the rst in the presacral series
of MSNM V345 to have an amphiplatyan centrum, the
common condition found in other hadrosaurids from d2
onwards (Horner et al., 2004). The cranial articular sur-
face of the centrum is high and heart-shaped; the caudal
one is slightly wider than tall. The neural canal is oblite-
rated by sediment. The diapophyses are directed dorso-
laterally, as in d1, and are slightly shorter than the neu-
ral spine. The whole left diapophysis is fused with the
head of the dorsal rib through a neoplastic mass of bone.
The nature of this pathology is discussed below. The
prezygapophyses are located above the neural canal and
have a suboval articular surface pointing dorsomedial-
ly. The postzygapophyses are located at the base of the
neural spine, at about the midlevel of the diapophyses.
Their articular surfaces are suboval in shape and face
ventrolaterally. Ventral to them, and dorsal to the neural
canal, the diapophyses are excavated by two elongate,
drop-shaped depressions. The neural spine is well deve-
loped, inclined caudally by 45°, long twice the height of
the centrum, and as wide as the centrum at its base. In
cranial view, the distal part of the spine is offset as it has
been incorrectly glued after breakage. In ventral view,
the ventral side of the centrum is hourglass-shaped due
to a medial constriction of the centrum. The medial keel
is present. Dorsal 6 is similar to the preceding vertebra,
although its centrum is rather deformed (Fig. 16A). The
prezygapophyses are enlarged, with suboval articular
surfaces facing more downwards than in previous verte-
brae. In lateral view, the cranial portion of the centrum
is diagenetically modied, so that the caudal margin of
the centrum is positioned at a lower level than the cra-
nial one. In caudal view, ventral to the postzygapophy-
ses, the two depressions visible on the caudal surface
of the diapophyses in d5 are present here as well, more
enlarged in their proximal area. Very little information
can be obtained from d7 because of its incompleteness
and high level of deformation (Fig. 16B); more than
half of the specimen is covered and/or replaced by pla-
ster. In lateral view, the amphiplatyan centrum is defor-
med and has a chair-like shape, with the cranial surface
strongly offset caudally from the midline. Only the base
of the craniocaudally compressed neural arch is preser-
ved. The diapophyses are directed more upwards than in
previous vertebrae (148°, contra 125° in d6; the angle
is measured from the main axis of the diapophysis to
the longitudinal axis of the centrum). Dorsal 8 has only
the centrum and the base of the neural arch preserved
(Fig. 16C). The centrum is amphiplatyan, higher than
long, and has oval-shaped cranial and caudal articular
surfaces. Only the oval left prezygapophysis is preser-
ved; both postzygapophyses are lost. The diapophyses
are almost completely missing, with only the proximal
portion of the right one present: it has a more horizontal
orientation than those of the previous vertebrae, which
point strongly upwards. In lateral view, a central con-
striction of the centrum produces a ventral concavity
between the cranial and caudal articular surfaces, giving
it an hourglass shape. A medial keel is visible in ventral
view. Dorsal 9 has an amphiplatyan centrum similar to
the preceding ones (Fig. 16D). A crack has offset the
caudal articular surface, which has been strongly remo-
delled. In lateral view, the central and ventral concavity
is missing, and the lower part of the centrum is almost
at. However, the central keel is still present in ventral
view. The neural arch is completely lost, broken at the
very base of the pedicels. Thanks to this condition, the
neurocentral surface articulating with the neural arch
and the oor of the neural canal is observable in dorsal
view. The latter is characterised by small nutrient fora-
mina that taper to the central area of the oor. Dorsal
10 is the nal presacral vertebra that we can identify
(Fig. 16E). It is smaller than the preceding dorsals. The
centrum is still amphiplatyan, but with the caudal ar-
ticular surface slightly concave. The prezygapophyses
are located above the neural canal, and their facets face
dorsally. The diapophyses are laterally directed and are
shorter than in other dorsals. The neural spine has been
reinforced by plaster, except for its apex. The distal-
most portion of the neural spine is drop-like in dorsal
view, with the tip directed cranially. In lateral view, the
centrum is very short craniocaudally and has a ventral
concavity. The postzygapophyses are not preserved. A
central keel is present in ventral view.
In summary, the dorsal vertebrae become taller, wider,
and shorter moving caudally. Of note, the neural spines
of MSNM V345 seem to be proportionally more elongate
than in other Gryposaurus specimens: indeed, d16 in “G.
incurvimanus” is 230 mm long (Parks, 1920), only 5 mm
longer than d10 of MSNM V345.
Tab. 5 - Dimensions of the centra and neural spines of the
dorsal vertebrae in MSNM V345.
Element Centrum Neural
spine
Height
(mm)
Width
(mm)
Length
(mm)
Length
(mm)
d1 92 96 72 96
d2 86 83 93 83
d5 81.5 78 101 78
d6 82.5 79 51 79
d7 n/a 91 n/a 91
d8 113 85 100 85
d9 113 90.5 102 90.5
d10 144 118 85 118
Dorsal ribs - The rib cage is poorly preserved, with
just four left and two right ribs present. Most of them are
covered by plaster or have been strongly remodelled by
the preparator. The best preserved left rib is long and was
probably located in the middle of the rib cage. The rib
segment between capitulum and tuberculum is horizontal
(Fig. 14D, E), and the two processes rise to the same level.
The smallest rib of the preserved series is a left element
that is quite short in length and has the capitulum placed
higher than the tuberculum (Fig. 14F). This rib has a ra-
ther straight shaft and was likely one of the caudalmost
elements of the rib cage.
28 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 14 - Dorsal vertebra n. 6 in cranial (A), caudal (B), and ventral (C) views. Left rib in caudal (D), and cra-
nial (E) views. Right rib in cranial view (F). For abbreviations, see text. Scale bar = 10 cm. Photos by FB.
Vertebra dorsale n. 6 in norma craniale (A), caudale (B), e ventrale (C). Costola sinistra in norma caudale (D), e craniale (E). Costola
destra in norma craniale (F). Le abbreviazioni sono riportate nel testo. Scala metrica = 10 cm. Foto di FB.
29
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 15 - Dorsal vertebra n.1 in cranial (A1), caudal (A2), right lateral (A3), left lateral (A4), dorsal (A5), and ventral (A6) views; dorsal
vertebra n. 2 in cranial (B1), caudal (B2), right lateral (B3), left lateral (B4), dorsal (B5), and ventral (B6) views; dorsal vertebra n. 5
in cranial (C1), caudal (C2), right lateral (C3), left lateral (C4), dorsal (C5), and ventral (C6) views. For abbreviations, see text. Scale
bars = 10 cm. Photos by FB. / Vertebra dorsale n.1 in norma craniale (A1), caudale (A2), laterale destra (A3), laterale sinistra (A4),
dorsale (A5), e ventrale (A6); vertebra dorsale n. 2 in norma craniale (B1), caudale (B2), laterale destra (B3), laterale sinistra (B4),
dorsale (B5), e ventrale (B6); vertebra dorsale n. 5 in norma craniale (C1), caudale (C2), laterale destra (C3), laterale sinistra (C4),
dorsale (C5), e ventrale (C6). Le abbreviazioni sono riportate nel testo. Scale metriche = 10 cm. Foto di FB.
30 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 16 - Dorsal vertebra n. 6 in cranial (A1), caudal (A2), left lateral (A3), dorsal (A4), and ventral (A5) views; dorsal vertebra n. 7 in
cranial (B1), caudal (B2), right lateral (B3), left lateral (B4), dorsal (B5), and ventral (B6) views; dorsal vertebra n. 8 in cranial (C1),
caudal (C2), right lateral (C3), left lateral (C4), dorsal (C5), and ventral (C6) views; dorsal vertebra n. 9 in cranial (D1), caudal (D2),
right lateral (D3), left lateral (D4), dorsal (D5), and ventral (D6) views; dorsal vertebra n. 10 in cranial (E1), caudal (E2), right lateral
(E3), left lateral (E4), dorsal (E5), and ventral (E6) views. Scale bars = 10 cm. Photos by FB. / Vertebra dorsale n. 6 in norma craniale
(A1), caudale (A2), laterale sinistra (A3), dorsale (A4), e ventrale (A5); vertebra dorsale n. 7 in norma craniale (B1), caudale (B2),
laterale destra (B3), laterale sinistra (B4), dorsale (B5), e ventrale (B6); vertebra dorsale n. 8 in norma craniale (C1), caudale (C2),
laterale destra (C3), laterale sinistra (C4), dorsale (C5), e ventrale (C6); vertebra dorsale n. 9 in norma craniale (D1), caudale (D2),
laterale destra (D3), laterale sinistra (D4), dorsale (D5), e ventrale (D6).; vertebra dorsale n. 10 in norma craniale (E1), caudale (E2),
laterale destra (E3), laterale sinistra (E4), dorsale (E5), e ventrale (E6) Scale metriche = 10 cm. Foto di FB.
31
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
The proximal portion of the fth rib is pathological,
being overgrown and fused to the lateral process of d5
(see above and pathological bones section below). In
cranial view, it is subrectangular, with the lateral portion
dorsocranially wider than the medial one.
Sacral vertebrae - In hadrosaurs, the sacrum con-
sists of 9-12 vertebrae; nine have been reported for G.
notabilis (Horner et al., 2004), but according to Parks
(1920) Gryposaurus had 10 sacrals. In MSNM V345,
only the ventral halves of two fused centra are preserved
(Fig. 17A, B), here interpreted as s4 and s5 as they well
match the size and proportions seen in G. notabilis AM-
NH FARB 5350 (Lull & Wright, 1942). In ventral view,
the centra are hourglass-shaped, with a median groove
running axially across the two vertebrae, incipient in
s4 and well marked in s5. This groove is reported for
many other hadrosaurines (Horner et al., 2004). The
caudal portions of the centra are wider than the cranial
ones. Longitudinal striations run parallel along the me-
dial concavity. The lateral sides of the centra are slightly
concave, and the wide and rugose attachment areas for
the robust sacral ribs are clearly visible at the level of the
intervertebral sutures.
Caudal vertebrae - The number of caudal vertebrae
differs among species; for hadrosaurs, this can range
from 50 to 70 (Horner et al., 2004). In MSNM V345,
42 vertebrae are preserved, but their number was un-
doubtedly higher in life (see below) as some elements,
and the distalmost fth of the tail, are missing (Table
6; Figs. 6, 17C). Consequently, the position numbers
indicated below must be regarded as not totally sure.
The rst recognizable caudal is ca2 (Fig. 17C). The
centrum is as wide as it is tall, subcircular, and almost
amphiplatyan. The articular surfaces are faintly con-
cave. Only the right pleurapophysis is preserved; it is
dorsoventrally enlarged in its proximal portion. A small
concave area is present in the middle of the proximal
surface of the transverse process. The left prezygapo-
physis is located above the small neural canal, and the
dorsomedially facing articular surface is suboval in sha-
pe. A deep sulcus occupies the proximal portion of the
neural spine, above the prezygapophyses. Next to it, a
second, smaller ridge projects from the transverse pro-
cess to the base of the neural spine. The neural spine
is tall (46.5 cm) but almost totally covered by plaster
and laterally deformed during preparation. In lateral
view, the spine maintains the same width along its leng-
th. In ventral view, the ventral sides of the centrum are
proximodistally compressed, with a central concavity.
The same morphology of the centrum and of the base
of the neural arch is shared by ca4 and ca5, the suc-
cessive preserved vertebrae of the caudal series (Fig.
17C). However, the ventral side of ca5 differs from the
others because of the presence of the rst articular sur-
face for the chevrons (Fig. 17D), as reported by Pinna
(1979). Caudals 8, 9 (former ca14), and 10 (former ca9)
have a more squared centrum, postzygapophyses that
are placed higher than in the preceding vertebrae, and a
neural spine that slightly expands distally when seen in
lateral view (Fig. 17C). In lateral view, the ventrodistal
margin of the ca8 centrum projects more ventrally than
the ventroproximal one, creating a small “knob”. In the
centrum of ca10 (former ca9), the ventral margins of
both faces are expanded ventrally when seen in lateral
view, creating a ventral concavity, and the transverse
processes are shorter than in the rst caudals. The cen-
trum of ca11 (former ca10) has a more squared ventral
side with well-formed articular surfaces for the chevron
and a large fossa in between them. When seen in lateral
view, the neural spines are slightly inclined distally at
the base and are slightly concave proximally; they also
decrease gradually in height from the proximal to the
distal region of the tail. Caudals 13 (former ca12), 16,
and 17 bear neural spines that are strongly deformed
in proximal and distal views (Fig. 17C): the reason for
this is difcult to understand (traumatic events or post-
mortem deformation?). Contrary to Pinna (1979), we
place former ca14 at the height of ca8 or ca9 mainly
because of the orientation of the neural spine (Fig. 17C,
18A). This attribution is corroborated by the width and
length of the centrum, although the height of the cen-
trum is not perfectly in line with the other adjacent ver-
tebrae. From ca15 on, the postzygapophyses migrate to
the lateral surface of the neural spine (Fig. 17C, 18B).
The middle caudals start with ca22. Pinna (1979) re-
ported erroneously that the transverse processes disap-
pear at ca18; in our re-examination, they persist until
ca21 (Fig. 17C). The proximal articular surface of the
centrum of the middle caudals is circular, whereas the
distal articulation retains a squared surface. In general,
the centrum of middle caudals is rectangular in lateral
view, the proximal articular surface is suboval to heart-
shaped, and the distal articular surface is more squared.
The prezygapophyses are reduced to small spur-like
processes located in a more dorsal position above the
neural canal than those of previous vertebrae. The post-
zygapophyses are more dorsally placed than those of the
proximal caudals and face more laterally than ventrally.
The base of the neural spine of ca23 bears longitudinal
striations where tendons probably attached. Caudals 25
and 26 present with a pathological outgrowth of bone,
described in detail below. Caudal 37 seems to be still
part of the middle region of the tail since it has well-de-
ned articular surfaces for chevrons on the ventral side
of the centrum. This centrum – as wide mediolaterally
as it is tall dorsoventrally – has subcircular-to-squared
articular faces and bears nutrient foramina on the lateral
sides. The neural spine is reduced here to a small bar
projecting distally at an angle of about 45° (measured
from the midline of the centrum). In dorsal view, there is
a deep sulcus between the two spur-like prezygapophy-
ses. This overall morphology is maintained up to ca42.
Caudals 43 and 44, although less complete, do not seem
to differ. The last vertebra to bear clear articular facets
for chevrons is ca44 (Fig. 17C). Chevron facets are faint
on ca46, and are completely absent on ca49. The distal-
most caudal vertebrae preserved are tentatively identi-
ed as ca46 and ca49 based on the size of the centra
with respect to the preceding ones (Fig. 17C, 18C). The
nal preserved vertebra is ca49: it still bears the base of
the neural arch, indicating that the distalmost portion of
the tail, consisting of vertebrae with little or no neural
spine, is entirely missing.
In conclusion, this caudal series is similar to those of
other hadrosaurids, with vertebrae gradually reducing
in size, and neural spines becoming increasingly shor-
ter distally and more rounded in cross-section rather
than attened on their sides, as in proximal caudals.
32 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Tab. 6 - Dimensions of the centra and neural spines of the caudal vertebrae in MSNM V345. In brackets, the
positions reported by Pinna (1979) for vertebrae that we have re-assigned.
Element Centrum Neural spine
Height (mm) Width (mm) Length (mm) Length (mm)
ca2 145 146 77 450
ca4 162 153 72 n/a
ca5 149 139 63 n/a
ca8 123 118 77 274
ca9 (ca14) 89 113 75 215
ca10 (ca9) 113 n/a 76 215
ca11 (ca10) 114 106.5 74 245
ca12 (ca11) 114 92 73 235
ca13 (ca12) 112 106 63 245
ca14 (ca13) 103 95 76 225
ca15 81 96.05 64.5 190
ca16 97 96 77.5 175
ca17 92.5 93.5 75 145
ca18 96 61 78 95
ca19 54 108 73 n/a
ca20 81 74 72 85.5
ca21 75 83 72 n/a
ca22 81 83 69 140
ca23 81 87 70 138
ca24 75 86 71 110
ca25 70 60 69 n/a
ca26 75 67 65 95
ca27 72.5 83.5 65 102
ca28 73.5 54.5 64 n/a
ca29 67 80 63 n/a
ca30 62 77 61 n/a
ca31 60 78 61 123
ca32 58 75 64 122
ca33 49 66 56 n/a
ca34 52.5 67 56 n/a
ca35 43 71 50 n/a
ca36 49 68 55.5 56
ca37 66 50 52.5 74.5
ca38 44 62 54 56
ca39 43 56.5 51 n/a
ca40 41 57 51 50
ca41 39 57 50 n/a
ca42 41.5 54 48.5 32.5
ca43 38 52 48 n/a
ca44 37 50 47 n/a
ca46 35 48 30 n/a
ca49 31 36 26 n/a
33
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 17 - Incomplete sacral vertebrae referable to positions 4 and 5 in ventral (A) and dorsal (B) views. Preserved caudal vertebrae and
haemal arches in their position along the series (C). Ventral view of the centra of caudal vertebrae n. 5 (D) and n. 44 (E), showing the
articular surfaces for the haemal arches. Scale bars = 10 cm. For abbreviations, see text. Photos by FB. / Vertebre sacrali incomplete,
riferibili alle posizioni 4 e 5, in norma ventrale (A), e dorsale (B). Vertebre caudali e archi emali nella loro posizione lungo la serie
vertebrale (C). Norma ventrale dei centri caudali n. 5 (D) e n. 44 (E), dove sono visibili le superci articolari per gli archi emali. Scale
metriche = 10 cm. Le abbreviazioni sono riportate nel testo. Foto di FB.
34 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 18 - Proximal caudal vertebra n. 14 in left lateral (A1), cranial (A2), right lateral (A3), caudal (A4), and ventral (A5) views; middle
caudal vertebra n. 27 in left lateral (B1), caudal (B2), right lateral (B3), ventral (B4), cranial (B5), and dorsal (B6) views; distal caudal
vertebra n. 46 in right lateral (C1), ventral (C2), and cranial (C3) views. For abbreviations, see text. Scale bars = 10 cm. Photos by FB.
/ Vertebra caudale prossimale n.14 in norma laterale sinistra (A1), craniale (A2), laterale destra (A3), caudale (A4), e ventrale (A5);
vertebra caudale intermedia n. 27 in norma laterale sinistra (B1), caudale (B2), laterale destra (B3), ventrale (B4), craniale (B5), e
dorsale (B6); vertebra caudale distale n. 46 in norma laterale destra (C1), ventrale (C2), e craniale (C3). Le abbreviazioni sono riportate
nel resto. Scale metriche = 10 cm. Foto di FB.
35
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Chevrons - Five chevrons are preserved. Pinna (1979)
assigned them to positions 7, 8, 13, 14, and 20. However,
we have re-assigned them to positions 6, 7, 11, 12, and 23
on the basis of their lengths (Figs. 17C, 19). Indeed, they
are slightly longer and more slender than the correspon-
ding neural spines. The necks of the pedicels bearing the
articular surfaces for the centra are constricted in caudal
view. The articular surfaces of the two arms – or chevron
heads – are subtriangular in shape, have rounded corners,
and are quite rugose in texture. In lateral view, the heads
of chevron 13 are proximodistally longer, with the pro-
ximal margin offset from the direction of the shaft of the
chevron. As observed by Pinna (1979), the longest preser-
ved chevron (375 mm) in MSNM V345 is the one situated
between ca11 and ca12: this element is 65 mm longer than
the longest chevron of “G. incurvimanus” (Parks, 1920).
Appendicular skeleton
The appendicular skeleton of MSNM V345 includes
the right sternal plate, left and right scapulae, left and
right humeri, left and right radii, left and right ulnae, me-
tacarpals II and III, and four phalanges (Table 7; Figs.
20-22); the left and right ischia, left pubis, left and right
femora, left and right tibiae, right bula, right astragalus,
right metatarsals II and IV, metatarsals III and IV, and se-
ven pedal phalanges (Table 8; Figs. 23-26). The forelimb
bones are as long as those of G. latidens AMNH FARB
5465. Humerus, radius, and ulna are about 120% the leng-
th of those of “G. incurvimanus” (Parks, 1919), indicating
that MSNM V345 was a larger individual. The forelimb
is about two-thirds the length of the hindlimb, as in “G.
incurvimanus” but in contrast with the majority of hadro-
saurids, in which the forelimbs are about half the length
of their respective hindlimbs. The massive femur and the
tibia are the same lengths as those of G. notabilis CMN
2278 (Lull & Wright, 1942).
Sternum - Only the right sternal plate is preserved
(Fig. 20E). Its dorsomedial side is completely covered by
plaster, so only the ventrolateral side is visible. The cau-
dolateral process (referred to as the “handle” by others;
see Prieto-Márquez, 2012), which is longer than in G.
latidens AMNH FARB 5465 (Prieto-Márquez, 2012), is
thicker and more expanded at its caudal end. It is slight-
ly sigmoid in ventromedial and dorsolateral views, like
Fig. 19 - Haemal arch n. 6 in lateral (A1), cranial (A2), and dorsal (A3) views; haemal arch n. 7 in lateral (B1), and dorsal (B2) views;
haemal arch n.11 in lateral (C1) and dorsal (C2) views; haemal arch n.12 in lateral (D1) and dorsal (D2) views; haemal arch 23 in
lateral (E1), cranial (E2), and dorsal (E3) views. Scale bar = 10 cm. Photos by FB. / Arco emale n. 6 in norma laterale (A1), craniale
(A2), e dorsale (A3); arco emale n, 7 in norma laterale (B1), e dorsale (B2); arco emale n. 11 in norma laterale (C1), e dorsale (C2);
arco emale n, 12 in norma laterale (D1), e dorsale (D2); arco emale n. 23 in norma laterale (E1), craniale (E2), e dorsale (E3). Scala
metrica = 10 cm. Foto di FB.
36 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
in AMNH FARB 5465 (Prieto-Márquez, 2012). Further-
more, there is a keel on the whole caudolateral process,
starting from the base of the craniomedial plate. The cra-
niomedial plate is axe-shaped with well-dened cranial
and medial processes. These two “knobs” are placed on
the same axis, whereas in G. latidens the craniomedial
process is higher than the caudomedial one. Moreover, the
two processes in MSNM V345 project more along the sa-
gittal axis than the longitudinal one. The long axis of the
craniomedial plate is oriented at about 45° from the long
axis of the caudolateral process, whereas in G. latidens it
is nearly perpendicular.
Scapula - MSNM V345 has both scapulae, but they
differ from each other because of post-mortem deforma-
tion (Fig. 20A-D). The right scapula has a better preser-
ved articular region, but its shaft is straight, having lost
the typical curvature displayed by the left scapula, and is
incomplete distally. The scapulae are robust elements: the
left is 890 mm long, and the right is 787 mm long (as pre-
served). The medial side is slightly concave, whereas the
lateral side is slightly convex at the distal end of the blade.
In the right scapula, the portion between the midshaft con-
striction and the articular proximal region is quite straight
and tapers distally. Prieto-Márquez (2012) writes that “the
entire proximal region [of the scapula] of MSNM V345 is
heavily reconstructed and missing part of the glenoid.” Ne-
vertheless, considering the reconstructed missing part to be
as accurate as possible, as pointed out by Vialli (1960) and
Pinna (1979), we calculate the ratio of the minimum dorso-
ventral length of the proximal constriction to the maximum
length of the proximal region (following Prieto-Márquez,
2010a; 2012) to be 0.51. This is lower than the value repor-
ted for G. notabilis ROM 764 (0.63), but is closer to that of
G. latidens, which has a narrow scapular neck. The pseu-
doacromion process is horizontal, as in G. latidens (Prieto-
Márquez, 2012), and it narrows towards the dorsal region
of the deep deltoid fossa. The caudal extension of the del-
toid ridge has been obscured by restoration work, which
has attened and remodelled the surface, so it cannot be
described. The coracoid facet is cranially developed, has a
triangular shape in lateral view, and a semilunate shape in
cranial view. Although the cranial half of the left scapula is
restored, the distal half maintains its original outline with
an expansion at the distal end of the blade.
Humerus - Both humeri are preserved (Fig. 21A).
These elements are slender bones, but stouter and wider
than those of G. latidens and other specimens of G. nota-
bilis (Prieto-Márquez, 2012): in MSNM V345, the overall
length of the humerus is three times the craniocaudal length
of the lateral surface of the proximal end, a ratio that is lo-
wer than the ve times of G. notabilis and G. latidens, and
the four times of “G. incurvimanus” (Parks, 1920), which
clearly has a more slender humerus. The articular head is
more rounded in MSNM V345 than in G. latidens AMNH
FARB 5465. The deltopectoral crest projects lateroven-
trally from the proximal half of the humerus, as reported
for G. latidens (Prieto-Márquez, 2012), but it is markedly
wider in MSNM V345. The ratio of the maximum width
of the deltopectoral crest in lateral view to the minimum
craniocaudal diameter of the humeral shaft is 1.55, close
to but lower than the ratios reported by Prieto-Márquez
(2012) for other hadrosaurines; however, the shaft is thi-
cker in MSNM V345. The length of the deltopectoral crest
is slightly less than half the overall length of the humerus,
whereas in most hadrosaurids it is slightly longer (Prieto-
Márquez, 2010a). In cranial view, the deltopectoral crest
becomes thicker towards its angular ventral margin (sensu
Prieto-Márquez, 2012). The caudal margin of the hume-
ral shaft is almost straight in lateral view, whereas in G.
latidens it is sigmoid. The prominent median tuberosity
reported for AMNH FARB 5465 and MOR 478-5-25-8-5
by Prieto-Márquez (2012) is not visible on the right hume-
rus of MSNM V345: the caudal surface of the bone, close
to the midlength, is poorly preserved and remodelled with
plaster. On the left humerus, it is preserved and is closer
to the proximal end than to the midshaft. The distal end of
the humerus is mediolaterally expanded, forming the ulnar
and radial condyles, which unfortunately are mostly cove-
red by plaster in the right humerus and are preserved only
on the lateral side in the left one. The ulnar condyle, placed
cranially, is wider and more craniocaudally expanded than
the radial condyle, placed caudally. A sulcus covered by
plaster divides the two condyles, so its depth cannot be
estimated with precision.
Ulna - Both ulnae are slender and only slightly bo-
wed (Fig. 21B). They are both expanded at their proximal
ends, whereas distally they are as thin as the shafts. The
proximal end is about twice the width of the shaft and
of the distal end in medial and lateral views. The lateral
ange is thick and projects dorsolaterally above the shaft
of the ulna, as in G. latidens (Prieto-Márquez, 2012). The
olecranon process is more complete in the right ulna. The
medial ange is less triangular than in AMNH FARB
5465. On the medial side of the ulna is a long depression
that hosts the radius, starting at midshaft height and be-
coming most pronounced below the medial ange. The
distal end is squared in lateral view and has a subtriangu-
lar, somewhat heart-like shape in distal view, with a at
cranial side for the distal end of the radius.
Radius - The radius is a long, straight, and slender
element (Fig. 21C). It is shorter than the humerus (660
contra 750 mm), just like in G. latidens AMNH FARB
5465 (Prieto-Márquez, 2012) and “G. incurvimanus”
(Parks, 1920) but in contrast with Brachylophosaurus,
Maiasaura, and the lambeosaurines (Horner et al., 2004),
in which the antebrachium is longer than the humerus. Its
distal and proximal ends are more expanded mediolate-
rally than dorsoventrally. As for AMNH FARB 5465, the
lateral side of the proximal end of the radius, which rests
on the medial side of the proximal region of the ulna, is
slightly concave. In proximal view, the proximal surface
is roughly circular, with a slightly concave surface. In la-
teral view, the radius is straighter than that of G. latidens
AMNH FARB 5465 (Prieto-Márquez, 2012) because in
the latter the distal end is more caudally expanded. Di-
stally, the shaft becomes wider and displays a at surface
corresponding with the concave articulation at the distal
end of the ulna. In cranial view, the “neck” of the distal
end is narrower than the proximal end, and is slightly con-
cave. In distal view, the distal surface is subtrapezoidal in
shape, with a caudal margin narrower and shorter than the
cranial one.
Manus - No carpals have been found associated with
MSNM V345. The identication of the manual phalanges
has been done following Johnson and Storer (1974), and
using TMP 1984.36.29 (an articulated manus of Hadro-
sauridae indet. from the Judith River Formation; photo
courtesy by Darren Tanke) for comparison.
37
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 20 - Shoulder girdle of MSNM V345. Right scapula in lateral (A), proximal (B), and medial (C) views; left scapula in lateral view
(D); right sternum in lateral view (E). For abbreviations, see text. Scale bar = 10 cm. Photos by FB. / Cinto pettorale di MSNM V345.
Scapola destra in norma laterale (A), mediale (B), e prossimale (C); scapola sinistra in norma laterale (D); sterno destro in norma
laterale (E). Le abbreviazioni sono riportate nel testo. Scala metrica = 10 cm. Foto di FB.
The only preserved metacarpals are mc II and mc III (Fig.
22A, B). Metacarpal II is a slender element, slightly twisted
in cranial view (Fig. 22A). The distal portion is as narrow as
its neck, whereas the proximal portion is wider than the rest
of the bone and is expanded mediolaterally. In medial view,
a long and thick central ridge runs from the apical portion to
the last third of the shaft. It forms a shallow depression close
to the lateral margin of the bone, made to receive the distal
part of mc IV. Both articular ends are convex. Metacarpal III
is not complete, missing both proximal and distal portions
(Fig. 22B). The preserved shaft is nearly as long as the who-
le mc II, but it is thicker. A small protrusion points laterally
towards mc IV in the last third of the shaft.
The rst phalanx of the left digit III is the stoutest of
the manus (Fig. 22C). Its proximal articular surface is al-
most at and only feebly concave because of slightly rai-
sed borders; it is wider than the distal articular surface. Its
concave lateral margins give the bone an hourglass-like
shape when seen in cranial (dorsal) or caudal (plantar)
views. The concave distal articular surface bears a small,
central depression that matches the shape of the proximal
articular surface of the second phalanx. The left phalanx
IV-1 (Fig. 22D) is longer than III-1 and appears identical
to the homologous element of TMP 1984.36.29. The distal
articular end of IV-1 is convex, whereas the proximal end
bears a central concavity to receive the distal articular end
of mc IV. The lateral sides of phalanx IV-1 are feebly con-
cave. Two manual ungual phalanges are associated with
the skeleton (Fig. 22E). As in other derived ornithopods
(Horner et al., 2004), these phalanges have an arrow-like
shape with a rounded tip and offset lateral margins, and
are more compressed than the pedal unguals.
38 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 21 - Forelimb of MSNM V345. Right humerus in lateral (A1), medial (A2), proximal (A3), and distal (A4) views: left ulna in
cranial (B1), lateral (B2), proximal (B3), and distal (B4) views; right radius in cranial (C1), lateral (C2), proximal (C3), and distal (C4)
views. For abbreviations, see text. Scale bars = 10 cm. Photos by FB. / Arto anteriore di MSNM V345. Omero destro in norma laterale
(A1), mediale (A2), prossimale (A3), e distale (A4); ulna sinistra in norma craniale (B1), laterale (B2), prossimale (B3), e distale (B4);
radio destro in norma craniale (C1), laterale (C2), prossimale (C3), e distale (C4). Le abbreviazioni sono riportate nel testo. Scale
metriche = 10 cm. Foto di FB.
39
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Tab. 7 - Dimensions of the right (R) and left (L) forelimb elements of MSNM V345. Asterisk (*) indicates
that measure is taken on the preserved portion of an incomplete bone.
Bone Measurement Value (mm)
R scapula length *787
distal width 185
median width 132
proximal width 255
R sternal plate length 390
proximal width 233
median width 70
distal width 92
L humerus total length 730
proximal width 230
distal width 160
length of deltopectoral crest 300
width at deltopectoral crest 180
R humerus length 750
proximal width of the shaft 170
L ulna length 675
R ulna length 780
proximal width, lateral view 138
median width 101
distal width 70
L radius total length 667
R radius total length 660
L metacarpal II length 225
L metacarpal III length *186
L IV-1 length 87
?L IV-4 (ungual) length 55
L III-1 length 75
?L II-3 (ungual) lenght 63
Pubis - The left pubis is preserved, although most of
its medial side has been xed with plaster (Fig. 23A). In
spite of seeming at rst glance incomplete, this element is
genuine (see Vialli, 1960). The right pubis is represented
only by the iliac peduncle (Fig. 23B). The prepubic pro-
cess, or distal blade, is subrectangular, with parallel dorsal
and ventral margins, and a marked angular craniodorsal
corner (sensu Prieto-Márquez, 2012), as in G. latidens
(Prieto-Márquez, 2012), Secernosaurus koerneri, Pro-
saurolophus maximus, “G. incurvimanus” (Horner et al.,
2004), and the other G. notabilis specimens (Prieto-Már-
quez, 2012). The distal end of the blade is squared and
cranioventrally directed, like in the other hadrosaurines.
Despite its incompleteness, the blade is dorsally longer
than the prepubic proximal constriction, and the dorso-
ventral depth of the blade is more than twice the depth of
the proximal constriction. In “G. incurvimanus”, this ratio
is 2.2 (Parks, 1920), and the distal blade is dorsoventrally
shorter than in MSNM V345. The angular craniodorsal
corner rises abruptly from the constriction at a sharp an-
gle of 160°, while in G. latidens AMNH FARB 5465 the
dorsal margin is arched more gently. The iliac peduncle
projects caudodorsally from the acetabular margin. The
length to width ratio of the iliac peduncle is 1.5, which
falls within the basal condition of a “very short peduncle”
(Prieto-Márquez, 2010a). The lateral margin of the iliac
peduncle extends ventrally to form a prominent ridge that
merges with the proximal region of the ischial peduncle.
The ischial peduncle arises from the rst third of the la-
teral side of the postpubic process (or pubic shaft), and
it projects caudoventrally, parallel to that process. The
postpubic process is shorter than the prepubic process,
although the original condition might have been different
because the distalmost tip is not preserved. The postpubic
process projects caudoventrally from the acetabular mar-
gin of the pubis, forming a 142° angle with the long axis
of the prepubic process. The distal end is thinner than the
proximal portion and more dorsally arched, resembling
the postpubic process of “G. incurvimanus” (Park, 1920),
although the latter is more sinuous. In contrast, AMNH
FARB 5465 (Prieto-Márquez, 2012) has a stiff, rod-like
postpubic process.
40 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 22 - Manual elements of MSNM V345. Left metacarpal II (A) and metacarpal III (B) in dorsal views; rst left phalanx of digit
III in dorsal (C1), lateral (C2), and proximal (C3) views; rst left phalanx of digit IV in dorsal (D1), lateral (D2), proximal (D3) and
distal (D4) views; unguals of digits II and IV in dorsal (E1 and E3) and lateral (E2 and E4) views. Scale bar = 10 cm. Photos by CDS.
/ Elementi della mano di MSNM V345. Metacarpali II (A) e III (B) della mano sinistra in norma dorsale; prima falange del terzo dito
sinistro in norma dorsale (C1), laterale (C2) e prossimale (C3); prima falange del quarto dito sinistro in norma dorsale (D1), laterale
(D2) prossimale (D3) e distale (D4); falangi ungueali del secondo e quarto dito in norma dorsale (E1 e E3) e laterale (E2 e E4); Scala
metrica = 10 cm. Foto di CDS.
Ischium - The ischium is represented only by the
left element (Fig. 23C). The iliac ramus resembles that
of the saurolophine Latirhinus uitstlani (Prieto-Már-
quez & Serrano Brañas, 2012) in being subrectangular
in lateral and medial views. The dorsocaudal corner
is more caudally pointed than in “G. incurvimanus”
(Parks, 1920). The angle between the articular surface
of the iliac ramus of the ischium and the acetabular
margin of the ramus is about 90°, contra Prieto-Már-
quez (2008), who reported an inclination of 120° for
MSNM V345. The acetabular and caudal margins of
the iliac ramus are straight and parallel to each other.
The iliac ramus projects caudodorsally with a knob-
like process. It is inclined caudodorsally to the shaft.
The articular surface of the pubic process is orien-
ted craniomedially. The dorsal acetabular margin of
the pubic peduncle is nearly at the same level as the
dorsal margin of the ischial shaft. The comma-shaped
obturator process is placed ventrocaudally to the ob-
turator notch, which does not seem to be a comple-
te foramen as possessed by other genera. The ischial
shaft is long and straight, ending in a distal tip (now
missing) that may have supported a very small distal
knob, as in G. notabilis ROM 764, “G. incurvimanus”
(Parks, 1920), TMM 42309 (Hadrosauridae indet.),
and Edmontosaurus annectens AMNH FARB 5730.
Femur - Both femora are preserved: the right is
in a better condition (Fig. 24A), the shaft of the left
being covered by plaster. They are stout and big ele-
ments, 1 m long. The ball-like femoral head is poorly
41
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 23 - Pelvic girdle of MSNM V345. Left pubis in lateral view (A); fragmentary right pubis in medial view (B); left ischium in
lateral (C1), dorsal (C2), and ventral (C3) views. For abbreviations, see text. Scale bars = 10 cm. Photos by FB. / Cinto pelvico di
MSNM V345. Pube sinistro in norma laterale (A); frammento di pube destro in norma mediale (B); ischio sinistro in norma laterale
(C1), dorsale (C2), e ventrale (C3). Le abbreviazioni sono riportate nel testo. Scale metriche = 10 cm. Foto di FB.
developed in cranial view and supported by a large
neck. In caudal view, the neck is arched, reaching the
point of maximum curvature of the femur. A rod-like
cranial, or lesser, trochanter is located on the cranio-
lateral surface. The greater trochanter – rounded in
lateral view – is positioned higher than the head and
forms the proximolateral border of the femur. The-
se two trochanters are separated by an open cleft. A
fourth trochanter, placed exactly at the midshaft, is
subtriangular in lateral view and has a sigmoid caudal
42 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
margin. The lateral profile of its caudodistal margin
is smooth and arcuate, ending in a caudally, slightly
ventrally directed point, as in more basal hadrosau-
rids. It forms a 121° angle with the shaft of the femur.
In cranial and caudal views, the shaft appears slightly
Fig. 24 – Hind limb of MSNM V345. Right femur in cranial (A1), medial (A2), caudal (A3), lateral (A4), proximal (A5), and distal
(A6) views; right tibia in lateral (B1), cranial (B2), medial (B3), caudal (B4), proximal (B5), and distal (B6) views. For abbreviations,
see text. Scale bars = 10 cm. Photos by FB. / Arto posteriore di MSNM V345. Femore destro in norma craniale (A1), mediale (A2),
caudale (A3), laterale (A4), prossimale (A5), e distale; tibia destra in norma laterale (B1), craniale (B2), mediale (B3), caudale (B4),
prossimale (B5), e distale (B6). Le abbreviazioni sono riportate nel testo. Scale metriche = 10 cm. Foto di FB.
bowed, with a concavity on the medial side; in late-
ral and medial views, the shaft is straight and slightly
tapering distally. The distal end of the femur is slight-
ly expanded cranially and greatly expanded caudal-
ly to form the lateral and medial condyles, which are
43
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
separated by a deep intercondylar groove. The con-
dyles are subrectangular in lateral and medial views
and have a sharp and straight caudal margin, so are
different from the caudally pointed condyles of “G.
incurvimanus” (Parks, 1920). The dorsocaudal region
of the medial condyle is flat, if not slightly concave,
rather than spherical as in other hadrosaurids, such
as Olorotitan arharensis AEHM 2/845 (Godefroit et
al., 2003). However, the lateral condyle is similar to
that of AEHM 2/845, with a straight, dorsoventrally
expanded dorsocaudal margin.
Tibia - Proximally, the right tibia is expanded cra-
niocaudally; distally, it is expanded mediolaterally
(Fig. 24B). The cnemial crest is more developed cra-
niolaterally than medially, as reported by Kirkland et
al. (2006). Although over half of the crest is missing,
we have reconstructed its overall outline, which re-
sults to be massive and robust. The resulting cnemial
crest follows the curvature of the femur, so that the
entire hindlimb is bowed in both cranial and caudal
views: in life, Gryposaurus might have walked with
the knees slightly laterally oriented, an adaptation to
make room for a big herbivorous gut cavity. This con-
dition was likely shared by all hadrosaurids (if not all
cerapods), but palaeoartistic reconstructions often do
not convey this posture. The medial condyle is larger
and protrudes more distally than the lateral condyle,
and they are separated by a well-developed intercon-
dylar groove. This broad distal epiphysis tapers gra-
dually towards the midshaft of the bone. Along the
shaft, this bone has lost its original twisting.
Fibula - Only the proximal part of the right fibula
shaft is preserved (Fig. 6). It is 550 mm long as pre-
served, half the length of the tibia, and 80 mm wide at
its maximum width. No anatomical characters can be
recognised other than it is completely straight.
Astragalus - Only the right astragalus is pre-
served (Fig. 25A). The lateral side of the astragalus is
slightly concave to accommodate the calcaneum. It is
cupped proximally for the tibia and very broadly con-
vex distally, where it articulates with the metatarsus.
The cranial ascending process is tall and shifted to the
medial side.
Pes - The identification of the pedal elements has
been done following Zheng et al. (2011) and John-
son and Storer (1974). The right mt II is a bowed and
thick element that forms the medial side of the pes
(Fig. 25B). The proximal side of the bone is flat and
remarkably expanded craniocaudally. In lateral view,
the proximal articular margin is cranially inclined at a
75° angle from the main axis (Fig. 25B2). The thick-
ness of the bone shaft remains constant throughout
its entire length, becoming slightly greater in the last
third of the metatarsal. The proximal portion of the
caudal margin of the metatarsal is eroded. The distal
end is deflected slightly medially, and its caudal mar-
gin is more ventrally inclined, resulting in an equally
inclined distal surface. The left mt III has a slightly
sinuous shaft, bowed in lateral view, which expands
on both proximal and distal regions (Fig. 25D). It
maintains a constant width along the central shaft.
The length to width ratio is 4.3, as measured by Prie-
to-Márquez (2008). In ventral view, the proximal re-
gion is tripartite, with three subcircular protuberances
separated from each other by depressions. In dorsal
view, a shallow concave area that accommodates mt
IV is visible on the lateral margin of the shaft. The
distal end bears two condyles separated by a central
sulcus. In dorsal view, the medial condyle has a me-
dioventrally expanded process that points towards mt
II. In lateral view, the lateral condyle is large, with
a circular margin, resulting much broader than the
proximal region. The right mt IV is nearly as long as
mt II, but has a more complex shape (Fig. 25C). In
dorsal view, the shaft is slightly sinuous and the distal
end is deflected slightly laterally. The proximal artic-
ular surface is flat with a circular caudal margin and a
bipartite cranial margin. The medial process is larger
than the lateral, and they are divided by a shallow
sulcus. In the proximal half, the shaft becomes medi-
olaterally wider, whereas in the distal half the lateral
sides are concave, and the shaft reaches its minimum
diameter. The medial concavity is more pronounced
than the lateral one in order to receive the distal part
of mt III. In lateral view, the plantar margin has two
projections. The distal end of mt IV bears two con-
dyles, both semicircular in lateral view: the medial
one is larger than the lateral. Part of the distal articu-
lar surface is covered by plaster, so its exact shape
cannot be reconstructed.
Only some phalanges of the left pes are preserved
in MSNM V345 (Fig. 25E). The left phalanx III-1 is
the stoutest element of the pes (Fig. 25E1-2). It is ex-
panded at its proximal and distal ends. The proximal
articular surface is elliptical, and slightly concave.
The distal articular surface is bean-like in outline,
with semicircular dorsal and plantar margins and with
a central concavity. We tentatively interpret a second
proximal pedal element as a ?left IV-1 (Fig. 25E5-
E6), as the proximal articulation seems dorsoventral-
ly collapsed on one side, thus reminiscent of a more
asymmetrical, trapezoid shape. The proximal articular
surface of the second phalanx of the left digit II (Fig.
26A) bears a central elongate fossa -likely vascular in
nature- and shows an even more asymmetrical trap-
ezoid shape. The right third phalanx of digit III (Fig.
26B) is typically semilunate, proximodistally com-
pressed, and mediolaterally expanded. The dorsal and
ventral articular surfaces are slightly concave, both
with a depression on the caudal margin. The right third
phalanx of digit IV (Fig. 26C) is a smaller semilunate
element, lateromedially expanded and proximodistally
short, with a central sulcus on both proximal and dis-
tal articular surfaces. Two unguals are associated to
the pes (Fig. 26D). They are similar in size and hoof-
like with typical arrow-like dorsal and plantar profiles
(Horner et al., 2004). However, they resemble a more
basal condition than that of Brachylophosaurus, being
longer than wide (Prieto-Márquez, 2008). The area
between the proximal articular surface and the two
proximolateral processes is longer in the right ungual
II (Fig. 26D1) than in the right ungual IV (Fig. 26D4).
They lack a plantar central keel, but they have a bulky
protrusion for the insertion of the flexor muscles. In
dorsal view, their medial sides are more vascularised
than the lateral sides. In ventral view, other foramina
are present on the hoof-like portion.
44 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 25 – Pedal elements of MSNM V345. Right astragalus in dorsal (A1), ventral (A2), and cranial (A3) views; right metatarsal II in
cranial (B1) and medial (B2) views; right metatarsal IV in cranial (C1) and lateral (C2) views; left metatarsal III in cranial (D1) and
lateral (D2) views; rst phalanx of left digit III in dorsal (E1) and proximal (E2) view; ?rst phalanx of ?left digit IV in dorsal (E3)
and proximal view (E4). Scale bars = 10 cm. Photos by FB and CDS. / Elementi del piede di MSNM V345. Astragalo destro in norma
dorsale (A1), ventrale (A2), e craniale (A3); metatarso II destro in norma craniale (B1), e mediale (B2); metatarso IV destro in norma
craniale (C1) e laterale (C2): metatarso III sinistro in norma dorsale (D1), e laterale (D2); prima falange del III dito sinistro in norma
dorsale (E1) e prossimale (E2); possibile prima falange del ?IV dito sinistro in norma dorsale (E3) e prossimale (E4). Scale metriche
= 10 cm. Foto di FB e CDS.
45
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Histology and ontogenetic assessment
We performed histological analysis on the right
femur (Fig. 27A) in order to define the ontogenetic
stage of MSNM V345 (see also Methods). The cylin-
drical core sample of the right femur was 17 mm thick
and 14 mm in diameter (Fig. 27AII). The core did not
include the medullary cavity. Indeed, while coring the
sample, we encountered a layer of plaster at around 20
mm of depth; given the uncertainty of the thickness
of this layer, we decided to stop drilling into the bone
at this point. The extracted sample was nevertheless
sufficient for our ontogenetic investigation.
The compacta was almost entirely constituted by
Haversian systems, covering up to the 95% of the entire
thin section (Fig. 27B). Up to four generations of secon-
dary osteons were counted. Primary bone was observed
only in the outermost part of the compacta, towards
the bone surface. The bone was lamellar. We observed
Sharpey’s fibers in the outermost area of the cortex,
which indicates an attachment site for muscles. Three
tightly spaced LAGs were present in the outermost
compacta (Fig. 27C). The few vascular spaces visible
in the outermost cortex are longitudinally oriented. The
combination of lamellar bone, reduced vascularization,
and tightly spaced LAGs was interpreted as an EFS.
The presence of EFS and the heavy remodelling ob-
served in the compacta suggest that MSNM V345 had
reached somatic and reproductive maturity at the time
of death.
Pathological bones
Three bones displaying pathologies were subjected to
specic analyses, including X-ray computed tomography
(CT): the predentary, the fth dorsal vertebra, and a cau-
dal vertebra.
Fig. 26 - Pedal elements of MSNM V345. Second left phalanx of digit II in dorsal (A1), lateral (A2) and proximal (A3) views; third
right phalanx of digit III in dorsal (B1) lateral (B2) and proximal (B3) views; third right phalanx of digit IV in dorsal (C1), lateral (C2)
and proximal (C3) views; unguals of right digit II in dorsal (D1), lateral (D2) and plantar (D3) views, right digit IV in dorsal (D4),
lateral (D5) and plantar (D6) views. Scale bar = 10 cm. Photos by CDS. / Elementi del piede di MSNM V345. Seconda falange del
II dito sinistro in norma dorsale (A1), laterale (A2) e prossimale (A3); terza falange del III dito destro in norma dorsale (B1), laterale
(B2) e prossimale (B3); terza falange del IV dito destro in norma dorsale (C1), laterale (C2) e prossimale (C3); falangi unguali del II
dito destro in norma dorsale (D1), laterale (D2) e plantare (D3), del IV dito destro in norma dorsale (D4), laterale (D5) e plantare (D6).
Scala metrica = 10 cm. Foto di CDS.
46 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
The predentary bears an anomalous, but naturally
large, central cavity (Fig. 28A and Fig. 29A-B). The
cavity was partly lled with plaster by preparators when
xing an iron bar to hold the bone in anatomical posi-
tion. This abnormal cavity is 6 cm wide, 2.2 cm high,
and about 4 cm deep, and produces a ventral slope on
the ventral surface of the predentary. A similar condition
has been found in a Maiasaura peeblesorum predentary
(Nabavizadeh, pers. comm. to FB, 2016). Nevertheless,
its uniqueness and our exclusion of it being artefactual
led us to speculate that it was pathological in nature. To
test this hypothesis, we CT-scanned the specimen and
prepared a histological sample, extracting a 4-mm-diam-
eter core from the caudodorsal surface above the cavity.
We found large resorption cavities and an unexpectedly
high remodelling rate (Fig. 29B1-B4). Although no his-
Tab. 8 - Dimensions of the right (R) and left (L) hindlimb elements of MSNM V345. Asterisk (*) indicates
that measure is taken on the preserved portion of an incomplete bone.
Bone Measurement Value (mm)
L pubis total length *1180
R pubis n/a n/a
L ischium total length *1160
height between the iliac ramus and the acetabulum 315
R ischium Length *1210
height between the iliac ramus and the acetabulum 300
L femur length 1140
proximal craniocaudal width in lateral view 300
distal craniocaudal width in lateral view 300
dorsoventral height of the fourth trochanter 330
maximum width at the fourth trochanter 310
distance between head and the fourth trochanter 530
R femur length 1070
proximal craniocaudal width in lateral view 305
distal craniocaudal width in lateral view, 260
dorsoventral height of the fourth trochanter 315
maximum width at the fourth trochanter 210
L tibia length 1000
R tibia length 1005
bula length *553
R metatarsal II length 325
L metatarsal III length 395
R metatarsal IV length 305
L II-2 length 50
width 68
R II-3 (ungual) length 82
width 60
L III-1 length 120
width 110
R III-3 length 30
width 90
?L ?IV-1 length 115
width 80
R IV-3 length 21
width 58
R IV-5 (ungual) length 85
Width 60
47
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 27 - Thin sections of the right femur (A, B, C). Overall view (A1), where the outer surface of the bone is at the top; draw-
ing of the sampled bone, the red dot corresponds to the drilling position (A2); detail of the Haversian system in the compacta
(B); close-up of the microstructure of the outermost cortex (C) showing the presence of an EFS, interpreted on the basis of
very reduced vascular canals, presence of lamellar bone, and presence of three tightly spaced LAGs. Green arrows point to
the LAGs. For abbreviations, see text. Scale bars =10 mm in A; 1 mm in B and C. Photos and drawings by MF. / Sezioni isto-
logiche del femore destro (A, B, C). Vista generale (A1), dove la superficie esterna si trova nella parte superiore della figura;
disegno schematico dell’osso preso in esame, il punto rosso corrisponde alla posizione di carotaggio delle sezioni (A2); det-
taglio del Sistema Haversiano nella compacta (B); dettaglio della microstruttura della compacta esterna, dove la presenza di
EFS è dedotta sulla base della quasi totale assenza di canali vascolari, della presenza di osso lamellare e di tre LAGs stret-
tamente ravvicinate (C). Le frecce verdi indicano le LAGs. Le abbreviazioni sono riportate nel testo. Scale metriche = 10 mm
in A e D; 1 mm in B e C. Foto e disegni di MF.
tology of “healthy” predentaries is available yet, we hy-
pothesize that the cavity is a product of osteomyelitis.
Comparison with other predentaries in the future will
lead to a more precise diagnosis.
The whole left transverse process of the fifth dorsal
vertebra is extensively fused to the proximal part of
the left rib (Fig. 28B). The rib also has an overgrowth
of bone tissue covering part of the lateral surface of
the vertebra. This pathological condition might be ex-
plained as hypertrophied osteosclerosis subsequent to
a fracture affecting both bones that ruptured or teared
the periosteal sac around each bone and led them to
fuse together. A similar pathology has been recently
reported by Ramírez-Velasco et al. (2016). They de-
scribe a proximal dorsal vertebra from the holotype
of the hadrosauroid Huehuecanauhtlus tiquichensis
IGM 6253, which shows a focal mass on the caudal
surface of the right costo-vertebral joint between the
vertebra and its right rib. In this specimen, the tuber-
culum of the rib is anomaly enlarged, and fused with
the vertebral centrum, whereas the capitulum and the
parapophysis are not affected by the costo-vertebral
mass. This condition seems similar to that of MSNM
V345, although in our specimen the central shaft of the
rib is lost. Ramírez-Velasco et al. (2016) conclude it
was probably the result of a pyogenic infection, based
on the presence of bone erosions. Comparison with
other costo-vertebral diseases in the future will lead to
a more precise diagnosis for MSNM V345.
The 26th caudal vertebra has two abnormities (Fig.
28C and Fig. 29C). The rst is pathological: a neural
spine fractured and healed in life with some minor
displacement of the affected portions prior to healing.
This is a common condition in Albertan hadrosaurs
(Tanke & Rothschild, 2014). Also, the centrum of this
vertebra has a strap of bone growing along the side of
the preceding centrum. This may represent a non-path-
ological condition, such as diffuse idiopathic skeletal
hyperostosis (DISH), or possibly a haemangioma, a
benign proliferation of vascular endothelium (Roth-
schild et al., 2003) that is a typical hadrosaur cancer
encountered in specic stressed regions of the skeleton.
The cause of DISH is uncertain, but it is believed to
be related to the body’s attempt to relieve stress points
along the vertebral column. It should not be confused
with arthritis, which is virtually unknown in dinosaurs
(Tanke, pers. comm. 2006) and does not affect verte-
bral articulations.
48 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 28 - Pathological bones in MSNM V345, and their locations in the skeleton. Predentary in ventral (A1), and caudal (A2) views;
dorsal vertebra 5 in cranial (B1), and caudal (B2) views; caudal vertebrae 26 and 25, as they appear fused together, in dorsal (C1), right
lateral (C2) and ventral (C3) views. The red arrow points to the enigmatic cavity of the predentary. Scale bars = 10 cm in A, B, and C;
1 m in D. Photos by FB, drawing by Marco Auditore. / Ossa patologiche e loro rispettive posizioni nello scheletro di MSNM V345.
Predentale in norma ventrale (A1) e caudale (A2); vertebra dorsale 5 in norma craniale (B1) e caudale (B2); vertebre caudali 26 e 25,
associate come apparivano fuse in vita, in norma dorsale (C1), laterale destra (C2) e ventrale (C3). La freccia rossa indica l’anormale
cavità del predentale. Scale metriche = 10 cm in A, B e C; 1 m in D. Foto di FB, disegno di Marco Auditore.
SKELETAL AND LIFE RECONSTRUCTION OF GRYPOSAURUS
Skeletal drawings are important to understand the pro-
portions, body mass, and posture of a specimen. Indeed,
a detailed reconstruction is a signicant part of any study
(Witton et al., 2014), and is not just intended for the gen-
eral audience. Regarding Gryposaurus, some specimens
have preserved skin remains, making in vivo restoration
more accurate. Here, we propose a new, updated restora-
tion of Gryposaurus notabilis based on our analysis.
Reconstruction history
Although iconographic history is usually not taken
into consideration, it is useful to summarize the different
hypotheses made in the past on the posture and general
appearance of a studied species. Gryposaurus is of par-
ticular interest in this regard on account of its intricate
taxonomic and iconographic history. A chronological
summary of the various renderings of Gryposaurus made
over the years is given in Fig. 30.
For a long time after its discovery, Gryposaurus was
thought to be a junior synonym of Kritosaurus (Brown,
1916). Palaeoartists therefore did not know they were spe-
cically portraying the former. Indeed, most of the skele-
tons used when depicting Kritosaurus, such as ROM 764,
actually belonged to the genus Gryposaurus, so much so
that the artistic morphotype of the “gryposaur” succeeded
and replaced that of the “kritosaur” in the public’s imagi-
nation. Portrayal of the characteristic nasal crest is one of
the clearest evidence of this. Because they were thought
to be the same genus, early 20th century restorations of
Kritosaurus depicted this hadrosaur with a nasal crest that
was more similar to that of Gryposaurus (for example,
see the crest modelled by Charles Gilmore and illustrated
by Richard Deckert in Barnum Brown’s 1916 research
paper). Synonymy apart, depictions of either Kritosaurus
49
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 29 - CT-scan images of the predentary in coronal (A1), longitudinal (A2), and sagittal section (A3); panoramic view of the drilled
core of the predentary under normal light (B1) and polarised ligth with lambda lter (B3), with a focus on the cortical bone (B2) and
the remodeled bone (B4) (magnied areas are marked with red squares); CT-scan images of the pathological caudal vertebrae 25-26
in coronal (C1), sagittal (C2), and longitudinal section (C3). The red line in A1 corresponds to the drilled area seen in B. Scale bars
in B1 and B3 = 4 mm. Photos by FB. / Immagini ottenute tramite TAC del predentale in sezione coronale (A1), longitudinale (A2) e
sagittale (A3); vista generale della sezione istologica del predentale a luce normale (B1) e luce polarizzata con ltro lambda (B3), con
dettaglio dell’osso corticale (B2) e dell’osso rimodellato (B4) (i riquadri rossi corrispondono alle zone ingrandite); immagini ottenute
tramite TAC delle due vertebre patologiche 25 e 26 in sezione coronale (C1), sagittale (C2) e longitudinale (C3). La linea rossa in A1
indica la posizione dove il carotaggio B è stato prelevato. Scale metriche in B1 e B3 = 4 mm. Foto di FB.
or Gryposaurus were rare in those early years. An impor-
tant exception is Disney’s 1940 animated movie Fantasia,
in which Kritosaurus appears continually. As a matter of
fact, Brown – one of the greatest scientic celebrities of
his day – was a scientic advisor for the movie: he pro-
duced several preparatory studies based on the AMNH’s
collection, and was responsible for the presence in the
movie of not particularly famous species. After Disney’s
Fantasia, Kritosaurus never appeared on screen again.
The characters and environments depicted in Dis-
ney’s Fantasia were based on the works of the famous
artist Charles Knight. Neither he nor his famous suc-
cessor Zdeněk Burian had ever depicted Kritosaurus, so
Disney’s artists had to create its appearance from scratch.
Charles Knight’s inuence in this was prominent: the de-
cision to show gryposaurs in a sitting position is clearly
based on his early reconstructions of Trachodon (Ballou,
1897). Similar postural reconstructions were presented
by Lull & Wright (1942) – following studies on Anomoe-
pus tracks – the authors responsible for consolidating the
synonymy between Gryposaurus and Kritosaurus, with
the overshadowing the former genus. “Kritosaurus” was
portrayed later also by Vialli (1960) and Rudolph Zal-
linger (Watson, 1965). An usual mistake in those early
50 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
Fig. 30 - Iconographic “evolution” of the genus Gryposaurus since its discovery. The models are drawn from the originals. A) Gil-
more, 1916; B) Deckert, 1916; C) Disney, 1940; D) Vialli, 1960; E) Sibal, 1964; F) Zallinger, 1963; G) Paul, 1980s; H) Sibbick, 1985;
I) Kirk, 1988; J) Braginetz, 1993; K) Franczak, 1993; L) Gryposaurus monumentensis by Felder, 2007; and M) Tethyshadros insularis
by Perentin, 1999 (about this taxon, see text). The dates correspond to the probable year of production of the artwork. Drawings by FM. /
“Evoluzione” iconograca del genere Gryposaurus, dalla sua scoperta in poi. I disegni sono basati sulle opere originali. A) Gilmore, 1916;
B) Deckert, 1916; C) Disney, 1940; D) Vialli, 1960; E) Sibal, 1964; F) Zallinger, 1963; G) Paul, 1980s; H) Sibbick, 1985; I) Kirk,
1988; J) Braginetz, 1993; K) Franczak, 1993; L) Gryposaurus monumentensis di Felder, 2007; M) Tethyshadros insularis di Perentin,
1999 (per questo taxon, vedi testo). Le date corrispondono al probabile anno di produzione delle opere. Disegni di FM.
reconstructions was the outline of the nasal crest, which
was depicted as a large bulge. However, Vialli (1960) did
correctly propose the presence of dorsal dermal spines on
the hadrosaur’s back and eshy cheeks on its face, antici-
pating modern depictions of Gryposaurus (Galton, 1973;
Paul, 1987). Kritosaurus was also described by Ostrom
(1964a) in his book The Strange World of Dinosaurs. At
the same time, Ostrom (1964b) revolutionised the study
of hadrosaur ecology and biology by proposing they had
a terrestrial life-style. Indeed, since the rst discoveries,
hadrosaurs were generally presumed to be amphibious
animals (e.g., Leidy, 1858; Osborn, 1912) with webbed
forefeet and at-sided tails. Although this view was not
completely abandoned by Ostrom (1964a), he did call it
partly into question, writing, “But the hadrosaurs do not
look much like other swimming animals we are familiar
with. They look more like land animals and it seems like-
ly that they were both”. Despite this, the reconstructions
in his book portrayed these dinosaurs only in an upright,
kangaroo-like posture.
The big shift away from representing these dinosaurs
in an erect pose to one in which they assumed a more hor-
izontal position occurred with a paper by Galton (1970),
in which a skeletal drawing of a running Edmontosaurus
depicts the tail being carried well above the ground. For
Galton, these animals were bipedal except when resting.
This emerging new view of hadrosaurs was underscored
and studied further by Bakker, who like Galton and Os-
trom shared the idea that dinosaurs were bird-like animals
that were more agile than previously thought (Bakker,
1986). Bakker (1986) also dismissed the traditional no-
tion of hadrosaurs having webbed hands (Osborn, 1912),
re-interpreting skin remains of specimen AMNH 5060 as
digital pads that had been deformed during mummica-
tion. As is clear from his own drawings, Bakker imagined
hadrosaurs as fully terrestrial quadrupeds or facultative
bipeds. His vivid illustrations inspired the general pub-
lic and researchers alike, and later became crucial for the
work of the palaeoartist Gregory S. Paul (http://www.gs-
pauldino.com/part2.html).
Paul produced some of the most inuential anatomical
illustrations of the end of the last century; some remain so
today. His skeletal reconstruction based on ROM 764 (G.
notabilis) was claimed to be a variation of Kritosaurus, a
controversial and unsupported taxonomy he continued to
maintain up to recent years (Paul, 2010). Paul also recon-
structed the musculature of Kritosaurus, and was the rst
to analyse in detail fossilised skin, such as dermal spines
(Paul, 1987). In fact, the rst dermal spines to be found
were from Gryposaurus (Parks, 1920; Bell, 2014). Paul’s
illustrations and diagrams have been used as reference by
several authors and artists (Hallett, 1987; Brett-Surman,
1989; Henderson, 1997; White, 2012; Henderson, 2014),
and his study on ROM 764 inuenced the depiction of
some lesser known genera, such as Tethyshadros insula-
ris, the rst Italian hadrosauroid, initially hypothesised to
be similar to Gryposaurus, as portrayed by Tullio Perentin
in 1996 and modelled by Mauro Scaggiante (Geo-Model)
in 1997. In addition to those by Paul, other important Kri-
tosaurus reconstructions were done by John Sibbick (see
works in Norman, 1985, and Lambert, 1993) and Steve
Kirk (see Dixon et al., 1988).
51
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 31 - A) midline feature scales in Gryposaurus notabilis ROM 764 (1), Gryposaurus sp.UMNH VP 12265 (2), Saurolophus
angustirostris UALVP 52748 (3), Edmontosaurus annectens MOR 007 (4), and Brachylophosaurus canadensis JRF 115 (5). Positions
of skin remains found in Gryposaurus specimens (B: red, ROM 764; green, CMN 2278; blue, UMNH VP 12265) and in Rhinorex
(C: red, BYU 13258). General morphology of the hadrosaurian manus (D) and pes (E) in lateral (left) and plantar (right) views;
redrawn from Bakker (1986) and Langston (1960). F) basement (BS) and feature (FS) scales of the skin of Rhinorex (from Anderson
et al., 1999). For abbreviations, see text. Drawings by FM. / A) confronto delle ”midline feature scales” negli adrosauri, in base alla
loro diversa disposizione, morfologia e circonferenza: Gryposaurus notabilis ROM 764 (1), Gryposaurus sp. UMNH VP 12265 (2),
Saurolophus angustirostris UALVP 52748 (3), Edmontosaurus annectens MOR 007 (4) e Brachylophosaurus canadensis JRF 115
(5). Mappatura dei resti di pelle negli esemplari di Gryposaurus (B, rosso: ROM 764, verde: CMN 2278, blu: UMNH VP 12265) e
Rhinorex (C, rosso: BYU 13258). Ricostruzione scheletrica della mano (D) e del piede (E) di un adrosauro, rispettivamente in norma
laterale (a sinistra) e plantare (destra); rielaborato da Bakker (1986) e Langston (1960). F), “basement” e “feature scales” nella pelle di
Rhinorex (da Anderson et al., 1999). Le abbreviazioni sono riportate nel testo. Disegni di FM.
Gryposaurus and Kritosaurus were eventually sepa-
rated by Horner (1992). The rst ofcial reconstructions
of Gryposaurus were made in 1993 by Brian Franczak
and Donna Braginetz (Wallace, 1993). Recent discov-
eries of several new Gryposaurus species and closely
related forms have revealed an unexpected diversity
(Gates & Sampson, 2007; Gates & Scheetz, 2014; Leh-
man et al., 2016). The discovery of G. monumenten-
sis was followed by a restoration by Larry Felder in
2007, in which he depicted the new species sporting a
bright, colourful crest and skin sac (http://www.wash-
ingtonpost.com/wp-dyn/content/article/2007/03/03/
AR2007030300998.html). Later, Scott Hartman recon-
structed the skeleton of G. monumentensis, with the
missing portions being based on G. notabilis speci-
mens (http://www.skeletaldrawing.com/ornithiscians/
gryposaurus).
Review of skin impressions
Some fossil specimens assigned to G. monumentensis
bear skin remains. A 2.4 m2 area of fossilised skin is present
in UMNH VP 12265 in close association with portions of
the tail and the pelvis, and a patch of skin is preserved in
UMNH VP 18568, a large individual. Skin remains are al-
so known for species closely related to Gryposaurus, such
as Rhinorex condrupus (Anderson et al., 1999; Gates &
Scheetz, 2014), or possibly referable to this genus, such as
?G. alsatei (see Palaeobiogeography of Gryposaurus).
Phylogenetic analysis of the integumentary morphol-
ogy in Hadrosauridae is still lacking. It would be a use-
ful tool to clarify afnities and differences within this
group. Bell (2014) has provided an exquisite summary
of all ndings, including those pertaining to G. notabi-
lis (Fig. 31). His summary does not take into account
52 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
skin remains on the jugal of ROM 873 (formerly ROM
5859) – a specimen of G. notabilis collected by Sternberg
in 1934 – that were briey mentioned but not shown by
Heaton (1972). Conrmation of these remains would be
important because fossilised skin belonging to a hadro-
saur head are very rare (Bell et al., 2013). Unfortunately,
we could not nd any close-up photographs of the speci-
men’s jugal, so we have not added this nding to Fig. 31.
Among the peculiarities of Gryposaurus is the pres-
ence of midline feature scales (MFSs). Indeed, it is one
of the few hadrosaurids known with this kind of charac-
ter (Bell, 2014). In G. notabilis ROM 764, two MFSs are
present at the level of the dorsosacral transition, sepa-
rated from each other by 21 cm (Parks, 1920), the same
space occupied by two vertebrae. Although these are the
only known G. notabilis MFSs, they can be distinguished
from those of other saurolophines, such as Edmontosau-
rus annectens, in which the dermal spines are taller and
more closely spaced, forming an almost continuous frill
(Horner, 1984). However, most modern restorations of
Gryposaurus seem to be inspired more by the arrange-
ment of the dermal spines on E. annectens. Ironically,
in Disney’s Fantasia the well-spaced spines typical of
Gryposaurus are depicted on Trachodon (= Edmontosau-
rus) – Trachodon now being considered a nomen dubium,
represented by teeth that more likely pertain to a lambeo-
saurine (Horner et al., 2004) – whereas the back of Grypo-
saurus is shown unornamented despite MFSs having been
described only for this genus at that time. Similar MFSs
have been recently found in UMNH VP 12265, referred
to G. monumentensis: these scales have a series of radiat-
ing, non-parallel grooves that converge along the dorsal
midline, just like in G. notabilis (Parks, 1920; Bell, 2014).
They vary irregularly in size (range, 7-11 cm) and spac-
ing along the series (Clayton et al., 2011). This irregular
pattern might be indicative of a certain degree of intraspe-
cic and individual variability, similar to that occurring in
the distribution of dermal spines in some extant reptiles.
A revised reconstruction based on MSNM V345
Our restoration of Gryposaurus depicts MFSs all along
the midline of the body. It also takes into account the most
up-to-date information we have on the beak and manus.
Indeed, on the basis of ndings from other hadrosaurids,
we reconstruct the beak with an extended, deep rhampho-
theca (Sternberg, 1935; Morris, 1970; Farke et al., 2013);
the beak’s lower margin traces the outline of the well-
developed denticles present on the predentary of MSNM
V345 described above. The manus is encased in a mitten
of skin: in all likelihood, the digits terminated with only
two exposed “hoof-like claws” (many reconstructions of
hadrosaurids erroneously add a third ungual phalanx).
To reconstruct the skeleton of our specimen, we took
into consideration the probable spaces – more or less 1 cm
long each – occupied by cartilage between each vertebra,
as well as those present in the appendicular skeleton, as
appearing in some hadrosaur mummies (Manning, 2008).
These spaces, which are often neglected, add at least one
metre of length to the bony elements. Body length also
depends on neck posture, which in hadrosaurids takes on
a subtle dorsoexed curvature. The neck was heavily mu-
scled, as conrmed by the discovery of JRF 115, an excel-
lent Brachylophosaurus mummy (Murphy et al., 2006),
which we used, along with Dilkes’ (2000) myological
diagrams of the limbs, to estimate the muscle silhouette.
Comparisons with other Gryposaurus skeletons (in par-
ticular ROM 764) were essential in restoring deformed,
pathological, or fragmentary bones and completing the
skeletal drawing. Ossied tendons are excluded from the
reconstruction, although obviously present in the living
animal. The nal in vivo restoration (Fig. 32) includes all
these characteristics, along with some more-speculative
interpretations. The pathological dorsal vertebra is imagi-
ned to be the result of intraspecic competition, with this
type of injury probably being not uncommon among gre-
garious hadrosaurs (Tanke & Rothschild, 2002, 2014). Ag-
gressive behaviour during territorial disputes or between
rival males was possibly prevented thanks to other forms
of competition. The spectacular crests of many hadrosau-
rs are often explained as having a social or territorial fun-
ction (Hopson, 1975), with visual signals being used even
during vocal communication. In the case of Gryposaurus,
the nasal crest is quite small and completely useless as
a resonating chamber, so these saurolophines may have
compensated for this with brilliant colours and patterns,
as portrayed by us. Nonetheless, their large nasal cavity
might have housed inatable sacs (Hopson, 1975) with
potential vocal capabilities. Only the discovery of more-
complete integumentary fossils will conrm or disprove
these interpretations.
CONCLUSIONS
Specimen MSNM V345 is a large, robust individual of
Gryposaurus notabilis. Our re-examination of all its bones
housed at the MSNM has allowed us to revise previous
estimates on the completeness of the skeleton, which now
reaches 32.68% (39.54% when taking into account the hid-
den cranial bones, and 48.37% when duplicating existing
counterlateral elements). The skull of MSNM V345 is one
of the largest known for Gryposaurus. Our recalculation
of the size of the skeleton, which takes into account the
spaces occupied in vivo by intervertebral and epiphyseal
cartilage, gives us an overall length of 800 cm in a neutral
pose and a height at the hip of 315 cm. The osteology of
the individual shows features related to other G. notabilis
specimens: a dorsoventrally narrow orbit, infratemporal
fenestra twice higher than wide, a well-developed nasal
arch, wide and irregular ventral embayment of the jugal,
a long and narrow quadratojugal, a predentary with nine
large denticles placed asymmetrically, and a tall neural
spine on the second caudal vertebra.
The advanced ontogenetic age of the skeleton – which
likely belonged to a senile individual – is corroborated by
palaeohistological analysis showing the presence of EFSs
and several generations of Haversian systems in a femur,
indicative of a specimen that was fully adult at time of
death.
Finally, this individual was affected by several skele-
tal disorders. The predentary bears a large, central fora-
men located in the caudomedian plane of the bone. The
53
REDESCRIPTION OF A REMARKABLY LARGE GRYPOSAURUS NOTABILIS (DINOSAURIA: HADROSAURIDAE) FROM ALBERTA, CANADA
Fig. 32 - Two large raging bull gryposaurs ght for supremacy of the herd in violent clash on alluvial plains of Canada, 76 million
years ago. Digital painting © by Davide Bonadonna. / Nelle piane alluvionali del Canada, 76 milioni di anni fa, due grossi maschi
bellicosi di griposauro danno vita a un violentissimo scontro per la supremazia all’interno del branco. Illustrazione digitale e © di
Davide Bonadonna.
histology of this anomaly reveals the presence of large
resorption cavities and a randomised pattern of osteo-
cytes, indicators of osteomyelitis. The transverse process
of dorsal vertebra 5 is fused with the proximal region
of the rib, affected by an abnormal overgrowth of bo-
ne tissue. CT-scanning of this vertebra indicates hyper-
trophied osteosclerosis likely consequent to traumatic
fracture. The caudal vertebrae 25 and 26 had their cen-
tra fused together, with that of vertebra 25 broken into
two halves. CT-scanning indicates that this condition
might represent skeletal hyperostosis or haemangioma.
Gryposaurus notabilis is one of the rst hadrosaurs
depicted for the general audience. Nevertheless, it is not
as popular as other duck-billed dinosaurs, such as Edmon-
tosaurus, Parasaurolophus, or Corythosaurus. We have
proposed new skeletal and in vivo restorations using the
anatomical data obtained from our analysis.
Acknowledgements
We are grateful to several people who helped us dur-
ing the analysis of specimen MSNM V345. We want to
thank Dr. Pietro Biondetti (Fondazione IRCCS Ca’ Granda
Ospedale Maggiore Policlinico, Milano) and Olaf Dulfer
(Universität Bonn, Germany) for their technical support,
respectively with CT-scan and histological preparation. We
also thank Ilaria Paola Crippa and Giovanni Longhi (Sie-
mens Milano), and Giovanni Terribile (TSRM, Fondazione
IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Mi-
lano) for CT data analysis. Darren H. Tanke (TMP) gave
precious information about the history of the specimen, as
well as relevant help in the recognition of the manual/pedal
phalanges, pathologies, and the subsequent discussions. Al-
bert Prieto-Márquez (The Field Museum, Chicago) helped
us with the anatomy of hadrosaurs and the recognition of
the Gryposaurus material. Jordan Mallon (CMN) and Ali
Nabavizadeh (Cooper Medical School of Rowan Univer-
sity, New Jersey) are kindly acknowledged for information
about DPF and hadrosaur predentaries, respectively.
Many thanks also to Debora Affer, Fabio Fogliazza and
Lorenzo Magnoni (MSNM) for partial restoration of the
specimen, and to Paolo Arduini, Luigi Cazzaro and Giorgio
Teruzzi (MSNM) for their logistic support during this study.
We want to thank Darren Tanke and David C. Evans
for their revision work, that much improved the quality of
the manuscript. Michele Latronico greatly improved the
English language.
Finally, we thank Marco Auditore for helpful discus-
sion on the vertebrae and for his detailed skeletal recon-
struction of the specimen, and Davide Bonadonna for the
amazing artwork of the battling gryposaurs.
54 FILIPPO BERTOZZO, CRISTIANO DAL SASSO, MATTEO FABBRI, FABIO MANUCCI & SIMONE MAGANUCO
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Matteo Fabbri, Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven (CT), 06511, USA
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Fabio Manucci, Geo-Model di Mauro Scaggiante, via Abbate Tommaso 78, Quarto D’Altino (VE), 30020, Italy
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Simone Maganuco, Museo di Storia Naturale di Milano, Corso Venezia 55, Milan, 20121, Italy;
corresponding author simonemaganuco@iol.it
Redescription of a remarkably large Gryposaurus notabilis (Dinosauria: Hadrosauridae) from Alberta, Canada
Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano
Volume XLIII
