Seazzadactylus venieri gen. et sp. nov.,
a new pterosaur (Diapsida: Pterosauria)
from the Upper Triassic (Norian) of
Fabio Marco Dalla Vecchia
1Research Group of Mesozoic Faunas, Institut Català de Paleontologia Miquel Crusafont (ICP),
Sabadell, Catalonia, Spain
2Museo Friulano di Storia Naturale, Udine, Italy
A new non-monofenestratan pterosaur with multicusped dentition, Seazzadactylus
venieri, is described from the Upper Triassic (middle-upper Norian) of the Carnian
Prealps (northeastern Italy). The holotype of S. venieri preserves a complete
mandibular and maxillary dentition, along with a nearly complete premaxillary one,
showing unique features. Furthermore, the arrangement of the premaxillary teeth
and the shape of jugal, pterygoid, ectopterygoid, scapula and pteroid are unique
within non-monofenestratan pterosaurs. S. venieri is similar and closely related to
Carniadactylus rosenfeldi and Austriadraco dallavecchiai, which are also from the
Alpine middle-upper Norian of Italy and Austria, respectively. In a parsimony-based
phylogenetic analysis, S. venieri is found to nest within a clade of Triassic
pterosaurs composed of Arcticodactylus cromptonellus,Austriadraco dallavecchiai,
Carniadactylus rosenfeldi and a trichotomy of Raeticodactylus ﬁlisurensis,Caviramus
schesaplanensis and MCSNB 8950. This unnamed clade is basal within the
Pterosauria, but is not the basalmost clade. Eudimorphodon ranzii lies outside this
clade and is more derived, making the Eudimorphodontidae paraphyletic. S. venieri
increases the diversity of Triassic pterosaurs and brings the number of pterosaur
genera and species in the Dolomia di Forni Formation to four.
Subjects Evolutionary Studies, Paleontology
Keywords Vertebrate palaeontology, Pterosauria, New taxon, Anatomy, Taxonomy, Phylogeny,
Late Triassic (Norian) pterosaurs are the oldest ones found to date (Dalla Vecchia, 2013).
They are represented by about 30 unequivocal remains, including fragmentary specimens
and single isolated bones and teeth (Dalla Vecchia, 2013,2014). Their record is rather
sparse and each new ﬁnd has therefore an impact upon our understanding of early
pterosaur history and phylogenetic relationships.
Eudimorphodon ranzii from the Upper Triassic of Italy was the ﬁrst valid Triassic
pterosaur species to be named (Zambelli, 1973). It appeared to be characterised by tri- to
pentacuspid maxillary and mandibular teeth. A relatively high number of skeletal remains
How to cite this article Dalla Vecchia FM. 2019. Seazzadactylus venieri gen. et sp. nov., a new pterosaur (Diapsida: Pterosauria) from the
Upper Triassic (Norian) of northeastern Italy. PeerJ 7:e7363 DOI 10.7717/peerj.7363
Submitted 29 March 2019
Accepted 27 June 2019
Published 25 July 2019
Fabio Marco Dalla Vecchia,
Additional Information and
Declarations can be found on
2019 Dalla Vecchia
Creative Commons CC-BY 4.0
from Italy, Austria, Greenland and USA, as well as many isolated teeth from Europe and
North America, have subsequently been referred to this genus, based mainly on the
presence of two to four accessory cusps in the tooth crowns (Dalla Vecchia, 2013,2014).
These specimens were initially referred to E. ranzii (MPUM 6009; Wild, 1979; MCSNB
8950; Wild, 1994; and BSP 1994 I 51; Wellnhofer, 2003), to a new Eudimorphodon species
(MFSN 1797, holotype of E. rosenfeldi (see Dalla Vecchia, 1995) and MGUH VP 3393,
holotype of E. cromptonellus (see Jenkins et al., 2001)), or just to the genus Eudimorphodon
(Clemens, 1980;Hahn, Lepage & Wouters, 1984;Chatterjee, 1986;Murry, 1986;Cuny, 1995;
Cuny, Godefroit & Martin, 1995;Godefroit, 1997;Godefroit & Cuny, 1997;Godefroit
et al., 1998,Dalla Vecchia, 2003,2004a,2004b,2006;Andres, 2006;Andres & Myers, 2013).
However, most of the isolated teeth are probably referable to cynodont therapsids (Andres,
2006;Dalla Vecchia, 2013,2014). Isolated multicusped teeth from Triassic rocks cannot
be unequivocally referred to pterosaurs because of the convergent morphology of the
teeth of some pterosaurs, cynodonts and also tanystropheid archosauromorphs.
Furthermore, the discovery of Caviramus schesaplanensis (see Fröbisch & Fröbisch, 2006)
and Raeticodactylus ﬁlisurensis (see Stecher, 2008) from the Upper Triassic of Switzerland
showed that tri- to pentacuspid teeth occur also in other Triassic pterosaur taxa. As a
consequence, multicusped teeth can no longer be considered a diagnostic feature of
Eudimorphodon.Dalla Vecchia (2009a) referred E. rosenfeldi to a new genus
Carniadactylus as Carniadactylus rosenfeldi.Dalla Vecchia (2009a,2014) also suggested
that the remains of E. cromptonellus, BSP 1994 I 51 and MCSNB 8950, belong to
three distinct taxa that are different from E. ranzii (holotype, MCSNB 2888) because of the
absence of shared apomorphies with the taxon and their morphological differences
from it. Furthermore, MGUH VP 3393, BSP 1994 I 51, MCSNB 8950, MFSN 1797 and
E. ranzii did not form a clade in the phylogenetic analyses of Dalla Vecchia (2009a,2009b).
Eudimorphodon as conceived by Wild (1979,1994),Wellnhofer (2003), and Jenkins
et al. (2001) is also paraphyletic within the phylogenetic analyses of Kellner (2003),
Wang et al. (2009) and Ősi (2010).Kellner (2015) made BSP 1994 I 51 the holotype of
Austriadraco dallavecchiai, and referred E. cromptonellus to the new genus Arcticodactylus
as Arcticodactylus cromptonellus.Kellner (2015) made MPUM 6009 the holotype of
Bergamodactylus wildi but Dalla Vecchia (2018) retained MPUM 6009 in Carniadactylus
Another pterosaur specimen, MFSN 21545 (Figs. 1,2;Fig. S1), was mentioned in
literature (see the list of synonyms below), but it was never described in detail. Initially,
it was provisionally referred to the genus Eudimorphodon because of its ‘eudimorphodontid’
dentition (Dalla Vecchia, 2003,2004a,2004b,2006,2008), but was later considered to
represent a yet unnamed taxon distinct from E. ranzii and Carniadactylus rosenfeldi (see
Dalla Vecchia, 2009a,2010,2012,2013,2014). It was not included in Dalla Vecchia’s (2009a,
2009b) phylogenetic analyses because at the time some skeletal elements of the specimen
were still under preparation.
Here, MFSN 21545 is described in detail and named, and the phylogenetic position of
this new taxon is investigated.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 2/59
Locality and geological setting
According to the discoverer, Mr. Umberto Venier, MFSN 21545 was preserved in a loose
boulder in the bed of the Seazza Brook (Preone Municipality, Friuli Venezia Giulia
Autonomous Region, NE Italy; Fig. S2) at ca. 435 m above the sea level, just upstream of
the angle bend in the ﬁnal tract of the brook before it issues into the Tagliamento River.
The boulder lithology (dark grey laminated dolostone) and the local stratigraphy
(Dalla Vecchia, 2012), as well as geomorphologic and topographic constraints, indicate
that the specimen comes from the lower member of the Dolomia di Forni Formation
Figure 1 Seazzadactylus venieri, MFSN 21545 (holotype). Photograph. Scale bar equals 20 mm. Full-size
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 3/59
(sensu Dalla Vecchia, 1991; see also Dalla Vecchia, 2012), possibly from its lower portion.
The fossiliferous portion of the Dolomia di Forni Formation was dated to the late
middle to late Norian (Alaunian 3-Sevatian) on the basis of its conodont assemblages
(Dalla Vecchia, 2014).
Figure 2 Seazzadactylus venieri, MFSN 21545 (holotype). Drawing. Abbreviations: c, carpus; co, coracoid; cv, cervical vertebra; dI–III, manus
digits I–III; dr, dorsal rib; dv, dorsal vertebra; ecp, ectopterygoid; f, frontal; fe, femur; g, gastralia; h, humerus; hy, ceratobranchial I (hyoid apparatus);
j, jugal; il, ilium; mar, mandibular ramus; mcI–IV, metacarpals I–IV; mt, metatarsal; mx, maxilla; n, nasal; ocp, occiput; pip, puboischiadic plate;
pmx, premaxillae; pmxth, premaxillary teeth; po, postorbital; pp, prepubis; pph, pes phalanges; pt, pteroid; pty, pterygoid; ra, radius; sac, sacrum; sc,
scapula; sq, squamosal; st, sternum; ti, tibiotarsus; u, ulna; wph1–4, wing phalanges 1–4. When it was possible to distinguish between right and left
elements, elements in parentheses are from the left side. Scale bar equals 20 mm.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 4/59
MATERIALS, TERMINOLOGY AND METHODS
MFSN 21545 is the only known specimen of the new taxon here described. It is a disarticulated
partial skeleton preserving skull elements, both mandibular rami with teeth, the ossiﬁed hyoid
elements, part of the cervical, dorsal and sacral vertebral column, most of the pectoral
girdle and forelimbs and part of the pelvic girdles with hind limbs (Figs. 1 and 2).
The term ‘non-monofenestratan pterosaur’is used for all the genera once included
in the Suborder Rhamphorhynchoidea of the traditional Linnean classiﬁcation (see
Wellnhofer, 1978), which is now a paraphyletic group according to multiple phylogenetic
analyses (Kellner, 2003;Unwin, 2003;Dalla Vecchia, 2009a). Enclosure in single
quotation marks in the following part of the text indicates that the validity of the taxon
is doubtful or in need of a formal revision.
Following Dalla Vecchia (2009a),E. ranzii is considered to be represented by the only
holotype (MCSNB 2888) and MPUM 6009 is retained in Carniadactylus rosenfeldi
(according to Dalla Vecchia, 2018 and contra Kellner, 2015). Raeticodactylus ﬁlisurensis is
probably congeneric with Caviramus schesaplanensis (see Dalla Vecchia, 2009a); however,
I followed Dalla Vecchia (2014) in keeping distinct the two taxa, pending their formal
revision hopefully based on further specimens. Specimen MCSNB 8950 (E. ranzii for
Wild, 1994) does not belong to E. ranzii and represents a distinct, still unnamed taxon
according to Dalla Vecchia (2009a,2014); it is used here as a terminal taxon in the
phylogenetic analysis. Specimen MCSNB 2887 (E. ranzii for Wild, 1979) is considered to
belong to an indeterminate pterosaur taxon following Dalla Vecchia (2014); it was used
in the taxonomic comparison but not in the phylogenetic analysis.
The orientation of the forelimb bones is in the ﬂight position and the terminology used
by Bennett (2001) was followed for the orientation of the bones in the space, but ‘cranial’
and ‘caudal’are preferred to ‘anterior’and ‘posterior’. The anatomical terminology for
the skeleton is that of Romer (1956), unless speciﬁed otherwise. The terminology used for
teeth and dentition is in general that suggested by Edmund (1969). The term ‘cusps’
indicates topographically separate elevations along the cutting margins of a tooth crown
that are few in number. A tooth is considered serrated when those elevations (denticles)
are small, of similar sizes, and set close to one other in a row along most of the cutting
margins of the crown. Crenulations are low, blunt, well-spaced and barely distinguishable
elevations along the cutting margins of the crown.
The specimen was studied at the MFSN using a Wild M3 binocular microscope.
Photographs of the individual skeletal elements were sometimes taken in ethanol
immersion to enhance the contrast between the specimen and the matrix. When paired
elements have different lengths, the mean was used in the calculation of the long bone
length ratios. In the drawings of the whole specimen and of details of the specimen,
the rock is shown pale grey, the parts reconstructed in resin are dark grey and the skeletal
elements are white, unless speciﬁed otherwise.
The phylogenetic relationships of Seazzadactylus venieri were investigated using the
data matrix of Britt et al. (2018).Seazzadactylus venieri was added to the version of
this data matrix that is inclusive of MCSNB 8950, and the resulting dataset was then
used to perform parsimony-based phylogenetic analysis by PAUP 4.0b10 for Microsoft
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 5/59
Windows (Swofford, 2002) using the default search parameters plus the instruction
hsearch addseq=random nreps=1000 nchuck=100 chuckscore=1 for the heuristic search.
The analysis was subsequently performed also by TNT (Goloboff & Catalano, 2016).
The matrix contains 93 characters; three are ordered and 90 unordered. The total number of
operational taxonomic units is 30 (three outgroup and 27 ingroup). Macrocnemus bassanii,
Postosuchus kirkpatricki and Herrerasaurus ischigualastensis were chosen as outgroup taxa.
Nodal support was calculated by TNT using the Bremer function, replicating the analysis
and saving all trees up to 10 steps longer than the shortest topologies.
The electronic version of this article in portable document format will represent a published
work according to the International Commission on Zoological Nomenclature (ICZN), and
hence the new names contained in the electronic version are effectively published under
that Code from the electronic edition alone. This published work and the nomenclatural acts it
contains have been registered in ZooBank, the online registration system for the ICZN.
The ZooBank Life Science Identiﬁers (LSIDs) can be resolved and the associated information
viewed through any standard web browser by appending the LSID to the preﬁx
http://zoobank.org/. The LSID for this publication is: urn:lsid:zoobank.org:pub:5F0C4B84-
F39D-436F-93FD-858B323C6A15. The online version of this work is archived and available
from the following digital repositories: PeerJ, PubMed Central and CLOCKSS.
Reptilia Laurenti, 1768 sensu Modesto & Anderson (2004)
Diapsida Osborn, 1903
Pterosauria Kaup, 1834
Seazzadactylus venieri gen. et sp. nov.
(Figs. 1–6,7A,7B,8,9A,9B,10A–10D,11–22,23A and 23B)
2000 a partial skeleton still to be prepared: Dalla Vecchia, p. 229.
2003 Eudimorphodon: Dalla Vecchia, p. 25.
2004a Eudimorphodon: Dalla Vecchia, p. 48, ﬁgs 1 and 5E.
2004b Eudimorphodon: Dalla Vecchia, p. 19, ﬁg. 14.
2006 Eudimorphodon sp.: Dalla Vecchia, p. 436, ﬁg. 12 left.
2006 Eudimorphodon: Fröbisch & Fröbisch, p. 1087.
2008 Eudimorphodon: Dalla Vecchia, p. 185, ﬁg. 182.
2009a neither Eudimorphodon ranzii nor Carniadactylus rosenfeldi: Dalla Vecchia, p. 164.
2010 a distinct taxon (with respect to Eudimorphodon): Dalla Vecchia, p. 183.
2012 una specie distinta da Carniadactylus rosenfeldi: Dalla Vecchia, p. 185, ﬁg. 8.141.
2013 probably (it) represents a new genus and species: Dalla Vecchia, p. 133.
2014 Genere e specie senza nome: Dalla Vecchia, p. 227, ﬁg. 4.1.164.
2015 a new and still unnamed taxon: Dalla Vecchia and Cau, p. 685, ﬁg. 2H.
2018 a still unnamed taxon with multicusped teeth: Dalla Vecchia, p. 333.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 6/59
Zoobank. urn:lsid:zoobank.org:act:1B567D5D-E9BC-41A0-BA73-04A29F496989; urn:
Etymology. ‘Seazza’after Seazza Brook where the holotype was found and ‘dactylus’, from
Greek ‘daktylos’for ‘digit’. The speciﬁc name pays hommage to Umberto Venier, who
found the specimen.
Holotype. MFSN 21545, disarticulated but associated partial skeleton including skull and
mandible elements (Figs. 1 and 2).
Locality and Stratigraphic horizon. Seazza Brook, Preone municipality, Friuli Venezia
Giulia Autonomous Region, Italy; Dolomia di Forni Formation (Alaunian 3- Sevatian,
Diagnosis. Non-monofenestratan pterosaur with multicusped dentition and the following
apomorphic features: teeth restricted to the rostral half of the body of the premaxilla;
deep maxillary process of jugal that tapers to a needle-like point ventrodistally; large
foramen in the middle of the jugal body; pterygoid with rostral ramus bent 90
laterally; ectopterygoid caudal to the pterygoid and with recurved lateral (jugal) and caudal
processes; multicusped dentition in the dentary and maxilla that includes hexa- and
heptacuspid crowns and no fully grown tricuspid teeth; recurved maxillary crowns 1–3
with curvature decreasing from tooth 1 to 3; ﬂared and fan-like scapular blade; small and
slender exclamation-mark-shaped pteroid.
Most of the skeleton was preserved in the slab, but the caudal segment of the vertebral
column is missing and only very small portions of the feet are present (Figs. 1 and 2).
The most disarticulated part of the skeleton is the vertebral column. The skull is
disarticulated, but its elements are closely associated, as are the mandibular rami that
are paired and still parallel to one other. The scapulocoracoids are also close and
parallel to one other. The bones of the right forelimb are articulated at least up to the wing
phalanx 2, whereas the nearly complete left forelimb is slightly disarticulated. Tibiotarsi
and femora of both hind limbs are closely associated and parallel to one other. The feet
are completely disarticulated and no metatarsals and metatarsal-like phalanges are
preserved. Before burial, the carcass probably macerated on a low-energy sea bottom
without signiﬁcative water currents, which prevented bone dispersal.
Comparison with other pterosaur taxa is employed here when it is necessary for the
identiﬁcation of the elements of MFSN 21545; comparison for systematic purposes is
reported in the Discussion section.
Many skull elements are preserved and can, because of their disarticulated state, be
observed in aspects not visible in articulated skulls (Fig. 3). Unfortunately, a wide fracture
crosses the caudal part of the skull and some bones, mainly those of the skull roof, were
either lost or incompletely preserved.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 7/59
Premaxillae. The premaxillae (Fig. 4) are fused but their suture is still evident. Both dorsal
and lateral sides of the right premaxilla are exposed, whereas only the dorsal portion
of the left one is visible. As exposed, the premaxillae are very narrow and long (18.2 mm
Figure 3 Seazzadactylus venieri, MFSN 21545 (holotype), skull and mandible. (A) Photograph;
(B) drawing. The postorbital is the only skull bone that is partially outside of the photograph, extending
further downwards from the lower left corner. Black dashed lines mark the broken margins of the bones
where they can be identiﬁed as such; brown dashed lines mark the reconstructed margin of the bones.
Abbreviations: bpt, basipterygoid process; cr, cervical rib; cv, cervical vertebra; ecp, ectopterygoid; ept,
epipterygoid; f, frontal; fe, femur; fo, foramen; h, humerus; hy, ceratobranchial I (hyoid apparatus);
j, jugal; mar, mandibular ramus; mx, maxilla; n, nasal; ocp, occiput; pmx, premaxilla; pmxth, premaxillary
teeth; po, postorbital; pty, pterygoid; q, quadrate; sq, squamosal; u, ulna; wph2, wing phalanx 2. Elements
in parentheses are from the left side. Scale bar equals 50 mm.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 8/59
long [excluding the apical tooth] and six mm maximum width) and slightly taper
rostrally. They are broken anterior to the rostral margin of the external naris. The rostral
tip of the joint premaxillae is blunt. The premaxillary body is low in lateral view. The ﬁrst
tooth of the left premaxilla is still in situ and points forwards, whereas four teeth have
dropped out of their alveoli. Only two large distal alveoli are fully exposed along the ventral
margin of the right premaxilla, because two displaced teeth conceal the mesial alveoli.
Teeth occur only in the rostral half of the premaxillary body.
Maxillae. Both maxillae (Fig. 5) show their lateral side, due to the upside-down ﬂipping of
the left maxilla. The left maxilla is complete and is 33.2 mm long. The premaxillary process
of the right maxilla is rostrally damaged by a fracture and its rostral end is covered by
matrix and the displaced left maxillary tooth 8. The maxilla is a triradiate element
with slender processes that taper distally to a point. The jugal process is the longest,
Figure 4 Seazzadactylus venieri, MFSN 21545 (holotype), premaxillae. (A) Premaxillae in right
dorsolateral view, with four premaxillary teeth displaced from their alveoli; (B) drawing. The broken
margins of the bones are marked by dashed lines. Abbreviations: al, alveolus; dcp, dorsocaudal (frontal)
process; mdl, midline (suture between the two premaxillae); mx, maxilla; pmx, premaxilla (body); pmxth,
premaxillary tooth. Elements in parentheses are from the left side. Scale bar equals ﬁve mm.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 9/59
whereas the premaxillary and the ascending processes are of about the same length
(the premaxillary process is 55% of the length of the jugal process). The ascending process
slopes caudally at 145and is slightly arched. It tapers apically to a narrow point and is
relatively short; apically, it has a long articular surface along the caudal side, like that
for the lacrimal in the reconstruction of the skull of Scaphognathus crassirostris by
Wellnhofer (1975b,ﬁg. 34a). A short and deep longitudinal groove on the lateral side of
the expanded base of the ascending process (Fig. 5) probably corresponds to the large
neurovascular foramen observed there in the maxilla of Preondactylus buffarinii and
Caelestiventus hanseni (see Britt et al., 2018). There is no trace of a maxillary contribution
to an antorbital fossa. The premaxillary process has a triangular and distally tapering
outline in lateral view. The dorsal margin of the premaxillary process is not straight but
slightly angled midway where a slit-like articular facet for the maxillary process of the
premaxilla starts. Therefore, the maxillary process of the premaxilla bordered the external
naris rostroventrally. The jugal process is lower than the premaxillary process; it tapers
distally, but tapering is minimal in the proximal segment and increases in correspondence
of a change in inclination of the dorsal margin (the ‘step’in Fig. 5). The segment caudal to
this change in inclination is the portion that articulated with the jugal.
The left maxilla preserves 11 teeth in situ. The ﬁrst tooth is missing, probably because of
the damage to the tip of the premaxillary process; tooth 8 slipped out of its alveolus
and covers the tip of the premaxillary process of the right maxilla; tooth 13 is represented
by an empty alveolus. Therefore, this maxilla has 14 tooth positions. The right maxilla
has 14 teeth in situ. Comparison with the left maxilla suggests that the ﬁrst tooth of the
series is tooth 1.
Nasal. An elongate (22 mm long), ﬂat and thin bone is preserved between the maxillae and
the mandibular rami (Fig. 3). Because of its position and morphology, it is tentatively
identiﬁed as a nasal. Its rostral extremity tapers to a premaxillary process bounding
dorsally a rostral notch corresponding to the dorsocaudal margin of the external naris.
Figure 5 Seazzadactylus venieri, MFSN 21545 (holotype), maxillae. Photograph. Abbreviations: ap,
ascending process; dcaf, dorsocaudal articular facet on the ascending process; fo, neurovascular foramen;
jp, jugal process; mth, maxillary tooth; mx, maxilla; pmxf, facet for the maxillary process of premaxilla;
pmxp, premaxillary process. Elements and processes in parentheses are from the left side. Scale bar equals
10 mm. Full-size
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 10/59
The maxillary process is overlapped and concealed by the right mandibular ramus and its
dentition. The body of the nasal is straight and its dorsal margin is rectilinear. Its caudal
end appears to be squared, but the caudoventral corner is concealed by other bones.
Its ventral or ventrolateral margin is irregular and probably not the actual margin of the
element but an artefact of preparation on a rather thin bone. As for its shape, size and
position, the element could only be alternatively identiﬁed as a palatine. However, if it were
the palatine, the notch corresponding to the choana should be situated caudally (see
Ősi et al., 2010,ﬁgs. 1-2). This would imply an unlikely 180rotation of the bone. The
identiﬁcation as a detached and drifted palatal plate of a maxilla (Ősi et al., 2010,ﬁg. 8)
seems also to be unlikely.
Frontal. A large fragment of a broad bone preserved dorsal to the occiput is tentatively
identiﬁed as part of a frontal or of the fused frontals (Fig. 3). It does not show any crests or
ridges and gives no information about the morphology of the frontals.
Postorbital. The postorbital is a triradiate (Y-shaped; Fig. 6A) and a very slender element.
It closely resembles the postorbitals of Carniadactylus rosenfeldi (MPUM 6009) and
Austriadraco dallavecchiai (see Dalla Vecchia, 2018,ﬁg. 3A-B), but it is even more gracile.
Its length from the distal extremity of the jugal ramus to the extremity of the exposed
portion of the frontal ramus is 10.5 mm. Only the proximal part of the squamosal ramus is
Figure 6 Seazzadactylus venieri, MFSN 21545 (holotype), postorbital and jugal. (A) Postorbital;
(B) right jugal, lateral view; (C) drawing of (B). Photographs were taken under ethanol immersion.
Abbreviations: afj, articular facet for the jugal; aofm, antorbital fenestra margin on the jugal; fo, foramen;
fra, frontal ramus of postorbital; jra, jugal ramus of postorbital; la, lacrimal; lap, lacrimal process of jugal;
mxp, maxillary process of jugal; no, notch; pop, postorbital process of jugal; qjp, quadratojugal process of
jugal; rd, ridge; sqra, squamosal ramus of postorbital; tm, thickened margin. Scale bar equals ﬁve mm.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 11/59
visible because the rest is covered by the left humerus. The slender frontal ramus is slightly
curved with a rostroventral concavity; its distal end is covered by a cervical vertebra
and the right tibia. The exposed portions of the squamosal and frontal rami form an angle
of about 85. This indicates that the upper temporal fenestra had a relatively acute
ventrolateral margin (this angle is about 70in Carniadactylus rosenfeldi and about 80in
Austriadraco dallavecchiai, but these values are based on more complete squamosal rami;
Dalla Vecchia, 2018). The long and very slender jugal ramus is curved with rostral
concavity and tapers distally where there is a caudoventral facet for the articulation with
the postorbital process of the jugal. Frontal and jugal rami border the caudal part of
the broad orbit; their curvature and length, united to those of the postorbital process
of the jugal, suggest the presence of a circular and very large orbit.
Jugal. The right jugal is exposed in lateral view (Figs. 6B and 6C) and is tetraradiate as in
many other basal pterosaurs (Wellnhofer, 1978,2003;Dalla Vecchia, 2014). It is not
fused with the maxilla, postorbital and quadratojugal. Its length is 17 mm from the caudal
extremity of the quadratojugal process to the rostral end of the maxillary process.
The postorbital process is much longer than the other processes; it is slender and tapers
distally. Although the distal termination of this process is broken and is not preserved,
its maximum length can be estimated based on the convergence of its cranial and caudal
margins and comparison with the jugal process of the postorbital (see Fig. 7A). The
postorbital process is nearly straight and caudally inclined at about 130with respect to the
axis of the jugal body. Its orbital margin is thickened. The maxillary process is ventrally
deﬂected at about 20with respect to the axis of the jugal body. It is deep proximally
where it contributes to the caudal end of the ventral margin of the antorbital fenestra
and tapers to a needle-like point distally. A very small notch is present along the ventral
margin. The lacrimal process is rostrodorsally directed and forms an angle of about
35with the axis of the jugal body. This process is very short, appearing as a triangular
spur. It is partially overlapped dorsally by a rod-like bone. Comparison with E. ranzii
(see Wild, 1979,ﬁg. 1), Carniadactylus rosenfeldi (see Dalla Vecchia, 2018,ﬁg. 2) and
Raeticodactylus ﬁlisurensis (see Stecher, 2008,ﬁg. 6) suggests that this latter element is part
of the damaged lacrimal. This suggests also that the short lacrimal process might be
incomplete and was longer originally, but its relatively narrow base and tapering margins
indicate that it could not be much longer than preserved. A short, triangular process of the
jugal is damaged distally and forms the ventral margin of the lower temporal fenestra.
This process is clearly separated from a ventral strip of bone by a gap, but the gap becomes
a ridge parallel to the ventral margin of the jugal rostrally (Figs. 6B and 6C). Comparison
with the 3D-ct scans of the jugal of Caelestiventus hanseni (see Britt et al., 2018,ﬁg. 3)
suggests that this strip of bone in MFSN 21545 belongs to the thin ventral part of the jugal
and is not the quadratojugal. The strip is broken and partly detached in MFSN 21545
because of the crushing of the jugal on other bones. Consequently, the quadratojugal
process of the jugal is made of the triangular process forming the ventral margin of the
lower temporal fenestra plus the caudal portion of the detached strip of bone and is
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The jugal body is rectangular in lateromedial view and is slightly constricted
dorsoventrally in the middle. The orbital margin is thickened. A large elliptical foramen
pierces the bone at the point of minimum depth.
Cranial fenestrae. The shape of the cranial openings can be reconstructed by
returning the preserved skull elements to their original position. The articulation
between the jugal and maxilla appears to differ among non-monofenestratan pterosaurs.
Figure 7 Seazzadactylus venieri, MFSN 21545 (holotype), assembly of skull bones and skull
reconstruction. (A) assembly of the jugal, maxilla, postorbital and presumed nasal with the jugal and
maxilla articulated to obtain a continuous ventral margin of the antorbital fenestra, but concealing the
last two maxillary teeth; (B) tentative skull reconstruction (the preserved bones are in grey colour);
(C); the jugal of the holotype of Austriadraco dallavecchiai (mirrored), for comparison. In (A), the right
jugal and maxilla are used in the assembly of the bones; the postorbital may be the right in lateral view or
the left in medial view; the presumed nasal may be the left or the right. In (A), the incompletely exposed
rostral end of the premaxillary process of the right maxilla was integrated with the rostral end of the
premaxillary process of the left maxilla (colour of the part from the left maxilla is darker to show this
integration). In (A), the ventral margin of the presumed nasal is irregular because it is covered by the right
mandibular ramus in the specimen. Abbreviations: af, articular facet; aof, antorbital fenestra; en, external
naris; j, jugal; la, lacrimal; lap, lacrimal process of the jugal; ltf, lower temporal fenestra; mx, maxilla; mxp,
maxillary process of the jugal; na, nasal; or, orbit; po, postorbital; pop, postorbital process of the jugal;
qjp, quadratojugal process of the jugal; utf, upper temporal fenestra. Scale bar is 10 mm in (A) and
ﬁve mm in (C). Full-size
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In Dimorphodon macronyx (see Sangster, 2003,ﬁg. 2.9) and Caelestiventus hanseni
(F.M. Dalla Vecchia, 2018, personal observation) the jugal overlaps the jugal process of
the maxilla laterally, whereas it overlaps the jugal process of the maxilla dorsally in
E. ranzii (see Wild, 1979,ﬁg. 1) and Carniadactylus rosenfeldi (see Dalla Vecchia, 2018,
ﬁg. 2). When the jugal and maxilla of MFSN 21545 are returned to their articular
position with the jugal that overlaps the jugal process of the maxilla dorsally (Fig. S3A),
the last two maxillary teeth lie below the jugal and the resulting antorbital fenestra is very
long and has a ‘step’in its ventral margin that is not observed in any other pterosaur.
When the jugal and maxilla are returned to their articular positions with the jugal being
overlapped medially by the jugal process of the maxilla, the overlap ends rostrally
where the change in inclination of the dorsal margin of the jugal process of the maxilla
occurs (the ‘step’in Fig. 5), as suggested by analogy with the maxillojugal of
Caelestiventus hanseni (F.M. Dalla Vecchia, 2018, personal observation). However, two
options exist. In the ﬁrst, the last three maxillary teeth lie below the maxillary process of
the jugal and are not covered labially by it, but the ventral margin of the antorbital
fenestra possesses an unusual ‘step’similar to that obtained by the dorsoventral overlap
(Fig. S3B). In the second option, the jugal and maxilla overlap to form a ‘smooth’(i.e.
‘step’-free) ventral margin of the antorbital fenestra (as is the case in other pterosaurs;
see Raeticodactylus ﬁlisurensis in Fig. S4), the maxillary process of the jugal entirely
covers the last tooth and partly also the penultimate tooth (Fig. 7A). This articulation
between jugal and maxilla resembles that of Dimorphodon macronyx butthepointofthe
maxillary process occurs ventrally in Seazzadactylus venieri instead of dorsally (cf.
Sangster, 2003,ﬁg. 2.9). The labial overlapping of the last two maxillary teeth could be a
consequence of the crushing and ﬂattening of the rostroventral margin of the jugal. This
second option is chosen here in the assembly of the jugal, maxilla, postorbital and
presumed nasal (Fig. 7A), and in the skull reconstruction (Fig. 7B). With this
articulation, the axis of the jugal is oriented dorsocranially-ventrocaudally and the
ventral margin of the skull at the articulation with the mandible is curved down caudally.
In the assembly, the jugal, maxilla, and postorbital articulate smoothly (Fig. 7A), but the
placement of the presumed nasal is somewhat problematic. The bone appears to be of
excessive size for a nasal, but it is now ﬂattened, whereas it was dorsolaterally arched
in vivo and thus would have been less exposed laterally than appears in Fig. 7A.
Caudally, the nasal probably overlapped the frontal and extended over the orbit as in other
pterosaurs. However, its exact position cannot be established because the rostroventral
(maxillary) process is concealed by the right mandibular ramus. How it articulated
with the maxilla is therefore unknown. The ascending process of the maxilla possesses
a caudal articular facet along its apical part. This facet likely received the lacrimal as in
the reconstructions of the skulls of E. ranzii,Carniadactylus rosenfeldi,Raeticodactylus
ﬁlisurensis,Campylognathoides liasicus,Dorygnathus banthensis and Scaphognathus
crassirostris (Wellnhofer, 1978;Sangster, 2003). The rostroventral process of the nasal
articulates dorsally with the ascending process of the maxilla in the reconstructions
of these taxa and in those of Rhamphorhynchus muensteri and Angustinaripterus
longicephalus (see Sangster, 2003). In the tentative reconstruction of the skull (Fig. 7B),
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the presumed nasal of MFSN 21545 is placed in a rostral position based on this dorsal
articulation of the nasal with the maxilla. The original slope of the nasal is unknown,
as also are the length and orientation of the caudal processes of the premaxilla.
Consequently, the reconstructed shape and size of the external naris are tentative.
Although most of the lacrimal is not preserved, the inclination of the lacrimal process of
the jugal and the ascending process of the maxilla show that the antorbital fenestra was
large and shaped like an isosceles triangle (Figs. 7A and 7B), more similar to the large
and oval antorbital fenestra of Raeticodactylus ﬁlisurensis (see Stecher, 2008;Fig. S4),
than the smaller and D-like antorbital fenestra of E. ranzii (see Wild, 1979). The orbit is
very large and sub-circular; as in many other basal pterosaurs, it is the largest skull
opening. The shape of the lower temporal fenestra cannot be known exactly because the
quadratojugal is not preserved, but the lengths of the postorbital process of the jugal and of
the jugal process of the postorbital indicate that it was very long caudodorsally to
rostroventrally and probably rather narrow. The lateroventral margin of the upper
temporal fenestra is V-shaped as in Carniadactylus rosenfeldi,Austriadraco dallavecchiai
and Campylognathoides liasicus. As in the reconstructions of the skull of Carniadactylus
rosenfeldi by Wild (1979,ﬁg. 2), the upper temporal fenestra had probably the outline
of an inverted tear-drop.
Squamosal. Part of the left squamosal appears still to be connected to the left side of the
occiput, but is intensely deformed and broken because of strong crushing. A large fragment
lateral to the left paroccipital process bears a shallow and rimmed, elliptical socket that
is 1.25 mm long, which corresponds in size with the proximal articular head of the
Figure 8 Seazzadactylus venieri, MFSN 21545 (holotype), pterygoid and ectopterygoid. (A) Right pterygoid and ectopterygoid in palatal view;
(B) drawing of (A); (C) left pterygoid and ectopterygoid. Abbreviations: cpect, caudal (pterygoid) process of the ectopterygoid; ect, ectopterygoid;
lpect, lateral (jugal) process of the ectopterygoid; pty, pterygoid; qrpty, quadrate ramus of the pterygoid; rd, ridge; rrpty, rostral ramus of the
pterygoid; ss, sutural surface. Scale bar equals ﬁve mm in (B) and three mm in (C). Full-size
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quadrate. This socket could be the cotyle for the quadrate. A rounded bone with a pointed
process, located close to the left wing phalanges 2 and 3 (Fig. 3), could be a disarticulated,
displaced and strongly crushed right squamosal. Identiﬁcation is based on the size and
shape of the element, in particular the shape of its process, which resembles the squamosal
descending ﬂange that overlaps the caudal or caudolateral surface of the quadrate in
Carniadactylus rosenfeldi (see Wild, 1979,ﬁg. 2), Dorygnathus banthensis (see Padian,
2008a,ﬁgs. 6 and 16), Campylognathoides liasicus (see Wellnhofer, 1974,ﬁg. 2; Padian,
2008b,ﬁgs. 4 and 6), Scaphognathus crassirostris (see Wellnhofer, 1975b,ﬁgs. 33 and 34a)
and in many other pterosaurs (e.g. Wellnhofer, 1978,ﬁgs. 2, 4 and 5; Codorniú, Paulina-
Carabajal & Gianechini, 2016,ﬁgs. 1D and 8).
Pterygoid and ectopterygoid. A skeletal element with four slender and pointed processes
(Figs. 8A and 8B) is preserved isolated just dorsal to the right maxilla and the right jugal.
Assuming that the element retains its anatomical orientation, its caudal portion bears two
paired, recurved, and caudally directed processes at its caudal end and a third, straight and
caudolaterally or caudomedially directed process in a more rostral position. The outer
margin of this third process is thickened and ridge-like; this ridge extends along the margin
of the rectangular main body of the skeletal element. The fourth and rostral process is
actually a 90bend in the bone and tapers distally. A ridge originating at the proximal part
of the rostral process extends longitudinally along the main body of the bone. A partially
exposed skeletal element with the same recurved caudal processes occurs between the
right jugal and the right mandibular ramus (Fig. 8C). However, the two recurved processes
are differently oriented with respect to their homologues on the other skeletal element,
suggesting that they may belong to a skeletal element that is tightly connected but distinct
from the main body and not fused to it. The possible boundary between these two elements
is indicated in Fig. 8B.
Their position with respect to the maxillae, right jugal and mandibular rami, and their
morphology, suggest that these bones are palatal elements. Because of their position
and size, they are plausibly the pterygoids with the ectopterygoids preserved in dorsal or
palatal view (e.g., Ősi et al., 2010,ﬁg.1 and 8B). They are probably ﬂattened by crushing
and the various processes may lie artiﬁcially in the same plane. Their right-left polarity
cannot be unambiguously established based on their position alone, but the completely
exposed bone is probably the right one in palatal view (see below).
The morphology of these elements is unlike that of the pterygoid-ectopterygoids of
other basal pterosaurs, namely Carniadactylus rosenfeldi (see Dalla Vecchia, 2009a,
ﬁg. 2A); Dorygnathus banthensis (see Ősi et al., 2010,ﬁgs. 2, 6B, and 8B), Campylognathoides
liasicus (see Wellnhofer, 1974,ﬁgs. 2 and 4; Padian, 2008b, pl. 7/ﬁgs 2 and 5, ﬁg. 8),
Cacibupteryx caribensis (see Gasparini, Fernandez & De La Fuente, 2004,ﬁg. 2D),
Scaphognathus crassirostris (see Wellnhofer, 1975b,ﬁgs. 33a and 34b; Bennett, 2014,ﬁg. 5B)
and Rhamphorhynchus muensteri (see Wellnhofer, 1975a,ﬁg. 3d; Ősi et al., 2010,ﬁgs. 1C-D
and 9A). The partially exposed pterygoid of Dimorphodon macronyx also appears to
be different from that of MFSN 21545 (Sangster, 2003,ﬁg. 2.9). Particularly, the
ectopterygoids of those pterosaurs occur in a rostral position with respect to the pterygoid.
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None of these other taxa has a rostral process that is bent at 90. The paired recurved
processes of the ectopterygoid resemble those of the ectopterygoid of the theropod
dinosaur Allosaurus fragilis (see Madsen, 1976, pls. 2B and 10D) in respect of their overall
morphology and their position relative to that of the pterygoid, although the ectopterygoid
of this dinosaur is proportionally larger than that of MFSN 21545. The pterygoid of
Allosaurus fragilis is straight in palatal view (Madsen, 1976, pls. 2B) unlike that of MFSN
21545. The pterygoid-ectopterygoid of the basal pterosaur Sordes pilosus (the paratype
PIN 2470 1B, F.M. Dalla Vecchia, 2018, personal observation on photographs) differs from
those of other pterosaurs reported in literature and may be like that of MFSN 21545,
including in regard to the 90bending of the rostral process of the pterygoid.
Unfortunately, the palate of Sordes pilosus was never described and ﬁgured in detail.
The tentative identiﬁcation of the processes of the pterygoid-ectopterygoid of MFSN
21545 in Fig. 8 is essentially based on the pterygoid-ectopterygoid of Allosaurus fragilis.
The longer and more slender of the two recurved processes of the ectopterygoid has a long
facet that could represent its sutural facet with the jugal (Figs. 8A and 8B), and can
therefore be interpreted as the jugal process, which was originally directed laterally and
forming the rostral margin of the subtemporal fenestra and the caudal margin of the
suborbital fenestra. Consequently, the other recurved process is the caudal process of the
ectopterygoid, which overlapped the pterygoid laterally in Allosaurus fragilis (Madsen,
1976, pl. 2); if so, the ectopterygoid would be somewhat displaced from its anatomical
articulation with the pterygoid. The rostral process of the pterygoid would be a
laterally bent palatine ramus, whereas the straight caudal process would be the
Two thin and paired bones occurring between the two pterygoids and partly overlapped
by the jugal process of the right maxilla (Fig. 3) may be tentatively identiﬁed as the
Quadrate. The left quadrate is exposed in caudomedial view. It is slightly shifted
craniomedially from its anatomical position and overlaps the basisphenoid (Figs. 9A
and 9B). The right quadrate is partly preserved and is rotated 90counter-clockwise in the
plane of the occiput from its anatomical position. In caudomedial view, the quadrate is
dorsoventrally elongate and strap-like as in other non-pterodactyloid pterosaurs.
The proximal portion tapers to a small and rounded articular condyle. The shaft has a
straight and thickened lateral margin. The thin and broad medial lamella is partly
preserved in the left quadrate. The distal portion with the mandibular condyle and the
pterygoid ramus is covered or poorly preserved in both elements.
Braincase. The trapezoidal occiput is exposed in caudal view (Figs. 9A and 9B). Unlike the
remaining part of the skull, it is not disarticulated, suggesting that the bones forming it
were ﬁrmly connected. The exposure and overall morphology of this part of the skull
resemble those of the holotype of Carniadactylus rosenfeldi (see Dalla Vecchia, 2009a,
ﬁg. 2A). The occipital condyle is 2.35 mm wide and 1.8 mm high, kidney-shaped
and convex. It is comparatively larger with respect to the condyles in pterodactyloids, which
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Figure 9 Seazzadactylus venieri, MFSN 21545 (holotype), occiput and basicranium in caudal view
and comparison. (A) MFSN 21545 (photograph taken under ethanol immersion); (B) MFSN 21545,
drawing; (C) holotype of Austriadraco dallavecchiai (BSP 1994 I 51); (D) Dorygnathus banthensis (SMNS
50164). The broken margins of the bones (where they can be identiﬁed as such) are marked by dashed
lines. Abbreviations: aic, atlas intercentrum; bbf, basioccipital-basisphenoid fossa; bo, basioccipital; bpt,
basipterygoid processes of the basisphenoid; bs, basisphenoid; bt, basal tuber; ct, crista tuberalis; dld,
dorsolateral depression; eo, exoccipital; fe, femur; fm, foramen magnum; fr, frontal; h, humerus; hy,
ceratobranchial I (hyoid apparatus); mar, mandibular ramus; oc, occipital condyle; pa, parietal; pcr,
paracondylar recess; pp, paroccipital process; ptf, posttemporal fenestra (closed); q, quadrate; qc, cotyle
for the quadrate on the squamosal; so, supraoccipital, sq, squamosal; ti, tibiotarsus; vmd, ventromedial
depression. Elements in parentheses are from the left side (when it was possible to distinguish between
right and left elements). Scale bar equals three mm in (A) and (C), 10 mm in (D).
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have occipital condyles with a rounded outline (e.g., Wellnhofer, 1985,ﬁg. 34; Bennett, 2001,
ﬁgs. 8-9). There are no visible sutures between the condyle and the basioccipital and
between the condyle and the exoccipitals, with the result that the contributions of these
bones to the condyle are unclear. The foramen magnum can be identiﬁed above the occipital
condyle, but its size and outline are affected by crushing. The foramen magnum is bordered
dorsally and laterally by the supraoccipital, which is strongly crushed, and its margins
cannot be identiﬁed with conﬁdence. Portions of the left squamosal and parietals are
probably present (Figs. 9A and 9B), but they are strongly crushed and their outlines are
unclear. The paroccipital processes project lateral to the occipital condyle, expanding at their
lateral extremities. The dorsoventrally narrow portions of the processes that border the
foramen magnum ventrally are probably formed by the exoccipitals as in other pterosaurs
(e.g. Rhamphorhynchus muensteri,Wellnhofer, 1975a,ﬁg. 4a; Padian, 1984,ﬁg. 2), but
sutures between the exoccipitals and opisthotics cannot be identiﬁed.
The posttemporal fenestrae, which are present in all pterosaurs (e.g., Wellnhofer, 1975a,
ﬁg. 4a; Wellnhofer, 1985,ﬁg. 34; Kellner & Tomida, 2000,ﬁg. 9; Bennett, 2001,ﬁg. 9;
Codorniú et al., 2016,ﬁg. 1c) cannot be identiﬁed dorsal to the paroccipital processes of
MFSN 21545, but they might have been closed by the strong compression and crushing
that affected the skull. The foramina for the caudal middle cerebral vein, which are
reported in Allkaruen koi (see Codorniú et al., 2016,ﬁg. 1c) and Rhamphorhynchus
muensteri (see Wellnhofer, 1975a,ﬁg. 4a) cannot be identiﬁed in Seazzadactylus venieri.
The basioccipital is hourglass-shaped, very narrow transversely, and much expanded at
its ventral boundary with the basisphenoid. The basioccipital and basisphenoid are
fused to one another without an apparent suture. The left basal tuber is more developed
than the right one, but it is less robust than the basal tubera of Allkaruen koi (see Codorniú
et al., 2016,ﬁg. 1c). Like the holotype of Carniadactylus rosenfeldi, MFSN 21545 has
large D-shaped to drop-shaped depressions that are each bordered by the basioccipital
medially, the basisphenoid ventrally and the paroccipital processes dorsally (Figs. 9A
and 9B). Each depression is bordered laterally by a thin crista tuberalis, which is possibly
the ventral ramus of the opisthotic fused to the basal tubera (Gower & Weber, 1998).
Plausibly, those depressions were originally deeper rostrocaudally in both specimens
before the strong crushing of the skulls and contained one or more foramina that were
closed and concealed by crushing. Dalla Vecchia (2009a,ﬁg. 2)reported this depression as
the ‘fossa with the vagus foramen’in Carniadactylus rosenfeldi, while it is referred to as
paracondylar recess by Codorniú et al. (2016) in the uncrushed skull of Allkaruen koi,
a term that is adopted here. The paracondylar recess of Allkaruen koi is comparatively
smaller than those of the two Italian taxa and is mostly occupied by a very large foramen
(referred to as the metotic foramen for the exit of nerves IX-XI by Codorniú et al., 2016).
A much smaller foramen occurs at the medial margin of the recess in Allkaruen koi
and is considered to be the foramen for nerve XII (Codorniú et al., 2016,ﬁg. 1c).
Rhamphorhynchus muensteri has an undivided and very large foramen in the paracondylar
recess (Wellnhofer, 1975a,ﬁg. 4a; Padian, 1984,ﬁg. 2B) that can be considered a metotic
foramen (Gower & Weber, 1998). The paracondylar recess of Dorygnathus banthensis
(SMNS 50164; Fig. 9D) is different: it is crossed by a septum that divides it into two large
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and deep depressions. The dorsolateral depression (as preserved, but in the uncrushed
skull was probably somewhat caudolateral) is twice the size of the ventromedial one.
Both depressions plausibly contained foramina and represent a divided metotic foramen.
Therefore, the larger dorsolateral depression may contain the jugular or vagus foramen
transmitting the cranial nerves X, XI (if present), and possibly IX and the jugular
vein, whereas the ventromedial depression may contain the fenestra pseudorotunda
(for the attachment of a secondary tympanic membrane) and possibly the foramen for the
nerve IX (Gower & Weber, 1998).
The paracondylar recess of Carniadactylus rosenfeldi is undivided (Dalla Vecchia,
2009a,ﬁg. 2). The condition of the paracondylar recess of Seazzadactylus venieri is not
immediately clear because the left recess appears to differ from the right one (Figs. 9A
and 9B). No bone septum divides the left recess, while a thick bar of bone crosses the right
recess close to its medial margin. This bar does not appear to be fused with the margins of
the recess, and is thus plausibly part of an underlying bone (the prootic?) emerging
through the recess because of crushing. Therefore, the paracondylar recesses of both
Seazzadactylus venieri and Carniadactylus rosenfeldi probably contained an undivided
The basisphenoid (probably a parabasisphenoid as in most reptiles) and its
basipterygoid processes are ﬂattened in the same vertical plane as the occipital condyle
and the foramen magnum, but were originally directed ventrorostrally (Codorniú et al.,
2016,ﬁg. 1a). As in Dorygnathus banthensis (see Padian, 2008a,ﬁgs. 12 and 17),
Bellobrunnus rothgaengeri (see Hone et al., 2012,ﬁg. 4) and probably Carniadactylus
rosenfeldi (Dalla Vecchia, 2009a,ﬁg. 2A) as well, the basisphenoid is subrectangular, nearly
as broad as long, and with basipterygoid processes projecting at its lateroventral
corners. The proximal part of the basisphenoid near the distal rim of the basioccipital is
concave as in Carniadactylus rosenfeldi (see Dalla Vecchia, 2009a,ﬁg. 2A). This concavity
corresponds to the basioccipital–basisphenoid fossa of Gower & Sennikov (1996).
The basipterygoid processes of the basisphenoid are long, rod-like, and slightly splayed
laterally as in other non-monofenestratan pterosaurs (e.g. Carniadactylus rosenfeldi,Dalla
Vecchia, 2009a,ﬁg. 2A; 2014,ﬁg. 4.1.103; Raeticodactylus ﬁlisurensis,Dalla Vecchia,
2014,ﬁg. 4.1.160; Dorygnathus banthensis,Padian, 2008a, pl. 5/ﬁg. 3, pl. 8/ﬁg. 2, ﬁgs. 12
and ﬁg. 17; and Fig. 9D;Rhamphorhynchus muensteri,Wellnhofer, 1975a,ﬁg. 3d).
Although unreported by Wellnhofer (2003) and Kellner (2015), the holotype of
Austriadraco dallavecchiai also has a partially preserved occiput (Fig. 9C) and
basipterygoid processes of the basisphenoid that are rod-like, elongated and slightly
splayed laterally. This specimen does not show any trace of the cultriform process of the
parasphenoid (reported also as “parasphenoidal rostrum”;Romer, 1956, p. 87) like that
observed in Dorygnathus banthensis (see Padian, 2008a,ﬁg. 12, but apparently absent in
Fig. 9D), Rhamphorhynchus muensteri (see Wellnhofer, 1975a,ﬁg. 3d), Scaphognathus
crassirostris (see Wellnhofer, 1975b,ﬁg. 35), Cacibupteryx caribensis (see Gasparini,
Fernandez & De La Fuente, 2004,ﬁg. 2D) and Bellobrunnus rothgaengeri (see Hone et al.,
2012,ﬁg. 4). This feature cannot be checked in Seazzadactylus venieri because the
basisphenoid is covered distally by the left quadrate; this is also the case in Carniadactylus
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rosenfeldi where most of the basisphenoid is overlapped by a cervical vertebra and the
parasphenoid rostrum—if present—is concealed by the right mandibular ramus (Dalla
Vecchia, 2009a,ﬁg. 2A). Maybe the cultriform process was not fused to the braincase in the
holotype of Austriadraco dallavecchiai and displaced. Alternatively, it might have been
broken or unossiﬁed.
Some elements occurring in the skull region close to the left wing phalanx 2 (Fig. 3)
remain indeterminate, but they may belong to the braincase due to their size, morphology
The two mandibular rami are associated with the skull and lie parallel to one other
(Figs. 10A and 10B). The left ramus was shifted caudally with respect to the right ramus.
The right ramus shows the lateral side and partly covers the left ramus in the middle.
The left ramus is partly damaged by a fracture. The mandibular ramus is slender with a
length/height ratio at mid ramus of 17.8 (length is 53.5 mm and height is only three mm).
Its rostral end is straight and sharply pointed, and the dentaries are not fused at
the symphysis, which was probably very short. The dorsal margin of the ramus is shallowly
concave in lateral view, while the ventral margin is straight. Height is constant along most
of dentary, but the ramus slightly ﬂares by mandibular tooth 4 and tapers rostrally to
tooth 2. An arched longitudinal ridge, which is bordered by narrow ventral and dorsal
grooves, runs along the lateral side of the dentary from tooth 4 to the last tooth. There is
no external mandibular fenestra. Just caudal to the position of the external mandibular
fenestra in Austriadraco dallavecchiai (Figs. 10C–10F), some teeth of the underlying left
mandibular ramus pierced the wall of the right ramus and are exposed. This suggests that the
wall was very thin in that area and could be easily broken, as in the case of Dimorphodon
macronyx (see Bennett, 2015)andCaelestiventus hanseni (see Britt et al., 2018).
The dorsal margin of the ramus between the last tooth and the glenoid for the quadrate
(Figs. 10C and 10D) shows the ‘two-peaked’shape reported by Dalla Vecchia (2009a,
p. 182; see also 2014, p. 82)as a peculiarity of Austriadraco dallavecchiai (Figs. 10E
and 10F). The dorsal margin of the ramus has a small convexity just caudal to the last tooth
which is followed by a straight segment (shallowly concave in the case of Austriadraco
dallavecchiai) and then by a rounded process (the dorsal process of the surangular or
‘coronoid’process). The latter is fractured at its base by crushing, which shows that it is a
mediolaterally thin prominence. The retroarticular process is long and its caudal end is
dorsoventrally expanded, lateromedially ﬂattened and possesses a rounded proﬁle in
lateral view. It is slightly ventrally deﬂected, making with the dentary axis an angle of only
Rod-like bones that lie parallel to one other and to the mandibular rami are the ossiﬁed
ceratobranchials I of the hyoid apparatus. One lies ventral to the mandibular rami in
its natural position, whereas the other is slightly displaced dorsocaudally and lies near the
caudal part of the left mandibular ramus (Fig. 3). They are nearly straight and slightly
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 21/59
expanded at their extremities like those of Carniadactylus rosenfeldi (see Dalla Vecchia,
The dentition of this specimen is the most completely preserved among known Triassic
pterosaurs with multicusped teeth except for that of the holotype of E. ranzii (see Dalla
Vecchia, 2014). It is composed of four premaxillary, 14 maxillary and 21 mandibular
teeth per side.
Premaxillary teeth. Four premaxillary teeth are outside their alveoli but close to the rostral
tip of the premaxillae. Two right alveoli can be identiﬁed, but only one—the last and
Figure 10 Seazzadactylus venieri, MFSN 21545 (holotype), mandible and comparison. (A) Man-
dibular rami of MFSN 21545; (B) drawing of (A) (the right ramus is pale green, whereas the left is dark
green; black dashed lines mark the broken margins of the bones where they can be identiﬁed as such);
(C) particular of the region caudal to the last tooth in the right ramus of MFSN 21545; (D) drawing of (C);
(E) right mandibular ramus of Austriadraco dallavecchiai, holotype (BSP 1994 I 51); (F) particular of the
region posterior to the last tooth in BSP 1994 I 51. Abbreviations: cot, cotyle; emf, external mandibular
fenestra; hy, ceratobranchial I (hyoid apparatus); lrth, teeth of the left mandibular ramus; rap, retro-
articular process; rd, ridge; sandp, dorsal process of the surangular; scclt, small convexity caudal to the last
mandibular tooth; th, teeth; th1–2, ﬁrst and second mandibular teeth. Scale bar equals 10 mm.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 22/59
presumably that of tooth 4—is clearly visible (Fig. 4), whereas the ﬁrst two alveoli are
covered by a shed tooth. The shed teeth may be the right teeth 1–4. The ﬁrst left tooth, still
in situ at the apex of the rostrum, points forwards and its crown is slightly recurved
rostroventrally. It is followed distally by another left tooth still in its alveolus, but pushed
inside the premaxilla by crushing and appearing as a small mound on the dorsal surface of
the bone (Fig. 4); since it occurs at the same distance from the tip of the snout as the
last right alveolus, it is probably the left tooth 4.
The crowns of the shed teeth are similar in shape and size to those of the symphysial
mandibular teeth, but they are slightly more slender. They are unicuspid, conical and
recurved. The crown of left tooth 1 is slightly ﬂattened labiolingually and is recurved with
the concave side facing ventrodistally. The other teeth are shed; thus, their orientation
must be deduced by comparison. Thin, straight and spaced apicobasal enamel ridges
are present only on one side, whereas the rest of the surface is smooth (compare Figs. 11A,
11B and 11C,11D). Crown curvature is seen in teeth showing the smooth side. The labial
side of the ﬁrst two unicuspid mandibular teeth is smooth, whereas the lingual side
has apicobasal enamel ridges. In the unicuspid mandibular teeth 1–3ofRaeticodactylus
ﬁlisurensis, the enamel wrinkles occur only on the lingual side (Stecher, 2008). This suggests
that the side with basoapical enamel ridges of the premaxillary teeth of Seazzadactylus
venieri is the lingual one; consequently, crowns of Figs. 11A and 11B are lingually and
linguodistally recurved, respectively, while those of Figs. 11C and 11D are distally recurved
(if they are all from the right premaxilla). The total basoapical length of the teeth is
4.2–4.5 mm. The ‘root’is only slightly longer than the crown and there is no constriction
between crown and ‘root’. One tooth (Fig. 11D) has an exposed pulp cavity because the side
of the tooth was damaged or it was reabsorbed by a growing replacement tooth.
Figure 11 Seazzadactylus venieri, MFSN 21545 (holotype), premaxillary teeth. (A–B) teeth in lingual
(A) and linguodistal (B) view; (C–D) teeth in labial view (if they are all right teeth). Photographs in (A–C)
were taken under ethanol immersion. Abbreviations: pc, pulp cavity; rd, apicobasal ridges; rt, ‘root’. Scale
bar equals 0.3 mm. Full-size
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Maxillary teeth. Maxillary crowns are exposed in labial view in both maxillae. All crowns
have smooth surfaces. Teeth 8, 10, 14 and possibly tooth 1 on the right maxilla and
teeth 6 and 14 on the left maxilla are not fully erupted. The positions of the left teeth 8
and 13 are represented by empty alveoli, but the displaced tooth 8 is preserved close by
its alveolus. Crowns 3, 5 and 7 are 1.75 mm high and crown 9 is 1.60 mm high; the
penultimate right crown is one mm high like the left crown 12. Maxillary tooth crowns are
slightly larger than mandibular crowns (like Raeticodactylus ﬁlisurensis;Dalla Vecchia,
2014,ﬁg. 4.1.161C); this size difference is more marked in the mesial half of the maxillary
dentition (see Fig. S5). In the right maxilla, crowns 1–7 are basoapically higher than
mesiodistally long, crown 9 is as high as long and the last three crowns are much longer
than high. In the left maxilla, crown 2 is basoapically higher than mesiodistally long,
crowns 5 and 8 are slightly apicobasally higher than mesiodistally long, whereas crowns
9–12 are longer than high. The ﬁrst three crowns are slightly procumbent and slightly
recurved backwards with curvature decreasing from tooth 1 to 3, whereas the following
crowns are upright and straight. Crowns are not contacting one other, but the mesiodistal
spacing between mid-maxilla fully erupted teeth is less than half the mesiodistal length of a
fully erupted crown.
With the possible exception of the ﬁrst tooth (Fig. 12A), crowns are multicusped
(Figs. 12B–12I). The main cusp is triangular in labial view and moderately ﬂattened
labiolingually. The ﬁrst three maxillary crowns differ slightly from the ﬁrst two or three
multicusped mandibular teeth, whereas crowns distal to maxillary tooth 3 have a similar
shape as the mandibular crowns distal to tooth 4 or 5.
In the left maxilla tooth 1 is missing. The crown of the right tooth 1 (Fig. 12A) has an
inﬂated basal part and a distally recurved apical part. It is smaller than the following teeth
and possibly not fully erupted. A very small accessory cusp might be present distally,
but the crown appears to be basically unicuspid and resembles the premaxillary crowns.
The cuspidation pattern of the following teeth is summarised in Fig. 13. Crowns are mainly
pentacuspid with two mesial and two distal accessory cusps (Figs. 12D,12E and 12I),
but there is also a pentacuspid crown with three distal and one mesial accessory cusps
(Fig. 12C), a heptacuspid crown with three mesial and three distal accessory cusps (Fig. 12E),
three hexacuspid crowns with two mesial and three distal accessory cusps (Fig. 12G)and
two tetracuspid crowns with one mesial and two distal accessory cusps (Figs. 12B and
12H). There are no fully erupted tricuspid teeth. Accessory cusps increase in size from the
basal to the apical one. The cuspidation pattern differs in corresponding teeth of the left
and right maxillae (Fig. 13), as it was observed in E. ranzii (see Wild, 1979).
The basal part of the crown has a more or less developed pit in all teeth, which could be
due to basal resorption by the growing replacement tooth, as in some mandibular crowns
(see below), but it was most probably caused by the collapse of its pulp cavity.
The ‘root’is visible only in the displaced left tooth 8: it is tongue-shaped and as deep as
the crown is high.
Details of the individual teeth are reported in SI2.
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Figure 12 Seazzadactylus venieri, MFSN 21545 (holotype), maxillary teeth. (A) Right crown 1;
(B) right crown 2; (C) left crown 2; (D) right crown 3; (E) right crowns 4–5; (F) left tooth 8 (displaced);
(G) right crown 9; (H) right crown 11; and (I) right crowns 12–14. Photographs were taken under ethanol
immersion. Abbreviations: 1–3, accessory cusps along each cutting margin, mcu, main cusp; rt, ‘root’.
Scale bar equals 0.3 mm. Full-size
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Mandibular teeth. The right mandibular ramus exposes its entire dentition (21 teeth) in
labial view (Fig. 14). Teeth 5, 18, 20 and 21 are not fully erupted. The ratio of tooth
number/mandible length is 0.39. The dentition of the left mandibular ramus, exposed in
lingual view, is mostly covered by the right ramus. The ﬁrst left mandibular tooth is
in situ whereas the second is out of its alveolus but close by. Crushing and probably
preparation caused three mid-distal left mandibular crowns (approximately
corresponding to teeth 13–15) to crop out through the right ramus and be partially
visible (Figs. 10C and 10D).
Figure 14 Seazzadactylus venieri, MFSN 21545 (holotype), cuspidation pattern of the mandibular
teeth. Cuspidation pattern in the right mandibular ramus. The upper row of numbers (alternate white
and red numbers) refers to the tooth position, the middle row (black numbers) is the total cusp number
per tooth and the lower row (blue numbers) contains the number of accessory cusps in mesial (right) and
distal (left) cutting margins of each crown. Teeth are described in SI2. Abbreviations: e, erupting tooth
that shows only part of the crown; S, replacement tooth. Scale bar equals 10 mm.
Figure 13 Seazzadactylus venieri, MFSN 21545 (holotype), cuspidation pattern of the maxillary teeth.
The outer row of numbers (alternating white and red numbers) refers to the tooth position, the middle row
(black numbers) is the total cusp number per tooth and the inner row (blue numbers) contains the number
of accessory cusps on the mesial (right) and distal (left) cutting margin of each crown. The left maxilla is
upside-down. Teeth are described in SI2. Abbreviations: e, erupting tooth that shows only part of the crown.
Scale bar equals 10 mm. Full-size
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The ﬁrst two mandibular teeth (Figs. 15A and 15B) have unicuspid, conical and
pointed crowns that are relatively stout and slightly recurved backwards. These crowns are
slightly bulkier than the premaxillary crowns. They are procumbent; the ﬁrst more than
the second. These crowns are not much larger than those of fully grown mid-mesial
multicusped mandibular teeth (they are ca. 2.6 and 2.2 mm basoapically high, respectively,
Figure 15 Seazzadactylus venieri, MFSN 21545, mandibular teeth. (A) Right teeth 1 and 2, labial view;
(B) left crown 1, lingual side with thin apicobasal ridges; (C) right crown 3; (D) right crown 4; (E) right
crown 6; (F) right crown 9; (G) right tooth 11 with the replacement tooth; and (H) right crown 13.
Photographs were taken under ethanol immersion. Abbreviations: 1–3, accessory cusps along each
cutting margin; rd, basoapical ridges; s, replacement tooth. Scale bar equals one mm in (A) and 0.3 mm in
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 27/59
whereas crown 12 is ∼1.5 mm high). The lingual side of the crown (visible in the left teeth)
has thin, straight and spaced basoapical enamel ridges, whereas the labial side is smooth.
A 1.3 mm-long gap separates crown 2 from crown 3. All crowns from crown 3 to
21 are multicusped, with one main central cusp and 1–3 accessory cusps along each mesial
and distal margin (Figs. 14 and 15C–15H). All multicusped crowns have smooth surfaces.
Crowns are conical and slightly labiolingually compressed, with an upright main cusp
and basally-positioned accessory cusps. Cuspidation pattern is summarised in Fig. 14.
Crowns are mainly pentacuspid with two mesial and two distal accessory cusps
(Figs. 15E–15G), but tooth 3 has a heptacuspid crown with three mesial and three distal
accessory cusps (Fig. 15C), tooth 13 has a hexacuspid crown with two mesial and three
distal accessory cusps (Fig. 15H), teeth 4 and 19 have tetracuspid crowns with two mesial
and one distal accessory cusps (Fig. 15D) and tooth 14 may have a tetracuspid crown
with one mesial and two distal accessory cusps. The overall shape of crowns 3–4 is unlike
that of the following crowns. Crowns 3–4 have small accessory cusps, whereas these cusps
are larger in tooth 6 and following teeth and the apical accessory cusps are larger than the
basal accessory cusps (Figs. 15C–15H). The main cusps are more ﬂattened labiolingually in
crown 6 onwards than in crowns 3–4. Crowns 3–4 are apicobasally much higher than
mesiodistally long (Figs. 15C and 15D); crowns 6–7 are also apicobasally higher than
mesiodistally long, but are comparatively longer mesiodistally than the preceding crowns
(Fig. 15E); crowns 12 and 14 are nearly as mesiodistally wide as apicobasally tall and
are the largest multicusped crowns in the mandible (height ∼1.5 mm). In the most distal
teeth, crowns become mesiodistally longer than apicobasally high and with a slightly
asymmetrical main cusp.
Spacing of the multicusped crowns is in general ca. 0.25 mm, that is, much less than half
the mesiodistal length of the crown of a fully grown tooth; the splayed accessory cusps of
adjacent teeth sometimes contact or even overlap.
Right teeth 11 and 16 (Fig. 15G) show the apical part of the replacement tooth growing
inside the pulp cavity of the functional tooth because the functional crown is labially
reabsorbed. Right crowns 10, 12–15 and 17 have a basal depression, possibly due to
reabsorption by the replacement crown growing inside the basal part of the functional
crown or because of the collapse of the pulp cavity.
The vertebral column is disarticulated and its elements scattered. The caudal segment is
Cervical vertebrae. Six cervical vertebrae can be identiﬁed based on their position, size and
peculiar morphology (Dalla Vecchia & Cau, 2015). Part of the atlas is preserved on the
left quadrate near the occipital region of the skull (Figs. 9A and 9B). It is craniocaudally
short, kidney-shaped and with remnants of the pedicels, potentially representing the
intercentrum of the atlas in craniocaudal view with part of the atlas neural arch
(cf. Bennett, 2001). A cervical vertebra in left lateral view close to this bone (Fig. 3)is
identiﬁed as the third cervical based on its position, size, outline of the neural spine and the
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well-developed prezygapophyses. The axis is mostly covered by the atlas intercentrum
and by the cervical vertebra 3. The other three cervicals occur near the scapulocoracoids
(Fig. 2); the most proximal of the three is exposed in left lateral view, while the other
two are probably in ventral view and badly crushed.
Dorsal vertebrae. Only seven out of the 14–16 dorsal vertebrae present in non-
monofenestratan pterosaurs (Wellnhofer, 1975a;Wild, 1979;Padian, 2008a,2008b;
Bennett, 2014) can be reliably identiﬁed in the slab. They are gathered in two groups: one,
proximal, is located between the scapulocoracoids (Fig. 2), whereas the other, distal, is
close to the sacral vertebrae and the pelvis (Fig. 16). The many missing vertebrae are
probably covered by other bones or were preserved in the portions of the slab that got lost.
The better preserved dorsal vertebra of the ﬁrst group is exposed in dorsal view and
has a long and thin transverse process. It is as large as the cervicals and thus it is one of the
anteriormost dorsals. Another vertebra that is close to the shaft of the right coracoid is
much smaller. It is exposed in ventral view and also has a long transverse process directed
caudolaterally; its centrum is cylindrical and unconstricted. The four dorsals of the second
group are disarticulated, but close to one other. The last dorsal is exposed in right lateral
view, the penultimate in caudal view and the other two in cranioventral view (Fig. 16).
In lateral view, the centrum has a concave ventral margin. The cranial articular surfaces of
the centra of the ﬁrst two vertebrae of the second group are kidney-shaped (lower than
wide) and concave; the caudal articular surface of the centrum of the penultimate
dorsal also appears to be kidney-shaped and slightly concave. The postzygapophyses are
smaller than the prezygapophyses. Although the last dorsal lacks transverse processes,
these processes appear to be present in the penultimate dorsal. The last dorsal has a square
neural spine that is slightly longer than high. The ﬁrst two dorsals of the second group have
Cervical and dorsal ribs. Only shaft fragments and portions of the tubercula and capitula of
the cervical and dorsal ribs are preserved. The ribs of the third to last dorsal vertebra are
apparently dicephalous and have an unusually short shaft with a blunt distal end (Fig. 16B).
Sacral vertebrae. Three co-ossiﬁed sacral vertebrae are exposed in left lateral view near the
last dorsal vertebra (Fig. 16). The faint suture between the centra of the sacrals 1 and 2 can
be seen only under ethanol immersion. The neural spines are rectangular and that of
the ﬁrst sacral is taller than long. A fan-shaped sacral rib crops out from below the sacral
vertebra 2. The sacrum is not co-ossiﬁed with the sacral ribs and the sacral ribs are not
fused with the ilia.
Sternum. Only the ?left half of the sternum is preserved (Fig. 17). It is a thin and broad
plate with a triangular cranial portion and a square posterior part bearing three short
lateral processes for the sternal ribs. Only the base of the cristospine is preserved and the
caudal portion of the plate is concealed by the right humerus. This sternum resembles
those of E. ranzii (see Wild, 1979,ﬁg. 14) and MPUM 7039 (Dalla Vecchia, 2014,
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Figure 16 Seazzadactylus venieri, MFSN 21545 (holotype), last dorsal vertebrae and the sacrum. (A)
Photograph; (B) drawing. Abbreviations: ce, vertebral centrum; dr, dorsal rib; dv, dorsal vertebra; fe,
femur; ns, neural spine; pna, pedicel of the neural arch; poz, postzygapophysis; ppi, preacetabular process
of ilium; ppl, pelvic plate; prz, prezygapophysis; sr, sacral rib; su, suture; sv1–3, sacral vertebrae 1–3; ti,
tibiotarsus; tp, transverse process. Elements in parentheses are from the left side (when it was possible to
distinguish between right and left elements). Scale bar equals ﬁve mm.
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Gastralia. The gastralia are very thin bones that are straight or curved at one extremity and
pointed at the other (Fig. 17). They are scattered around the sternum and the girdles.
The scapula and coracoid are fused. The right and left scapulocoracoids are exposed in
lateral and medial view, respectively (Fig. 18). They are close and parallel to one other as is
sometimes found to be the case in disarticulated pterosaur skeletons (e.g., Wild, 1979, pl. 8;
Padian, 2008a, pl. 4/ﬁg. 7).
The right coracoid lacks the distal portion of its shaft, and both scapulae also lack their
distal portions. The shaft of the left coracoid is mostly missing; it is unclear whether
this is due to the loss of fragments of the damaged slab and or to preparation and the
imprecise ﬁt of the slab fragments. The coracoid has a prominent biceps tubercle
(sensu Bennett, 2003) at its dorsal extremity like the coracoids of Carniadactylus rosenfeldi
and Austriadraco dallavecchiai and a coracoid tubercle (sensu Bennett, 2003)craniolaterally
in the same position as in the coracoid of Carniadactylus rosenfeldi (Dalla Vecchia,
2009a;ﬁg. 3). A small tubercle that is lower than the biceps tubercle occurs dorsal to the
lower tuberosity (sensu Sangster, 2003) along the dorsal margin of the scapulocoracoid as in
other Triassic pterosaurs (Dalla Vecchia, 2009a;ﬁg. 3). This could be a remnant of the
‘acromion’of the scapula after the fusion of scapula and coracoid. The glenoid is bordered by
the lower tuberosity cranially and by the supraglenoidal buttress (sensu Sangster, 2003)
caudally. The shaft of the right coracoid is ﬂat and broad like those of Carniadactylus
rosenfeldi and Austriadraco dallavecchiai, with parallel cranial and caudal margins
(or craniomedial-caudolateral, according to its—unknown—articulation with the sternum).
The angle between the right scapula and right coracoid is 76. Distal to the glenoid the
Figure 17 Seazzadactylus venieri, MFSN 21545 (holotype), sternum. (A) The preserved portion of the
sternum (photograph taken under ethanol immersion); (B) drawing. Black dashed lines mark the broken
margins of the bones where they can be identiﬁed as such. Abbreviations: cs, cristospine; dr, dorsal rib; g,
gastrale; h, humerus; srp, processes for the sternal ribs; st, sternum. Scale bar equals ﬁve mm.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 31/59
Figure 18 Seazzadactylus venieri, MFSN 21545 (holotype), scapulocoracoids. (A) Photograph;
(B) drawing. Dashed lines mark the broken margins of the bones where they can be identiﬁed as such.
Abbreviations: bt, biceps tubercle; co, coracoid; ct, coracoid tubercle; cv, cervical vertebra; dr, dorsal rib;
dv, dorsal vertebra; fe, femur; gf, glenoid fossa; h, humerus; ltu, lower tuberosity; po, postorbital; ra,
radius; scb, scapular blade; scn, scapular neck; sgb, supraglenoidal buttress, t, tubercle; ti, tibiotarsus.
Elements in parentheses are from the left side (when it was possible to distinguish between right and left
elements). Scale bar equals 10 mm. Full-size
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deep scapula exhibits a slight constriction (the scapular neck), beyond which the dorsal
(dorsomedial, if crushing and ﬂattening altered its original orientation) and ventral
(ventrolateral) margins of the scapula diverge and the scapular blade ﬂares markedly
distally (Fig. 18).
The right forelimb preserved in articulation from the humerus to the wing phalanx 1
(Figs. 1 and 2). Only the proximal part of the wing phalanx 2 is preserved, along the margin
of the slab. The left forelimb is moderately disarticulated and lacks only the greater part
of the wing phalanx 4. Both forelimbs are ﬂexed at the elbow with the humerus and
paired radius and ulna aligned parallel to one other.
Humerus. The right humerus (Fig. 2) is exposed in dorsal view. Part of the external
tuberosity and the saddle-like articular margin are preserved, but the deltopectoral crest is
missing and was reconstructed. The distal part of the shaft is recurved cranially; the distal
articular end is missing and was reconstructed. The left humerus is represented only by
most of its crushed shaft (Fig. 2).
Radius and ulna. Radius and ulna are paired and lie parallel to one another in both
forelimbs as is common in moderately disarticulated skeletons of early pterosaurs
(e.g., Wellnhofer, 1975a,1975b;Padian, 2008a,2008b;Dalla Vecchia, 2014). The proximal
portions of both radii and ulnae pairs are not preserved. The shafts of both elements are
straight and have similar diameters. The right ulna (Figs. 19A and 19B) is exposed in
dorsal view; its distal end bears a broad, ﬂattened and wing-like crest like that on the upper
surface of the distal part of the ulna in the holotype of Carniadactylus rosenfeldi (see Dalla
Vecchia, 2014,ﬁg. 4.1.113C1-2). The distal end of the right radius has a prominent
longitudinal ridge bounded cranially by a broad furrow (Figs. 19A and 19B). The ridge
could correspond to the distal tubercle of radii reported in other early pterosaurs
(i.e. Carniadactylus rosenfeldi [see Dalla Vecchia, 2014,ﬁg. 4.1.113C1-2] and Dimorphodon
macronyx [see Sangster, 2003,ﬁg. 3.7]); in which case the right radius is rotated so that
its cranial side is partly exposed. The distal portions of the left radius and ulna differ
noticeably in morphology from the distal ends of the right bones (Fig. S6). The distal
termination of the left ulna, although partly reconstructed, is much more expanded
than the distal termination of the radius. It closely resembles the distal end of the ulna of
Rhamphorhynchus muensteri ﬁgured by Wellnhofer (1975a,ﬁg. 12h)and comparison
with it and with the associated radius indicates that the left ulna is exposed in cranial
view (see also Bennett, 2001,ﬁg. 76). It sends ventrally a ﬂange like other pterosaurs
(e.g. Rhamphorhynchus muensteri,Wellnhofer, 1975a,ﬁg. 12h; Dorygnathus banthensis,
Padian & Wild, 1992, pl. V, ﬁg. 5). The moderately expanded distal end of the radius is
divided into two condyle-like parts by a longitudinal furrow; comparison with the radius
of Rhamphorhynchus muensteri ﬁgured by Wellnhofer (1975a,ﬁg. 12g)and with the
right radius suggests that the left radius is also in cranial view. The distal tubercle seems to
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Carpus. Both left and right carpi are exposed in dorsal view. The right carpus (Figs. 19A
and 19B) is articulated with the radius-ulna and metacarpus. There is a single proximal
syncarpal that is interlocked with a very large distal carpal. At least one, possibly two,
other distinct and smaller elements crop out from below the cranial end of the proximal
syncarpal, and do not contact the metacarpus. They are plausibly distal carpals that
articulated with metacarpals I–III (Wellnhofer, 1975a,ﬁg. 12a-b; Dalla Vecchia, 2009a,
ﬁg. 5A), which are slightly displaced and partially covered by the proximal syncarpal. They
are damaged and their shape is therefore unclear.
A preaxial carpal with the same appearance as the right preaxial carpal of the holotype
of Carniadactylus rosenfeldi and a similar position to it (see Dalla Vecchia, 2009a,ﬁg. 5A)
crops out cranially from the proximal part of metacarpal I.
The left carpus (Figs. 19C and 19D) is represented by a single carpal ‘block’that is
disarticulated and isolated but still very close to the radius-ulna and the wing metacarpal of
the left wing (Figs. 1 and 2). The ‘block’is made up of the interlocked proximal syncarpal
and the large distal carpal. The cranial half of the left large distal carpal is apparently
Figure 19 Seazzadactylus venieri, MFSN 21545 (holotype), carpus. (A) Right carpus, dorsal view;
(B) drawing of (A); (C) left carpus, dorsal view; (D) drawing of (C). Dashed lines mark the broken
margins of the bones where they can be identiﬁed as such. Abbreviations: afu, articular facet for ulna; dc,
distal carpal; dtr, distal tubercle of radius; fu, furrow; ldc, large distal carpal; mcI–IV, metacarpals I–IV;
paxc, preaxial carpal; psc, proximal syncarpal; ra, radius; u, ulna; wc, wing-like crest in the ulna; wph1,
wing phalanx 1. Scale bar equals ﬁve mm in (A) and two mm in (B).
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 34/59
divided into at least two parts, but it is unclear whether this represents crushing of the
irregularly shaped carpal or the existence of separate, distinct and smaller distal carpals.
Comparison with the apparently homogeneous ‘nose’of the right large distal carpal
suggests that they are not distinct carpals. The carpal ‘block’is rotated with respect to the
left wing metacarpal and shows its dorsal side, as indicated by the position of the deep
articular facet for the ulna in the proximal syncarpal.
The proximal syncarpals are saddle-like in dorsal view, thicker cranially (radial side),
thinner caudally (ulnar side) and with a depressed ulnar facet. There is no suture between
the radial and ulnar parts that compose each syncarpal. These elements resemble the
proximal syncarpal of Carniadactylus rosenfeldi (see Dalla Vecchia, 2009a,ﬁg. 5B),
E. ranzii (see Wild, 1979,ﬁg. 17) and Rhamphorhynchus muensteri (see Wellnhofer, 1975a,
In dorsal view, the large distal carpals of MFSN 21545 are as craniocaudally broad as the
proximal syncarpal and are proximodistally longer. The caudal half of each large distal
carpal, which articulates with the wing metacarpal, is squared and massive, whereas
the cranial half, which articulates with the metacarpals III, II and possibly I, is nose-like.
The actual shape of the preaxial carpal is unknown because it is partly concealed by the
metacarpus (cf. Dalla Vecchia, 2009a,ﬁg. 5).
Pteroid. A pteroid (Fig. 20) is preserved close by and parallel to the proximal part of the
right wing phalanx 1. It is therefore shifted away from its natural articulation with the
proximal syncarpal. Although it is closest to the right manus, the left manus is also close
and disarticulated. Thus, it cannot be established whether it is a right or left pteroid.
If it is the right pteroid, its proximal portion is exposed in ventro-caudal view, whereas
the distal part is exposed in caudal view, due to mid-shaft fracturing and the slight
rotation of the distal part. The distal portion is partly damaged, but its shape can be
reconstructed without ambiguity. The pteroid has the shape of an exclamation mark, with
a craniocaudally ﬂattened shaft that broadens and becomes thinner distally. The distal
end is spatula-shaped, thin and ﬂattened. The shaft is straight, but it is slightly bent
caudally at its beginning just distal to the proximal articular head. The latter is slightly
Figure 20 Seazzadactylus venieri, MFSN 21545 (holotype), pteroid. (A) Photograph taken under
ethanol immersion; (B) drawing. Dashed lines mark the missing margins of the bone. Abbreviations: pah,
proximal articular head. Scale bar equals three mm. Full-size
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 35/59
expanded and subspherical. This 12.3 mm long pteroid is comparatively short compared
with those of other Triassic pterosaurs (Table S1).
Metacarpus. The right metacarpus is perfectly articulated (Fig. 21). The metacarpals lie
parallel to one another and metacarpals I–III overlap proximally and partly longitudinally.
The distal ends of metacarpals II and III are covered by the ungual phalanx of left
digit II. The left metacarpus is slightly disarticulated. The left wing metacarpal is close to
the left wing phalanx 1, whereas the left metacarpals I–III have shifted ventrally as a
unit. Left metacarpals I and II remained articulated to one other, while metacarpal III
is disarticulated. Left metacarpals I and II expose their cranial side, showing the distal
ginglymi, which have a broad intercondylar sulcus. The proximal extremities of left
metacarpals I and II are convex. The shaft of left metacarpal I has a broad longitudinal
groove, probably caused by the collapse of the thin cortex. The left metacarpal III has an
asymmetrically expanded proximal end. Left metacarpals II and III have the same
length (18 mm), whereas metacarpal I is decidedly shorter (it is 78% the length of
The wing metacarpals (IV) are similar to the wing metacarpals of the other Triassic
pterosaurs (Dalla Vecchia & Cau, 2015). They are much more robust than metacarpals
I–III and slightly longer than metacarpals II–III. They have the same length as the wing
metacarpal of the holotype of Carniadactylus rosenfeldi (21 mm). The left wing metacarpal
is exposed in cranial view and shows a well-developed proximal ventral ﬂange, a hint
Figure 21 Seazzadactylus venieri, MFSN 21545 (holotype), mani. (A) Photograph; (B) drawing. Bones of the left manus are in green tones,
whereas those of the right manus are in red-pink tones. Abbreviations: cm, crista metacarpi; co, coracoid; dc, distal carpal; dco, dorsal condyle of the
wing metacarpal; dr, dorsal rib; etp, extensor tendon process of wing phalanx 1; ldc, large distal carpal; mcI–III, metacarpals I–III; mcIV, wing
metacarpal; mt, medial tuberosity of the wing metacarpal; pacx, preaxial carpal; phI-1, phalanx 1 of digit I; phII-1 and 2, phalanges 1 and 2 of digit II;
phIII-1, 2 and 3, phalanges 1, 2 and 3 of digit III; psc, proximal syncarpal; pt, pteroid; ra, radius; se, sesamoid; uphI–III, ungual phalanges I–III; vco,
ventral condyle of the wing metacarpal; vcr, ventral crest of the wing metacarpal; wph1, wing phalanx 1. Bones in parentheses are from the left side
(when it was possible to distinguish between right and left elements). Scale bar equals 10 mm. Full-size
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 36/59
of the median tuberosity, the proximal depression for metacarpals I–III and the distal
condylar end with a larger and slightly dorsally splayed dorsal condyle. The right
wing metacarpal is exposed in caudodorsal view, showing a prominent crista metacarpi
(Dalla Vecchia & Cau, 2015).
Phalanges of manual digits I–III. The left manus is disarticulated and the scattered
phalanges of digits I–III are mixed together with those of the right manus, but left phalanges
can be distinguished from right ones (Fig. 21). The phalangeal formula is 2-3-4-4-0.
All non-ungual phalanges of digits I–III are straight. The penultimate (pre-ungual)
phalanges are the longest (see Table S2); phalanx III-2 is the shortest phalanx in these digits
(it is nearly half the length of phalanx III-3). In the penultimate phalanges, the shafts taper
distally and the distal ginglymi are well-shaped, with a semicircular outline and lateral pits
for the collateral ligaments. There is a small antungual sesamoid dorsally on all of these
ginglymi. Similar sesamoids are reported in E. ranzii,Carniadactylus rosenfeldi,Peteinosaurus
zambellii and MCSNB 8950 (Wild, 1979,1994). The ungual phalanges are of similar sizes
to one another (length range 6.2–7 mm, when not damaged). They are sharply pointed,
moderately recurved and dorsoventrally ﬂattened. They have a longitudinal groove for
the attachment of the horny sheath and a large ﬂexor tubercle. They resemble the pedal
phalanges of the holotype of Carniadactylus rosenfeldi (see Dalla Vecchia, 2009a,ﬁg. 8; 2014,
ﬁg. 4.1.128) and are only slightly larger than them (cf. Dalla Vecchia, 2009a,tab.1).
Unfortunately, no ungual phalanges of the pedes are preserved in MFSN 21545. Thus, it
cannot be established whether Seazzadactylus venieri had manual unguals only slightly larger
than pedal unguals (as comparison with the similarly-sized holotype of Carniadactylus
rosenfeldi would suggest) or just smaller manual unguals with respect to Carniadactylus
rosenfeldi. The rounded ginglymi of the penultimate phalanges allowed a high range of ﬂexion
and extension of the unguals.
Wing phalanges. Wing phalanx 3 is the longest and wing phalanx 1 the shortest
(Table S1), but the length of wing phalanx 4 is unknown. As in other Triassic pterosaurs,
the proximal part of wing phalanx 1 is enlarged and bear a robust extensor tendon
Figure 22 Seazzadactylus venieri, MFSN 21545 (holotype), wing phalanges. (A) Right wing phalanx 1,
dorsal view; (B) left wing phalanx 1, dorsal view; (C) left wing phalanx 2, dorsal view; (D) left wing
phalanx 3, dorsal view. Abbreviations: caiet, additional insertion of the extensor tendon of wing phalanx 1;
etp, extensor tendon process of wing phalanx 1. Scale bar equals 10 mm.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 37/59
process and a broad preaxial crest for additional insertion of the extensor tendon of the
phalanx (cf. Wellnhofer, 1991,ﬁg. 34). The extensor tendon process is fused without visible
suture to the proximal part of the phalanx. Wing phalanges 1 and 2 are straight,
whereas the distal end of wing phalanx 3 is slightly bent caudally.
Pelvic plate. The pelvic plates are close to the sacral vertebrae and the hind-limb
elements (Figs. 1 and 2). One of them preserves the postacetabular process of the ilium and
the upper part of the caudal process of the ischium, which have a similar caudal length
(Fig. 23A). The postacetabular process is short, low, and slightly recurved ventrally;
it tapers slightly distally to a blunt end. The caudal process of the ischium is short and
its upper part has a rounded end that is slightly recurved dorsally. Both processes are
similar to those of the holotype of Austriadraco dallavecchiai (Fig. 23C). The postacetabular
process is also like that of Carniadactylus rosenfeldi (MPUM 6009, which does not preserve
the caudal process of the ischium). The caudal process of the ischium is unlike the
trapezoidal and more elongated process of Peteinosaurus zambellii (Fig. 23D). The caudal
margin of the pelvic plate is deeply concave in MFSN 21545; a very small dorsocaudal
process of the ischium occurs in the middle of the concavity as in the pelvic plate of the
holotype of Austriadraco dallavecchiai (Fig. 23C) and Peteinosaurus zambellii (Fig. 23D).
The ilium and ischium appear to be fused to one other but the pelvic plate and the
sacrum were not fused to each other.
A broad, plate-like bone is partially preserved close to the described pelvic plate and the
sacral vertebrae (Figs. 2 and 16). It is possibly the cranial portion of the other pelvic plate.
It has a straight and vertical cranial (pubic) margin as in other pelvic plates of Triassic
pterosaurs (cf. Fig. 23C), and also a spatula-like cranial process that could be the
preacetabular process of ilium. However, this process is shorter and morphologically
unlike the preacetabular process of all other pterosaurs (e.g. Carniadactylus rosenfeldi,
Dalla Vecchia, 2014,ﬁg. 4.1.145; Austriadraco dallavecchiai,Fig. 23C; MCSNB 8950,
Wild, 1994,ﬁg. 5; Dimorphodon macronyx,Sangster, 2003,ﬁg. 3.15; Dorygnathus
banthensis,Padian, 2008a,ﬁgs. 14, 19C and 21; Campylognathoides liasicus,Wellnhofer,
1974,ﬁg. 9; Campylognathoides sp., Padian, 2008b,ﬁg. 9; and Rhamphorhynchus
actually is the preacetabular process of the ilium.
Prepubis. A prepubis (10.5 mm long) is partly covered by the postacetabular process of
an ilium (Fig. 23A). The exact outline of the expanded prepubic blade cannot be seen.
However, this prepubic plate is probably shovel-like with a prepubic blade slightly more
expanded ventrally than dorsally (Fig. 23B) like that of E. ranzii (Fig. 23E).
Both right and left femora and tibiotarsi are partly preserved and the missing portions were
restored (Figs. 1 and 2). Both femora are close and parallel to the corresponding tibiotarsi;
both femur-tibiotarsus sets are close to one other and to the pelvic plates. No free
tarsals can be identiﬁed. Only a few fragments are preserved of the elements of the foot.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 38/59
Femur. The proximal third of the left femur (identiﬁed as such by its association with the left
tibiotarsus) is preserved in cranial view, whereas the median third is missing and only
a fragment remains of the distal third. The length of this preserved portion is 32 mm.
In cranial view, the proximal head of the femur is dorsoventrally broad with only a hint of
the neck (Fig. S7A). The angle between the proximal head of the femur and the shaft is 115.
The greater trochanter was damaged and has been reconstructed. Only a long and slightly
sigmoidal portion of the shaft is preserved on the right femur. Because of the incompleteness
of both elements, the exact total length of the femur cannot be known, but exceeds 32 mm.
Tibiotarsus and ﬁbula. Right and left tibiotarsi are distinguished from one another on the
basis of their position in the slightly disarticulated skeleton, the position of the associated
Figure 23 Seazzadactylus venieri, MFSN 21545 (holotype), pelvic elements and comparison.
(A) Pelvic plate (caudal portion of ilium and ischium) and one prepubis of MFSN 21545; (B) prepubis
of MFSN 21545 (photograph taken under ethanol immersion); (C) ?left pelvic plate of Austriadraco
dallavecchiai, holotype (BSP 1994 I 51), ?lateral view; (D) drawing of the left ischiopubic plate of
Peteinosaurus zambellii (MCSNB 3496), lateral view; (E) drawing of the left prepubis of E. ranzii,
holotype (MCSNB 2888), lateral view. (D) and (E) are redrawn from Wild (1979). Dashed lines mark the
margins of the missing parts. Abbreviations: ac, acetabulum; cpi, caudal process of ischium; dcpi, dor-
socaudal process of ischium; fob, foramen obturatorium; il, ilium; is, ischium; popi, postacetabular
process of ilium; ppb, prepubic blade; pps, prepubic stalk; ppu, prepubis; prpi, preacetabular process of
ilium; pu, pubis; vpi, ventral process of ischium. Scale bar equals ﬁve mm.
Dalla Vecchia (2019), PeerJ, DOI 10.7717/peerj.7363 39/59
ﬁbula and the shape of their distal condyles (the lateral condyle is more developed than
the medial one and projects more cranially than caudally in Triassic pterosaurs; Dalla
Vecchia, 2003). Both tibiotarsi are strongly crushed and their shafts collapsed. The right
tibiotarsus is exposed in caudal view and preserves the distal portion with the condyles
(Fig. S7B) and fragments of most of the shaft with some fragments of the parallel and
appressed ﬁbula along the lateral side. The length of the preserved portion is 50 mm.
The left tibiotarsus preserves the distal portion with the condyles and a proximal segment
of the shaft. It is probable that it is exposed in medial view as the asymmetrical outline
of the condyle (Fig. S7C) resembles that of the medial condyle of the left tibiotarsus of
the holotype of Carniadactylus rosenfeldi (Dalla Vecchia, 2009a,ﬁg. 9A; 2014,ﬁg. 4.1.126
B-C); both elements also share a comma-like medial epicondyle. The proximal portion
of the left tibiotarsus is covered by the blade of the left scapula, but part of its proximal end
crops out from the ventral side of the blade where it is mostly concealed by vertebrae.
The total length of the left tibiotarsus is approximately 55 mm.
Pes. Two phalanges and possibly a further two, all preserved close to the tibiotarsi
(Figs. 1 and 2), belong to the completely disarticulated feet. The most complete phalanx
is close to the left tibiotarsus and is short (4.9 mm) and stout.
Unlike the data matrix of Britt et al. (2018), the state of the character 61 has been considered
unknown for Austriadraco dallavecchiai here because of the dubious identiﬁcation of
the sternum in this taxon (see below). Codings of Seazzadactylus venieri are reported in
the Supplemental Information. The analysis produced six equally parsimonious trees,
each with a length of 290 steps, consistency index = 0.5759, homoplasy index = 0.5483,
retention index = 0.7050, and rescaled consistency index = 0.4060. The analysis with TNT
obtained the same topology and a tree length of 254 steps (polymorphic characters are
treated as unknown by TNT).
The strict consensus tree topology (Fig. 24) differs from that obtained by Brittetal.
(2018;ﬁg. 5, suppl. ﬁgs. 2-4). The addition of MFSN 21545 to the matrix including
MCSNB 8950 resolved the big polytomy at the base of the strict consensus tree (see Britt
et al., 2018,suppl.ﬁgs. 2-3). The basal clade of the Pterosauria is Preondactylus buffarinii +
Austriadactylus cristatus, which is followed crownwards by an unnamed clade composed
of Arcticodactylus cromptonellus +Austriadraco dallavecchiai +Seazzadactylus venieri +
Carniadactylus rosenfeldi + (trichotomy of Raeticodactylus ﬁlisurensis,Caviramus
schesaplanensis and MCSNB 8950). Seazzadactylus venieri is nested within this unnamed
clade as the sister taxon of Carniadactylus rosenfeldi + (trichotomy of Raeticodactylus
ﬁlisurensis,Caviramus schesaplanensis and MCSNB 8950). There is no support for a
clade Eudimorphodontidae sensu Dalla Vecchia (2014), because E. ranzii is located in the
tree between the Dimorphodontidae and Campylognathoides spp. Bremer support values
for the clades in the analysis are mostly low: all nodes within the unnamed clade
mentioned above have Bremer values of +1 (Fig. 24). Only Pterosauria, Preondactylus
buffarinii +Austriadactylus cristatus; Dimorphodontidae; Anurognathidae; Jeholopterus
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ningchengensis +Dendrorhynchoides spp.; Dorygnathus banthensis + Rhamphorhynchidae;
Rhamphorhynchidae; Pterodactyloidea; and Anhanguera spp. + Pteranodon longiceps
have Bremer values 3.
MFSN 21545 is similar in size to the holotype of Carniadactylus rosenfeldi. It is slightly
larger than the holotype of Austriadraco dallavecchiai and is nearly twice the linear size of
the specimen MPUM 6009 of Carniadactylus rosenfeldi (Tables S1 and S3). MFSN 21545 is
larger than specimens MCSNB 2887 and MCSNB 8950 and is much larger than the
holotype of Arcticodactylus cromptonellus. Although the mean of the percent length of
some selected skeletal elements of the holotype of E. ranzii is only 118% those of
MFSN 21545 (Table S3), the latter appears much smaller when the fossils are compared
(Fig. S8), because body mass is proportional to the length raised to the third power.
MFSN 21545 is much smaller than the holotype of Raeticodactylus ﬁlisurensis.
The holotypes of Carniadactylus rosenfeldi and Austriadraco dallavecchiai are not
juveniles, although the holotype of Austriadraco dallavecchiai shows some features of
osteological immaturity (Dalla Vecchia, 2018). Osteological features of immaturity
alsooccurinMPUM6009andMCSNB8950(Dalla Vecchia, 2018).Theholotypeof
Figure 24 Seazzadactylus venieri, MFSN 21545 (holotype), phylogenetic relationships. Strict con-
sensus tree of six most parsimonious trees as computed in PAUP 4.0b10 (length = 290, consistency index =
0.5759, RI = 0.7050) (see Materials, Terminology and Methods). Numbers +1 to +10 refer to Bremer
values. Legend: 1, Pterosauria; 2, Macronychoptera; 3, Dimorphodontidae; 4, Lonchognatha;
5, Novialoidea; 6; Caelidracones; 7,Monofenestrata;8, Pterodactyloidea; 9, Anurognathidae. Outgroup
taxa are not shown. Full-size
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Arcticodactylus cromptonellus is a young individual, based on histological analysis
(Padian, Horner & De Ricqlés, 2004). The holotype of E. ranzii is usually considered an
adult, but it also shows some features indicating osteological immaturity (Dalla Vecchia,
2018). The holotype of Raeticodactylus ﬁlisurensis does not show any features of osteological
immaturity (F.M. Dalla Vecchia, 2018, personal observation), but it is incomplete (e.g. pelvis
and sacrum are not preserved).
Some features suggest osteological immaturity also for MFSN 21545. Roof and
palatal elements of the skull are unfused. A suture is visible between the premaxillae.
The mandibular rami are unfused at the symphysis (but see Dalla Vecchia, 2018). There are
possibly three unfused distal carpals (but see Dalla Vecchia, 2009a,2018). The ilium is
not fused to the sacral ribs, which are not fused with the sacral vertebrae. Prepubes are
not fused at the symphysis. On the other hand, the elements of the occipital region
and basicranium appear to be fused, although is impossible to state whether the sutures
among the elements were fully obliterated or not. The neural arches of the last dorsal
vertebrae appear to be fused to their centra. The sternum is ossiﬁed with processes for the
sternal ribs. Scapulae and coracoids are fused. There is a single proximal syncarpal.
The extensor tendon of the ﬁrst wing phalanx is fused to the phalanx (however, this
occurred early during ontogeny in Triassic pterosaurs; Dalla Vecchia, 2018, contra Kellner,
2015). The phalanges of the manus are well-ossiﬁed with well-formed ginglymi. The ilium is
fused with the puboischiadic plate and the sacral vertebrae are fused into a synsacrum.
The fusion of the sacral vertebrae seems to have occurred relatively late during ontogeny in
Triassic pterosaurs (Kellner, 2015;Dalla Vecchia, 2018). The rounded condylar end of the
tibia indicates that it is actually a tibiotarsus with the proximal tarsals fused to the tibia.
These features indicate that MFSN 21545 was not a juvenile, but probably was still growing
when it died (Dalla Vecchia, 2018).
Multicusped maxillary and mandibular teeth like those of Seazzadactylus venieri are reported
only in the Triassic taxa E. ranzii,Carniadactylus rosenfeldi,Arcticodactylus cromptonellus
and Austriadraco dallavecchiai (Dalla Vecchia, 2014). Caviramus schesaplanensis and
Raeticodactylus ﬁlisurensis also have multicusped teeth, but their crowns are distinctly
bulkier than those of Seazzadactylus venieri and have a peculiar constriction at their base
(Dalla Vecchia, 2014,ﬁgs. 4.1.57A–C and 4.1.161B–C). Two other specimens (MCSNB 2887
and MCSNB 8950) do not preserve any trace of dentition, but they have been considered
closely related to the taxa listed above in the literature (Wild, 1979,1994). Seazzadactylus
venieri must ﬁrst be compared with specimens of Carniadactylus rosenfeldi because
the holotype of this species comes from the same formation and geographic region
(Dalla Vecchia, 2009a). Although both pterosaurs are from the Dolomia di Forni Formation,
it cannot be known whether they are from the same stratigraphic level or not, as the exact
stratigraphic provenance of MFSN 21545 is unknown and the fossiliferous part of the
Dolomia di Forni Formation is about 500 m thick (Dalla Vecchia, 2006). The holotype of
Carniadactylus rosenfeldi comes from a stratigraphically mid-low position within the
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Dolomia di Forni Formation (see Dalla Vecchia, 2014) and the boulder containing
MFSN21545 was located in the lower part of the formation.
Premaxilla. The body of the premaxilla is more elongated in Seazzadactylus venieri than in
Carniadactylus rosenfeldi (MPUM 6009), and teeth occur only in the rostral half of the
premaxilla, whereas the last premaxillary tooth is at the premaxilla/maxilla boundary
in MPUM 6009 (Dalla Vecchia, 2018,ﬁg. 2). No other non-monofenestratan pterosaurs
have premaxillary teeth restricted to the rostral half of the premaxilla (i.e. Preondactylus
buffarinii,Dalla Vecchia, 2014,ﬁg. 4.1.3; Austriadactylus cristatus, Dalla Vecchia et al.,
2002,ﬁg. 2; Raeticodactylus ﬁlisurensis,Stecher, 2008,ﬁg. 6; E. ranzii,Wild, 1979,ﬁg. 1;
Dimorphodon macronyx,Sangster, 2003,ﬁgs. 1.6A and 2.1A; Dorygnathus banthensis,
Padian, 2008a,ﬁg. 18); Campylognathoides liasicus and Campylognathoides zitteli,
Padian, 2008a,ﬁg. 10; Scaphognathus crassirostris,Bennett, 2014,ﬁg. 5; Jianchangopterus
zhaoianus,Lü & Bo, 2011,ﬁg. 3; Jianchangnathus robustus,Zhou, 2014,ﬁg. 3;
Rhamphorhynchus muensteri, Wellnhofer, 1975a,ﬁg. 3); Anurognathus ammoni,
Bennett, 2007,ﬁg. 4; and Batrachognathus volans,Riabinin, 1948,ﬁg. 1).
Maxilla. The maxilla of Seazzadactylus venieri has an elongated foramen at the base
of the ascending process in lateral view, which is lacking in Carniadactylus rosenfeldi,
Arcticodactylus cromptonellus, E. ranzii and Raeticodactylus ﬁlisurensis.Unlike
Arcticodactylus cromptonellus, the maxilla of Seazzadactylus venieri lacks a row of
largeforaminaalongthelateral side of the jugal process (Jenkinsetal.,2001,ﬁg. 4).
The maxillary process of the jugal overlaps the jugal process of the maxilla laterally in
Seazzadactylus venieri, whereas the jugal overlaps the jugal process of the maxilla
dorsally in Carniadactylus rosenfeldi (MPUM 6009; Dalla Vecchia, 2018,ﬁg. 2) and
E. ranzii (see Wild, 1979,ﬁgs. 1 and 25b). Seazzadactylus venieri lacks the small
notch for the maxillary process of the premaxilla that occurs on the dorsal margin
of the premaxillary processes of the maxilla of E. ranzii (see Dalla Vecchia, 2014,
Jugal. The jugal of Seazzadactylus venieri differs from that of Carniadactylus rosenfeldi
(MPUM 6009; Wild, 1979,ﬁg. 2; Dalla Vecchia, 2018,ﬁg. 2), as well as those of other
non-monofenestratan pterosaurs (i.e. Austriadraco dallavecchiai,Wellnhofer, 2003,ﬁg. 3A;
ﬁg. 7C; E. ranzii,Wild, 1979,ﬁg. 1; Raeticodactylus ﬁlisurensis,Stecher, 2008,ﬁg. 6;
Dimorphodon macronyx,Sangster, 2003,ﬁg. 2.7; Caelestiventus hanseni,Britt et al., 2018,
ﬁg. 3h and i; Parapsicephalus purdoni,Newton, 1888, pl. 78, ﬁg. 2; O’Sullivan & Martill,
2017,ﬁg. 5A; Campylognathoides liasicus,Wellnhofer, 2003,ﬁg. 3C; Dorygnathus
banthensis,Wellnhofer, 2003,ﬁg. 3D; Scaphognathus crassirostris,