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A new specimen of the Azhdarchoid pterosaur Tapejara wellnhoferi

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A new specimen of the Early Cretaceous azhdarchoid Tapejara wellnhoferi is described from the Romualdo Member of the Santana Formation, NE Brazil, providing the first detailed account of the postcranial skeleton. Although limited in its preservation, the osteology is typical of other azhdarchoid pterosaurs from these deposits and represents a juvenile animal with a relatively small wing span of <1.5 m. The ratios of the pedal elements are identical to those noted for larger, indeterminate azhdarchoids of the Nova Olinda Member of the Crato Formation, where the unguals of the pes are greatly enlarged relative to those of the ornithocheiroids that co-inhabited the Santana lagoon. The ratios of these elements suggest that, as part of a larger suite of characters, these animals were likely better adapted for life on the ground than their ornithocheiroid relatives.
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A new specimen of the azhdarchoid pterosaur Tapejara wellnhoferi
R.A. Elgin
a
* and H.B.N. Campos
b
a
Staatliches Museum fu
¨
r Naturkunde Karlsruhe, Erbprinzenstraße 13, 76133, Karlsruhe, Germany;
b
Campina Grande,
Paraı
´
ba 58406-025, Brazil
(Received 24 May 2011; final version received 8 August 2011)
A new specimen of the Early Cretaceous azhdarchoid Tapejara wellnhoferi is described from the Romualdo Member of the
Santana Formation, NE Brazil, providing the first detailed account of the postcranial skeleton. Although limited in its
preservation, the osteology is typical of other azhdarchoid pterosaurs from these deposits and represents a juvenile animal
with a relatively small wing span of , 1.5 m. The ratios of the pedal elements are identical to those noted for larger,
indeterminate azhdarchoids of the Nova Olinda Member of the Crato Formation, where the unguals of the pes are greatly
enlarged relative to those of the ornithocheiroids that co-inhabited the Santana lagoon. The ratios of these elements suggest
that, as part of a larger suite of characters, these animals were likely better adapted for life on the ground than their
ornithocheiroid relatives.
Keywords: pterosaur; Azhdarchoidea; Tapejara; Santana Formation
Institutional abbreviations:
AMNH, American Museum of Natural History, New
York, USA; CPCA, Centro de Pesquisas Paleontolo
´
gicas
da Chapada do Araripe, Crato, Brazil; IMNH, Iwaki City
Museum of Coal and Fossils, Iwaki, Japan; MCT,
Palaeontology section of the Department Nacional da
Produc¸a
˜
o (Museu de Cie
ˆ
cias da Terra), Rio de Janeiro,
Brazil; MN, Museu Nacional, Rio de Janeiro, Brazil;
SMNK, Staatliches Museum fu
¨
r Naturkunde Karlsruhe,
Germany; SAO, Collection of Urs Oberli, St Gallen,
Switzerland.
Introduction
The Early Cretaceous azhdarchoid Tapejara wellnhoferi is
well represented by several excellent cranial examples
recovered from the Romualdo Member of the Santana
Formation, NE Brazil (AMNH 24440, Wellnhofer and
Kellner 1991; MN 6595-V, Kellner 1989; MCT 1500-R,
Kellner 1996; SAO 12891, Wellnhofer and Kellner 1991;
SMNK PAL 1137, personal observation, RAE). In spite of
this, specimens preserving an association between the
cranial and postcranial elements are rare, where the skull
appears to have detached from the body early in the decay
process and settled separate from the torso or wings
(Unwin and Martill 2007). Although more recent
acquisitions (i.e. SMNK PAL 1137 and IMNH 1053)
preserve significant portions of the postcranial skeleton,
and may yet provide a more robust diagnosis based on
non-cranial characters, this material remains to be
formally published. Herein, a new specimen of Tapejara
wellnhoferi that preserves elements of both the cranial and
postcranial skeleton is figured and formally described. The
material is listed under the collection number of SMNK
PAL 3986.
Description
Preservation and provenance
The fossil was unearthed from the concretion-bearing unit
within the Chapata do Araripe, NE Brazil, commonly
referred to as Romualdo Member of the Santana
Formation (e.g. Kellner and Tomida 2000; Martill 2007;
but see Neumann and Cabrera 1999 for an alternative
stratigraphical framework), and deposited during the Early
Cretaceous, Albian (e.g. Pons et al. 1990, 1996). This
fossil is preserved on a single split concretion, typical of
fossils unearthed from this unit, and preserves the remains
of two isolated cranial elements (jugal and quadrate), the
mandible, two cervical vertebrae, the radii and ulnae,
metacarpals, the first wing finger phalanges, in addition to
three metatarsals and six phalanges of the first four digits
of the left pes (Figure 1). Only digit I is complete and
preserves the ungual. The skeleton was disturbed as
indicated by several small and indeterminate fragments of
bone scattered about the concretion and the juxtaposition
of the pes against the cervical vertebrae. The bones are 3D
in form and although they remain in a generally good state
of preservation many have been damaged, where the
concretion was split and portions of the compacta were
ISSN 0891-2963 print/ISSN 1029-2381 online
q 2011 Taylor & Francis
DOI: 10.1080/08912963.2011.613467
http://www.informaworld.com
*Corresponding author. Email: rosselgin@hotmail.com
Historical Biology
iFirst article, 2011, 1–6
Figure 1. (A) Photograph and (B) line tracing of T. wellnhoferi, SMNK PAL 3986; cv, cervical vertebra; crp, carpal elements; m,
mandible; msc, mandibular sagittal crest; r, radius; ul, ulna; wph, wing finger-phalanx; j, jugal; q, quadrate; mc, metacarpal; mt,
metatarsal; d?p?, digit and phalanx number. Scale bars represent 50 mm.
R.A. Elgin and H.B.N. Campos2
lost from the top (i.e. visible) surface. Several of the long
bones are cut by the margin of the concretion indicating
that the remains were originally more extensive. No
counter slab is known for this specimen.
Anatomy
Two elements of the skull can be clearly identified, these
being the dorsally directed branch of jugal, which would have
articulated with the lacrimal in life and formed the
caudal/caudoventral margin of the nasoantorbital fenestra,
and the dorsal half of right quadrate. The jugal element is very
thin and blade-like, the cranial and caudal margins of which
are gently concave. In its lateral aspect, the bone has broad
ventral base that tapers dorsally. The quadrate, which is
observed in its caudal aspect, terminates naturally by the
margin of the concretion. The dorsal articular face of the bone
is small and oval in cross section, with a smoothly convex
termination. Ventral to this, a dorsoventrally orientated
concave depression has developed on the caudomedial face of
the bone, becoming gradually more pronounced towards the
ventral portion of the quadrate. The cross section of the ventral
half of the bone is
L-shaped, formed by the presence of a
medially and caudally directed blade.
Mandible
The edentulous mandible is visible in its right lateral
aspect. The dorsal margin is typically straight with the
rostral portion of the bone defected ventrally at an angle of
138, beginning at a position 42 mm short of the rostral
tip. The dorsal margin of this deflection is weakly concave
and merges with the rostral tip of the bone, which is
rounded. The ventral margin of the mandible supports a
median sagittal crest that reaches a maximum depth of
35 mm directly ventral to the initial point of deflection.
Rostral to the apex of the dentary crest, the ventral margin
of the bone is weakly concave when viewed from its lateral
aspect (Figures 1 and 2(A)).
Cervical vertebrae
Two cervical vertebrae are observed in their ventrolateral
aspects and represent elements from the middle of the
cervical column, likely cervicals four and five. The bones
are long and narrow, being 3.8 times longer than the
narrowest point at the middle shaft (based on the
caudalmost element), and display wide blunt postzygapo-
physes. The lateral margins of the corpora are concave in
profile and, in the cranialmost element, are pierced by two
small foramina.
Radius and ulna
The radii and ulnae are long and narrow bones, observed in
their ventral aspects, and preserve a circular cross section
of 4 mm in diameter at the middle portion of the shaft. The
elements from both left and right sides of the wing are
present; however, only the left ulna is complete with a total
length of 107 mm. The shaft of the ulna curves caudally
and becomes craniocaudally compressed towards the
distal articulation. A pronounced tubercle is observed on
the dorsal margin of the right radius and left ulna that
would have braced against the capitulum of the humerus
during life. A small pneumatic foramen is observed on the
ventral half of the cranial face of the ulna, immediately
adjacent to the proximal articular surface. An elongate
Figure 2. Cranial morphology of several specimens attributed to T. wellnhoferi. A, SMNK PAL 3986; B, MCT 1500-R (Kellner 1989);
C, AMNH 24440 (Wellnhofer and Kellner 1991); D, SMNK PAL 1137; E, IMNH 1053; F, SAO 12891 (Wellnhofer and Kellner 1991).
Dashed lines represent reconstructed portions of the cranium. Scale bars represent 50 mm.
Historical Biology 3
depression, presumably for the attachment of antebrachial
muscles, is visible on the cranioventral margin of the bone.
Carpus
Immediately adjacent to the distal margin of the left ulna,
two carpal bones are observed, which are still partially
buried within the concretion. Their visible surfaces are
transversely concave and pierced by two foramina.
Adjacent to the left carpals, two partially preserved
bones are regarded as the displaced carpals of the right
carpus due to the similarities in size and form when
compared with the left carpal elements. Sediment cover
prevents any further description.
Metacarpals
A single long bone aligned with the left radius is regarded
as the fourth metacarpal based on its position and circular
cross section. The element, however, is cut by the margin
of the concretion after a length of 54 mm and the proximal
portion of the shaft is covered by sediment, making this
diagnosis uncertain. Two elements underlie the distal
portion of this bone and are regarded as the wing
metacarpal of the right arm and one of the three preaxial
metacarpals. The smaller metacarpal craniocaudally
compresses and expands dorsoventrally towards its distal
termination to create the articular surface for the manual
digits.
Wing finger phalanges
The distal ends of both first wing finger phalanges lie
parallel to one another with their shafts displaying a
circular cross section about the middle shaft that becomes
dorsoventrally compressed towards the distal termination.
The caudal margins of the phalanges curve caudally to
create an expanded articular surface, convex in profile and
10 mm in width craniocaudally.
Pes
The left pes preserves three metatarsals and six elements
of the first four digits. The metatarsals are long and
narrow with mediolaterally compressed proximal mar-
gins. The bones become more circular in section towards
their midpoints and have a diameter of 1.7 mm. All
metatarsals are at least 28 mm in length and preserve a
slight ventral curvature. The first phalanx of digit one is
complete and preserves a length of 15 mm, along with a
very slight ventral curvature of the shaft. The phalanx
terminates in a weak condyle, lying in natural articulation
with its ungual which itself is 11 mm in length. In its
lateral aspect, the proximal half of the ungual is almost
trapezoidal in its outline while that of the distal half is
curved strongly in a ventral direction and compressed
dorsoventrally. The first phalanx of the second digit is
4.5 mm in length and lies in natural articulation with the
second phalanx, which is estimated to have been 13 mm
in length. The first phalanx of the third digit is 6 mm in
length and lies in articulation with the second phalanx.
The phalanx of the fourth digit is broken after only 5 mm
but was at least 9 mm long.
Discussion
The specimen described herein does not preserve the
cranium and the high sagittal crest on its rostral margin
that are diagnostic for T. wellnhoferi; however, the form
of the mandible matches perfectly the amended diagnosis
of Wellnhofer and Kellner (1991, p. 101), ‘Lower jaw
ventrally with sagittal crest on the symphysis. Upper
margin of symphysis inclined downwards [ventrally] with
concave depression dorsally. The upper margin of the
symphysis is turned ventrally at an angle of 138relative to
the dorsal margin of the ramus and is sufficiently similar
to that noted in other examples of the T. wellnhof eri (i.e.
168, AMNH 24440; 128, SMNK PAL 1137; 148, IMNH
1053) for the mandible to be considered complemen tary
(Figure 2). Although a similar mandible is also noted for
Tupandactylus imperator (CPCA 3590, Pinheiro et al.
2011), the ventral deflection is flat not concave, and the
cranial margin of the mandibular crest is dominantly
convex rather than concave, as note d in all individuals
of T. wellnhoferi. The form of the mandibular crest
in Tupandact ylus navigans (Frey et al. 2003b) is
unknown.
The shape of the ventral margin of the mandible is
noteworthy in that the cranial and caudal margins of the
crest show a shallow concave curvature relative to IMNH
1053 and the reconstructed margins of AMNH 24440. As
such the profile of SMNK PAL 3986 is more comparable
to that of SMNK PAL 1137, which also preserves a more
gentle convex curvature (Figure 2D). There is, however,
little reason to consider such a small divergence in crest
morphology to be of taxonomic significance and it is
instead likely to be the result of intraspecific variation or
perhaps even slight differences in development or relative
ontogenetic age. With regard to the latter point, the
described specimen is relatively ontogenetically immature
based on the lack of fusion between the cranial elements,
which are found isolated, and the individual carpals, which
have been disassociated from one another.
Although very little work has focused on the
postcranial remains of azhdarchoid pterosaurs, any
comparison of the described specimen with those of
more complete azhdarchoids is restricted owing to a lack
of preserved elements. The radius and ulna, which here
represent the most complete long bones, are identical in
R.A. Elgin and H.B.N. Campos4
form to that of all derived pterosaurs with the exception of
the size and position of pneumatic features. A large
pneumatopore positioned on the cranial face of the ulna is
known in other indeterminate azhdarchoids from NE
Brazil (e.g. SMNK PAL 3985); however, no reference is
made to such a feature in Chinese azhdarchoids (e.g.
Sinopterus, Wang and Zhou 2003), largely due to the
preserved orientation of the specimens and the degree of
lateral compression. The form of the ungual is identical to
that of Sinopterus dongi (IVPP V 13363), whe re the distal
half is very narrow and ventrally curved. It is not possible
to comment on the degree of mobility available to the
ungual of SMNK PAL 3986 as the proximal margin is
slightly convex with no presence of a large dorsally
located cotyle as observed in other taxa (e.g. SMNK PAL
3830, 3900, 6409).
The ratio of the ungual to the length of the preceding
phalanx in digit one of the pes is similar to that observed in
larger and more mature azhdarchoids (i.e. 0.67 versus 0.62
in the azhdarchoid SMNK PAL 3830), and as such is
sufficiently distinct from other pterodactyloids (e.g. 0.4 for
the ornithocheiroid SMNK PAL 3854). The development
of large unguals in T. wellnhoferi and the likely presence of
large claw sheaths as demonstrated by Frey et al. (2003a;
SMNK PAL 3830) form a part of a broader suite of
characters (including the elongate femur/tibiotarsus and
the increased development of the greater trochanter),
suggesting that azhdarchoids were well adapted to life
both on the ground and in the air.
Based on the size of the mandible, the described
specimen was larger than that of SMNK PAL 1137 but
slightly smaller than AMNH 24440 and SAO 12891, the
latter specimens having an estimated wing span of 1.35
1.5 m (Wellnhofer and Kellner 1991). Although the only
complete long bone observed herein is the ulna, regression
relationships are fairly well established in pterosaurs such
that wing length can be calculated from the comparison of
additional azhdarchoid specimens, where ulna
length ¼ 1.5789 £ humerus length7.615 (R
2
¼ 0.97
based on 14 azhdarchoid specimens from 10 genera) and
total span ¼ 14.485 £ humerus length þ 413.94
(R
2
¼ 0.76 based on six azhdarchoid specim ens from
four ge nera). Despite the relatively low confidence
coefficient for total span, the estimated wing span between
1.15 and 1.47 m agrees well with those estimates of other
specimens (Wellnhofer and Kellner 1991).
Although the chaotic displacement of several bone
elements indicates that the specimen was disturbed after
settling, the presence of delicate bones that remained in situ
(i.e. metacarpalia, elements of the pes) indicates that at
least parts of the soft tissue remained viable for a
prolonged period following death.
Conclusions
The specimen described herein represents a small and
ontogenetically immature azhdarchoid pterosaur of the
genus Tapejara wellnhoferi along with the partial remains
of the postcranial skeleton. This individual developed the
large curved unguals of the pes noted for other tapejarid
examples (e.g. SMNK PAL 3830, 3900) and is inferred to
have spent substantially more time on the ground than the
ornithocheiroids, with whom they co-inhabited the
Santana locality. The relatively small wing span compared
to other pterosaurs known from the Lagersta
¨
tten deposits
of NE Brazil is interpreted as a result from the
morphologically immature nature of the skeleton and it
is likely that it woul d have grown to have become much
larger in size.
Acknowledgements
Thanks are extended to Eberhard ‘Dino’ Frey and the SMNK for
access to the described specimen and Urs Oberli for access to
both SAO 12891 and other material within his collection.
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... In the family Tapejaridae (including Tapejarinae, Thalassodrominae and Chaoyangopterinae) (sensu Pinheiro et al. 2011), the chaoyangopterines are more like the azhdarchids in cranial structure, but with moderately elongated mid-cervical vertebrae (Zhou 2010a). However, our knowledge of the postcranial morphology of coexisting tapejarines is very limited, especially in respect to the cervical vertebrae, such as the Brazilian Tapejara (Wellnhofer and Kellner 1991;Kellner 1995Kellner , 2004Eck et al. 2011;Elgin and Campos 2012). In the Jehol Biota, the Chinese Sinopterus-like tapejarines are excellently preserved, providing an opportunity for understanding the morphology of the cervical vertebrae. ...
... It is about 35 mm in maximal length and 10 mm in minimal width. Therefore, the ratio of the length versus width is 3.5, comparable to that in Tapejara (Eck et al. 2011;Elgin and Campos 2012). The cervical is remarkable with the tightly curved anterior and posterior margins. ...
... In the Pterodactyloidea, the specimen (PMOL-AP00030) can be confidently assigned as an azhdarchoid pterosaur by several features, such as elongate scapula, well-developed and unwarped deltopectoral crest, presence of the postexapophyses and the lateral pneumatic foramen absent on the bony wall of the mid-cervicals. Furthermore, within the suprafamily Azhdarchoidea, the specimen can be excluded from the extremely elongated mid-cervicals azhdarchids, and from the Brazil tapejarids (including thalassodromines), in which lateral pneumatic foramina present in mid-cervicals, and the coracoidal tubercle is less developed (Eck et al. 2011;Elgin and Campos 2012;Aires et al. 2013). In contrast, PMOL-AP00030 shows a similarity with the Chinese tapejarids (including tapejarines and chaoyangopterines) in postcranial morphology, such as moderately elongated mid-cervicals, absence of the lateral pneumatic foramen on the bony wall of the midcervicals and the moderately developed tubercle of the coracoid. ...
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In the Jehol Biota, the edentulous azhdarchoid pterosaurs are flourished, with well-known Sinopterus-like and Chaoyangopterus-like cranial morphotypes. In contrast, their postcranial morphology is obscure, especially in cervical vertebrae. Here, new material of the Chinese tapejarine from the Early Cretaceous Jiufotang Formation in western Liaoning is described that provides more information about the mid-cervical vertebrae. As in Chaoyangopterus, the mid-cervicals are moderately elongated and lack the lateral pneumatic foramen; the prezygapophyses are horn-like and slightly divergent, and basally bear a longitudinally oriented sulcus. This similarity implies that the mid-cervical structure is inconsistent with the cranial disparity in the early radiation of the Azhdarchoidea, and further supports the hypothesis that the extremely elongated mid-cervicals are possibly evolved latterly in the Azhdarchidae after branching from the Azhdarchoidea.
... The unguals are laterally compressed, slightly curved, and sharply pointed. Proximally, the flexor tubercle is weakly developed at the base, different from the well-developed tubercles in "Nemicolopterus", Sinopterus, and Tapejara [52,62,63]. Distally, the ungual curves slightly (inner and outer curvatures are 64 and 57.6 degrees, respectively) and points sharply, differing from tightly curved unguals in tapejarids and possibly in thalassodromines (e.g. ...
... Distally, the ungual curves slightly (inner and outer curvatures are 64 and 57.6 degrees, respectively) and points sharply, differing from tightly curved unguals in tapejarids and possibly in thalassodromines (e.g. Sinopterus,"Nemicolopterus", and Tapejara) [3,52,[62][63][64][65]. The ungual of pedal digit I is slightly larger relative to those of digits II-IV. ...
... The manual unguals are large and strongly recurved, possibly suitable for the grasping, but the pedal unguals are reduced in size and curvature, possibly implying terrestrial adaptation. The pedal unguals also vary in curvature in other azhdarchoids [39,52,[62][63][64]. The unguals of azhdarchids (e.g. ...
... In many instances of this, the local author is not affiliated to any research institution (e.g. [32,68,99,200,201] (figures 4 and 5, electronic supplementary material, tables S1 and S2). While we advocate for giving credit where it is due, this 'token authorship' represents the power dynamics at play and is a clear attempt at 'fossil laundering'. ...
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... has since been referred to the Dsungaripteridae (Averianov, 2014). SMNK PAL 2342 and 3830 from the Aptian Crato Formation were identified as azhdarchids because the crosssection of the wing phalanges was said to be 'T'-shaped Frey, 1998, 1999;Frey et al., 2003), but this shape results here from the crushing of a triangular cross-section and is missing in SMNK PAL 3830, and these specimens have since been reidentified as tapejarids (Unwin, 2002;Frey et al., 2003;Kellner, 2004;Sayão and Kellner, 2006;Unwin and Martill, 2007;Elgin and Campos, 2011;Vila Nova and Sayão, 2012). Conversely, two tapejarids from the Crato Formation (MN 4729-V and SMNK PAL 3843) were referred to the Azhdarchidae by Averianov (2014), based on a similar 'T'-shaped cross-section that has not been confirmed and a coracoid crest that is also found in tapejarids, respectively. ...
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The Azhdarchidae have come to be known as the most diverse clade of Late Cretaceous pterosaurs and the largest flying creatures in existence. Since the erection of the taxon nearly four decades ago, many partial specimens have been referred to it from the Early Cretaceous and Late Jurassic, but none of these identifications can be confirmed. The most comprehensive phylogenetic analysis and taxonomy of Pterosauria is presented, and the evolutionary history of the Azhdarchidae is reviewed. As currently known, azhdarchids are restricted to the Late Cretaceous (Turonian–Maastrichtian). Fourteen species are currently included in the Azhdarchidae: Quetzalcoatlus northropi and Q. lawsoni are recovered as sister taxa in a monophyletic Quetzalcoatlus, with Arambourgiania philadelphiae, Hatzegopteryx thambema, a trichotomy with Cryodrakon boreas and Wellnhopterus brevirostris, Zhejiangopterus linhaiensis, Eurazhdarcho langendorfensis, a Phosphatodraco mauritanicus + Aralazhdarcho bostobensis sister group, as well as an Azhdarcho lancicollis + Albadraco tharmisensis + Aerotitan sudamericanus + Mistralazhdarcho maggii clade are recovered as successive outgroups to Quetzalcoatlus in the Azhdarchidae. The previous azhdarchid species Montanazhdarcho minor and Radiodactylus langstoni are recovered as non-azhdarchid azhdarchiforms; Alanqa saharica and Argentinadraco barrealensis are thalassodromines; Cretornis hlavaci and Volgadraco bogolubovi are pteranodontians; and Bakonydraco galaczi is a tapejarine. Up to a dozen pterosaur lineages persist into the latest Cretaceous (Maastrichtian Age) including azhdarchids, pteranodontids, and nyctosauromorphs. In the Late Cretaceous, an ornithocheirid, cimoliopterids, a lonchodrachonid, a lonchodectid, pteranodontians, tapejarines, thalassodromines, a chaoyangopterine, and azhdarchiforms are present. The pterosaurs did not have a terminal decline in diversity and were increasing in species number at the end of the Cretaceous Period.
... leonardii IMCF 1052), whereas that relation is respectively close to and over 0.7 for pteranodontids and archaeopterodactyloids [5,50]. Although compressed, the ulnae show a gentle, dorsally oriented distal curvature, as found in Ta. wellnhoferi [6,61]. ...
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A remarkably well-preserved, almost complete and articulated new specimen (GP/2E 9266) of Tupandactylus navigans is here described for the Early Cretaceous Crato Formation of Brazil. The new specimen comprises an almost complete skeleton, preserving both the skull and post-cranium, associated with remarkable preservation of soft tissues, which makes it the most complete tapejarid known thus far. CT-Scanning was performed to allow the assessment of bones still covered by sediment. The specimen can be assigned to Tupa . navigans due to its vertical supra-premaxillary bony process and short and rounded parietal crest. It also bears the largest dentary crest among tapejarine pterosaurs and a notarium, which is absent in other representatives of the clade. The new specimen is here regarded as an adult individual. This is the first time that postcranial remains of Tupa . navigans are described, being also an unprecedented record of an articulated tapejarid skeleton from the Araripe Basin.
... First, the midcervicals of the new specimen show a lateral pneumatic foramen, contrasting with the absent condition in other Chinese tapejarids (Lü et al. 2006b, Liu et al. 2014. In fact, among the Brazilian tapejarids (including thalassodromines) (e.g., Kellner 2004, Eck et al. 2011, Elgin and Campos 2012, Aires et al. 2013, Vila Nova et al. 2015, Buchmann et al. 2017, midcervicals also present a lateral pneumatic foramen. Second, the neural spine of the midcervical vertebrae in this specimen is higher than that found in another Chinese tapejarid specimen (PMOL-AP00030) (Liu et al. 2014). ...
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Tapejaridae is a clade of toothless pterosaurs typically characterized by a large nasoantorbital fenestra and a premaxillary crest that extends from the anterior to the posterior part of the skull. Sinopterus dongi was the first reported Chinese tapejarid. Another genus “Huaxiapterus” was described, but it was later on determined that “Huaxiapterus” is in fact an invalid name. Here, we report on a new juvenile specimen of Sinopterus atavismus from the Jiufotang Formation of western Liaoning, China, and revise the diagnosis of this species. Sinopterus atavismus does not present a square-like crest. Moreover the feature that groove in the ventral part of the second or third phalanx of manual digit IV is not diagnostic of the species. In the new material, the skull preserves a pointed process in the middle part of the dorsal margin of the premaxillary crest, which is different from other Chinese tapejarids. Considering the new specimen is known from a large skeleton that differed from the holotype, this difference may be related to ontogeny, as the premaxillary crest of the holotype is short and does not extend as long as that of the new specimen.
... Concerning the Chinese "tapejarids," the presence of T-shaped wing phalanges have never been demonstrated for them, and it was explicitly stated that the lack of this feature exclude them from Azhdarchidae (Lü et al. 2006: 321). SMNK 3843 was previously identified as a possible tapejaroid (Frey et al. 2003: fig.1c), non-azhdarchid azhdarchoid (Elgin and Campos 2012), or an azhdarchid (Geist et al. in press). The scapulacoracoid of SMNK PAL 3843 has a coracoid flange rather than a tubercle and is more similar to that of azhdarchids (Frey et al. 2003: fig. ...
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Citation: Averianov A (2014) Review of taxonomy, geographic distribution, and paleoenvironments of Azhdarchidae (Pterosauria) ZooKeys 432: 1–107. doi: 10.3897/zookeys.432.7913 Abstract The taxonomy, geographic distribution, and paleoenvironmental context of azhdarchid pterosaurs are reviewed. All purported pteranodontid, tapejarid, and azhdarchid specimens from the Cenomanian Kem Kem beds of Morocco are referred to a single azhdarchid taxon, Alanqa saharica. The four proposed autapomorphies of Eurazhdarcho langendorfensis from the lower Maastrichtian Sebeş Formation of Ro-mania are based on misinterpretations of material and this taxon is likely a subjective junior synonym of Hatzegopteryx thambema. Among 54 currently reported azhdarchid occurrences (51 skeletal remains and 3 tracks) 13% are from lacustrine deposits, 17% from fluvial plain deposits, 17% from coastal plain depos-its, 18% from estuarine and lagoonal deposits, and 35% from costal marine deposits. Azhdarchids likely inhabited a variety of environments, but were abundant near large lakes and rivers and most common in nearshore marine paleoenvironments. Copyright Alexander Averianov. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. A peer-reviewed open-access journal
... The partial skeleton consists of at least five cervical vertebrae, six thoracic vertebrae, the sternum and pectoral girdles, right and left humeri, radii and ulnae, the right wing metacarpal, elements of the pelvic girdle, and the left femur, and is estimated to have possessed a wing span of approximately 1.2 m, based on comparisons of the humerus with the early complete azhdarchoid SMNK PAL 3900 (where the half span is 8.6 times the humeral length). Although only partially complete, the presence of an unwarped deltopectoral crest on the humerus (Unwin, 2003) distinguishes SMNK PAL 3985 from the numerous ornithocheiroids known to have inhabited the region (e.g., Wellnhofer, 1991;Kellner and Tomida, 2000), while large pneumatopores on the ventral and posterior faces of the humerus and femur, respectively, remain a feature only observed within the Azhdarchoidea, specifically for Tapejara wellnhoferi where numerous postcranial elements are known (Wang et al., 2009;Eck et al., 2011;Elgin and Campos, 2011). Beyond that of an indeterminate azhdarchoid, no further taxonomic identification is possible owing to a lack of diagnostic anatomical or morphometric characters. ...
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Background In the Early Cretaceous Jehol Biota, the toothless pterosaurs flourished with the chaoyangopterids and tapejarids playing a key role in understanding the early diversity and evolution of the Azhdarchoidea. Unlike the more diverse tapejarids, the rarer chaoyangopterids are characterized by a long and low rostrum, supporting a close relationship with the huge azhdarchids. Unfortunately, our knowledge is still limited in the osteology, paleoecology, and taxonomy of the Chaoyangopteridae. As one of the best preserved skeletons, the type and only specimen of Jidapterus edentus provides an opportunity to understand the morphology and paleoecology of the chaoyangopterids. Results Our study of the osteology of Jidapterus edentus reveals valuable information about the morphology of the Chaoyangopteridae such as a rostrum with a curved dorsal profile, high Rostral Index (RI), larger angle between the dorsal and postorbital processes of the jugal, sequentially shorter fourth to seventh cervical vertebrae, sternum with a plate wider than long, contact of the metacarpal I with the distal syncarpal, pneumatic foramen on first wing phalanx, hatchet-like postacetabular process with unconstricted neck and small dorsal process, distinctly concave anterior margin of pubis, subrectangular pubic plate with nearly parallel anterior and posterior margins, longer proximal phalanges of pedal digits III and IV, as well as reduced and less curved pedal unguals. These features further support the validity of Jidapterus edentus as a distinct species and the close relationship of the chaoyangopterids with the azhdarchids. Paleoecologically, the chaoyangopterids are probably like the azhdarchids, more terrestrial than the contemporaneous and putatively arboreal tapejarids, which may have been limited to the forest-dominated ecosystem of the Jehol Biota. Discussion The osteology of Jidapterus edentus further supports the close relationship of the Chaoyangopteridae with the Azhdarchidae in sharing a high RI value and reduced and mildly-curved pedal unguals, and it also implies a possible paleoecological similarity in their terrestrial capability. Combined with the putatively arboreal and herbivorous tapejarids, this distinct lifestyle of the chaoyangopterids provides new insights into the diversity of pterosaurs in the ecosystem of the Jehol Biota.
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Tapejarids are edentate pterosaurs recovered mainly from Early Cretaceous deposits. They are diagnosed by five synapomorphies, among which only one is postcranial: a broad and well-developed tubercle at the ventroposterior margin of the coracoid. Regarding the clade Thalassodrominae, most phylogenetic studies are based on cranial elements, as postcranial skeletons of these pterosaurs are rare. Here, new postcranial material from the Romualdo Formation (Aptian–Albian) from the Araripe Basin is described. The material comprises the three posteriormost cervical vertebrae, the first seven dorsal vertebrae (fused into a notarium), both scapulocoracoids, a fragment of a sternum, a partial right humerus, a small fragment of a 4th phalanx of the wing finger, a distal extremity of the right femur and the proximal portions of both tibia and fibula. Comparisons with other specimens and morphological features examined in a phylogenetic context, such as the presence of three foramina lateral and dorsal to the neural canal of the cervical vertebrae, the presence of a notarium and a pneumatic foramen on the ventral side of the proximal portion of the humerus, allow the assignment of this specimen as Thalassodrominae indet. Regarding palaeobiogeographical aspects, to date, this clade is exclusively found in the Romualdo Formation. It is the most complete postcranial material assigned to the Thalassodrominae described so far.
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New specimens of pterosaurs with soft-part preservation from the Solnhofen Lithographic Limestone (S Germany) and the Crato Formation (northeastern Brazil) yield hitherto unknown and unexpected details of pterosaur anatomy: the presence and internal anatomy of soft-tissue crests, the internal anatomy of the brachiopatagium, including a blood vessel system and structural details of foot and hand. Some consequences for pterosaurian flight, thermoregulation and aspects of evolution are discussed.
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This beautifully illustrated 2007 volume describes the entire flora and fauna of the famous Lower Cretaceous Crato Formation of Brazil - one of the world's most important fossil deposits, exhibiting exceptional preservation. A wide range of invertebrates and vertebrates are covered, including extended sections on pterosaurs and insects. Two chapters are devoted to plants. Many of the chapters include descriptions of new species and re-descriptions and appraisals of taxa published in obscure places, rendering them available to a wider audience. Fossil descriptions are supported by detailed explanations of the geological history of the deposit and its tectonic setting. Drawing on expertise from around the world and specimens from the most important museum collections, this book forms an essential reference for researchers and enthusiasts with an interest in Mesozoic fossils.
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Introduction The first significant account of a pterosaur from the Crato Formation was published over a decade ago (Frey and Martill, 1994). In the short intervening period between then and now, more than 30 individuals have come to light. This is a modest total, especially when compared to the 1000+ individuals recovered, for example, from the Solnhofen Limestones of southern Germany or the Niobrara Chalk of Kansas. Still, several finds notable for their completeness, or for the exceptional preservation of soft-tissue structures, such as extensions to cranial crests or of the integument associated with the foot, have already demonstrated the importance of this lagerstätte for our understanding of pterosaur palaeobiology (Frey and Martill, 1994; Campos and Kellner, 1997; Frey and Tischlinger, 2000; Frey et al., 2003c). The Crato pterosaur assemblage also contains a number of genera (e.g. Arthurdactylus, Ludodactylus, Ingridia gen. nov.) that are unique to this deposit (Frey and Martill, 1994; Frey et al., 2003b; this chapter). They represent several Lower Cretaceous pterosaur lineages and throw some much-needed light on the ecology, palaeobiogeography and evolutionary history of pterosaurs during an interval when they appear to have reached their highest levels of global diversity (Unwin, 2005). Fragments of several limb bones from the Upper-Triassic Caturrita Formation of southern Brazil (Bonaparte et al., 2006) may represent the earliest occurrence of pterosaurs in South America.
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This paper is concerned with the famous fossil-bearing carbonate concretions of the Romualdo Member of the Santana Formation Konservat Lagerstätten of north-east Brazil. This palaeontologically important horizon was first dated as Cretaceous by the French palaeoichthyologist Louis Agassiz on the basis of fish fossils obtained by Bavarian explorers Spix and Martius between 1817 and 1820 and Scottish botanist and explorer George Gardner between 1836 and 1841. Gardner equated the concretion level with the English Albian ‘Upper Greensands’ on the basis of an imagined similarity of stratigraphic sequence with that of the Isle of Wight, southern England. Since then high precision dating of this remarkable deposit has proved elusive and the concretion-bearing part of the Santana Formation has been variously dated as early Late Cretaceous or late Early Cretaceous. Attempts at greater precision over the last 30 years have cited its age variously as Aptian, Albian or possibly Cenomanian, but few reliable data have been presented to support these dates.