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New material of Chaoyangopterus (Pterosauria: Pterodactyloidea) from the Early Cretaceous Jiufotang Formation of western Liaoning, China


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A new edentulous pterosaur from the Yuanjiawa beds of the Early Cretaceous Jiufotang Formation in Yuanjiawa, Chaoyang, western Liaoning, China, is described. The fossil, an incomplete and scattered skeleton, including partial skull and lower jaws, is identified as Chaoyangopterus zhangi, based on similar proportions of the limb bones. The specimen shows that Chaoyangopterus possessed moderately elongate mid-cervical vertebrae with low, blade-like neural spines and lacked lateral pneumatic foramina. This discovery not only further supports a distinct Chaoyangopteridae within the Azhdarchoidea, but also provides a new scope for reviewing the evolution of the family Azhdarchidae.
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New material of Chaoyangopterus (Pterosauria:
Pterodactyloidea) from the Early Cretaceous Jiufotang Formation
of western Liaoning, China
Chang-Fu Zhou, Shenyang
With 4 figures and 1 table
, C.-F. (2010): New material of Chaoyangopterus (Pterosauria: Pterodactyloidea) from the
Early Cretaceous Jiufotang Formation of western Liaoning, China. – N. Jb. Geol. Paläont. Abh.,
257: 341– 350; Stuttgart.
Abstract: A new edentulous pterosaur from the Yuanjiawa beds of the Early Cretaceous Jiufotang
Formation in Yuanjiawa, Chaoyang, western Liaoning, China, is described. The fossil, an incomplete
and scattered skeleton, including partial skull and lower jaws, is identified as Chaoyangopterus
zhangi, based on similar proportions of the limb bones. The specimen shows that Chaoyangopterus
possessed moderately elongate mid-cervical vertebrae with low, blade-like neural spines and lacked
lateral pneumatic foramina. This discovery not only further supports a distinct Chaoyangopteridae
within the Azhdarchoidea, but also provides a new scope for reviewing the evolution of the family
Key words: Pterosauria, Pterodactyloidea, Azhdarchoidea, Chaoyangopterus, Early Cretaceous,
Jiufotang Formation, western Liaoning.
1. Introduction
Pterosaurs, along with feathered dinosaurs, basal
birds, and mammals, flourished in the Jehol Biota
during the Early Cretaceous of western Liaoning
Province and adjacent areas of northeastern China.
Until now, 26 nominal species of pterosaurs have been
reported from the Jehol Group, including both basal
pterosaurs and pterodactyloids (A
& J
et al. 2006a, 2007, 2008; W
et al. 2007, 2008a,
b). Apart from the anurognathid Dendrorhynchoides
curvidentatus J
& J
, 1998, pterodactyloid pterosaurs
dominated the Jehol Biota with 25 taxa, representing
a significant diversity of pterosaurs in Cretaceous
terrestrial ecosystems (W
et al. 2005).
Recently, 11 edentulous pterosaur taxa have been
named, including the tapejarids Sinopterus dongi
& Z
, 2003, Sinopterus gui L
et al., 2003,
Huaxiapterus jii L
& Y
, 2005, Huaxiapterus
corollatus L
et al., 2006b, and Huaxiapterus ben-
xiensis L
et al. 2007, having a deep snout and
dentary crest; and the possible azhdarchoids Chao -
yangopterus zhangi W
& Z
, 2003, Jidapterus
edentus D
et al., 2003, Eopteranodon lii L
, 2005, Eoazhdarcho liaoxiensis L
& J
, 2005,
Nemicolopterus crypticus W
et al., 2008b, and
Shenzhoupterus chaoyangensis L
et al., 2008, having
a low and strongly elongate snout and lower jaws. Of
these azhdarchoids, Nemicolopterus crypticus is a tiny
pterosaur apparently specialized for an arboreal
© 2010 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany
DOI: 10.1127/0077-7749/2010/0081 0077-7749/2010/0081 $ 2.50
N. Jb. Geol. Paläont. Abh. 257/3, 341– 350 Article
published online June 2010
342 Chang-Fu Zhou
forest-dwelling lifestyle(W
et al.2008b). However,
the other five taxa are similar to each other, having
a long and low skull and lower jaws, but are clearly
different from the Chinese tapejarids (Sinopterus
and Huaxiapterus). Except for the recently-erected
Shenzhoupterus, the other four azhdarchoid taxa were
thought to be synonymous with Chaoyangopterus and
were included within the Pteranodontidae by W
(2006), but L
& J
(2006), L
et al. (2006a),
& J
(2008), and L
et al. (2008) disputed a
pteranodontid affinity. Consequently, L
et al. (2008)
erected Chaoyangopteridae to include the five taxa,
and assigned it to the Azhdarchoidea on the basis
of several characters: relatively large nasoantorbital
fenestra; relatively short wing-finger, elongate first
wing phalanx; and relatively long hindlimb. In ad -
dition, the recently described Lacusovagus magni -
ficens from the Early Cretaceous (?Aptian) of Brazil
has been referred to the Chaoyangopteridae, implying
a wide geographical distribution for this group
2008). Thus chaoyangopterids perhaps
represent an early radiation of long-snouted and
edentulous azhdarchoid pterosaurs in the Early Creta-
The present study describes a new specimen of
Chaoyangopterus collected from the Early Cretaceous
Jiufotang Formation in Yuanjiawa Village, Daping-
fang, Chaoyang City, western Liaoning Province in
2005. Resembling the above five taxa, this specimen
has a long and low skull and lower jaws, and adds
further insight into the anatomy of these edentulous
pterosaurs. The specimen is identified as Chaoyang-
opterus zhangi based on similar proportions of the
limbs. This discovery of the specimen described here
not only provides new knowledge of the anatomy of
Chaoyangopterus, but also provides important in -
sights on the evolution of the Azhdarchoidea.
2. Geological setting
In 2004 and 2005, the Paleontological Institute of
Shenyang Normal University undertook a field col -
lecting program in western Liaoning. The two-
year program resulted in the collection of hundreds
of vertebrate fossils, including specimens of the
feathered dinosaur Microraptor, the birds Jeholornis,
Confuciusornis, Dapingfangornis, and Alethoala -
ornis, the pterosaurs Longchengopterus and Chao -
yangopterus, and aquatic reptiles, including turtles
and choristoderes (D
et al. 2006; L
et al. 2006,
2007; L. W
et al. 2006). The fossil locality
(41°34’20”N, 120°09’30”E; Fig. 1) is situated on a
hill near Yuanjiawa Village, Dapingfang, Chaoyang
City, western Liaoning Province. The fossil-bearing
layer occurs within the Yuanjiawa beds of the Early
Cretaceous (Aptian) Jiufotang Formation (H
et al.
Fig. 1. (A) Locality map showing the fossil site (asterisk; 41°34’20”N, 120°09’30”E) of Yuanjiawa Village, Dapingfang,
Chaoyang City, western Liaoning Province, Northeast China. (B) Photo of outcrop in the fossil site of Yuanjiawa Village.
Arrows point the three brown-yellow marl layers, by numbered as I-III.
2004), which is a lacustrine unit consisting mainly of
dark-gray mudstone, shale, and sandstone with three
brown-yellow marl layers (D
et al. 2006; Fig. 2).
The pterosaur fossil described here is from a layer
2.1 m below the second brown-yellow marl layer.
3. Material and methods
The specimen, LPM (Liaoning Paleontological
Museum)-R00076, is an incomplete and scattered
skeleton, including a partial skull and lower jaws,
six cervical vertebrae, at least nine dorsal vertebrae,
partial pectoral girdles, humeri, ulnae, radii, wing
metacarpals, wing phalanges 1-4; femora and tibio -
tarsi. It was collected in 2005 from a locality
(41°34’20”N, 120°09’30“E), which is near Yuan -
jiawa Village, Dapingfang, Chaoyang, western Liao-
ning. The specimen was prepared carefully by using
mechanical tools in LPM, and is deposited in LPM,
Shenyang Normal University.
4. Description
The specimen (LPM-R00076) is a medium-sized
pterosaur with an estimated wingspan of 1.45 m, less
than the holotype, in which the wingspan is estimated
as 1.71 m. It most probably represents a juvenile
individual and displays several immature features,
such as an unfused extensor tendon process of the first
wing phalanx, and separated scapula and coracoid
(e.g. B
Sku ll. The anterior part of the skull is the most
extensive part preserved. The snout is low, long, and
pointed, with a large nasoantorbital fenestra, but the
complete boundaries of the fenestra are uncertain
because of poor preservation. In addition, a part of the
braincase isolated from the skull exposes its roof
in ventral view. Two large and smooth depressions
separated by a low sagittal ridge possibly represent the
cerebral region, as in Rhamphorhynchus, Anhanguera,
and Pteranodon (B
2001; W
et al. 2003);
each depression is semicircular as in Anhanguera and
Pteranodon. The sagittal ridge is deeper anteriorly
than posteriorly and distally is confluent with a bony
wall. Posterolaterally, an elliptical depression meets
the sagittal ridge at an acute angle. This depression is
smaller and slightly higher than the cerebral region,
and may mark the position of the optic lobe. The
shape of the optic lobe is swollen, more like that in
Rhamphorhynchus than in Anhanguera and Pterano -
don. Another smaller, circular depression just behind
Chaoyangopterus from the Early Cretaceous Jiufotang Formation of western Liaoning, China 343
Fig. 2. The stratigraphic section of the fossil site and adja-
cent area, identified as the Yuanjiawa beds of the Jiufotang
Formation. The pterosaur fossil (LPM-R00076) is from the
shale layer that is marked by asterisk, and associated fossils
include fish and bird fossils. I-III, representing three brown-
yellow marl layers. Modified from D
et al. (2005).
Scale equals 50 cm.
344 Chang-Fu Zhou
the cerebral region represents an unknown part of the
The lower jaws overlap each other, and are missing
their proximal ends. The preserved length of the lower
jaws is about 190 mm, of which the symphysis is
about 105 mm, but there is no evidence of a ventral
sagittal crest at the distal end of the symphysis, and
thus differing from Eopteranodon (L
& Z
Fig. 3. Chaoyangopterus zhangi W
& Z
, 2003, an incomplete and scattered skeleton, LPM-R00076, collected from
a site (41°34’20”N, 120°09’30”E) near Yuanjiawa Village, Dapingfang, Chaoyang, western Liaoning, China. Its precise
horizon is Yuanjiawa beds of Jiufotang Formation (middle Early Cretaceous, Aptian) with a radiometrical dating of 120 Ma.
Abbreviation: br, braincase; c, coracoid; cve, cervical vertebrae; dve, dorsal vertebrae; lf, left femur; lh, left humerus;
lr, left radius; lu, left ulna; lw, lower jaws; mc I-III, metacarpal I-III; mds, manual digits; rf, right femur; rh, right humerus;
ribs, ribs; rr, radius; ru, right ulna; s, scapula; sa, sacrum; sk, skull; t, tibiotarsus; u, ulna; wmc, wing metacarpal; wp1-4,
wing phalanges 1-4; ?, unknown bones. Scale equals 50 mm.
2005). The elongate symphysis is similar to that in
Chaoyangopterus and Jidapterus (W
& Z
2003; D
et al. 2003).
Axial skeleton. – The caudal-most four cervical
and as many as six dorsal vertebrae are articulated in a
series. A second series comprises three or four dorsal
vertebrae and the sacrum. In addition, two isolated
vertebrae appear to be anterior cervicals. The smaller
of these two may be the axis in posterior or anterior
view. The centrum appears to be broken away from the
neural arch. A small neural canal that is 4 mm wide
and 2 mm high is enclosed by the neural arch. Above
the canal, however, the detailed morphology of the
neural arch is obscure. In contrast, the second cervical
vertebra is elongate and exposed in ventral view with
a length of 26 mm. Much of its morphology is
obscured by damage to its lateral wall. There is a
shallow and longitudinal groove at the base of the
prezygapophysis. A possible rib is preserved against
the second cervical vertebra; but other cervicals lack
evidence of ribs.
Chaoyangopterus from the Early Cretaceous Jiufotang Formation of western Liaoning, China 345
Fig. 4. The mid-cervical vertebrae of Chaoyangopterus zhangi W
& Z
, 2003 (LPM-R00076). Abbreviations:
dve, dorsal vertebrae; ls, longitudinal sulcus; ns, neural spine; pc, posterior condyle; pex, postexapophysis; poz, post -
zygapophysis; prz, prezygapophysis; przt, prezygapophysis tubercle. Scale equals 20 mm.
346 Chang-Fu Zhou
The posteriormost four cervicals (Fig. 4) that are
articulated with the dorsals are distinctly longer
than the second cervical, having lengths of 40 mm,
40.4 mm, 37.9 mm, and 37.5 mm respectively. The
neural arch is fused to the centrum. No pneumatic
foramina penetrated the lateral side of the cervicals,
resembling Jidapterus, Eopteranodon and Eoazh -
darcho in this respect. In the cervical series, the first
vertebra is exposed laterally and ventrally and is
strongly procoelous. The preserved posterior part
of the neural spine is low and blade-like. The right
prezygapophysis is exposed laterally, with a shallow
and long groove at its base, resembling the longi -
tudinal sulcus of the long-necked azhdarchids, such
as Azhdarcho, Phosphatodraco, Arambourgiania,
Quetzalcoatlus, and an unnamed Hungarian azhdar-
chid (e.g. M
et al. 1998; ˝
et al. 2005;
& P
2006). The medial side of
the prezygapophysis is exposed with an oval articular
surface that faces more medially than dorsally, having
a flat ventromedial tubercle, the prezygapophysis
tubercle, as in the long-necked azhdarchids (˝
et al.
2005). The postzygapophysis is stout and extends
posterolaterally. In contrast, the posterior articular
condyle and the postexapophyses, which form the
posterior end of the cervical centrum, extend poster -
iorly far beyond the postzygapophysis. The left
postexapophysis is obscured by the prezygapophysis
of the next successive vertebra. The second cervical
is almost complete except for damage to the neural
spine, seen in lateral view. The well-developed pre -
zygapophysis is ventral to the level of the postzygapo-
physis, as an artifact of compaction. The postzygapo-
physis is comparable to the distal end of the centrum
in size. Distally, the postexapophysis extends slightly
beyond the articular condyle. The penultimate cervical
is exposed in ventral view. The centrum gradually
increases in width from its mid-part to the anterior and
posterior ends, respectively. The prezygapophyses are
well developed and nearly parallel to each other, as in
the long-necked azhdarchid pterosaurs. However, the
cervical has a low ratio (2.1) of length (from the tip of
the prezygapophysis to the end of the postexapopysis)
to width (across the prezygapophyses), differing from
the extremely elongate cervicals of azhdarchids.
The centrum is smooth without a ventral keel. The
postexapophyses are well developed with a width
of 13 mm and forming prominent corners on the
centrum. The last cervical vertebra is exposed ven -
trally and slightly laterally; it is slightly shorter
than the penultimate cervical. In addition, the distal
extension of the postexapophyses is strongly reduced
to the level of the postzygapophyses.
Compared with the cervicals, the dorsal vertebrae
are poorly preserved. There are two series of dorsals:
the anterior series is articulated with the cervicals;
the posterior part is adjacent to the sacrum. The first
of the dorsal series is cervicalized, representing a
transition from the neck to the dorsal column, with
a length of 11 mm. It well articulates with the last
cervical vertebra. Other dorsals of the anterior series
are damaged and yield no useful information, thereby
it is uncertain whether the notarium is present or not in
LPM-R00076. The posterior part of the dorsal series is
preserved with the centra exposed in lateral view. The
dorsal centra are smooth ventrally without a keel.
Their mean length is about 7 mm. The sacrum is
damaged, lacking any useful information.
Rib s. A possible cervical rib is present near the
isolated cervical vertebra. Anterior dorsal ribs are
short and robust, and are in articulation with the dorsal
vertebrae, but they are poorly preserved. Other ribs
are scattered around the skull.
Pectoral girdle. – The pectoral girdle is composed
of the scapula and coracoid; these are separated in
LPM-R00076, rather than fused as in adult pterosaurs.
The scapula is relatively stronger and slightly longer
than the coracoid. The right scapula is well exposed
and weakly curved. Its blade is mostly straight and
unconstricted, but curves medially and ventrally in its
proximal third. Because the right coracoid is obscured
by the right scapula, its morphology cannot be de -
termined except at its distal end. In contrast, the left
coracoid is well-exposed, and has a broad proximal
end with a distinct flange. The shaft is clearly con -
stricted at its midpoint, and then slightly broadens
near its distal end. The distal end of the coracoid
exhibits two small condyles separated by a shallow
groove, forming a concave facet for articulation with
the sternal plate.
Forelimb. – The forelimb bones are scattered, so
the original position of its elements are difficult to
determine. Both humeri are well preserved. The left
humerus is exposed in dorsal view, and the right
one in ventral view. The pneumatic foramen is not
preserved on the proximal end of the humerus. The
humeral head is saddle-shaped, as in other pterosaurs.
A well-developed deltopectoral crest is situated at the
proximal end of the humerus. Its medial margin is at
the same level as the humeral head. The deltopectoral
crest extends down about 21% of the humeral shaft,
and quite distinct from the high ratio (40 %) seen in
pteranodontids, and is not warped as in the Pterano -
dontidae (B
1989). Associated with the delto-
pectoral crest, a prominent posterior tuberosity is
developed on the opposite side. However, the tubero -
sity is obscured by the overlapping tibiotarsus. Distal
to the deltopectoral crest, the humeral shaft is straight
and strongly constricted, and then the shaft is slightly
expanded distally in its distal half. The condyles at the
distal end of the humerus are not well ossified, further
implying that LPM-R00076 is an immature indi -
The ulna and radius are comparable to each other in
size, as in Jidapterus (D
et al. 2003), but different
from Eoazhdarcho, in which the ulna is much wider
than the radius (L
& J
2005), and they are distinctly
elongate (40 % longer than the humerus).
The wing metacarpal is well developed, with a
length of 148 mm, and is notable for its broad
proximal end and oval, bicondylar joint distally.
Proximally, the wing metacarpal is expanded antero-
posteriorly. However, the shaft is gradually constricted
anteroposteriorly and expanded dorsoventrally to form
the distal bicondylar joint. The two well-defined
condyles are separated by a deep intercondylar groove
for articulating with the first wing phalanx. Meta -
carpals I-III are scattered around the wing metacarpal.
They are very slender and much shorter than the wing
metacarpal. Compared with their slender shafts, the
distal ends of the metacarpals I-III are distinctly
expanded for articulation with digits I-III.
The wing phalanges of digit IV are also disarti -
culated. There are four of these phalanges that are
preserved together, with the distal three in a row; these
decrease in length and are the phalanges of the wing
finger. The first three phalanges have a constricted
shaft between the expanded ends. The first wing
phalanx is the longest limb element of LPM-R00076.
Associated with the wing metacarpal, the first wing
phalanx has a convex proximal articular surface.
However, the extensor tendon process is not fused to
the proximal end of the first wing phalanx, which is
an important immature feature in pterosaurs (e.g.
1993). The pneumatic foramen is not pre -
served on the proximal end of the first wing phalanx
in LPM-R00076. The distal end of the first wing
phalanx is expanded to form a foot-like process. In
contrast, the distal wing phalanges are distinctly
reduced in size (Table 1). The fourth wing phalanx as
preserved has a length of 54 mm, but its distal end is
damaged. Other digits are poorly preserved and yield
no useful information.
Hindlimb. – The right femur is exposed in posterior
view, and the left in anterior view. The femoral head is
mediodorsally oriented, resulting in a total length of
the femur of 107.7 mm. Below the head, a distinct
neck joins the femoral shaft. The shaft of the right
femur is straight, while that of the left is slightly
curved medially. The shaft gradually becomes slightly
broader distally, and is best seen in the left femur. The
distal end of the right femur has two condyles; these
are comparable to each other in size, except that the
external condyle is expanded more posteriorly than
the internal one. The distal end of the left femur is
obscured by the overlapping lower jaws.
As in other edentulous pterosaurs, the tibiotarsus
is slightly shorter than the first wing phalanx in
LPM-R00076, with a length of 156 mm. The shaft of
the tibiotarsus is straight; its proximal end is expanded
and its distal end constricted. The pes is not preserved
in this specimen.
4. Discussion
In the Jehol Biota, there are six possible azhdarchoids
Chaoyangopterus zhangi, Jidapterus edentus, Eopte -
ranodon lii, Eoazhdarcho liaoxiensis, Nemicolopterus
crypticus, and Shenzhoupterus chaoyangensis, with a
low and strongly elongate snout and lower jaws
& Z
2003; D
et al. 2003; L
& Z
2005; L
& J
2005; L
et al. 2008; W
et al.
2008b). Based on the above description, LPM-
R00076 is comparable to these taxa in cranial
morphology. However, LPM-R00076 differs from
Eopteranodon in lacking the dentary crest and the
wing metacarpal that is equal in length to the second
wing phalanx. LPM-R00076 differs from Eoazhdar-
Chaoyangopterus from the Early Cretaceous Jiufotang Formation of western Liaoning, China 347
Table 1. Measurements of Chaoyangopterus zhangi W
& Z
, 2003 (LPM-R00076).
Right (length mm) Left (length mm)
Scapula/Coracoid 56.3/45.2 ?/44.8
Humerus 78 79
Ulna/Radius 110.5/111.3 >108/>110
Wing metacarpal 149.4 151
Wing phalanges 1-4 164/112/71/>34 162/112/70/?
Femur 107.7 106
Tibiotarsus 158 156
348 Chang-Fu Zhou
cho by lacking the humerus and femur that are equal
in length, and the deltopectoral crest that is 33 % of
the length of the humerus. The difference of LPM-
R00076 from the recently erected Shenzhoupterus is
lacking the convex lower jaw margin, and relatively
short tibiotarsus. In contrast, LPM-R00076 is com -
parable to Chaoyangopterus zhangi and Jidapterus
edentus in the proportions of the limbs. However,
LPM-R00076 lacks a pneumatic foramen on the
proximal end of first wing phalanx that has been
reported in Jidapterus edentus (L
et al. 2006a).
Therefore, LPM-R00076 is identified as Chaoyango -
pterus zhangi on the basis of the similar skull shape
and limb proportions.
Recently, W
& Z
(2006) argued that Jida -
pterus, Eopteranodon, and Eoazhdarcho are syno-
nyms of Chaoyangopterus in the Pteranodontidae, but
without providing an explicit justification. However,
the opposite opinion that these taxa are valid, and most
or all of them pertain to the Azhdarchoidea, is pre -
ferred by L
& J
(2006), L
et al. (2006a), A
& J
(2008), and L
et al. (2008). A phylogenetic
analysis by L
& J
(2006) suggested that these
Chinese taxa may pertain to the Azhdarchoidea,
and that Chaoyangopterus and Jidapterus are more
derived than Eopteranodon and Eoazhdarcho within
this clade. However, L
et al. (2006a: 66-71) initially
identified these taxa as pteranodontids (Chaoyango -
pterus, Jidapterus, and Eopteranodon) and azhdar-
choids (Eoazhdarcho), but later indicated that they are
all possible azhdarchoids (see L
et al. 2006a: 97), or
possible pteranodontid (Eopteranodon) and azhdar-
choids (Chaoyangopterus, Jidapterus, and Eoazh -
darcho) (see L
et al. 2006a: 115). Recently, a phylo-
genetic analysis by A
& J
(2008) showed that
Chaoyangopterus, Jidapterus, and Eoazhdarcho unite
together as the sister group of Azhdarchidae, while
Eopteranodon falls within the Tapejaridae. Lastly, a
clade, Chaoyangopteridae, erected by L
et al. (2008)
to include the five taxa, was assigned to the Azhdar-
choidea. In fact, these arguments are mainly due to the
limited anatomical information about these taxa in
their original descriptions. Therefore, a more reliable
phylogeny can only be performed by reexamining
specimens of these taxa, but this is not the purpose of
this study. In this context, based on the new material
(LPM-R00076), the taxonomic position of Chaoyang-
opterus itself is discussed.
Within the Pterodactyloidea, there are three eden-
tulous clades: Nyctosauridae, Pteranodontidae, and
Azhdarchoidea (Tapejaridae and Azhdarchidae) (e.g.
2003). LPM-R00076 differs from the
Nyctosauridae in lacking a hatched-shaped delto -
pectoral crest and an extremely elongate wing meta-
carpal IV (250 % the length of the humerus); and from
the Pteranodontidae in lacking tall and spike-like
neural spines on the mid-cervical vertebrae, a scapula
shorter than the coracoid; and a warped deltopectoral
crest on the humerus. Chaoyangopterus possibly
belongs to the Azhdarchoidea by sharing one synap-
morphy, the ratio of the length of the second wing
phalanx to that of the first is less than 0.70 (K
2003). Within the Azhdarchoidea, however, Chao -
yangopterus can be confidently excluded from the
Tapejaridae by the low and strongly elongate snout
and lower jaws, and can be distinguished from the
Azhdarchidae by its moderately elongate mid-cervical
vertebrae. Except for the moderately elongate mid-
cervicals, however, Chaoyangopterus (LPM-R00076)
shares a character with the Azhdarchidae: the lateral
pneumatic foramina are absent on the cervical verte-
brae. Additional characters of the cervical vertebrae
are similar to the extremely elongate mid-cervicals of
the Azhdarchidae, such as the horn-like and slightly
divergent prezygapophyses (H
1986), and a
longitudinal sulcus at the base of the prezygapophysis
et al. 2005). Therefore, Chaoyangopterus appears
to have a close relationship with the Azhdarchidae,
consistent with the phylogenetic results of L
& J
(2006), L
et al. (2006a), A
& J
(2008), and
et al. (2008); but the moderately elongate mid-
cervicals and the blade-like neural spines imply that
Chaoyangopterus possibly represents a distinct clade
(the family Chaoyangopteridae) from the Azhdarchi-
dae, as suggested by A
& J
(2008) and L
et al.
The Azhdarchidae characteristically possess ex -
tremely elongate mid-cervical vertebrae with strongly
reduced or absent neural spines, and flourished to the
end of the Cretaceous (e.g. L
1975; W
1991; H
& P
2006). How -
ever, a similar condition of the mid-cervical vertebrae
has been reported in the tooth-bearing Ctenochas -
matidae, implying a homoplasy of the extremely
elongate mid-cervical vertebrae between the two
clades (e.g. A
& J
2008). Associated with the
elongate mid-cervical vertebrae, the strongly reduced
or absent neural spines and well-developed postexapo-
physes are present in both groups. In contrast, the
mid-cervical vertebrae of the azhdarchids are distinct
from those of the ctenochasmatids in lacking lateral
pneumatic foramina. However, the evolution of the
Azhdarchidae is still poorly understood, especially in
the extremely elongate mid-cervical vertebrae.
Recently, a hypothesis further enhanced the argument
on the evolution of the azhdarchids by A
& J
(2008) that low and blade-like neural spines were
absent in the lineage from which the azhdarchids were
As the recent phylogenetic results, the Chao -
yangopteridae is a sister group of the Azhdarchidae
& J
2008; L
et al. 2008). The moderately
elongate mid-cervicals with low and blade-like neural
spines are present in Chaoyangopterus, well opposing
to the hypothesis of A
& J
(2008). A similar
condition was reported in the holotype of Eoptera -
nodon (L
& Z
2005), but not in its referred
specimen (L
et al. 2006c). The moderately elongate
mid-cervicals with low and blade-like neural spines
have not been reported in other Chaoyangopterus-like
taxa, perhaps because of the poor preservation of
the mid-cervical vertebrae, or a primitive position
of Chaoyangopterus relative to other taxa in the
Chaoyangopteridae, but this need be further con -
firmed by additional material. In fact, several azhdar-
chid taxa have been reported with a tall and blade-like
neural spine on the first or last mid-cervical vertebra,
such as Quetzalcoatlus, Zhejiangopterus and Phos-
phatodraco (P
et al. 2003; A
& J
2008). Therefore, these discoveries may suggest
that the Azhdarchidae are possibly derived from a
Chaoyangopterus-like lineage that has moderately
elongate mid-cervical vertebrae with low and blade-
like neural spines.
This study was supported by grants from the National
Scientific Foundation of China (Grant #40802007) and
from the Ph.D. Start-up Foundation of Shenyang Normal
University. The author would like to thank the director of
Institute of Paleontology, S
for accessing the
fossil, and S
and Q
for their skillful
preparation. I would like to express my gratitude to Prof.
C. F
(University of Alberta, Canada) and Prof.
(Peking University, China) for encouraging me
to study this field and for their stimulating discussions and
helpful corrections about the earlier versions of the
manuscript. I would like to thank Dr. S. C
(Fort Hays State University, Kansas, U.S.A) and
Dr. D
(University of Portsmouth, Portsmouth,
UK) for their critical reviews of the manuscript that their
suggestions have greatly improved the quality of the
, B. & J
, Q. (2008): A new pterosaur from the
Liaoning Province of China, the phylogeny of the Ptero-
dactyloidea, and convergence in their cervical vertebrae.
– Palaeontology, 54: 453-469.
, S. C. (1989): A pteranodontid pterosaur from
the Early Cretaceous of Peru, with comments on the
relationships of Cretaceous pterosaurs. – Journal of
Paleontology, 63: 669-677.
(1993): The ontogeny of Pteranodon and other ptero-
saurs. – Paleobiology, 19: 92-106.
(2001): The osteology and functional morphology of the
Late Cretaceous pterosaur Pteranodon: Part I. General
description of osteology. – Palaeontographica, (A), 260:
, Z.-M., S
, Y.-W. & W
, S.-Y. (2003): On a new
pterosaur from the Lower Cretaceous of Chaoyang
Basin, western Liaoning, China. – Global Geology, 22:
1-7 (in Chinese with English abstract).
, Y., Z
, L.-J., L
, L. & C
, S.-L. (2006):
Division and correlation of unique fossil-bearing beds of
Jiufotang Formation in Dapingfang-Meileyingzi Basin
of western Liaoning. – Global Geology, 25: 113-119 (in
Chinese with English abstract).
, H.-Y., W
, X.-L., Z
, Z.-H., W
, F., B
, A.,
, G.-H. & Z
, R.-X. (2004): Timing of the Jiufotang
Formation (Jehol Group) in Liaoning, northeastern
China and its implications. – Geophysical Research
Letters, 31: L12605.
, M. D. & P
, J. E. (2006): An azhdar-
chid pterosaur cervical vertebra from the Hell Creek
Formation (Maastrichtian) of southeastern Montana. –
Journal of Vertebrate Paleontology, 26: 192-195.
, S. C. B. (1986): On the cervical vertebrae of the
Pterodactyloidea (Reptilia: Archosauria). – Zoological
Journal of the Linnean Society, 88: 307-328.
, S.-A. & J
, Q. (1998): A new fossil pterosaur (Rhamphor-
hynchoidea) from Liaoning. – Jiangsu Geology, 22:
199-206 (in Chinese with English abstract).
, A. W. A. (2003): Pterosaur phylogeny and com-
ments on the evolutionary history of the group. – In:
, E. & M
, J.-M. (Eds.): Evolution and
Palaeobiology of Pterosaurs. – Geological Society of
London, Special Publications, 217: 105-137.
, D. A. (1975): Pterosaur from the Latest Creta-
ceous of west Texas: discovery of the largest flying
creature. – Science, 187: 947-948.
, L., D
, Y., H
, D.-Y., W
, L., C
, S.-L. & H
L.-H. (2006): New eoenantiornithid bird from the Early
Cretaceous Jiufotang Formation of western Liaoning,
China. – Acta Geologica Sinica, 80: 38-41.
, L., H
, D.-Y., D
, Y., G
, E.-P. & H
, L.-H.
(2007): Alethoalaornithidae fam. nov.: a new family of
enantiornithine bird from the Lower Cretaceous of
western Liaoning. – Acta Palaeontologica Sinica, 46:
365-372 (in Chinese with English abstract).
, J.-J., L
, J.-C. & B.-K. Z
. (2003): A new Lower
Cretaceous sinopterid pterosaur from the western
Liaoning, China. – Acta Palaeontologica Sinica, 42:
Chaoyangopterus from the Early Cretaceous Jiufotang Formation of western Liaoning, China 349
350 Chang-Fu Zhou
, J.-C. & J
, Q. (2005): New azhdarchid pterosaur the
Early Cretaceous of western Liaoning. – Acta Geologica
Sinica, 79: 301-307.
(2006): Preliminary results of a phylogenetic analysis of
the pterosaurs from western Liaoning and surrounding
areas. – Journal of the Paleontological Society of Korea,
22: 239-261.
, J.-C. & Y
, C.-X. (2005): New tapejarid pterosaur
from western Liaoning, China. – Acta Geologica Sinica,
79: 453-458.
, J.-C. & Z
, B.-K. (2005): New pterodactyloid
pterosaur from the Yixian Formation of western Liao-
ning. – Geological Review, 51: 458-462 (in Chinese with
English abstract).
, J.-C., G
, C.-L., L
, J.-Y., M
, Q.-J. & J
, Q.
(2006c): New material of the pterosaur Eopteranodon
from the Early Cretaceous Yixian Fromation, western
Liaoning, China. – Geological Bulletin of China, 25:
, J.-C., G
, Y.-B., X
, L.-D., L
, Z.-X. & J
, Q. (2007):
A new species of Huaxiapterus (Pterosauria: Tape -
jaridae) from the Early Cretaceous of western Liaoning,
China. – Acta Geologica Sinica, 81: 683-687.
, J.-C., J
, S.-A., Y
, C.-X. & J
, Q. (2006a): Pterosaurs
from China. – 147 pp.; Beijing (Geological Publishing
House). (In Chinese).
, J.-C., J
, X.-S., U
, D. M., Z
, L.-J., A
, Y.
& J
, Q. (2006b): A new species of Huaxiapterus (Ptero-
sauria: Pterodactyloidea) from the Lower Cretaceous
of western Liaoning, China with comments on the
sys tematics of tapejarid pterosaurs. – Acta Geologica
Sinica, 80: 315-326.
, J.-C., U
, D. M., X
, L. & Z
, X.-L. (2008): A
new azhdarchoid pterosaur from the Lower Cretaceous
of China and its implications for pterosaur phylogeny
and evolution. – Naturwissenschaften, 95: 891-897.
, D. M., F
, E., S
, R. M. & K
, H.
N. (1998): Discovery of the holotype of the giant ptero-
saur Titanopteryx philadelphiae A
1959, and
the status of Arambourgiania and Quetzalcoatlus. –
Neues Jahrbuch für Geologie und Paläontologie, Ab -
handlungen, 207: 57-76.
, A., W
, D. B. & J
, C. M. (2005): First
evidence of azhdarchid pterosaurs from the Late Creta-
ceous of Hungary. – Acta Palaeontologica Polonica, 50:
, X., B
, N., J
, S., I
M., B
, B. & A
, M. (2003): A new azhdar-
chid pterosaur from the Late Cretaceous phosphates of
Morocco. – In: B
, E. & M
, J.-M. (Eds.):
Evolution and Palaeobiology of Pterosaurs. Geological
Society of London, Special Publications, 217: 79-90.
, L., L
, L., D
, Y. & C
, S.-L. (2006): A new
istiodactylid pterosaur from western Liaoning. – Geo -
logical Bulletin of China, 25: 737-740.
, X.-L. & Z
, Z.-H. (2003): Two new pterodacty -
loid pterosaurs from the Early Cretaceous Jiufotang
Formation of western Liaoning, China. – Vertebrata
PalAsiatica, 41: 34-41.
(2006): Pterosaur assemblages of the Jehol Biota and
their implication for the Early Cretaceous pterosaur
radiation. – Geological Journal, 41: 405-418.
, X.-L., C
, D.
A., Z
, Z.-H. & K
A. W. A. (2008a): A primitive istiodactylid pterosaur
(Pterodactyloidea) from the Jiufotang Formation (Early
Cretaceous), northeast China. – Zootaxa, 1813: 1-18.
, X.-L., K
, A. W. A., Z
, Z.-H. & C
D. A. (2005): Pterosaur diversity and faunal turnover in
Cretaceous terrestrial ecosystems in China. – Nature,
437: 875-879.
(2007): A new pterosaur (Ctenochasmatidae, Archaeo -
pterodactyloidea) from the Lower Cretaceous Yixian
Formation of China. – Cretaceous Research, 28: 245-
(2008b): Discovery of a rare arboreal forest-dwelling
flying reptile (Pterosauria, Pterodactyloidea) from
China. – Proceedings of the National Academy of Scien-
ces of the United States of America, 106: 1983-1987.
, P. (1991): The Illustrated Encyclopedia of
Pterosaurs. – 192 pp.; London (Salamander Books).
, L. C
, M., F
, S. J. & R
, T.
(2003): Neuroanatomy of flying reptiles and impli -
cations for flight, posture and behaviour. – Nature, 425:
, M. P. (2008): A new azhdarchoid pterosaur from
the Crato Formation (Lower Cretaceous, Aptian?) of
Brazil. – Palaeontology, 51:1289-1300.
Manuscript received: May 18th, 2009.
Revised version accepted by the Stuttgart editor: July 1st,
Address of the author:
, Ph. D., Paleontological Institute,
Shenyang Normal University, 253 North Huanghe Street,
Shenyang, Liaoning 110034, China;
... Position of UFC-721 cervical vertebrae within the cervical column As general for azhdarchoids, mid-cervicals are distinctively more elongate than cervicals I -II and VIII-IX (e.g. Cai & Wei 1994;Zhou 2010;Vila Nova et al. 2015). Furthermore, cervicals VIII and IX exhibit a dorsalized morphology in many pterodactyloids (e.g. ...
... The cervical series of Shenzhoupterus has not been described in detail (Lü et al. 2008). A Chaoyangopterus specimen figured by Zhou (2010) was reported to exhibit an axis and five other elongate cervical vertebrae. Its purported first dorsal vertebra was described as 'cervicalized' and lacks a preserved rib, while the following vertebra exhibits a rib that bends slightly forward unlike the following dorsal vertebrae, but shaped much like in the cervical IX of tapejarids (Vila Nova et al. 2015). ...
... Its purported first dorsal vertebra was described as 'cervicalized' and lacks a preserved rib, while the following vertebra exhibits a rib that bends slightly forward unlike the following dorsal vertebrae, but shaped much like in the cervical IX of tapejarids (Vila Nova et al. 2015). We therefore propose that the first two purported dorsal vertebrae of the Chaoyangopterus specimen figured by Zhou (2010) represent, in fact, the last two cervicals VIII -IX (Fig. 5). In this case, similar to tapejarids, cervicals IV -VI would be rather similar in length (with V being the longest), but longer than cervical VII (1.25 -1.30 times its length) and much longer than cervicals VIII -IX (c. ...
Full-text available
The Brazilian Crato Formation (Lower Cretaceous, Aptian) is well known for its rich pterosaur fauna. This paper deals with a new find represented by four articulated mid-cervical vertebrae. The vertebrae show a morphology consistent with that seen in the Chaoyangopteridae, especially the relative elongation, low neural spines, lack of pneumatic foramina on the lateral face of the centra and the presence of well-developed postexapophyses. Chaoyangopterids are, so far, represented with confidence only in Chinese deposits; the only record outside the Jehol Group is the Crato Formation form Lacusovagus magnificens, a partial skull whose assignment to the Chaoyangopteridae has been disputed. Given this controversy, we review the phylogenetic position of Lacusovagus, and discuss the nesting of our new specimen among theChaoyangopteridae, providing some comments concerning the composition of the group. We conclude that our new specimen provides further support for the presence of chaoyangopterids in the Early Cretaceous of Brazil.
... This latter trichotomous clade is supported by the following synapomorphy: char. 25(1), jaws, lateral S-shaped flaring of the jawline: present (see Witton, 2008b;Zhou, 2010). Chaoyangopteridae is supported by three synapomorphies: char. ...
... Here, we note two interesting features that Xericeps shares with some chaoyangopterids: a gentle upcurve of the mandibular tip, and a lateral foramina row close to the ventral margin, and not to the occlusal margin (Fig 14). A gentle upcurve of the mandibular tip can be seen in Chaoyangopterus (Wang and Zhou, 2003;Zhou, 2010) and Jidapterus (Dong et al., 2003;Wu et al., 2017), but not in other azhdarchoids. A lateral foramina row close to the ventral margin can also be seen in Chaoyangopterus (Fig. 14). ...
Aerotitan sudamericanus, from the Upper Cretaceous of the Neuquén Basin (Patagonia, Argentina), is known from a partial jaw fragment which has been interpreted as either an azhdarchid upper jaw, azhdarchid lower jaw, or thalassodromine upper jaw (as the sister-group of Alanqa). Here, we compare it in detail to upper and lower jaws of taxa belonging to all azhdarchoid lineages. It possesses a lateral angle (angle of divergence between occlusal and apex margins in lateral view) that is too low for an upper jaw of any azhdarchoid group. It further differs from thalassodromine upper jaws in exhibiting a convex occlusal margin (in lateral view), a sulcate occlusal surface, and lacking a sagittal crest. Furthermore, Aerotitan differs from Alanqa in 5 aspects: (1) occlusal margin shape in lateral view (convex in Aerotitan, straight in Alanqa), (2) median dentary eminence shape (slender in Aerotitan, posteriorly expanded in Alanqa), (3) median dentary eminence position (anterior in Aerotitan, close to the posterior end of the symphysis in Alanqa), (4) tomial edges shape (thick and blunt in Aerotitan, thin and sharp in Alanqa), and (5) occlusal surface anterior to the median eminence (cross-section concave in Aerotitan, slightly convex in Alanqa). We also conclude that the holotype of A. sudamericanus is a match for an azhdarchid lower jaw, being extremely similar to that of Mistralazhdarcho. When scored as a lower jaw in our phylogenetic analysis, it is recovered as a close relative of Mistralazhdarcho, in a polytomy that also includes Arambourgiania. In contrast, Alanqa is recovered as the sister-group of Keresdrakon, both located at the base of a broader clade of long-snouted azhdarchoids that also includes chaoyangopterids and azhdarchids, to the exclusion of tapejarines and thalassodromines.
... In order to assess the phylogenetic position of Aymberedactylus cearensis, we coded it in a data matrix modified from [7], itself based on previous works [2,3,8], and ran a phylogenetic analysis using the software TNT [35], default traditional search. We modified a character (52) by splitting the original state in two. The original derived state refers to a mandibular symphysis that accounts for over 30% of mandibular length. ...
... All azhdarchoid clades-the Azhdarchidae, Chaoyangopteridae and Tapejaridae (Tapejarinae + Thalassodrominae; sensu Kellner & Campos, 2007 [5])-are edentulous [43]. Among these, elongate mandibular symphyses accounting for at least 60% of total mandibular length are found in the Pteranodontidae [38], Nyctosauridae [40], Azhdarchidae [41,42], Chaoyangopteridae [43,52] and Thalassodrominae ( Table 1). The same is true for the probable basal tapejarine Caupedactylus ybaka [6], though not for other known tapejarines. ...
Full-text available
A three-dimensional and almost complete pterosaur mandible from the Crato Formation (Early Cretaceous of Northeastern Brazil), Araripe Basin, is described as a new species of a tapejarine tapejarid. Tapejarines are a particular group of toothless pterosaurs, characterized by well-developed cranial crests, downturned rostra, and have been proposed to represent frugivorous flying reptiles. Though comparatively well represented and distributed, the evolutionary history of the group is still poorly known, and the internal relationships of its members are not well understood. The new species here reported, named Aymberedactylus cearensis gen. et sp. nov., adds new data concerning the evolution of the group, concerning their morphology and geographical origin. It differs from known tapejarids due to its unusually elongate retroarticular process and a shallow fossa on the splenial exhibiting distinctive rugose texture. Furthermore, it exhibits a suite of basal and derived conditions within the Tapejaridae, demonstrating how their morphological traits probably evolved and that these forms were even more diverse than already acknowledged. The discovery of Aymberedactylus cearensis sheds new light on the evolutionary history of the Tapejarinae.
... et sp. nov. in having the typical centrum elongation of chaoyangopterids (Zhou 2010;Leal et al. 2018), azhdarchids (Suberbiola et al. 2003;Ösi et al. 2005;Vremir et al. 2013) and ctenochasmatids (Andres and Ji} 2008). ...
Full-text available
The Tapejaridae were an apparently worldwide distributed clade of edentulous pterosaurs, being a major component of several Lower Cretaceous terrestrial faunas. Despite their distribution across Gondwana and Laurasia, the oldest tapejarid remains were found in Barremian units from Europe, what led to the assumption that the clade originated in Eurasia and later dispersed southwards. Here we present a new tapejarid pterosaur species (Kariridraco dianae gen. et sp. nov.) from the Lower Cretaceous Romualdo Formation of Brazil. The holotype (MPSC R 1056) comprises an incomplete, three dimensionally preserved skull, lower jaw, and cervical vertebrae. It shows a unique combination of features such as unusually tall and comparatively short nasoantorbital fenestrae, as well as a premaxillary crest forming an angle of about 45° with respect to main skull axis. Phylogenetic analyses recover the new taxon as a Tupuxuara-related Thalassodrominae, a clade of early-diverging tapejarids that were apparently indigenous to central Gondwana. The inclusion of the new taxon in current phylogenetic frameworks, in addition to similarity cluster analyses of Early Cretaceous tapejarid-bearing pterosaur faunas, indicate Gondwana as the most parsimonious origin center for Tapejaridae, and show that pterosaur communities were affected by large scale tectonic-driven vicariant events.
... The mandible is preserved in lateral aspect in Chaoyangopterus and Shenzhoupterus. In Chaoyangopterus zhangi Wang and Zhou, 2003 the mandible appears to have a gently convex ventral profile (Zhou, 2010), and an almost straight profile for the dorsal (occlusal) margin. A gentle curvature of the occlusal margin that seems to result in a gape with the corresponding margin of the rostrum in Chaoyangopterus might be an artefact of compaction, and the same seems to apply to Shenzhoupterus chaoyangensis (Lü et al., 2008). ...
A new genus and species, Xericeps curvirostris gen. et sp. nov., is erected for a highly distinctive pterosaur mandible from the mid-Cretaceous (?Albian to lower Cenomanian) Kem Kem beds of south east Morocco. The new taxon is referred to Azhdarchoidea based on the absence of teeth, slenderness of its mandible with sulcate occlusal surface, presence on the posterior section of the mandibular symphysis of short paired ridges bounding a central groove, and the presence of elongate foramina on its occlusal and lateral surfaces. A slight dorsal curvature determines it as a distinct genus of azhdarchoid, as does an autapomorphy: the presence of a continuous longitudinal groove on the ventral midline of the mandibular symphysis. The new species brings to three the number of named pterosaurs from the Kem Kem beds and together with an unnamed tapejarid, points to a relatively diverse pterosaur assemblage in these deposits.
Full-text available
Quetzalcoatlus is the largest flying organism ever known and one of the most familiar pterosaurs to the public. Despite a half century of interest, it remains very incompletely described. This shortfall is addressed here through a full morphological description of Quetzalcoatlus and the other pterosaur material of Big Bend National Park, Texas. The first reported material was described and named Quetzalcoatlus northropi by Douglas Lawson in 1975, but in two separate publications. A ruling by the International Commission of Zoological Nomenclature was required for the name to be made available. Review of the pterosaur fauna of the Park recovers three valid species of azhdarchid pterosaurs in the latest Cretaceous Period Javelina and Black Peaks formations. The size and occurrence of these species are correlated with depositional environment. The holotype of the giant Quetzalcoatlus northropi and six other giant specimens referred to it occur in stream-channel deposits, including the youngest reported pterosaur. The vast majority of specimens (200+) are from large pterosaurs found in the abandoned channel-lake deposits at Pterodactyl Ridge; they form a diagnosable natural group erected as the new species Quetzalcoatlus lawsoni. A moderate-sized partial skull and cervical series also found in the abandoned channel-lake deposits at Pterodactyl Ridge, but lower in the section, is distinct from both species and is erected as Wellnhopterus brevirostris, gen. et sp. nov. Overbank flood-plain facies preserve another eleven specimens of extreme size variation, including small azhdarchids. The Big Bend pterosaur fauna provides the greatest known sample of azhdarchid pterosaurs and three-dimensional pterosaur morphology.
Full-text available
A new and articulated specimen of a pterosaur wing including upper arm, forearm, parts of the carpus and metacarpus, and a wing phalanx from Maastrichtian phosphatic deposits of Morocco are assigned to Tethydraco cf. regalis Longrich et al., 2018. The specimen comes from the village of Ouled Abdoun, close to the Oued Zem basin and its phosphatic mines (Morocco). The fossil is part of the collection of the Université Hassan II of Casablanca (ID Number FSAC CP 251). In the first part, the thesis presents a synthetic introduction about the morphology, anatomy, physiology and evolution of pterosaurs in order to offer a comprehensive framework on this fascinating group of extinct flying tetrapods. The main goal of this work is the taxonomic identification of the specimen, principally by morphological and morphometric/statistic analysis, based on the comparison with the most similar pterosaurs of the same epoch. Aspect of the humerus morphology and dimensional ratios of the wing elements suggest that T. cf. regalis is an azhdarchid rather than pteranodontid, as originally proposed. A high abundance of azhdarchid remains in the open marine setting of the Moroccan phosphates casts doubt on suggestions that Azhdarchidae were largely terrestrial pterosaurs.
A historic specimen described for the first time revealed important autapomorphic characters, permitting the definition of a new species, Javelinadactylus sagebieli gen. n. et sp. n., which represents the second toothless species from the Javelina Formation, Big Bend National Park of West Texas (United States of America). The remains of J. sagebieli (Azhdarchoidea: Tapejaridae) were found in 1986, but were never properly studied, and its taxonomic affinity remains undefined. The description is based on a partially articulated skull and mandible, which offer information on the anatomy of a single azhdarchoid pterosaur. J. sagebieli exhibit a large nasoantorbital fenestra, a rostral index of medium value and is assigned to the clade Thalassodrominae, a group of tapejarid pterosaurs that were reported exclusively from the Romualdo Formation of Brazil, with only two genera known. Thalassodromines are characterized by a typical cranial configuration with toothless jaws and a high and wide premaxilla bar, formed by sub-parallel or parallel borders. The new specimen described here represents the first record of the Tapejaridae group in the Maastrichtian of North America, and the cranial morphology of the new taxon increase the richest of the diversity of the azhdarchoid pterosaurs during the end of the Late Cretaceous, suggesting that the tapejarids were still diversifying in the Maastrichtian.
A new and articulated specimen of a pterosaur wing including the humerus, radius/ulna, parts of the carpus and metacarpus and a first wing phalanx from Maastrichtian phosphatic deposits of Morocco are assigned to Tethydraco regalis Longrich et al., 2018. Aspect of the humerus morphology, shape of the deltopectoral crest and ratios of the wing elements suggest that T. regalis is an azhdarchid rather than pteranodontian pterosaur, as originally proposed. A high abundance of azhdarchid remains in the open marine setting of the Moroccan phosphates casts doubt on suggestions that Azhdarchidae are largely terrestrial pterosaurs.
Full-text available
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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New remains of an azhdarchid pterosaur were discovered from the Upper Cretaceous (Santonian) Csehbánya Formation at the Iharkút vertebrate locality in the Bakony Mountains, western Hungary. Among the isolated bones, consisting principally of 21 symphyseal jaw fragments, four cervical vertebrae, a right radius, and some fragmentary limb bones, is a complete articulated mandible that represents one of the best-preserved mandibular material of any presently known azhdarchid pterosaur. The complete edentulous jaw, referred to Bakonydraco galaczi gen. et sp. nov. posesses several features diagnostic for azhdarchids which prove that Bakonydraco belongs to this group. The cervical vertebrae exhibit azhdarchid features and consequently are referred to as Azhdarchidae indet. The discovery of these fossils helps to understand the construction of the azhdarchid mandible and provides new insight for studying the feeding style of the edentulous azhdarchid pterosaurs.
The diagnostic features of Eopteranodon are amended on the basis of new material. The amended features are as follows: the neural spines in the mid cervical vertebrae are absent; the ratio of the length of the deltopectoral crest to the humerus length is approximately 0.25 ; and the length of the metacarpal IV is almost equal to the length of the second wing phalange; the ratio of the length of wing phalange 2 to wing phalange 1 is approximately 0.76. The new specimen of Eopteranodon is slightly different from its holotype, probably due to ontogenetic development.
The first occurrence of a pterosaur fossil from the Early Cretaceous of Peru is reported. The specimen consists of a nearly complete right humerus of a pteranodontid pterosaur preserved in three dimensions, presumably in a concretion. The Pteranodontidae is rediagnosed, and included genera and materials are listed. The Nyctosauridae and Dsungaripteridae are also diagnosed on the basis of postcranial characters, and the relationships of those three taxa plus the Azhdarchidae are discussed. The species Santanadactylus spixi Wellnhofer (1985) is reassigned to the Dsungaripteridae. -Author
A new istiodactylid pterosaur, Longchengpterus zhaoi gen. et sp. nov., is erected, based on an incomplete skeleton with a part of skull from the Jiufotang Formation at Chaoyang, western Liaoning. The skull and tooth morphologies indicate that Longchengpterus zhaoi is more closely related to Istiodactylus latidens than to other pterosaurs. Longchengpterus zhaoi is the only istiodactylid pterosaur from the Jiufotang Formation of western Liaoning. The family Istiodactylid originally had only a genus and species, which was found in the Early Cretaceous strata of Britain. The discovery of the new Early Cretaceous istiodactylid from western Liaoning not only expands its geographical distribution but also proves that western Liaoning is an important region for the istiodactylid radiation and diversity during the Late Jurassic to Early Cretaceous. It has great implications for the study of the origin and evolution of pterosaurs.
Two portions of the missing holotype cervical vertebra of Titanopteryx philadelphiae were rediscovered in the collection of the University of Jordan at Amman. No documentation was associated with the specimen, but it matches photographs and drawings in ARAMBOURG'S original papers and compares with plaster replicas made in Paris in the 1950's. A central portion of the vertebra is still missing and is presumed to be destroyed. The taxon Arambourgiania used by NESSOV & JARKOV (1989) to replace Titanopteryx is valid. Quetzalcoatlus is significantly distinct from Arambourgiania. Long-necked azhdarchid pterosaurs could not scavenge from the carcasses of large dinosaurs, nor could they feed on infaunal invertebrates, rather they were aerial piscivores or planktivores.
Immature specimens of the Late Cretaceous pterosaur Pteranodon were identified using three size-independent criteria: (1) fusion of various cranial and postcranial elements; (2) degree of epiphyseal ossification; and (3) bone grain or degree of ossification of limb-bone shafts. Immature individuals make up 15% of available specimens of Pteranodon and do not differ significantly in size from mature individuals. This and the extensive fusion of the mature skeleton suggests that Pteranodon had determinate growth. The bone of limb-bone shafts of immature individuals is fibro-lamellar bone, which suggest that they grew rapidly to adult size. The size-independent criteria can also be used to identify immature and mature individuals of other pterosaur taxa, and other large pterodactyloids also probably exhibited rapid determinate growth. -Author