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A new azhdarchid genus and species, Volgadraco bogolubovi gen. et sp. nov., is described based on an anterior fragment of the mandibular symphysis (mandibular beak) and some postcranial elements from the Rybushka Formation (Upper Cretaceous, Lower Campanian) of the Shirokii Karamysh 2 locality, Saratov Region. The new taxon is intermediate in size and vascularization of the mandibular beak between medium-sized Turonian-Santonian azhdarchids (Azhdarcho, Bakonydraco) and the giant Maastrichtian azhdarchid Quetzalcoatlus.
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ISSN 0031-0301, Paleontological Journal, 2008, Vol. 42, No. 6, pp. 634–642. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © A.O. Averianov, M.S. Arkhangelsky, E.M. Pervushov, 2008, published in Paleontologicheskii Zhurnal, 2008, No. 6, pp. 61–68.
Several localities of Campanian vertebrates, con-
taining azhdarchid pterosaurs and hesperornithid birds,
have recently been discovered in the Volga Region near
Saratov (Fig. 1; Panteleyev et al., 2004; Averianov
et al., 2005; Averianov, 2007). It is noteworthy that, in
the localities with hesperornithids (Karyakino in the
Saratov Region and Rychkovo in the Volgograd
Region; the last locality was described by Nessov and
Yarkov (1993) and Yarkov and Nessov (2000)), ptero-
saurs are extremely infrequent and represented by inde-
terminable fragments of large tubular bones. On the
contrary, in the localities with identifiable azhdarchid
bones (Malaya Serdoba, Shirokii Karamysh 2, Beloe
Lake, Saratov 2), hesperornithid bones have not yet
been recorded. The difference in occurrence of azh-
darchids and hesperornithids is probably attributable to
different paleoenvironments and competitive relation-
ships between the two groups of specialized ichthyoph-
agous vertebrates. In the present study, pterosaur bones
from the Shirokii Karamysh 2 locality of the Saratov
Region, which were collected in 2004 and 2005 by the
Saratov amateur collectors M.A. Grigor’ev, A.L. Gor-
bunov-Gusev, and A.N. Gurenko and assigned to a new
azhdarchid taxon, are described.
Abbreviations: (SGU) Saratov State University,
Saratov, Russia; (ZIN PH) paleoherpetological collec-
tion of the Zoological Institute of the Russian Academy
of Sciences, St. Petersburg.
The Shirokii Karamysh 2 locality is situated in the
upper part of the Lisii gully north of the village of Shi-
rokii Karamysh at the road to the village of Uritskoe
(Lysogorskii District, Saratov Region). This is the sec-
ond gully from the northern boundary of the village, the
upper part of which cuts a slope of erosion terrace.
The gully opens the following section of Upper Cre-
taceous deposits, described downward the section:
, Bed 1. Greenish gray, glauconitic quartz,
inequigranular sandstone, spotty because of nonuni-
form siliceous cement, solid, furrowed by surface
weathering. The horizon gradually passes into the
underlying strata, with the transition marked by a pro-
jection of denser sandstones in the slope of the gully.
The lower surface is uneven. Thickness, up to 0.5 m.
, Bed 2. Phosphorite horizon: the upper
part is composed of bright green, quartz–glauconitic,
strongly bioturbinated sand, with phosphorites up to
0.5–1 cm in size, regularly scattered and slightly accu-
mulated in the roof. In the lower part, phosphorites are
dark brown, black, sabulous, and angular and black,
more rounded. Phosphorites and phosphorite accumu-
lations are abundant. In places, phosphorite inclusions
are widely spaced; in some sites (up to 1.5–2.5 m in
size), they are accumulated, smaller in size, 1–1.5 cm in
diameter. The grayish yellow and grayish brown aleu-
ritic inclusions are more rounded, with signs of bioero-
sion, more widely spaced and mostly smaller in size.
The lower surface is uneven, pitted and nest-shaped.
A New Late Cretaceous Azhdarchid (Pterosauria, Azhdarchidae)
from the Volga Region
A. O. Averianov
, M. S. Arkhangelsky
, and E. M. Pervushov
Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, St. Petersburg, 199034 Russia
Geological Faculty, Saratov State University, Astrakhanskaya ul. 83, Saratov, 410026 Russia
Received June 29, 2007
—A new azhdarchid genus and species,
Volgadraco bogolubovi
gen. et sp. nov., is described based on
an anterior fragment of the mandibular symphysis (mandibular beak) and some postcranial elements from the
Rybushka Formation (Upper Cretaceous, Lower Campanian) of the Shirokii Karamysh 2 locality, Saratov
Region. The new taxon is intermediate in size and vascularization of the mandibular beak between medium-
sized Turonian–Santonian azhdarchids (
Azhdarcho, Bakonydraco
) and the giant Maastrichtian azhdarchid
Key words
: Pterosauria, Azhdarchidae, new taxa, Cretaceous, Saratov Region, Russia.
Vol. 42
No. 6
The accumulations of phosphorite inclusions at the
lower boundary are up to 0.1 m thick. This layer con-
tained isolated, frequently well-preserved specimens of
marine reptiles (Elasmosauridae indet., Polycotylidae
sp., and
sp.). Ptero-
saur bones come from this layer. Thickness, 0.4–0.5 m.
, Bed 3. Dirty green, nonuniformly colored,
quartz–glauconitic sand, strongly bioturbinated; bur-
rows up to 1.5–5 cm in diameter extend to a depth of
0.5–0.6 m from the roof. This layer contains small, iso-
lated subovate aleuritic inclusions, strongly rounded
and, sometimes, positioned vertically (up to 2 cm in
diameter). Near the roof, narrow (1–2 mm in diameter)
and short (up to 1–3 cm) burrows are sporadically dis-
tributed. Below, the sand is uniformly grayish green,
medium-grained; signs of bioturbidites are almost
absent, which explains the abundance of poorly phos-
phatized biogenic remains preserved in these strata.
Fossils are mostly represented by fish scales, which are
accumulated in nests and lower parts of decapod bur-
rows (in the upper part of the horizon); coprolites, bur-
ied subautochthonously (scattered at a distance of 1 m);
fish vertebrae; teeth and dental plates of cartilaginous
fish; and small phosphate mollusk shells, buried in dif-
ferent positions.
At 1.3–1.5 m below the roof of sand, there is a layer
containing infrequent, variously oriented aleuritic pel-
lets and shingles, rare nests (up to 0.1 m in diameter) of
accumulated phosphate pellets. Below this level, faunal
remains are scarce. Visible thickness, 1.9 m.
Vertebrates occur in the phosphorite horizon. The
bones are dirty yellow, strongly phosphatized, very
dense, slightly rounded, exposed to bioerosion,
diversely oriented. Tetrapods were buried within an
active sublittoral zone, under conditions of general
immersion of the territory; this provided rather exten-
sive accumulation of terrigenous material, psammitic
and aleuritic matter. As a result of movements within
the sublittoral and supralittoral zones, a sandy–pebble
beach was formed from time to time, where large ele-
ments of the substrate were phosphorite pellets, verte-
bral centers, and other reptile bones. The subsidence,
short-term of exposure on the surface, and the rapid fos-
silization (phosphatization) provided good primary
preservation of many bones. In some cases, long, nar-
row bones and vertebral centers in natural articulation
with neural spines are preserved, while large vertebral
centers of plesiosaurs are usually most rounded and dam-
aged. The presence within a locality of some bones
undoubtedly belonging to the same individual (vertebral
centers, teeth of fish, etc.) suggests slight scattering of
dead bodies and body fragments, in particular, primary
burial not influenced by active hydrodynamic factors.
In general, the burial of marine and subcontinental
vertebrates in Bed 2 should be classified as synchro-
nous, tabular, nonuniformly scattered.
A distinctive feature of this locality is the fact that,
during the short period of the formation of the phospho-
rite horizon, erosion had a minor effect on underlying
sands rich in invertebrate and vertebrate remains (see
description of Bed 3). The development of diverse dig-
ging organisms, which resulted in almost complete dis-
appearance of biogenic inclusions in the upper part of
the early deposits, resulted in the stratification and pres-
ervation of autochthonous and subautochthonous buri-
als of vertebrates and mollusks. As is usually observed
in the majority of localities with similar stratification,
the upper part of Bed 3 is eroded and elements of this
bed occur in the overlying phosphorite horizon. These
results of comparative analysis of a number of rela-
tively synchronous localities (Campanian units) sug-
gest a relatively low position (hypsometric) of the area
of the Shirokii Karamysh 2 locality in the time of the
formation of terrigenous deposits and, in particular, of
the phosphorite horizon.
The distribution of pterosaurs and birds (hesperorni-
thids) in the Late Cretaceous of the southeastern Euro-
pean paleobiogeographic region was connected with
the history of the formation and arrangement of subflat
islands of archipelagoes and banks in this region.
Within a relatively shallow area between the Voronezh
Region on the west and an extensive marine basin in the
Recent Caspian Region, local positive elements reflect-
ing a block structure of the base and composing com-
plex systems in the shape of swells were formed for a
long time. Changes in both the geodynamic mode and
the level of basins in this area had an effect on the man-
70 km3503570
Volga R
Fig. 1.
Localities of pterosaurs and birds in the Campanian
of the Saratov and Penza regions: (
) Malaya Serdoba,
) Karyakino, (
) Shirokii Karamysh, (
) Beloe Lake, and
) Saratov.
Vol. 42
No. 6
ifestation of these positive structures on the bottom of
the basin, including a series of archipelagoes.
Pterosaur and avian records occur mostly in the area
of the former banks and islands in the southern and cen-
tral parts of the right bank of the Volga Region and have
not yet been recorded to the north of the latitude of the
town of Serdobsk (Penza Region).
The Shirokii Karamysh 2 locality is a series of sites
of this type in the middle zone on the right bank of the
Volga Region, which differs from sites in the adjacent
area in the more abundant vertebrate specimens; this is
accounted for by concurrence of a number of factors:
(1) The presence of many islands in a large part of
the right bank of the Volga Region (from the latitude of
Volgograd to the latitude of Saratov), which allowed
sublatitudinal and submeridional migration of ptero-
saurs and birds.
(2) Long-term existence of many islands, including
elevations (Uritskoe and Shirokii Karamysh), a slope of
which retained the locality under study.
(3) The wide zone of the sublittoral and supralit-
toral, the gently sloping shore, and warmed water pro-
vided abundant food.
(4) Currents in the basin and seasonal movements of
water masses developed within certain periods stable
routes of migration of marine organisms between
islands. This provided habitats and migration patterns
of pterosaurs and birds within the coastal zone near the
migration routes of fish and other marine organisms.
Superorder Pterosauria
Order Pterodactylida
Superfamily Azhdarchoidea Nessov, 1984
Family Azhdarchidae Nessov, 1984
Arkhangelsky et Pervushov, gen. nov.
Etymology. From the Volga River and the Latin
Type species.
Volgadraco bogolubovi
sp. nov.
Diagnosis. Mandibular beak long, with slightly
convex lateral outline of dorsal margin. Dorsal surface
of mandibular beak concave between sharpened lateral
edges. Vascularization of mandibular beak reduced to
three irregular foramina on each side. Cervical vertebra 3
with anteriorly high neural arch, large central pneu-
matic foramen above spinal canal on anterior side, and
with series of small pneumatic foramina in lateral sur-
face. Cervical vertebra 9 with large hypapophysis and
large slitlike depression on lateral surface of neural arch
just anterior to postzygapophysis. Last vertebra of
notarium with slitlike, dorsoventrally compressed fora-
men of spinal canal. Lesser trochanter of femur weakly
Species composition. Type species.
Comparison. The new genus differs from
Nessov, 1984 from the Turonian of Uzbeki-
stan in the longer mandibular beak, with the less convex
lateral outline of the dorsal margin; in the fewer foram-
ina for blood vessels in the mandibular beak; the higher
neural arch of cervical vertebra 3 on the anterior side,
the large central pneumatic foramen above the spinal
canal and a series of small pneumatic foramina on the
lateral surface of this vertebra; in the larger hypapophy-
sis and the greater volume of the slitlike depression on
the lateral surface of the neural arch just anterior to the
postzygapophysis of cervical vertebra 9; and in the
weaker developed lesser trochanter of the femur.
It differs from
Lü et Ji, 2005 from the
Aptian of China in the longer mandibular beak.
It differs from
Nessov, 1991 from the
Albian of the United States in the slitlike, dorsoven-
trally compressed foramen of the spinal canal of the last
thoracic vertebra of the notarium.
It differs from
Ösi, Weishampel et
Jianu, 2005 from the Santonian of Hungary in the
longer and less massive mandibular beak with a convex
lateral outline of the dorsal margin (in
this margin is posteriorly concave and anteriorly con-
vex) and the fewer slitlike foramina for blood vessels in
the mandibular beak.
It differs from
Averianov, 2007 from
the Santonian–Campanian of Kazakhstan in the less
developed lesser trochanter of the femur.
It differs from
Cai et Wei, 1994
from the Campanian of China in the convex rather than
concave lateral structure of the dorsal margin and the
concave rather than flat dorsal surface of the mandibu-
lar beak.
It differs from
Pereda Suberbiola
et al., 2003 from the Maastrichtian of Morocco in the
larger foramen of the spinal canal on cervical vertebra 9.
It differs from
Lawson, 1975 from
the Maastrichtian of the United States in the shorter and
more massive mandibular beak; the concave rather than
flat dorsal surface of the mandibular beak; the presence
of slitlike foramina for blood vessels in the mandibular
beak; the better developed hypapophysis of cervical
vertebra 9; and in the presence of a large slitlike depres-
sion on the lateral surface of the neural arch of this ver-
tebra just anterior to the postzygapophysis.
Remarks. It is impossible to compare the new
genus with
Padian et al., 1995
(Campanian of the United States),
Nessov, 1989 (Campanian of Russia),
Nessov, 1987 (Maastrichtian of Jordan), and
Buffetaut et al., 2002 (Maastrichtian of Romania)
because of incomparability of available material.
It is not improbable that the genus described is a jun-
ior synonym of
Nessov, 1989, which is
represented by a fragment of a middle cervical vertebra
and, probably, by some other bones from the Rybushka
Vol. 42
No. 6
Formation near the village of Malaya Serdoba in the
Penza Region (Bogolyubov, 1914; Averianov, 2007).
Bakhurina and Unwin (1995) and Unwin and Bakhu-
rina (2000) designated this taxon as a nomen dubium;
we tentatively adhere to this point of view and, hence,
describe the new azhdarchid from the Campanian of the
Volga Region based on the better identifiable material.
If more complete skeletal material combining charac-
ters of
gen. nov. are
found, the first name should be restored according to
the principle of priority and the second name should be
regarded as a junior subjective synonym. At the same
time, it is possible that several azhdarchid genera
existed in the Campanian of the Volga Region.
The assignment of isolated and noncomparable
skeletal elements from one locality to the same taxon is
always tentative, because it is impossible to exclude the
presence of two or more closely related taxa in the same
assemblage. To overcome this obstacle a new taxon is
sometimes based only on the holotype, while other
skeletal elements are not included in the same taxon.
For example,
Bakonydraco galaczi
Ösi, Weishampel et
Jianu, 2005 from the Santonian of Hungary is only
based on the holotype (lower jaw), whereas accompa-
nying postcranial azhdarchid bones from this locality
are determined as Azhdarchidae indet. (Ösi et al.,
2005). However, from the taxonomic point of view, this
conclusion means the presence of two azhdarchid
taxa in the assemblage,
Bakonydraco galaczi
Azhdarchidae indet. We are inclined to assign all spec-
imens of a medium-sized azhdarchid from the Shirokii
Karamysh 2 locality to the same taxon,
sp. nov., until the presence of other azh-
darchid taxa in this assemblage is shown with certainty.
Volgadraco bogolubovi
Averianov, Arkhangelsky et Pervushov, sp. nov.
Plates 5 and 6
Azhdarchidae indet.: Averianov, 2007, p. 76.
Etymology. The species is named in honor of
N.N. Bogolyubov, who described the first pterosaur
from Russia, which was the first representative of the
family Azhdarchidae known to science (Bogolyubov,
Holotype. SGU, no. 46/104a, anterior part of the
lower jaw symphysis (mandibular beak); Russia, Sara-
tov Region, Shirokii Karamysh 2 locality; Upper Creta-
ceous, Lower Campanian, phosphorite conglomerate of
the Rybushka Formation.
Description. The mandibular beak (holotype,
Pl. 5, fig. 1) is triangular in lateral, dorsal, and ventral
views. The dorsal and ventral surfaces are positioned at
an angle of approximately 13c and the lateral surfaces
are at an angle of approximately 4
, forming a pointed
end of the beak (the tip of which is broken off). In lat-
eral view, the outline of the dorsal surface is slightly
convex, almost straight. On the dorsal surface, the lat-
eral margins form sharp elevated margins, with a
slightly concave area between them. The lateral sur-
faces of the beak are convex in the dorsal part and
almost straight in the ventral part; converge ventrally at
an angle of approximately 37
, forming a sharp ventral
crest along the entire beak. In the anterior part, the beak
is almost rhomboidal in cross section, with lateral keels
near the midheight of the beak. The ventral margin is
straight in lateral view. A few slitlike foramina for
blood vessels (three on each lateral and dorsal sides) are
arranged irregularly.
The third cervical vertebra is almost completely pre-
served (specimen SGU, no. 47/104a; Pl. 5, fig. 2). The
vertebral center is relatively short; its length is only
2.4 times as great as the minimum diameter at the cen-
ter. The lateral sides of the vertebral center are concave,
so that, in ventral view, it is in the shape of a sand-glass.
The ventral side of the vertebral center is strongly con-
vex in the central part. The anterior side has a short
crest of the hypapophysis. The posterior part of the ven-
tral surface of the vertebral center is flat; laterally, it is
limited by weak crests extending from the postexapo-
physes to the center of the ventral surface. The anterior
articular depression of the vertebral center is wide and
relatively low, it is three times as wide as high. The dor-
sal surface of the depression is convex, with a small
concavity at the center. The ventral surface is divided
by the hypapophysis into two concave parts. The ven-
trally curved lateral margins of the anterior articular
depression correspond to rudimentary parapophyses
separated by a wide groove from rudimentary diapo-
physes on the neural arch. The posterior condyle of the
vertebral center is ovate, compressed strongly dors-
oventrally, 3.6 times as wide as high. The ventral mar-
gin of the condyle is at a distance from the ventral mar-
gin of the vertebral center that is greater than the
condyle height. This interval is occupied by a shallow
depression restricted on the sides by the crests extend-
ing from the condyle to the postexapophyses. The pos-
texapophyses are stout, ventrolaterally oriented. The
lateral sides of the vertebra have a series of small irreg-
ular depressions (four on the right and three on the left)
at the boundary between the neural arch and the center.
Some depressions (two on the right and, probably, one
on the left) contain small pneumatic foramina. Dor-
sally, a prominent crest extends along the entire neural
arch, connecting the prezygapophysis and the postzyg-
apophysis (it corresponds to the parasagittal carina of
succeeding cervical vertebrae). This crest is positioned
at an angle of approximately 15
to the anteroposterior
axis of the vertebral center. Anteriorly, the neural arch
is relatively high, higher than the anterior articular
depression. The spinal canal is very small, rounded in
cross section. The oval pneumatic foramen, which is
only slightly smaller than the spinal canal, is positioned
somewhat dorsally. On each side of the foramina
described, there is an extensive triangular depression,
which is restricted ventrally by the vertebral center and
dorsolaterally by sharp crests extending from the
prezygapophyses to the base of the neural spine. This
region is either damaged (on the left side) or covered
Vol. 42
No. 6
Plate 5
Vol. 42
No. 6
with phosphorite (on the right); therefore, it remains
uncertain whether or not the lateral pneumatic canals,
which have foramina on the posterior side of the neural
arch, open here. The prezygapophysis is massive, with
a convex ovate articular surface oriented dorsally and
slightly anteriorly. On the posterior side of the neural
arch, the foramen of the spinal canal is larger than on
the anterior side. This foramen is ovate, except for the
ventral border, which is straight and coincides with the
dorsal border of the posterior condyle. On the sides and
somewhat dorsally, there are large foramina of the lat-
eral pneumatic canals. The dorsal (central) pneumatic
foramen is absent from the posterior side. A massive
horizontal crest passes above the foramina, connecting
the postzygapophyses. The central vertical crest, which
forms the posterior margin of the neural spine, is
located more dorsally. The postzygapophyses are
mostly damaged. The articular surface of the postzyga-
pophysis (partially preserved on the left side) is con-
cave, oriented ventrally and slightly posteriorly. The
neural spine is relatively high; its base occupies the
entire extent of the neural arch. The maximum height of
the neural spine is probably close to the posterior mar-
gin, in line with the base of the postzygapophyseal pro-
cesses. At the same point, the neural spine shows the
maximum width, which is almost three times as wide as
near the anterior margin.
The ninth (last) cervical vertebra (specimen SGU,
no. 48/104a; Pl. 5, fig. 3) is also almost completely pre-
served. The vertebra is high and very short anteroposte-
riorly. On the vertebral center, the anterior articular sur-
face is strongly concave and the posterior condyle is
strongly convex. The hypapophysis is well developed,
approximately to the same extent as in the third cervical
vertebra (in cervical vertebra 9 of
, it is strongly reduced). The surface of
the posterior condyle is damaged; the concave lateral
surfaces of this condyle, if present, were probably
developed to a much lesser extent than in
. The ventral surface of the vertebral
center is slightly convex (in
, it is flat). The foramen of the spinal canal is rel-
atively large, ovate, its ventral border is straight anteri-
orly and convex posteriorly. The lateral pneumatic
foramina were probably present anteriorly (this area of
the vertebra is covered with phosphorites). The neural
arch is high, with a longitudinal central crest located
anteriorly. A pair of transverse depressions extend
between this crest and prezygapophyses (
lack similar depressions). The artic-
ular surfaces of the prezygapophyses and postzygapo-
physes are not preserved. On the lateral surface of the
vertebra at the boundary between the vertebral center
and neural arch, there is the base of a massive diapo-
physis (most of the process is broken off), which is
divided by a wide groove of a relatively small parapo-
physis. A large slitlike depression is located just ante-
rior to the base of the postzygapophysis (in
this depression is very small; in
, it is
absent). A very large ovate, dorsoventrally extended
depression is located above the postzygapophyses. The
same depression is present in cervical vertebra 9 of
Quetzalcoatlus, Phosphatodraco
, and
(Bennett, 2001, text-fig. 42B; Pereda Suberbiola et al.,
2003, text-fig. 3e); the structure of this region in
is not known. The neural spine is not preserved;
its base is short and wide, located close to the center of
the neural arch.
The material includes a posterior fragment of the
notarium, consisting of four fused dorsal vertebrae
(specimen SGU, no. 49/104a; Pl. 6, fig. 1). In this frag-
ment, the suture between the first and second vertebral
centers is hardly discernible. The ventral side of the
vertebral center is more concave in two posterior verte-
brae than in two anterior vertebrae. The posterior
condyle of the center of the last vertebra is strongly
convex, ovate (the transverse diameter exceeds the
height). The dorsal border of the condyle is concave,
forming the bottom of the spinal canal. The foramen of
the spinal canal is slitlike, compressed dorsoventrally to
a greater extent than in
, it
is ovate and higher).
A fragment of a long tubular bone (specimen SGU,
no. 50/104a; Pl. 6, fig. 2) is most likely a part of the dia-
physis of the first phalanx of the wing (fourth) digit.
The diaphysis is ovate in cross section; the anteroposte-
rior diameter is 1.6 times as long as the dorsoventral
diameter (in
Azhdarcho lancicollis
, specimen ZIN PH,
no. 37/44, it is two times as long). The anteroposterior
diameter is uniform throughout the fragment preserved;
this is evidence that the bone was long.
The femur (specimen SGU, no. 50/104a; Pl. 6, fig. 3)
is only represented by the diaphysis. The bone is hol-
low, thin-walled and relatively large; the total length
was probably at least 17 or 18 cm. The diaphysis is
strongly curved in the frontal plane. This curvature is
Explanation of Plate 5
Figs. 1–3.
The pterosaur
Volgadraco bogolubovi
sp. nov. from the Rybushka Formation (Lower Campanian) of the Shirokii
Karamysh 2 locality, Saratov Region, Russia: (1) holotype SGU, no. 46/104a, anterior part of the mandibular beak: (1a) dorsal,
(1b) lateral, (1c) ventral, and (1d) proximal views,
1.30; arrows indicate slitlike foramina for blood vessels; (2) SGU, no. 47/104a,
cervical vertebra 3: (2a) anterior, (2b) lateral, (2c) ventral, (2d) posterior, and (2e) dorsal views,
0.69; (3) SGU, no. 48/104a, cer-
vical vertebra 9: (3a) anterior, (3b) dorsal, (3c) lateral, (3d), posterior, and (3e) ventral views,
1.10. Designations: (
) posterior
condyles of the vertebral center, (
) anterior articular depression of the vertebral center, (
) diapophysis, (
) slitlike depression,
) hypapophysis, (
) foramen of the spinal canal, (
) neural spine, (od) oval depression, (pa) parapophysis, (pe) postexapo-
physis, (pf) pneumatic foramen, (poz) postzygapophysis, (prz) prezygapophysis, and (su) sulcus between the parapophysis and
Plate 6
Explanation of Plate 6
Figs. 1–3. The pterosaur Volgadraco bogolubovi sp. nov. from the Rybushka Formation (Lower Campanian) of the Shirokii
Karamysh 2 locality, Saratov Region, Russia: (1) SGU, no. 49/104a, posterior part of the notarium, consisting of four thoracic ver-
tebrae: (1a) lateral, (1b) posterior, and (1c) ventral views ×1.50; (2) SGU, no. 51/104a, fragment of the presumably first right pha-
lanx of the wing digit: (2a) proximal (?) view and (2b) dorsal or ventral view, ×1.28; (3) SGU, no. 50/104a, left femur fragment:
(3a) posterior and (3b) anterior views, ×0.95. Designations: (cn) posterior condyles of the vertebral center, (lt) small trochanter,
(nc) foramen of the spinal canal, and (spnf) foramen of the spinal nerve.
much more pronounced than in the femoral diaphysis
of giant Quetzalcoatlus sp. from the Campanian of
Alberta, Canada (Currie and Russell, 1982, text-fig. 1)
and approximately equal to that of the significantly
smaller Azhdarcho lancicollis (specimen ZIN PH,
no. 44). The diaphysis is ovate in cross section. The
proximal end is broken off at the base of the greater tro-
chanter. A very small rough area of the lesser trochanter
for the iliofemoralis internus muscle is located on the
anterior side, near the proximal margin preserved,
closer to the dorsal margin. The lesser trochanter is
much weaker than in Azhdarcho and Aralazhdarcho
(Averianov, 2007).
Remarks. The symphysis of the dentaries of
azhdarchids, which is up to 60% of the lower jaw
length, consists of two distinctly differentiated parts,
the anterior mandibular beak and the posterior part.
These parts are connected by a sutural articulation
(synosteosis) and probably completely fused only in
old animals. Judging from the presence and abundance
of large foramina for blood vessels in the anterior part
and complete absence of similar foramina in the poste-
rior part of the symphysis, only the mandibular beak
was covered by horny tissue. Isolated mandibular beaks
of Azhdarcho lancicollis relatively frequently occur in
fluvial deposits of the Bissekty Formation (Turonian)
of Uzbekistan (Nessov, 1984, pl. 7, figs. 10, 11; Nessov,
1997, pl. 15, figs. 1–5). The relative length and shape of
the mandibular beak of azhdarchids vary widely
(Fig. 2); this is probably connected with different feed-
ing modes, the study of which lies ahead. The shortest
and most massive mandibular beak is characteristic of
Bakonydraco, the longest and most slender beak is in
Quetzalcoatlus. The lateral outline of the dorsal margin
of the beak is concave in Zhejiangopterus and partially
(posteriorly) in Bakonydraco. In Azhdarcho and
Quetzalcoatlus, it is convex. The shape of the mandib-
ular beak of Volgadraco gen. nov. is most similar to that
of Azhdarcho and differs in the less convex, almost
straight dorsal margin in lateral view.
The number of foramina for blood vessels in the
mandibular beak probably decreased in the evolution of
azhdarchids. Turonian Azhdarcho, Santonian Bakony-
draco, and Azhdarchidae indet. from the Campanian of
Spain have many large foramina arranged in two rows
on the dorsal side and on each lateral side (Nessov,
1984, pl. 7, figs. 10, 11; Nessov, 1997, pl. 15, figs. 1–5;
Buffetaut, 1999, text-fig. 1a; Ösi et al., 2005, text-fig. 2).
In Maastrichtian Quetzalcoatlus, these foramina have
not been described (Kellner and Langston, 1996);
apparently, this taxon lacks these foramina. Volgadraco
gen. nov. has three relatively small foramina in each of
three sides of the beak, i.e., it is intermediate between
the two extreme variants. The reduction of vasculariza-
tion of the azhdarchid beak was probably connected
with increasing ceratinization of the horn cover. Appar-
ently, the foramina considered provided passage not
only for blood vessels but also for sensitive fibers of the
mandibular ramus of cranial nerve VII (facial nerve);
thus, the horn beak of early azhdarchids possessed cer-
tain tactile sensitivity, which was important for feeding.
The reduction of these foramina could have been con-
nected with changes in feeding strategy.
The Cenomanian beds of Morocco has yielded three
fragments of the jaw symphysis of toothless pterosaurs,
which are determined as an anterior end of the premax-
illa (upper jaw beak) of Pteranodontidae (?), anterior
end of the premaxilla of Azhdarchidae (?), and an ante-
rior fragment of the mandibular symphysis of Tape-
jaridae (Wellnhofer and Buffetaut, 1999, text-figs. 2, 4, 5).
In our opinion, the three fragments belong to one azh-
darchid taxon; these are a mandibular beak, an upper
jaw beak, and a more posterior fragment of the premax-
illa, with an anterior fragment of the cranial crest. The
Cenomanian azhdarchid from Morocco has fewer vascu-
lar foramina in the mandibular beak, the lateral foramina
form only one (dorsal) row and dorsal foramina are only
present in the anterior part of the beak. However, the
extent of vascularization of the mandibular beak of this
taxon is higher than in Volgadraco gen. nov.
The incomplete cervical vertebra of a pterosaur
from the Campanian of Delaware, United States, that
was referred to Ornithocheiridae (Baird and Galton,
1981, text-fig. 2), is almost identical to specimen SGU,
no. 47/104a and could have been cervical vertebra 3 of
an azhdarchid. As in Volgadraco gen. nov., this speci-
men has a small lateral pneumatic foramen.
Material. In addition to the holotype, the type
locality has yielded cervical vertebra 3 (SGU,
no. 47/104a), cervical vertebra 9 (SGU, no. 48/104a),
posterior part of the notarium consisting of four verte-
brae (SGU, no. 49/104a), a fragment of the presumable
first right phalanx of the wing digit (SGU, no. 51/104a),
and a fragment of the left femur (SGU, no. 50/104a).
Fig. 2. The shape of the mandibular beak of the lower jaw
in representatives of the family Azhdarchidae: (a) Bakony-
draco (after Ösi et al., 2005); (b) Zhejiangopterus (after
Unwin, Lü, 1997); (c) Quetzalcoatlus (after Kellner and
Langston, 1996); (d) Azhdarcho (based on specimen ZIN
PH, no. 85/44); and (e) Volgadraco gen. nov. The specimens
are shown on different scales, such that the mandibular
beaks are approximately equal in length.
The study was supported by the Board of the Presi-
dent of the Russian Federation (MD-255.2003.04) and
the Foundation for Assistance to Domestic Science.
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... The analysis resulted in four equally parsimonious trees (Figure 9). These trees are the result of four phylogenetic positions for Volgadraco bogolubovi Averianov et al. 2008 [42] (a rogue taxon in Longrich et al. 2018 [17]) with V. bogolubovi recovered in a trichotomy with Alamodactylus byrdi Andres & Myers 2013 [43] and for all of the other pteranodontians that are more closely related to Nyctosaurus; in a tetranomy with Simurghia robusta Longrich et al. 2018 [17], Alcione elainus Longrich et al. 2018 [17], and the Angola specimens; in a trichotomy with these taxa and the Nyctosauridae; and in a trichotomy with C. hlavaci and all of the pteranodontians that are more closely related to Nyctosaurus than A. byrdi. The phylogenetic placement of V. bogolubovi has no specific bearing on the relationships of the Angola specimen, so it can be safely deactivated (i.e., with the taxcode command) to highlight the relationships of E. otyikokolo. ...
... Epapatelo otyikokolo is a non-nyctosaurid pteranodontian. [42], which is shown at its most basal position recovered. [42], which is shown at its most basal position recovered. ...
... [42], which is shown at its most basal position recovered. [42], which is shown at its most basal position recovered. ...
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Here, we describe the first pterosaur remains from Angola, an assemblage of fourteen bones from the Lower Maastrichtian marine deposits of Bentiaba, Namibe Province. One new species is introduced, Epapatelo otyikokolo, gen. et sp. nov., which comprises an articulated partial left humerus and ulna as well as an articulated left ulna and radius (from a second individual). Phylogenetic analysis confirms a non-nyctosaurid pteranodontian attribution for this new taxon and supports a new apomorphy-based clade, Aponyctosauria, which is here defined. Late Cretaceous pteranodontians are rare in Sub-Saharan Africa and throughout the Southern Hemisphere. Preliminary histological analysis also reveals a likely sub-adult age for one of the specimens. This fossil assemblage provides a first glimpse of Angolan pterosaur paleobiodiversity providing further insight into the Gondwanan ecosystems of the Upper Cretaceous.
... Andres and Ji (2008) referred these specimens to the contemporaneous Ctenochasmatidae, instead of regarding them as inordinately early azhdarchids, and suggested that the known Azhdarchidae remained exclusively from the Late Cretaceous. Since then, however, the Tendaguru specimens have been again regarded as azhdarchids (Costa et al., 2013(Costa et al., , 2015, a Solnhofen species has been placed in the 'Protazhdarchidae' , and a number of new species have been referred to the Azhdarchidae (Averianov, 2007;Averianov et al., 2008;Ibrahim et al., 2010;Buffetaut et al., 2011;Sullivan and Fowler, 2011;Agnolin and Varricchio, 2012;Novas et al., 2012;Vremir et al., 2013Vremir et al., , 2015Averianov and Ekrt, 2015;Kellner and Calvo, 2017;Vullo et al., 2018;Hone et al., 2019;Solomon et al., 2020), all without explicit phylogenetic analysis. A phylogenetic analysis of the species referred to the Azhdarchidae and the relationships of the Pterosauria is presented here to delineate the evolutionary origin and history of the azhdarchid pterosaurs in order to resolve these issues. ...
... Late Cretaceous Pterosaurs-Although there has been a tendency to refer Late Cretaceous pterosaurs to the Azhdarchidae, the phylogenetic analysis recovered up to 19 pterosaur lineages extending into this epoch: Siroccopteryx moroccensis Mader and Kellner, 1999; Aetodactylus halli Myers, 2010; Cimoliopterus cuvieri (Bowerbank, 1851); Cimoliopterus dunni Myers, 2015; Lonchodraco giganteus (Bowerbank, 1846); Lonchodectes compressirostris (Owen, 1851); Pteranodon with possibly Volgadraco bogolubovi Averianov et al., 2008, andTethydraco regalis Longrich et al., 2018 In addition, not all Late Cretaceous pterosaur species that have been referred to the Azhdarchidae belong to that group: The Turonian Cretornis hlavaci from the Jizera Formation of Czech Republic was suggested to be an azhdarchid by Averianov (2010) but later identified as a non-azhdarchid azhdarchoid by Averianov and Ekrt (2015); the phylogenetic analysis recovers C. hlavaci as a nyctosauromorph. Similarly, Volgadraco bogolubovi from the Campanian Rybushka Formation of Russia was originally referred to the Azhdarchidae by Averianov et al. (2008) but is recovered here in the Pteranodontidae. ...
... Late Cretaceous Pterosaurs-Although there has been a tendency to refer Late Cretaceous pterosaurs to the Azhdarchidae, the phylogenetic analysis recovered up to 19 pterosaur lineages extending into this epoch: Siroccopteryx moroccensis Mader and Kellner, 1999; Aetodactylus halli Myers, 2010; Cimoliopterus cuvieri (Bowerbank, 1851); Cimoliopterus dunni Myers, 2015; Lonchodraco giganteus (Bowerbank, 1846); Lonchodectes compressirostris (Owen, 1851); Pteranodon with possibly Volgadraco bogolubovi Averianov et al., 2008, andTethydraco regalis Longrich et al., 2018 In addition, not all Late Cretaceous pterosaur species that have been referred to the Azhdarchidae belong to that group: The Turonian Cretornis hlavaci from the Jizera Formation of Czech Republic was suggested to be an azhdarchid by Averianov (2010) but later identified as a non-azhdarchid azhdarchoid by Averianov and Ekrt (2015); the phylogenetic analysis recovers C. hlavaci as a nyctosauromorph. Similarly, Volgadraco bogolubovi from the Campanian Rybushka Formation of Russia was originally referred to the Azhdarchidae by Averianov et al. (2008) but is recovered here in the Pteranodontidae. Bakonydraco galaczi from the Santonian Csehbánya Formation of Hungary was originally referred to the Azhdarchidae, recovered as the sister group to the Azhdarchidae by Andres and Ji (2008) and Averianov and Ekrt (2015) in part, in a trichotomy with the Azhdarchidae by Averianov (2010) in part, and as sister group to the Neopterodactyloidea by Averianov and Ekrt (2015) in part. ...
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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.
... In addition, there are several non-azhdarchid ornithocheiroid taxa with well-preserved notarium, which do not exhibit the characteristics defined in Thanatosdrakon, related to the development of the neural arch, the location of the transverse processes and the reduced neural spine, namely: Volgadraco bogolubovi (Averianov et al., 2008, SGU 49/ 104a: Pl. 6: Fig. 1), Pteranodon sp. (Bennett, 2001a, UALVP 24238, KUVP 16487, YPM 2692, YPM 2451, UNSM 50036, UNSM 50128, FHSM 2065), Nyctosauridae indet. ...
The largest pterosaur discovered in South America and one of the largest flying vertebrates in the world is described. Thanatosdrakon amaru gen. et sp. nov. is a new azhdarchid found in the upper-most levels of the Plottier Formation (upper Coniacian–lower Santonian, Neuquén Basin), Mendoza, Argentina. Two specimens were identified, the holotype (UNCUYO-LD 307) and the paratype, with an estimated wingspan of ∼ 7 m and ∼ 9 m, respectively. The cladistic analysis, based on 216 characters and 97 taxa, recovered Thanatosdrakon deeply nested within Azhdarchidae. Relationships within this clade are well resolved and the clade Quetzalcoatlinae presents two well-defined sister-groups: (Arambourgiania, Mistralazhdarcho, Aerotitan, Hatzegopteryx, Albadraco) + (Cryodrakon, Thanatosdrakon, Quetzalcoatlus ssp.). Thanatosdrakon is the oldest taxon of the clade Quetzalcoatlinae so far. It is represented by several well-preserved axial and appendicular bones in three dimensions. Some of these elements have never been described in giant azhdarchids (e.g. complete norarium, dorsosacral vertebrae and caudal vertebra) and this allows to expand the knowledge about the anatomy of this diverse group of pterosaurs. Finally, from a paleoecological point of view, Thanatosdrakon was found in floodplain deposits of ephemeral meandering systems indicating that this large flying species inhabited continental environments.
... Other past investigations of the Rybushka Formation in the Saratov Oblast documented a rather varied assortment of vertebrates from the unit, including plesiosaurs (Arkhangelsky et al. 2007;Pervushov et al. 1999;Zverkov et al. 2017), mosasaurs (Pervushov et al. 1999;Grigoriev et al. 2015), pterosaurs (Averianov et al. 2005(Averianov et al. , 2008(Averianov et al. , 2016Averianov & Arkhangelsky 2020Averianov & Popov 2014), turtles (Arkhangelsky 1999;Danilov et al. 2018;Pervushov et al. 1999), birds (Panteleyev et al. 2004;Zelenkov et al. 2017), and the chimaeroids Amylodon karamysh, Edaphodon sp., Elasmodus sp., and Ischyodus bifurcatus. These investigations indicated that the vertebrate fauna of the Rybushka Formation is much more diverse than previously documented, as numerous bony fishes and some elasmobranchs were listed but not described in detail. ...
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A diverse fish paleofauna occurs in the upper Campanian portion of the Rybushka Formation exposed near Saratov city in the Saratov Oblast, Russia. Twenty taxa have been identified, including two holocephalans (Ischyodus bifurcatus and Amylodon karamysh), twelve elasmobranchs (Synechodus sp., Cederstroemia sp., Cretalamna cf. C. borealis, C. cf. C. sarcoportheta, Archaeolamna kopingensis, Eostriatolamia segedini, E. venusta, Pseudocorax laevis, Squalicorax kaupi, Squalicorax Morphology 1, Squalidae indet., and Squatirhina sp.), and six teleosts (Pachyrhizodus sp., Saurocephalus lanciformis, Paralbula casei, Enchodus cf. E. dirus, E. cf. E. gladiolus, and E. petrosus). Many of these taxa are new to the Campanian fish record of Russia, and the assemblage demonstrates that there is significant taxonomic overlap between the Rybushka Formation paleofauna and that of North America.
... Pterosaurs of the family Pteranodontidae were clearly dominant here. Only their remains were found in deposits of the Rybushka Formation (early Campanian) from the Malaya Serdoba locality in the Penza Oblast and Shirokiy Karamysh locality in the Saratov Oblast and in unnamed Campanian deposits from the Polunino 2 locality in the Volgograd Oblast (Bogolyubov, 1914;Averianov et al., 2008;Averianov and Arkhangelsky, 2021;Averianov and Yarkov, 2021). Remains of two pterosaur families, pteranodontids and azhdarchids, were found in the Beloe Ozero (Saratov Oblast), which is the richest pterosaur locality in the Rybushka Formation; however, most of the bones belong to pteranodontids (Averianov and Arkhangelsky, 2021). ...
... In Azhdarchoidea, a group often found to be a sister taxon to Dsungaripteroidea (e.g., Pinheiro et al. 2011), the femur is known for several prominent taxa of Tapejaridae and Azhdarchidae. In Volgadraco bogolubovi, only the diaphysis of the femur is preserved, and it is a large, hollow, thin-walled bone, with a bowed shaft (Averianov et al. 2008). Hatzegopteryx has a slightly bowed femur with a thin wall, the fourth trochanter lacks a marked tuberosity, and a small knob is located close to the proximal ridge, perhaps corresponding to the internal trochanter (Buffetaut et al. 2003). ...
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The pterosaur fossil record in Portugal is scarce, comprising mainly isolated teeth and rare postcranial material. Here, we describe a well-preserved right proximal femur of a pterodactyloid pterosaur from the Kimmeridgian, Upper Jurassic Praia da Amoreira–Porto Novo Formation of Peniche, Portugal. It is noteworthy for its relatively large size, compared to other Jurassic pterosaurs. It shows affinities with dsungaripteroids based on a combination of features including the bowing of the shaft, the mushroom-like cap of the femoral head, and the distinctly elevated greater trochanter. The femur has a relatively thinner bone wall compared to dsungaripterids, and is more similar to basal dsungaripteroids. A histological analysis of the bone cortex shows it had reached skeletal maturity. The preserved last growth period indicates fast, uninterrupted growth continued until the final asymptotic size was reached, a growth pattern which could best be compared to pterodactyloid femora from the Early Cretaceous. The specimen is the second confirmed report of a dsungaripteroid from the Jurassic, and it is the first record of this group from the Iberian Peninsula.
Bogolubovia orientalis, the first pterosaur taxon described from Russia, was known for more than a hundred years from a single specimen, the posterior fragment of the middle cervical vertebra from the Upper Cretaceous (upper Campanian) Rybushka Formation at Malaya Serdoba locality in Penza oblast, Russia. First classified as a pteranodontid, Bogolubovia was long thought to be an azhdarchid, and only very recently has it been again reclassified as a pteranodontid. Here, we describe the second pterosaur vertebra from the Malaya Serdoba locality, an atlantoaxis, which shows distinct pteranodontid characters, such as round cotyle, lack of hypapophysis, rudimentary diapophysis placed anterior to the lateral pneumatic foramen, and pair of posterior lateral pneumatic foramina. The pteranodontid characters of the holotype middle cervical vertebra include high neural arch, which is higher than the centrum and has the postzygapophyses placed well above the condyle, and the large posterior lateral foramina, similar in size with the posterior opening of the neural canal. Both vertebrae can be assigned to the same taxon, Bogolubovia orientalis. Bogolubovia can be distinguished from the pteranodontids Pteranodon and Volgadraco and thus is considered a valid taxon.
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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.
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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.
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A pterosaurian cervical vertebra, fragment of humerus, and associated femur and tibia from the Merchantville Formation (early Campanian, Late Cretaceous) of northern Delaware provide the second record of Cretaceous flying reptiles in eastern North America. These bones resemble Pteranodon in morphology and size but are not securely assignable to a particular genus of the family Ornithocheiridae. Comparison with Pteranodon skeletons from the Niobrara Chalk of Kansas indicates a wingspan of about 5.8 m (19 ft) for the Delaware pterosaurs. The successive Upper Cretaceous reptile faunas of the Merchantville, Marshalltown, and Mount Laurel Formations along the Chesapeake and Delaware Canal are listed for the first time.
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A large azhdarchid pterosaur is described from the Late Maastrichtian phosphatic deposits of the Oulad Abdoun Basin, near Khouribga (central Morocco). The material consists of five closely associated cervical vertebrae of a single individual. The mid-series neck vertebrae closely resemble those of azhdarchids Quetzalcoatlus and Azhdarcho in that they are elongate, with vestigial neural spines, prezygapophysial tubercles, a pair of ventral sulci near the prezygapophyses, and without pneumatic foramina on the lateral surfaces of the centra. The Moroccan pterosaur is referred to a new genus and species of Azhdarchidae: Phosphatodraco mauritanicus gen. et sp.nov. It is mainly characterized by a very long cervical vertebra eight, bearing a prominent neural spine located very posteriorly. Based on comparisons with azhdarchid vertebrae, the estimated wing span of Phosphatodraco is close to 5 m. This discovery provides the first occurrence of Late Cretaceous azhdarchids in northern Africa. Phosphatodraco is one of the few azhdarchids known from a relatively complete neck and one of the latest-known pterosaurs, approximately contemporaneous with Quetzalcoatlus.
Numerous remains of the azhdarchid pterosaur Quetzalcoatlus sp., have been recovered over the last twenty years from the Late Cretaceous (Maastrichtian) rocks in Big Bend National Park in Trans-Pecos Texas. Among more than 200 bones found at one locality are four incomplete skulls and mandibles, which provide the most complete information about cranial structures in the Azhdarchidae. What is currently known indicates that the Azhdarchidae is the sister group of the Tapejaridae from Early Cretaceous deposits in northeastern Brazil.
Remains of pterosaurs, the dominant aerial vertebrate throughout much of the Mesozoic were, until relatively recently, almost exclusively known from marine and marginal marine sediments of western Europe and North America. Prior to the 1960s Mesozoic deposits in the former Soviet Union and Mongolia had produced very few pterosaurs, but, in the last thirty years, many remains, including some from continental environments, have been found. Most important among these are Sordes and Batrachognathus from the Late Jurassic of Karatau in Kazakhstan, Azhdarcho from the Late Cretaceous of the Kyzylkum desert in Uzbekistan, and a number of new Mongolian pterosaurs, including a possible anurognathid from the Mid Jurassic of Bakhar, a dsungaripterid from the early Early Cretaceous of Tatal and an ornithocheirid from the late Early Cretaceous of Khuren‐Dukh. Although already documented to some extent, the significance of these discoveries remains underappreciated.The discovery and collection of these pterosaurs is described and the bearing of some of the more important material on current problems of pterosaur biology is discussed. We confirm Sharov's observation that the hind limbs of Sordes form an integral part of the flight apparatus, attached externally to the cheiropatagium and internally to the uropatagium, which is supported and manipulated by the fifth toe. The former Soviet and Mongolian pterosaurs also help to fill a number of important morphological and temporal gaps in the pterosaur fossil record and provide the best available evidence of pterosaurs from continental environments. With the exception of insectivores, these and other continental pterosaurs appear to have pursued lifestyles similar to those of their marine counterparts, leading us to suspect that pterosaurs largely failed to exploit terrestrial habitats.