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A new archaeopterodactyloid pterosaur from the Jiufotang Formation of western Liaoning, China, with a comparison of sterna in Pterodactylomorpha

  • Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences

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Eleven species of archaeopterodactyloid pterosaurs have been reported in China, mostly from the Yixian Formation of western Liaoning. The first uncontroversial archaeopterodactyloid from the Jiufotang Formation is described here. A new genus and species, Forfexopterus jeholensis, is erected on the basis of a unique combination of characters and one autapomorphy: the first wing phalanx is shorter than the second, but longer than the third. The sternum of Forfexopterus is nearly complete and provides the first incontrovertible evidence about the position of sternocoracoid articulations in the Archaeopterodactyloidea. A preliminary geometric morphometric analysis of sterna was carried out with data from 17 species of Pterodactylomorpha. The results document the variation in the shape of the sternum, including the length of the cristospine, the shapes of the lateral, posterior, and anterior margins, and the constriction and expansion of the cristospine. These characters can be used to compare sterna i...
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Journal of Vertebrate Paleontology
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A new archaeopterodactyloid pterosaur
from the Jiufotang Formation of western
Liaoning, China, with a comparison of sterna in
Shunxing Jiang, Xin Cheng, Yingxia Ma & Xiaolin Wang
To cite this article: Shunxing Jiang, Xin Cheng, Yingxia Ma & Xiaolin Wang (2016): A new
archaeopterodactyloid pterosaur from the Jiufotang Formation of western Liaoning, China,
with a comparison of sterna in Pterodactylomorpha, Journal of Vertebrate Paleontology, DOI:
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Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology,
Chinese Academy of Sciences, P.O. Box 643, Beijing 100044, China,;;;
University of Chinese Academy of Sciences, Beijing 100049, China;
Laboratory of Systematics and Taphonomy of Fossil Vertebrates, Department of Geology and Paleontology, Museu Nacional/
Universidade Federal do Rio de Janeiro. Quinta da Boa Vista s/n, S~
ao Crist
ao, 20940–040, Rio de Janeiro, Rio de Janeiro, Brazil;
Hami Museum, Hami 839000, China,
ABSTRACTEleven species of archaeopterodactyloid pterosaurs have been reported in China, mostly from the Yixian
Formation of western Liaoning. The first uncontroversial archaeopterodactyloid from the Jiufotang Formation is described
here. A new genus and species, Forfexopterus jeholensis, is erected on the basis of a unique combination of characters and
one autapomorphy: the first wing phalanx is shorter than the second, but longer than the third. The sternum of Forfexopterus
is nearly complete and provides the first incontrovertible evidence about the position of sternocoracoid articulations in the
Archaeopterodactyloidea. A preliminary geometric morphometric analysis of sterna was carried out with data from 17
species of Pterodactylomorpha. The results document the variation in the shape of the sternum, including the length of the
cristospine, the shapes of the lateral, posterior, and anterior margins, and the constriction and expansion of the cristospine.
These characters can be used to compare sterna in different pterosaur taxa.
Citation for this article: Jiang, S., X. Cheng, Y. Ma, and X. Wang. 2016. A new archaeopterodactyloid pterosaur from the
Jiufotang Formation of western Liaoning, China, with a comparison of sterna in Pterodactylomorpha. Journal of Vertebrate
Paleontology. DOI: 10.1080/02724634.2016.1212058.
Pterosauria is an important group of reptiles that were the first
vertebrates to evolve powered flight. Because their bones are
fragile, with an extremely thin bone wall (Ricql
es et al., 2000;
Steel, 2008), pterosaur fossils are rare worldwide (Barrett et al.,
2008) and often fragmentary. Indeed, only a few deposits yield
abundant and complete pterosaur fossils, with the Jehol Biota
being one such Lagerst
atte. Pterosaur fossils have been discov-
ered in two formations of the Jehol Group: the stratigraphically
lower Yixian Formation, in which archaeopterodactyloids domi-
nate, and the stratigraphically higher Jiufotang Formation, in
which dsungaripteroids dominate (Wang, Cheng, et al., 2014).
The first archaeopterodactyloid pterosaur to be reported
from China was Huanhepterus quingyangensis from the Lower
Cretaceous Huanhe Formation (Dong, 1982; Wang et al.,
2014a). Most archaeopterodactyloids discovered in the Jehol
Biota, including Eosipterus yangi, Beipiaopterus chenianus,
Zhenyuanopterus longirostris, Boreopterus cuiae, Feilongus
youngi, Gegepterus changae, Elanodactylus prolatus, Pterofil-
trus qiui,andBoreopterus giganticus, come from the lower
part of the Yixian Formation (Ji and Ji, 1997; L
u, 2003, 2010;
u and Ji, 2005; Wang et al., 2005, 2007; Andres and Ji, 2008;
Jiang and Wang, 2011a; Jiang et al., 2014), the absolute age of
which is 125 Ma (Swisher et al., 2002). Cathayopterus grabaui
and Gladocephaloideus jingangshanensis are from the middle
and upper parts of the Yixian Formation (Wang and Zhou,
2006; L
u et al., 2012a), with absolute ages of 122 and 121 Ma
(Smith et al., 1995), respectively. Although Moganopterus
zhuianus was reported as having been collected from the Yix-
ian Formation (L
u et al., 2012b), many other vertebrate fossils
from its type locality, Xiaosanjiazi Village, Lamadong Town,
are considered to be from the Jiufotang Formation (Zhou,
2010; Evans and Wang, 2012; Li et al., 2014). We have previ-
ously investigated this locality and collected tuff samples from
above the fossil-bearing shale for laser ablation sampling and
multiple collector inductively coupled plasma mass spectrome-
try (LA-MC-ICPMS) U-Pb zircon analysis. Our result was 120
§1.0 Ma (unpubl. data), which is the same as the age
reported for the Jiufotang Formation at another locality (He
et al., 2004). Hence, Moganopterus is probably derived from
the Jiufotang Formation, rather than the Yixian Formation as
originally reported.
Recently, a second archaeopterodactyloid specimen from the
Jiufotang Formation was collected at the Xiaotaizi locality,
which is less than 500 m away from the locality that yielded
Moganopterus. In this paper, we describe this new archaeoptero-
dactyloid pterosaur, which is the most complete specimen of this
group discovered in China, and present a preliminary compari-
son of Pterodactylomorpha sterna.
*Corresponding author.
Color versions of one or more of the figures in this article can be found
online at
Journal of Vertebrate Paleontology e1212058 (12 pages)
Óby the Society of Vertebrate Paleontology
DOI: 10.1080/02724634.2016.1212058
The new specimen reported here was collected by a local
farmer, who told us where he had discovered the specimen. We
confirmed the fossil locality and horizon through our own field
work. Unfortunately, the farmer had removed some of the
matrix covering the fossil with his own tools, and in doing so had
damaged the surface of the specimen. The specimen was pre-
pared by a technician who removed the matrix and glued three
major parts back together. All fossil elements preserved in these
pieces clearly belong to the same individual.
Geometric Morphometric (GM) Analysis
Geometric morphometric (GM) analysis using a two-dimen-
sional (2D) approach was carried out on the half outline of
sterna for 17 species of the Pterodactylomorpha (sensu Andres
et al., 2014), for all of which sterna were completely preserved or
have been confidently reconstructed (Fig. 1). Geometric mor-
phometric analysis aims to quantitatively analyze shape variation
among specimens based on landmark and/or semi-landmark
coordinate data (Adams et al., 2004; Zelditch et al., 2004). In
this analysis, we assumed that the left and right outlines of the
sterna were symmetrical, and that the outlines in dorsal and ven-
tral views were the same. Considering that specimens with com-
plete sterna are rare, we did not analyze the left and right halves
separately, although the sternocoracoid articulations are asym-
metric in some taxa, making the right and left outlines have a
slight difference.
In this analysis, four landmarks were chosen: (1) the anterior
tip of the cristospine; (2) the widest point of the anterior margin;
(3) the posterior point of the lateral margin; and (4) the midpoint
of the posterior margin (Fig. 1). Some other points, such as the
posterior end of the keel and the anterior point of the pneumatic
foramen in the sternal plate, would also make suitable land-
marks, but were not chosen because they could not be identified
on the majority of the sterna assessed.
The margin of the sternum between the first and second land-
marks was divided into 19 equidistant parts using the program
TpsDig2 (Rohlf, 1998a), and the dividing points were treated as
semi-landmarks (Fig. 1), the positions of which depend on other
landmarks and thus contain less shape information. The outlines
between the second and third landmarks and the third and fourth
landmarks were divided into seven and nine equidistant parts,
respectively. Equidistant semi-landmarks do not necessarily
show geometric or biological correspondence across specimens.
Therefore, the spacing of semi-landmarks is arbitrary (Gunz and
Mitteroecker, 2013). However, the effect of the arbitrary spacing
could be removed by using the sliding technique, which mini-
mizes the Procrustes distance of the semi-landmarks relative to
the average shape of the entire sample (Gunz and Mitteroecker,
The program TpsRelw (Rohlf, 1998b) was used to conduct
superimposition on the raw coordinate data with the method of
generalized Procrustes analysis (GPA), and the relative warp
analysis (RWA; or principal component analysis, PCA) of shape
variables. The GPA method minimizes the total sum of the
squared distances between corresponding landmarks (Hammer
and Harper, 2006). RWA (PCA) finds principal components of
the thin-plate spline deformations from average shape to each
individual shape (Hammer and Harper, 2006).
CTENOCHASMATIDAE Nopcsa, 1928, sensu Andres et al.,
(Figs. 2–5)
Etymologyforfex,’ Latin, meaning scissors, referring to the
shape of the upper and lower jaws; ‘pterus,’ Greek, meaning
‘wings’; ‘jehol,’ referring to the ancient name of the region where
the specimen was collected.
HolotypeThe specimen is housed at the Hami Museum
(HM V20), Hami, China. The specimen contains most parts of
the skull and mandible and a nearly complete postcranial
Locality and HorizonXiaotaizi, Lamadong, Jianchang,
Liaoning Province, China; Jiufotang Formation, late Early Cre-
taceous (120 §1.0 Ma).
DiagnosisForfexopterus jeholensis is a large-sized archaeop-
terodactyloid, which can be distinguished from all other mem-
bers of the clade by a single autapomorphy: the first wing
phalanx is shorter than the second phalanx but longer than the
third. The specimen can be further distinguished from other
archaeopterodactyloids on the basis of the following combina-
tion of characters: teeth are slender, with a total count of approx-
imately 120 for the upper and lower jaws; tooth row occupying
more than a third of the skull length, but ending anterior to the
anterior margin of the nasoantorbital fenestra; cristospine long;
sternocoracoid articulations asymmetric; and coracoid flange
The holotype of Forfexopterus is nearly completely preserved,
but is lacking the posterior part of the skull, some cervical verte-
brae, most sacral verterbae, all dorsal and caudal vertebrae, and
part of the pelvis (Figs. 2, 3). It represents a large individual,
with a wingspan of 3 m. Some bones that are typically fused in
adult pterosaurs remain unfused in this specimen, such as the
axis and atlas, scapula and coracoid, humerus shaft and its distal
epiphysis, and first wing phalanx and its extensor tendon process.
These observations indicate that this specimen is not an adult
individual (Bennett, 1993, 1996; Kellner and Tomida, 2000; Kell-
ner, 2015). The syncarpals are fused, which occurs at the third of
the six ontogenetic stages for pterosaurs identified by Kellner
(2015), indicating that the specimen is older than a juvenile (the
second stage). Hence, this is a subadult individual.
SkullThe skull is compressed laterally (Fig. 4A; Table 1). It
is low and elongated, with an estimated length of 510 mm. The
nasoantorbital fenestra is incomplete; its estimated length is
112.3 mm, occupying 22.0% of the skull length. Most elements
posterior to the nasoantorbital fenestra are not preserved. Only
the anterior part of the left quadrate is preserved, and it connects
with the articular. The occipital region is displaced from its natu-
ral position and is now preserved next to the nasoantorbital
fenestra. The occipital condyle is nearly complete and is fused
with the opisthotic and exoccipital. The premaxilla is extremely
elongated and lacks a crest.
MandibleThe mandible is complete, although the left ramus
is overlain by the right. Because the posterior region of the right
ramus was overturned during preservation, both rami are
exposed in medial view (Fig. 4B; Table 1). The adductor fossa is
oblate and very small. The angular and surangular form the ven-
tral and dorsal margins of the posterior mandible, respectively.
The surangular occupies more than one third of the entire length
of the mandible. The articular is ventrally inclined and forms the
curved ventral margin of the mandible. There is no crest on the
DentitionThe teeth in both the upper and lower jaws are
slender and slightly curved (Fig. 4; Table 1). Because the tips of
the upper and lower jaws are missing and the last one or two
alveoli in the lower jaw are overlain by other bones, the exact
Jiang et al.Forfexopterus from China (e1212058-2)
FIGURE 1. Sterna of pterosaurs sampled by our geometric morphometric analysis, showing landmarks (blue and large) and semi-landmarks (red and
small). A,Forfexopterus jeholensis, gen. et sp. nov. (reversed); B,Darwinopterus linglongtaensis (after Wang et al., 2010); C,Darwinopterus robust-
dens (after L
u et al., 2011); D,Kunpengopterus (after Wang et al., 2010); E,Pterodactylus antiquus (after Wellnhofer, 1970); F,Ardeadactylus longi-
collum (after Meyer, 1854); G,Auruazhdarcho primordius (after Frey et al., 2011); H,Haopterus (reversed, after Wang and L
u, 2001); I,Anhanguera
piscator (after Kellner and Tomida, 2000); J,Muzquizopteryx (after Frey et al., 2006); K,Nurhachius (after Wang et al., 2005); L,Nyctosaurus gracilis
(after Wilston, 1903); M,Pteranodon (after Eaton, 1903); N,Dsungaripterus (reversed; after Young, 1973); O,Eopteranodon (reversed, after L
u et al.,
2006); P,Jidapterus (Dong et al., 2003); Q,Tapejara wellnhoferi (after Eck et al., 2011). Not to scale.
Jiang et al.Forfexopterus from China (e1212058-3)
number of teeth is unknown. However, we estimate 30 and 28
per side for the upper and lower jaws, respectively. The sixth to
10th teeth (see Fig. 4 for our estimated tooth positions) are lon-
ger than the other teeth in both upper and lower jaws. The teeth
become apicobasally shorter posteriorly starting from the 10th
tooth. Each of the anterior teeth is located within an alveolus,
and the last few teeth are located in a groove formed by their
alveoli. The surface of each tooth is smooth, and no longitudinal
striations can be observed, similar to the tooth morphology in
many ctenochasmatids such as Ctenochasma elegans, Cathayop-
terus, Gegepterus, and Pterofiltrus (Wagner, 1861; Wang and
Zhou, 2006; Wang et al., 2007; Jiang and Wang, 2011a). None-
theless, the teeth of HM V20 curve more strongly than those of
other ctenochasmatids. Additionally, the number of teeth is simi-
lar to that of Huanhepterus, Gnathosaurus, Plataleorhynchus,
Boreopterus, and Pterofiltrus (Dong, 1982; Howse and Milner,
1995; L
u and Ji, 2005; Jiang and Wang, 2011a), but there are
fewer teeth than in Cathayopterus and Gegepterus (Wang and
Zhou, 2006; Wang et al., 2007), and more teeth than in Feilon-
gus, Gladocephaloideus, and Moganopterus (Wang et al., 2005;
u et al., 2012a, 2012b). The tooth row ends anterior to the ante-
rior margin of the nasoantorbital fenestra, which is similar to
Huanhepterus, Cathayopterus, and Gegepterus (Dong, 1982;
Wang and Zhou, 2006; Wang et al., 2007), but is a longer tooth
row than in Feilongus, Gladocephaloideus, and Moganopterus
(Wang et al., 2005; L
u et al., 2012a, 2012b), and a shorter one
than in Gnathosaurus, Pterodaustro, Ctenochasma, and boreop-
terids (Meyer, 1834; Sanchez, 1973; L
u and Ji, 2005; Bennett,
2007; L
u, 2010; Jiang et al., 2014).
VertebraeThe second to seventh cervical vertebrae and one
sacral vertebra are preserved (Figs. 2, 3, 5C; Table 2). The axis is
short, and the neural spine is low, differing from the high neural
spine present in the Boreopteridae (L
u and Ji, 2005; L
u, 2010;
Jiang et al., 2014) and the knob-like expansion in Gegepterus
(Wang et al., 2007), but similar to the axis of Moganopterus (L
et al., 2012b). All cervicals are preserved in lateral view and are
elongate with a reduced neural spine. Cervicals 2 to 4 are articu-
lated and complete, but the anterior part of cervical 5 is incom-
plete; the posterior part is visible in dorsal view and shows well-
developed postzygapophyses and postexapophyses (Fig. 5C).
FIGURE 2. Forfexopterus jeholensis, gen. et sp. nov., HM V20 (holotype). Scale bar equals 100 mm.
Jiang et al.Forfexopterus from China (e1212058-4)
In cervical 5, the width of the element at midlength, the width
between the postzygapophyses, and the width between the
postexapophyses are 22.7, 16.0, and 33.9 mm, respectively. The
ratio of the anteroposterior length of the vertebra to its width at
mid-length is 4.7, which is similar to the condition in most
archaeopterodactyloids, such as Beipiaopterus (3.4 for cervical
7), Gegepterus (4.4), Elanodactylus (4.0 for cervical 7), and Gla-
docephaloideus (3.1 for cervical 3) (L
u, 2003; Wang et al., 2007;
Andres and Ji, 2008; L
u et al., 2012a), but not as elongated as in
Huanhepterus (Dong, 1982) and Moganopterus (L
u, Ji, et al.,
2012), and much more elongated than in boreopterids (L
u and
Ji, 2005; L
u, 2010). Cervical 5 has two rod-like elements below
the vertebral centrum, which are interpreted as cervical ribs.
Cervical ribs are also reported in Beipiaopterus and Gegepterus
u, 2003; Wang et al., 2007). Cervicals 6 and 7 are similar in
morphology to cervical 5, but lack ribs. The ratio of the centrum
length to its height in cervicals 3–7 is 3.9, 6.6, 5.1, 4.5, and 4.7,
respectively. The presence of lateral foramina on the centra of
the cervicals is difficult to determine because their surfaces are
The single preserved sacral vertebra centrum is 11.9 mm long
and 8.0 mm wide. The transverse processes are developed and
are longer than the centrum (Figs. 2, 3); each process extends lat-
erally for 30.7 mm. There is a stick-like bone near the left tibia
that is interpreted as the first dorsal rib. This bone is robust and
has two articulation facets on the proximal end; the anterior and
posterior parts of this bone form an angle of approximately 150
to one another.
SternumThe sternum is well preserved and is exposed in
dorsal view (Fig. 5A, B). The length is slightly greater than the
width (108.9 versus 100.9 mm). The cristospine accounts for
approximately one third of the length of the entire sternum.
There is a low ridge on the middle of the anterior cristospine,
which tapers anteriorly. There are two articular facets for
FIGURE 3. Line drawing of Forfexopterus jeholensis, gen. et sp. nov., HM V20 (holotype). Abbreviations:afo, adductor fossa; art, articular; ax, axis;
car, carpal; cor, coracoid; cv37, third to seventh cervical vertebrae; dri, dorsal rib; fe, femur; , fibula; hu, humerus; man, mandible; mcIIV, metacar-
pals I–IV; mtIV, metatarsals I–V; naof, nasoantorbital fenestra; oc, occipital condyle; pel, pelvis; phd13, manual digits I–III; ph14d4, first to fourth
phalanges of manual digit IV; pra, prearticular; pt, pteroid; q, quadrate; ra, radius; san, surangular; sca, scapula; sk, skull; st, sternum; sv, sacral verte-
bra; tar, tarsal; te, teeth; ti, tibia; ul, ulna; ?, uncertain; l, left; r, right. Scale bar equals 100 mm.
Jiang et al.Forfexopterus from China (e1212058-5)
coracoids on the posterior cristospine; the right one is positioned
anterior to the left one. Both the facets are oval and nearly flat-
tened, and each one is as wide as the cristospine. Although some
incomplete sterna of archaeopterodactyloids have been reported
(Dong, 1982; Wang et al., 2007; Andres and Ji, 2008), this is the
first specimen with a sternum providing incontrovertible evi-
dence about the position of sternocoracoid articulations in this
group. The cristospine is not constricted near the sternal plate.
The plate is fan-like, with its length longer than its width. The
entire plate is thin, except at the anterior margin, which is much
thicker than the other parts. The lateral margins of both sides
are incomplete, and none of the costal articulations is preserved.
The posterior margin is arc-like and lacks the concave structure
in the middle seen in Zhejiangopterus or the convex structure in
Nyctosaurus (Cai and Wei, 1994; Williston, 1901). A large
depression lies behind the anterior margin of the plate, and at
the bottom of this depression, a pneumatic foramen opens into
the body of the cristospine.
Pectoral GirdleThe scapulae and coracoids of both sides
are well preserved; the right scapula is partially overlain by
the left coracoid (Figs. 2, 3; Table 3). The elements are not
fused together on either side. The left coracoid is preserved
in anterior view and the right in posterior view. There is a
ventral process near the articulation of the coracoid with the
scapula, which represents the coracoid flange. A coracoid
flange is also reported in some archaeopterodactyloids, such
as Beipiaopterus and Gegepterus (L
u, 2003; Wang et al.,
2007), but not in Pterodactylus, Cycnorhamphus,andGerma-
nodactylus (Wellnhofer, 1978). The articulation with the ster-
num is slightly concave. Both scapulae are incomplete and
slightly curved. The entire scapula has a uniform thickness
FIGURE 4. The upper and lower jaws of Forfexopterus jeholensis, gen. et sp. nov., HM V20 (holotype). A, photograph of upper jaw; B, interpretive
drawing of upper jaw; C, photograph of lower jaw; D, interpretive drawing of lower jaw. Numbers indicate the tooth positions. Abbreviations:afo,
adductor fossa; art, articular; bo, basioccipital; d, dentary; eo, exoccipital; m, maxilla; naof, nasoantorbital fenestra; oc, occipital condyle; pm, premax-
illa; pra, prearticular; san, surangular; l, left; r, right. Scale bars equal 100 mm.
TABLE 1. Measurements of the cranial elements in the holotype (HM
V20) of Forfexopterus jeholensis, gen. et sp. nov. (in mm).
Element Length
Skull (pr-sq) 510.0
Rostrum (pr-naof) 305.9
Nasoantorbital fenestra 112.3
Tooth row of the upper jaw 184.8
Lower jaw 434.1
Tooth row of the lower jaw 173.2
Estimated length.
Jiang et al.Forfexopterus from China (e1212058-6)
and does not taper. The scapula is longer than the coracoid,
similar to the condition in Beipiaopterus, Zhenyuanopterus,
and Elanodactylus (L
u, 2005, 2010; Andres and Ji, 2008).
HumerusBoth humeri are well preserved (Figs. 2, 3, 5D;
Table 3). The right humerus is exposed in dorsal view and is
straight (Fig. 5D); the left is exposed in posteroventral view and
bends slightly along its length, indicating that the humeri bend
ventrally towards their distal ends. The deltopectoral crest is
present on the proximal end of the shaft. The length of the crest
base is 30.0 mm, occupying approximately a quarter of the length
of the shaft, which is similar to the condition in Beipiaopterus
and Zhenyuanopterus (L
u, 2005, 2010) but shorter than in
Huanhepterus (Dong, 1982) and Elanodactylus (Andres and Ji,
2008), in which the crest base extends for one third of the shaft
length. The crest is slightly curved distally, with the cross-section
gradually tapering from the base to the distal end, which is a
character of ctenochasmatids (Andres et al., 2014). The head of
the humerus cannot be observed. Although crushed, the poste-
rior tuberosity is large and well developed. Two pneumatic
foramina are observed in the humeri: one lies on the posterodor-
sal surface of the left deltopectoral crest base, and the other lies
on the dorsal surface of the right humerus, at one third
of humeral length. The pneumatic foramen near the base of the
deltopectoral crest is similar to that in Boreopterus cuiae and
Elanodactylus (L
u and Ji, 2005; Andres and Ji, 2008) but has not
been reported in Pterodaustro (Bonaparte, 1970). The distal end
of the humerus has an expanded ectepicondyle, which forms a
130angle with the shaft. One epiphysis can be observed near
FIGURE 5. Postcranial elements of Forfexopterus jeholensis, gen. et sp. nov., HM V20 (holotype). A, photograph of the sternum in dorsal view; B,
photograph of the cristospine of the sternum in dorsal view; C, interpretive drawing of cristospine of the sternum in dorsal view; D, photograph of the
fifth cervical vertebra in dorsolateral view; E, interpretive drawing of the fifth cervical vertebra in dorsolateral view; F, photograph of the right
humerus in dorsal view; G, interpretive drawing of the right humerus in dorsal view. Abbreviations:ac, articulation for coracoid; cri, cervical rib; cs,
cristospine; dep, depression; dpc, deltopectoral crest; ec, ectepicondyle; pf, pneumatic foramen; pl, sternal plate; poex, postexapophysis; poz, postzyga-
pophysis; prz, prezygapophysis; rid, ridge. Scale bars equal 10 mm (B) and 20 mm (A,E,G).
Jiang et al.Forfexopterus from China (e1212058-7)
the distal end and it is not fused with the shaft of the left
Ulna and RadiusMost of the left ulna and radius are over-
lain by other bones, but the right elements are exposed (Figs. 2,
3; Table 3). The ulna and radius are straight, and the diameter of
the ulna is slightly larger than that of the radius, as also reported
in Huanhepterus and Beipiaopterus (Dong, 1982; L
u, 2005).
However, the diameter of the ulna is about twice that of the
radius in Eosipterus, Boreopterus cuiae, Elanodactylus, and Zhe-
nyuanopterus (Ji and Ji, 1997; L
u and Ji, 2005; Andres and Ji,
2008; L
u, 2010). The ulna is more than 150% of the length of the
CarpusFour carpals can be observed in this specimen
(Figs. 2, 3). The carpal surfaces are badly crushed. Two of them
are proximal syncarpals, and two are distal syncarpals.
MetacarpusMost of the right metacarpals are overlain by
other bones, but the left wing metacarpal is well exposed
(Figs. 2, 3; Table 3). Of the other metacarpals, only metacarpal I
can be observed, and its length is similar to that of the wing
metacarpal. This indicates that it connects with the distal carpals,
but the condition of the other metacarpals is difficult to deter-
mine. Metacarpals I–III of Elanodactylus and Gegepterus con-
nect with the distal carpal (Wang et al., 2007; Andres and Ji,
2008), and in some other archaeopterodactyloids, such as Bor-
eopterus cuiae, at least metacarpal I connects with the distal car-
pal (L
u and Ji, 2005). Neither end of the wing metacarpal is well
preserved, and only the two condyles of the distal end can be
identified, even though the distal end is overlain by the isolated
extensor tendon process.
PteroidBoth pteroids are slender (Figs. 2, 3; Table 3); the
right one is straight, and the left one is curved. The pteroids taper
distally, and each has a pointed tip, similar to Zhenyuanopterus
u, 2010) but unlike the slight expansion knob of Elanodactylus
(Andres and Ji, 2008). The ratio of the length of the pteroid to
the ulna is 46.7%, which is similar to that of boreopterids (41.0–
44.2%; L
u and Ji, 2005; L
u, 2010).
PhalangesThe wing phalanges become thinner and more
slender from the first to the fourth (Figs. 2, 3; Table 3); the sec-
ond is the longest, and the first is longer than the third, which has
not been reported in any other archaeopterodactyloid (Dong,
1982; Ji and Ji, 1997; L
u, 2003; L
u and Ji, 2005). Only Elanodac-
tylus is similar, with the second phalanx being the longest but the
first shorter than the third (Andres and Ji, 2008). The extensor
tendon processes have ossified but are not fused together with
the first wing phalanx. The articular facets between the wing pha-
langes are nearly flat. The fourth phalanx is curved and tapers
distally with an expanded distal end, similar to Elanodactylus
and Gegepterus (Andres and Ji, 2008; Jiang and Wang, 2011a)
but differing from the pointed tip in Huanhepterus, Eosipterus,
and Boreopterus cuiae (Dong, 1982; Ji and Ji, 1997; L
u and Ji,
2005). Of the other manual digits, digit I is the shortest, digit III
is the longest, and the phalangeal formula is 2-3-4 for digits I–III.
Each digit ends in a large and curved ungual.
Pelvic GirdleOnly part of an ilium is preserved (Figs. 2, 3).
It is incomplete and has a concave dorsal margin.
FemurThe right femur is preserved in posterior view,
whereas the left femur is exposed in anterolateral view (Figs. 2,
3; Table 3). The shaft of the femur curves slightly anteriorly.
The head is demarcated by a constricted neck, and the proximal
facet of the head is nearly flat, similar to the condition reported
in Huanhepterus and Elanodactylus (Dong, 1982; Andres
and Ji, 2008). The head and shaft form an angle of 130. The
greater trochanter lies on the lateral side of the head. The distal
end of the femur consists of a small medial condyle and a
slightly larger lateral condyle separated by a shallow intercon-
dylar sulcus. The lateral condyle forms a 115angle with the
Tibia and FibulaThe tibia is straight and is not fused with the
tarsus to form a tibiotarsus (Figs. 2, 3; Table 3). The tibia is longer
than the femur, as is the case in most other archaeopterodactyloids
(Ji and Ji, 1997; L
u, 2003; Jiang and Wang, 2011b), with the exception
of boreopterids (L
u, 2010). The fibula tapers distally,
and its length is approximately 40% that of the tibia, a slightly lower
ratiothaninBeipiaopterus (49%; L
u 2003) and Gegepterus (44.2%;
Jiang and Wang, 2011b).
TarsusThe tarsi are incomplete on both sides (Figs. 2, 3).
Only one distal tarsal is preserved on the right side, and it articu-
lates with metatarsals II–IV. One large rounded proximal tarsal
and two slightly smaller distal tarsi are preserved, all of which
are badly crushed.
MetatarsusAll the metatarsals are well preserved, and the
fifth one is reduced (Figs. 2, 3; Table 3). The right metatarsals
are exposed in dorsal view, and the left ones in ventral view.
Metatarsal III is 37.1% the length of the tibia, which is similar to
most other archaeopterodactyloids, such as Beipiaopterus
(37.3%; L
u, 2003), Gegepterus (39.7%; Jiang and Wang, 2011b),
and Gladocephaloideus (40.2%; L
u et al., 2012a), but much
longer than that of boreopterids (13–15.6%; L
u and Ji, 2005; L
Pedal DigitsAll digits except the fifth are well preserved
(Figs. 2, 3). The phalangeal formula is 2-3-4-5-? for pedal digits
I–V. Each of the unguals has a length of 10 mm, and is 5 mm in
transverse width at its base, and as such are much smaller than
the manual unguls. One and two small phalanges are preserved
in the third and fourth digits, respectively, which indicates that
this specimen is not a very young individual (Kellner and
Tomida, 2000).
TABLE 3. Measurements of postcranial elements in the holotype (HM
V20) of Forfexopterus jeholensis, gen. et sp. nov. (in mm).
Element Left Right
Scapula 80.5 79.5
Coracoid 80.8 82.0
Humerus 117.6 118.3
Radius/ulna 192.2
Metacarpal IV 146.4 147.2
Pteroid 81.3
First phalanx of manual digit IV 194.5 191.1
Second phalanx of manual digit IV 208.6 217.6
Third phalanx of manual digit IV 159.6
Fourth phalanx of manual digit IV 133.2 135.4
Manual digit I 24.0 / 13.1 23.7 /
Manual digit II 15.5 / 21.1 / 15.1 12.7 / 21.7 / 16.5
Manual digit III 22.7 / 7.2 / 19.2 /
/ 8.2 / 20.9 /
Femur 110.3 109.5
Tibia 178.0 178.2
Fibula 69.9 64.7
Metatarsals I–IV 66.9 / 75.3 / 66.1 /
68.4 / 72.3 / 64.6 /
Estimated length.
Preserved length.
TABLE 2. Measurements of cervical vertebrae in the holotype (HM
V20) of Forfexopterus jeholensis, gen. et sp. nov. (in mm).
Vertebra Length (prz–poz) Height of centrum
Cervical 2 19.4 12.6
Cervical 3 65.4 16.8
Cervical 4 107.6
Cervical 5 106.3 20.8
Cervical 6 101.7 22.4
Cervical 7 83.6 17.7
Estimated length.
Jiang et al.Forfexopterus from China (e1212058-8)
The clade Archaeopterodactyloidea was first established by
Kellner (2003) and is similar to the Ctenochasmatoidea (sensu
Unwin, 2003) but with the additional inclusion of the aberrant taxon
Germanodactylus. Both clades have been recovered in various ptero-
saur studies (Andres and Myers, 2013; Andres et al., 2014; Hyder
et al., 2014; Wang et al., 2014b). In the most recent phylogenetic
analysis, Andres et al. (2014) considered the Ctenochasmatoidea to
be an ingroup of the Archaeopterodactyloidea.
The new specimen described herein can be assigned to Ptero-
dactyloidea based on the following characters: an elongated
metacarpal IV and a reduced fifth metatarsal. The elongated cer-
vical vertebrae with a low neural spine and the shape of the del-
topectoral crest indicate that this specimen is a member of
Archaeopterodactyloidea (Kellner, 2003; Andres et al., 2014).
The teeth are slender and needle-like, and some anterior teeth
have a crown height that is four times longer than the width of
the base, which indicates that this specimen can be referred to
Ctenochasmatoidea (Ctenochasmatidae CCycnorhamphus;
sensu Andres et al., 2014). This specimen can be tentatively
assigned to Ctenochasmatidae based on several characters, such
as elongated rostrum (Kellner, 2003; Unwin, 2003; Andres et al.,
2014), number of teeth greater than 100 (Unwin, 2003; Andres
et al., 2014), metatarsal III longer than a third of the length of
tibia (Unwin, 2003), and presence of postexapophyses in the
mid-cervical vertebrae (Andres et al., 2014).
Most members of Archaeopterodactyloidea that have been
described based on nearly complete specimens have been discovered
in Europe and China (Barrett et al., 2008), with the additional dis-
covery of Pterodaustro from a Lower Cretaceous deposit in Argen-
tina (Bonaparte, 1970). Most of the European specimens are from
Upper Jurassic deposits, except for Gnathosaurus macrurus and Pla-
taleorhynchus streptophorodon from the lowermost Cretaceous Pur-
beck Limestone Formation (Howse and Milner, 1995; Barrett et al.,
2008). All the Chinese archaeopterodactyloids originate from Lower
Cretaceous deposits (Wang et al., 2014a).
Pterodaustro is a highly unusual pterosaur that has hundreds of
slender and needle-like teeth in the lower jaw. This morphology
is very different from the type specimen of Forfexopterus. Addi-
tionally, the manual unguals are less than twice the size of the
pedal unguals, and the pneumatic foramen is absent on the dor-
sal surface of the humerus in Pterodaustro (Bonaparte, 1970),
differing from the conditions seen in Forfexopterus.
The archaeopterodactyloid pterosaurs discovered in Europe
are also different from the type specimen of Forfexopterus.Cte-
nochasma has slender teeth, as does Forfexopterus (Meyer, 1851;
Wagner, 1861; Jouve, 2004); however, Ctenochasma has at least
60 teeth on each side of its upper and lower jaws (Bennett,
2007), which is much more than in Forfexopterus. The tooth rows
are also much longer relative to skull length, and the tooth den-
sity of Ctenochasma (2.9–7 teeth/cm; Bennett, 2007) is higher
than that of Forfexopterus (1.6 teeth/cm).
The slender teeth, presence of cervical vertebral postexapophyses,
and presence of the coracoid flange distinguish Forfexopterus from
Pterodactylus (Bennett, 2013a), Cycnorhamphus (Bennett, 2013b),
and Ardeadactylus (Bennett, 2013a). Forfexopterus possesses more
teeth than those three genera, but the tooth row is proportionately
shorter than that of Pterodactylus (Bennett, 2013a) and longer than
that of Cycnorhamphus (Bennett, 2013b).
The slender tooth shape, number of teeth, and tooth row
length in Gnathosaurus and Plataleorhynchus are similar to those
in Forfexopterus (Meyer, 1834; Howse and Milner, 1995). How-
ever, the anterior part of the rostrum is spatulate in the first two
genera (Meyer, 1834; Howse and Milner, 1995), which differs
from the unexpanded rostrum tip in the latter. The preserved
skull of Gnathosaurus subulatus shows a low premaxillary crest
(Meyer, 1834), which is absent in Forfexopterus.
The archaeopterodactyloids discovered in China display high
diversity, but all of them are different from the new specimen.
Huanhepterus was discovered in a different locality to all other
archaeopterodactyloids known from China. This taxon has a
long premaxillary crest starting at the anterior part of the ros-
trum (Dong, 1982), a characteristic that is not present in Forfex-
opterus. The cervical vertebrae are extremely elongated in
Huanhepterus, such that the ratio of anteroposterior length to
width at midlength is about 7 (Dong, 1982), which is not the
case in Forfexopterus. The deltopectoral crest of the humerus in
Huanhepterus is more elongated proximodistally relative to the
shaft than that in Forfexopterus (Dong, 1982).
The Boreopteridae (sensu Jiang et al., 2014), including Boreopte-
rus cuiae, B. giganticus,andZhenyuanopterus longirostris, differ sub-
stantially from the new taxon. The long tooth row, medium-length
mid-cervical vertebrae, high neural spines of the mid-cervicals, and
short tibia and foot relative to the femur in boreopterids are absent
in Forfexopterus (L
u and Ji, 2005; L
u, 2010; Jiang et al., 2014).
Both the slender teeth and the number of teeth of Pterofiltrus
are similar to those of Forfexopterus (Jiang and Wang, 2011a).
However, the length of the tooth row is 55.8% that of the skull
in Pterofiltrus (Jiang and Wang, 2011a), which is a much higher
percentage than that of Forfexopterus (36.2%). Moreover, the
tooth density in Pterofiltrus (2.5 teeth/cm; Jiang and Wang,
2011a) is higher than that of Forfexopterus (1.6 teeth/cm).
Feilongus, Gladocephaloideus, and Moganopterus have sub-
stantially fewer teeth than Forfexopterus (Wang et al., 2005; L
et al., 2012a, 2012b). The parietal crests preserved in the first
three genera are absent in the latter due to poor preservation.
However, both Feilongus and Moganopterus have a low premax-
illary crest (Wang et al., 2005; L
u et al., 2012b), which is not
developed in Forfexopterus. The cervical vertebrae are
extremely elongated in Moganopterus (L
u et al., 2012b) but less
so in Forfexopterus.
Three archaeopterodactyloids in the Jehol Biota are known only
from postcranial material: Eosipterus, Beipiaopterus,andElano-
dactylus (Ji and Ji, 1997; L
u, 2003; Andres and Ji, 2008). Beipiaop-
terus has an extremely elongated first wing phalanx, even longer
than the sum of the lengths of the second and third phalanges,
which is unique among Pterosauria (L
u, 2003). The lengths from
the first to the fourth wing phalanges are in descending order in
most pterodactyloids (Andres et al., 2014; Wang et al., 2014b).
However, the second wing phalanx is the longest one in Forfexop-
terus and Elanodactylus (Andres and Ji, 2008), and in Elanodacty-
lus, the third wing phalanx is even longer than the first one
(Andres and Ji, 2008), which is contrary to the situation in Forfex-
opterus. The ratio of the length of the ulna to the humerus in For-
fexopterus is greater than 1.5, which is much larger than that of
the other archaeopterodactyloids found in China.
Cathayopterus and Gegepterus have more teeth (128 and 150,
respectively) and higher tooth densities (2.7 teeth/cm and 5.25
teeth/cm, respectively) than Forfexopterus (116 teeth, 1.6 teeth/
cm) (Wang and Zhou, 2006; Wang et al., 2007). Gegepterus also
has a low premaxillary crest (Wang et al., 2007), which is not
present in Forfexopterus. The posterior margin of the sternum in
Gegepterus is straight (Wang et al., 2007), whereas it is curved in
Comparison of SternaThe sterna of extant and extinct birds
are characteristic skeletal elements because they are highly
adapted for flight (Zhang et al., 2011; Zheng et al., 2012, 2014),
and this situation should be similar to that in pterosaurs because
pterosaur sterna are also adapted for flight (Bennett, 2003).
However, specimens of pterosaurs are limited, and sterna are
especially rare. Hence, the sternum is not well known, and well-
preserved sterna are available for only a few taxa, such as Nycto-
saurus, Anhanguera, and Pteranodon (Williston, 1901; Kellner
and Tomida, 2000; Bennett, 2001). Although the specimens from
western Liaoning provide some new information about sterna,
Jiang et al.Forfexopterus from China (e1212058-9)
most of them are incomplete (Dong, 1982; Dong et al., 2003;
Wang et al., 2005, 2007, 2010).
The pterosaur sternum comprises a cristospine and a sternal
plate. A midline ridge on the anterodorsal part of the cristospine is
present in all well-preserved pterosaurs, such as Forfexopterus,
Nyctosaurus, Istiodactylus latidens, Anhanguera,andPteranodon
(Williston, 1901; Hooley, 1913; Kellner and Tomida, 2000; Bennett,
2001). Posterior to the midline ridge are two articulations for cora-
coids, whose positions are symmetric in Nyctosaurus, Anhanguera,
and Pteranodon (Williston, 1901; Kellner and Tomida, 2000; Ben-
nett, 2001) but asymmetric in Istiodactylus latidens, Dsungaripterus,
Rhamphorhynchus, Azhdarcho, Hamipterus,andForfexopterus
(Hooley, 1913; Young, 1973; Wellnhofer, 1978; Averianov, 2010;
Wang et al., 2014b). These articulations are shallow in Forfexopte-
rus, as they are in many pterosaurs, but they are deep in Istiodacty-
lus latidens, Anhanguera,andPteranodon (Hooley, 1913; Kellner
and Tomida, 2000; Bennett, 2001). A lateral constriction of the
posterior cristospine is found in Istiodactylus latidens, Anhanguera,
Nurhachius, Ornithocheirus,andHamipterus (Hooley, 1913; Kell-
ner and Tomida, 2000; Wang et al., 2005; Rodrigues and Kellner,
2013; Wang et al., 2014b). Although the length of the sternal plate
differs, we found that both lateral margins are nearly parallel to
the midline in all complete specimens. The posterior margins of
the sternal plate can be convex, concave, or straight. In Nyctosau-
rus, there is an apparent xiphoid process that is not reported in any
other pterosaur (Hooley, 1913). However, some small concavities
of the posterior margins are found in Anhanguera, Pteranodon,
Haopterus,andEopteranodon (Kellner and Tomida, 2000; Ben-
nett, 2001; Wang and L
u, 2001; L
u et al., 2006), which can be inter-
preted as the suture with the xiphoid process.
Geometric morphometric (GM) analysis was carried out on the
sterna of 17 species in Pterodactylomorpha (Fig. 6, see Methods).
These 17 species can be divided into Haopterus and four clades,
Wukongopteridae, Archaeopterodactyloidea, Pteranodontia, and
Azhdarchoidea, based on previous systematic studies (sensu Andres
et al., 2014). The result of relative warp analysis includes 16 princi-
pal components (PCs), and the first six PCs explain 93.1% of the
total variation. Principal components 1, 2, 3, 4, 5, and 6 account for
37.2%, 31.7%, 11.0%, 6.1%, 3.9%, and 3.2% of the variation,
respectively. PC 1 represents the variation in width relative to length
of the whole sternum. PC 2 represents the variation in length of the
cristospine. PC 3 represents the variation in position of the lateral
margin. PC 4 represents variation of the posterior margin and the
constriction of the base of cristospine. PC 5 represents variation in
length of the anterior margin. PC 6 represents variation of expan-
sion of the sternocoracoid articulation.
Six characteristics of sterna are incorporated into the most
recent phylogenetic analysis (Andres et al., 2014), including
almost all the sternal characters identified in previous phyloge-
netic studies (Bennett, 1994; Kellner, 2003; Unwin, 2003; L
et al., 2010; Andres and Myers, 2013; Wang et al., 2014b). These
characteristics include the shapes of the sternum, cristospine and
sternocoracoid articulation, the position of the articulations, and
the posterior constriction and expansion of the cristospine. The
FIGURE 6. Relative warp analysis of the outlines of the sternum in Pterodactylomorpha. The taxonomic groupings follow Andres et al. (2014). TPS
grids correspond to the extremes of the first six PCs. The percentage of variation is listed below each PC axis. The labels (¡) and (C) indicate the neg-
ative and positive values, respectively. Abbreviations:Anh,Anhanguera piscator;Ard,Ardeadactylus longicollum;Aur,Aurorazhdarcho primordius;
Dal,Darwinopterus linglongtaensis;Dar,Darwinopterus robustodens;Dsu,Dsungaripterus;Eop,Eopteranodon;For,Forfexopterus jeholensis, gen. et
sp. nov.; Hao,Haopterus;Jid,Jidapterus;Kun,Kunpengopterus;Muz,Muzquizopteryx coahuilensis;Nur,Nurhachius;Nyc,Nyctosaurus gracilis;Ptd,
Pterodactylus antiquus;Ptn,Pteranodon;Tap,Tapejara wellnhoferi.
Jiang et al.Forfexopterus from China (e1212058-10)
shape and the position of sternocoracoid articulation do not
relate to our GM analysis. The shapes of the cristospine are
divided into (0) shallow and elongated and (1) deep and short
(Andres et al., 2014). Cristospine variation can be partly
explained by PC 2 because the depth is not measured by our GM
analysis. The constriction and expansion of the cristospine can
be explained by PCs 4 and 6, respectively. Shape of the sternum
has been divided into (0) narrow, (1) quadrangular, (2) semicir-
cular, and (3) triangular (Andres et al., 2014). These four charac-
ter states are correlated with PC 1. The difference between
states 1, 2, and 3 is the shape of the posterior margin, which can
be explained by PC 4. The difference between states 1 and 3 is
the position of the lateral margins, which can be explained by PC
3. The anterior margin is not considered in the phylogeny of
Andres et al. (2014), although its variation (PC 5) accounts for
3.9% of total variation in our GM analysis. We suggest that in
future analyses, the shape of the sternum should be divided into
three characters: the ratio of the length to width of sternal plate;
the position of the lateral margins; and the shape of the posterior
margin. Based on our analysis, these three characters can explain
most of the observed variation in sternal shape.
We thank L. Xiang (Institute of Vertebrate Paleontology and
Paleoanthropology, Chinese Academy of Sciences) for the prep-
aration of the specimen and S. Xing (IVPP) for his help with the
GM analysis; we also thank L. Xu, S.-H. Jia (Henan Geological
Museum), and C.-L. Sun (Jilin University) for access to ptero-
saur specimens. We would also like to express our gratitude to
the three reviewers and the editor for their comments, which
improved the manuscript. We are also indebted to D. Hone and
the editor R. J. Butler for their polishing of the manuscript and
several comments. This study was supported by the National
Key Basic Research Program of China (2012CB821900), the
National Natural Science Foundation of China (41572020), the
Hundred Talents Project of CAS, the National Science Fund for
Distinguished Young Scholars (40825005), and the Key Labora-
tory of Economic Stratigraphy and Palaeogeography, CAS
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Jiang et al.Forfexopterus from China (e1212058-12)
... mm) is longer than the width (88.86 mm of posterior margins). The cristospine accounts for 25.8 % of the sternal length, smaller than the ratio in Forfexopterus and Elanodactylus [26,27]. The anterior portion of the cristospine is much thinner than its posterior portion. ...
... The proximal end of the coracoid has a strongly concave articulation with a posterior expansion ( Fig. 3D and E). The coracoid does not have an expansion at its contact with the scapula, distinguishing it from other archaeopterodactyloids, such as Pterodactylus, Gegepterus, Elanodactylus, and Forfexopterus [26,[28][29][30]. The coracoid process (or biceps tubercle) is less prominent than other pterosaurs, such as Kunpengopterus [31], Hamipterus [32], Anhanguera [33], and Dsungaripterus [34], but taphonomic crushing can result in the partial absence of this process. ...
... Based on this process, the distal part of the humerus is reconstructed with an estimated length of approximately 113 mm. The deltopectoral crest is relatively short and proximally located, which is similar to that of other archaeopterodactyloids, such as Pterodactylus [28], Huanhepterus [38], and Forfexopterus [26]. It is worth noting that this crest is also similar to that of Noripterus complicidens [34] and that the exact condition of Dsungaripterus is unknown. ...
... The sternum may have smooth lateral margins or may have a serrated appearance with articulation points along the lateral edges to connect to the sternal ribs (Geist et al., 2014), or these may be fused to the sternum itself. In a few, there is a distally projecting xiphoid process from the middle of the ventral margin of the sternal plate (Jiang et al., 2016). The plate often has a thickened anterior rim and there might be a slight keel on the anterior part of the ventral face. ...
... Only two papers in the last decade make any attempt to compare the sterna of different pterosaur clades. Lü et al., (2011a) provided some very brief comments comparing the sternum of Darwinopterus to other pterosaurs, while Jiang et al. (2016) complete an outline analysis of the sternum shape of 17 monofenestratan taxa. This included members of the wukongopterids, archaeopterodactyloids, pteranodontids and azhdarchoids (plus the genus Haopterus which remains of uncertain placement). ...
... Based on this, they suggested that in future phylogenetic analyses, the shape of the sternum should be divided into three characters for which their principal components analysis showed would cover most of the variation seen. These would be "the ratio of the length to width of sternal plate; the position of the lateral margins; and the shape of the posterior margin" (Jiang et al., 2016), though there were no further details about how these characters and their states might be constructed or coded. In FIGURE 2. Photographs of a variety pterosaur sterna to show the variation in shape and preservation. ...
... This specimen was collected from Xiaosanjiazi Village, Lamadong Town, Jianchang County, Liaoning Province, China, and the horizon was assigned to the Yixian Formation (Lü et al., 2012). It was, however, later reassigned to the Jiufotang Formation (Jiang et al., , 2016. ...
... The condyle can be observed in the anterior end of each quadrate, demonstrating that those bones have helical articulation surface. The left quadrate is well articulated with the left articular of the mandible, forming a 152° angle with the ventral margin of the upper jaw, which is similar to what is observed in most archaeopterodactyloids (Wang et al., 2007;Jiang et al., 2016). The right quadratojugal is exposed on slab A. It is a V-shaped element, and the longer and shorter processes are fused with the jugal and quadrate, respectively. ...
... Lü et al. (2012) first proposed an estimated wingspan of more than 7 m; Witton (2013) estimated a smaller wingspan of 4.2 m. In order to establish the wingspan of the holotype of M. zhuiana, length measurements of published ctenochasmatids (Wellnhofer, 1970(Wellnhofer, , 1978Jiang et al., 2016) were used to calculate a simple regression equation for the wingspan versus skull length (Table 3), and the assignment of Ctenochasma specimens follows Bennett (2007). Two types of wingspans are present in pterosaur researches: the differences are a result of either excluding or including the length of the carpus and coracoid, also known as normal and maximized wingspan, respectively (Bennett, 2001;Kellner et al., 2013). ...
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Moganopterus zhuiana Lü et al., 2012 was erected as a member of the Boreopteridae, which was questioned by different researchers shortly after the publication. Although the new assignment to the Ctenochasmatidae is widely accepted by pterosaur researchers, some characteristics still require a detailed description. Here, the holotype of this taxon is restudied, and some ambiguous characteristics are re-identified. The diagnosis of this taxon has been revised as the following: a large ctenochasmatid pterosaur, which can be distinguished from other members of this clade by a single autapomorphy: an elongated rod-like parietal crest that extends posterodorsally, forming an angle of about 15° with the ventral margin of the skull. This taxon can be further distinguished from other ctenochasmatids on the basis of the following combination of characteristics: straight occlusal surfaces of the upper and low jaws; presence of a low premaxillary crest confined anterior to the nasoantorbital fenestra; rostrum about two thirds of the skull length; nasoantorbital fenestra occupying slightly more than 20% of the skull length; about 100 slender teeth; and a mid-cervical length/width ratio of about 7. The wingspan of M. zhuiana has been re-estimated according to a simple regression equation for wingspan versus skull length in ctenochasmatids. It confirms that M. zhuiana, although smaller than previous thought, is still the largest known ctenochasmatid. When comparing the sizes of ctenochasmatids in the Jurassic and Cretaceous, ctenochasmatids showed a rough tendency to increase their sizes.
... Ctenochasmatid pterosaurs flourished in the Jehol Biota with well-preserved fossil specimens, enriching our knowledge of the biodiversity and palaeobiology of this clade (e.g. Wang and Zhou 2006;Jiang et al. 2016;Zhou et al. 2020). Recently, a partial mandible of a ctenochasmatid pterosaur Forfexopterus was collected from the Jiufotang Formation at the Dayaogou site, Jianchang Township, Jianchang County, western Liaoning Province. ...
... The new specimen (SDUST-V1007; housed in the vertebrate palaeontological collection of Shandong University of Science and Technology; Figs 1-2) is a partial mandible, collected from the Jiufotang Formation at the Dayaogou site, Jianchang Township, Jianchang County, western Liaoning Province. Two ctenochasmatid pterosaurs, Forfexopterus and Moganopterus, are known from this area (Lü et al. 2012a;Jiang et al. 2016;Zhou et al. 2020). The lacustrine deposits are composed of grey shales overlain by a brown weathered layer (Fig. 1). ...
... Zhou et al. 2020). Of these, cranial morphology is known in eight genera: Cathayopterus, Feilongus, Forfexopterus, Gegepterus, Gladocephaloideus, Moganopterus, Pangupterus and Pterofiltrus (Wang et al. 2005(Wang et al. , 2007Wang and Zhou 2006;Andres and Ji 2008;Jiang and Wang 2011a;Lü et al. 2012aLü et al. , b, 2016Jiang et al. 2016). Their teeth appear to vary in morphology, quantity and density (e.g. ...
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Ctenochasmatid pterosaurs flourished and diversified in the Early Cretaceous Jehol Biota. Here, a partial mandible of Forfexopterus is described based on a three-dimensional reconstruction using high-resolution X-ray Computed Tomography (CT) data. The first nine pairs of functional teeth of the rostral dentition revealed along with their replacements. The functional teeth are evenly arranged with a tooth density of 2.2 teeth/cm. The tooth crown is distinctly reduced from its base to the tip, and framed by two weak ridges, possibly as a pair of vestigial carinae. The replacement teeth are sharp and pointed, and have erupted slightly against the medial surface of the functional teeth. Surprisingly, tooth wear is observed in this specimen, the first record of tooth-tooth occlusion in ctenochasmatids. The wear facets exhibit high-angled lingual and lower-angled labial facets, implying a tooth-tooth occlusion in pterosaur clade. This discovery indicates that the Jehol ctenochasmatids possibly employed a more active feeding strategy than other filter-feeding pterosaurs (e.g. Ctenochasma , Pterodaustro , Gnathosaurus ). Supplementary material at
... The Jianchang Basin is located in the western Liaoning and northern Hebei, and contains a near-complete succession of the Upper Mesozoic bearing the two famous lagerstättes, that is, the Middle-Late Jurassic Yanliao Biota and the Early Cretaceous Jehol Biota (e.g., Chu et al., 2016;Yu et al., 2021). Especially, the extensive good exposed outcrops of the Jiufotang Formation in Jianchang Basin, holding promise to precise constraints on the Jiufotang Formation containing the important vertebrate fossils of the late Jehol Biota, e.g., pterosaurs, birds, lizards, mammals, and turtles (Dong et al., 2017;Evans and Wang, 2012;Jiang et al., 2016;Li et al., 2015a;Mao et al., 2021;Meng et al., 2011;Wang et al., 2014a;Wang et al., 2020;Zhou, 2010). ...
... Three tuff samples, the XTZ17-1, XTZ17-2, and XTZ17-3 ( Fig. 3D), for SIMS U-Pb zircon dating were collected from above the fossil-bearing shale layer that contains handful of vertebrates, including the pterosaurs Ikrandraco avatar (IVPP V18199, Wang et al., 2014b) and Forfexopterus jeholensis (Jiang et al., 2016), the early ornithuromorphs Zhongjianornis yangi , Piscivoravis lii and Mengciusornis dentatus , the enantiornithines Bohaiornis guoi (Hu et al., 2011;Li et al., 2014) and Fortunguavis xiaotaizicus (Wang et al., 2014a), the turtles Liaochelys jianchangensis (Zhou, 2010) and Perochelys lamadongensis (Li et al., 2015a); lizard Yabeinosaurus (Evans and Wang, 2012;Dong et al., 2017), the Choristodera Philydrosaurus (Lü et al., 2015), the eutriconodont mammal Liaoconodon hui (Meng et al., 2011), and the tritylodontid Fossiomanus sinensis (Mao et al., 2021). ...
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The Lower Cretaceous Jiufotang Formation in western Liaoning Province, northeastern China contains important vertebrate fossils of the late Jehol Biota, e.g., the four-winged non-avian dinosaur Microraptor. This formation documents the late phase of the Jehol Biota, producing the most abundant fossil records of the Mesozoic birds. However, the precise age constraints on the fossiliferous layers of this formation remain scarce and chronological consensus of this formation has not been reached, limiting our understanding of the evolutionary history of the Jehol Biota and its time-spatial distribution. Here we present secondary ion mass spectrometry (SIMS) U-Pb zircon analysis results of four tuff samples interbedded within the Jehol fossil-bearing layers from the Jiufotang Formation outcrops at the Sanmendian and Xiaotaizi sections in the Jianchang Basin, western Liaoning. Stratigraphic correlation between two outcrop sections is achieved by combining lithostratigraphic, biostratigraphic, and SIMS U-Pb zircon dating results. One tuff bed SMD17-1 closed to the boundary of the Yixian/Jiufotang formations from the Sanmendian section yielded an age of 122.0 ± 0.9 Ma, and three tuff beds XTZ17-1, XTZ17-2, and XTZ17-3 from the Xiaotaizi section dated to 118.9 ± 0.8 Ma, 118.8 ± 0.6 Ma, and 118.6 ± 1.1 Ma, respectively. These ages suggest that the Jiufotang Formation in Jianchang Basin was deposited at ca. 122.0–118.9 Ma, the latest Barremian–Aptian stage of the Lower Cretaceous and provides stringent constraints on the Mesozoic vertebrates discovered in the Jianchang Basin. Furthermore, the late Jehol Biota documents in the Jiufotang Formation has been placed between ~123 and ~119 Ma based on our new chronology and previous radiometric dates. It is critical to evaluate the evolutionary history of various important Mesozoic taxa discovered from the Jehol Biota and explore the patterns and modes of major vertebrate lineages documented in this interval.
... Since the early 1990s, the Early Cretaceous terrestrial Jehol Biota has been famous around the world for producing feathered dinosaurs and many other exceptionally wellpreserved vertebrate fossils (Zhou, 2014;Jiang et al., 2016;Wang et al., 2018Wang et al., , 2019Zhang et al., 2019). It includes, from the oldest to the youngest, the Dabeigou, Yixian and Jiufotang formations, which respectively represent the early, middle, and late periods of this biota (Pan et al., 2013). ...
... It includes, from the oldest to the youngest, the Dabeigou, Yixian and Jiufotang formations, which respectively represent the early, middle, and late periods of this biota (Pan et al., 2013). Pterosaur is a representative group of the Jehol Biota, which includes more than 30 genera and species, all from the middle and late periods (Jiang et al., 2016;Lü, 2016;Wu et al., 2017;Zhang et al., 2019;Zhou et al., 2019;Hone et al., 2020). During the middle period, archaeopterodactyloids were dominating, mainly from the lower Yixian Formation, while in the late period, the dominant pterosaurs were ornithocheiroids (Pteranodontoidea + Tapejaroidea, sensu Kellner et al., 2019) (Wang and Zhou, 2006;Wang et al., 2014a;Wu et al., 2017). ...
Full-text available
Pterosaurs in the Jehol Biota have been found in the Yixian and Jiufotang formations. The Jingangshan bedding is in the upper part of the Yixian Formation. The first two pterosaur embryos ever discovered in the world, two archaeopterodactyloid specimens, and the questionable Yixianopterus jingangshanensis have been reported in previous literature. Here, we describe a forelimb from this horizon and confirm its phylogenetic position in the Pteranodontoidea. The holotype of Y. jingangshanensis, now housed at Benxi Geological Museum, has been examined. The diagnosis of this taxon has been revised without the consideration of the artificial parts as following, a pteranodontoid pterosaur with a distinguished combination of characters: triangular and labiolingually compressed teeth with the first two more slender and longer than the others; teeth vertical to the occlusal surface; the second wing phalanx about 93% the length of the first wing phalanx. In the Jehol Biota, archaeopterodactyloid specimens have been mainly discovered from the Yixian Formation, while tapejaroids are almost found from the Jiufotang Formation. Including the new forelimb and Y. jingangshanensis, the pteranodontoids from the Jiufotang Formation are slightly greater in number than those from the Yixian Formation in species and specimens, differing from the previous thoughts on the distribution.
... The atlas and axis are fused into the atlantoaxis in adult specimens of pterodactyloids (Howse 1986). They are separate in subadult specimens of pterodactyloids, as reported for Pterodactylus, Forfexopterus, Anhanguera, Nyctosaurus, Pteranodon, Tapejara, Jidapterus, and unidentified ornithocheirids (Seeley 1870;Williston 1903;Wellnhofer 1970;Bennett 1993;Kellner and Tomida 2000;Eck et al. 2011;Jiang et al. 2016;Wu et al. 2017). This character was considered a synapomorphy for the Monofenestrata (Andres et al. 2014), although the atlas and axis are not fused in the skeletally mature wukongopterids (Cheng et al. , 2017. ...
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.
... Most of the known pterosaurs come from sedimentary rocks that were formed in marine environments with relatively calm waters, which allowed their fragile bones to have a better chance of being preserved (Padian y Clemens, 1985;Unwin, 1987Unwin, , 2006 (Wang and Zhou, 2006;Jiang and Wang, 2011a, b;Jiang et al., 2016). ...
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In this contribution, we present an updated summary of the knowledge about the pterosaurs that inhabited what is now Chilean territory. These animals were very diverse during the Mesozoic. While pterosaurs ruled the sky, dinosaurs occupied firm land, and an impressive diversity of reptiles occupied the aquatic environment. Their great diversity is demonstrated by the extensive fossil record that we currently have of these animals, which spans all continents, including Antarctica. However, much of what we currently know about pterosaurs comes from fragmentary bones, which often do not allow us to have a clear overview of aspects as diverse as their appearance, behavior and evolutionary history. Favorably, an increasing number of specialists have begun to give a new impetus to the study of pterosaurs, and Chile is not left out. In our country, the findings are scarce and fragmentary. However, this is compensated by the extraordinary scientific value that these specimens possess. So far, four locations with pterosaur findings are known in Chile. The first of them corresponds to Quebrada La Carreta, in the Cordillera Domeyko, Antofagasta Region, a locality where the first remains of a pterosaur were discovered in Chile, found in Lower Cretaceous rocks, and which allowed the description of the only species recognized to date in our country: Domeykodactylus ceciliae. Two other localities correspond to Cerro La Isla and Cerros Bravos, both in the Atacama Region, in which Lower Cretaceous rocks outcrop. The presence of pterosaur bones in Cerro La Isla has been known since the late 1980s. In this place, a large accumulation of bones has been described, which belong to at least one indeterminate species of the clade Ctenochasmatidae. On the other hand, in Cerros Bravos, a new deposit has recently been located, which has been named “Cerro Tormento” by its discoverers. Future studies will be able to answer several questions concerning the origin of the site and the identity of the pterosaurs preserved in it. Finally, in the vicinity of Calama, the remains of what is so far the oldest pterosaur found in our country were discovered in Upper Jurassic rocks. Recent studies have shown that this specimen possesses characters that allow its referral to Rhamphorhynchidae, a group of longtailed pterosaurs that until before this discovery had only been recorded in the northern hemisphere. The presence of this group of pterosaurs in these latitudes, and the fauna that lived with it, constitute a body of evidence that indicates that, at the end of the Jurassic, the faunal connection between the faunas of Laurasia and Gondwana was relatively constant. It is very possible that future prospects in the old and new locations will deliver more surprises helping to understand about the ancient dragons that dominated the skies of what is now Chile.
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As the lowest horizon of the Early Cretaceous Jehol Biota, the Huajiying Formation of the northern Hebei Province, China is rich with avians and feathered dinosaurs, but lacks pterosaur record. Here the first pterosaur fossil is reported from the Huajiying Formation. The new pterosaur specimen is characterized by an unusual pedal configuration of a short and spread metatarsus with elongate digits, showing a close resemblance to the dentulous Ornithocheiroidea. The pedal configuration is diverse in pterosaurs, and is often associated with ecological adaptations. In contrast to the general pattern of the elongate metatarsus and short digits, the elongate digits of the dentulous ornithocheiroids (e.g. boreopterids and istiodactylids) might offset the shortened metatarsus to enlarge the pedal surface for paddling, representing a new strategy in adaptation to the aquatic environment.
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Morphology forms the most fundamental level of data in vertebrate palaeontology because it is through interpretations of morphology that taxa are identified, creating the basis for broad evolutionary and palaeobiological hypotheses. Assessing maturity is one of the most basic aspects of morphological interpretation and provides the means to study the evolution of ontogenetic changes, population structure and palaeoecology, life‐history strategies, and heterochrony along evolutionary lineages that would otherwise be lost to time. Saurian reptiles (the least‐inclusive clade containing Lepidosauria and Archosauria) have remained an incredibly diverse, numerous, and disparate clade through their ~260‐million‐year history. Because of the great disparity in this group, assessing maturity of saurian reptiles is difficult, fraught with methodological and terminological ambiguity. We compiled a novel database of literature, assembling >900 individual instances of saurian maturity assessment, to examine critically how saurian maturity has been diagnosed. We review the often inexact and inconsistent terminology used in saurian maturity assessment (e.g. ‘juvenile’, ‘mature’) and provide routes for better clarity and cross‐study coherence. We describe the various methods that have been used to assess maturity in every major saurian group, integrating data from both extant and extinct taxa to give a full account of the current state of the field and providing method‐specific pitfalls, best practices, and fruitful directions for future research. We recommend that a new standard subsection, ‘Ontogenetic Assessment’, be added to the Systematic Palaeontology portions of descriptive studies to provide explicit ontogenetic diagnoses with clear criteria. Because the utility of different ontogenetic criteria is highly subclade dependent among saurians, even for widely used methods (e.g. neurocentral suture fusion), we recommend that phylogenetic context, preferably in the form of a phylogenetic bracket, be used to justify the use of a maturity assessment method. Different methods should be used in conjunction as independent lines of evidence when assessing maturity, instead of an ontogenetic diagnosis resting entirely on a single criterion, which is common in the literature. Critically, there is a need for data from extant taxa with well‐represented growth series to be integrated with the fossil record to ground maturity assessments of extinct taxa in well‐constrained, empirically tested methods.
A new incomplete pterosaurian skeleton, Eosipterus yangi gen. et sp. nov. , collected from western Liaoning is briefly described. It is the first occurrence of the pterosaurs from the famous Jehol Fauna in Northeast China; thus it is of great value to biostratigraphy and biogeography. According to the nature of the new pterosaur and other fossils in the same beds, this flying animal is supposed to have lived along the coast of a large freshwater lake which developed during the Late Jurassic and Early Cretaceous. The new genus and species should be assigned to the suborder Pterodactyloidea. Its main characters are given as follows: Medium-sized pterodactyloid pterosaur with a total width about 1.2m across two ends of distal wing-fingers. Tail short. Gastralia narrow and weak. Forelimb strong; radius and ulna 1.3 times as long as wing-metacarpal. Wing-finger joints extensible transversely. Femur slightly straight, occupying the 2/3 length of tibia. Radius, the first wing-finger as long as tibia. Metatarsal I-IV long and narrow; phalange V of hindlimb degenerated and small.
The holotype specimens of Cycnorhamphus suevicus (Quenstedt, 1855), one of the rarest pterosaur species known from the Upper Jurassic Solnhofen and Nusplingen limestones of southern Germany, and C. canjuersensis (Fabre, 1974), known from a single specimen from roughly contemporary deposits of the Petit Plan de Canjuers, France, are redescribed and their skulls reinterpreted in light on new shape information from a complete isolated skull nicknamed the 'Painten Pelican'. The skulls are quite similar in shape, the holes in the C. canjuersensis mandible that had been interpreted as alveoli are merely artifacts, and differences between the two holotypes are the result of differences in ontogenetic age and quality of preservation. Based on reinterpretation of the two holotypes, C. canjuersensis does not exhibit any features that distinguish it from C. suevicus and so must be considered a junior synonym. © 2012 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.