Ctenochasmatidae

Ctenochasmatidae is a group of pterosaurs within the suborder Pterodactyloidea.

The earliest known ctenochasmatid remains date to the Late Jurassic Kimmeridgian age. Previously, a fossil jaw recovered from the Middle Jurassic Stonesfield Slate formation in the United Kingdom, was considered the oldest known. This specimen supposedly represented a member of the family Ctenochasmatidae,[1] though further examination suggested it actually belonged to a teleosaurid stem-crocodilian instead of a pterosaur.[2]

Ctenochasmatids
Temporal range:
Late Jurassic - Early Cretaceous 152–105 Ma
Ctenochasma elegans 1
Cast of a Ctenochasma elegans specimen
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Order: Pterosauria
Suborder: Pterodactyloidea
Clade: Euctenochasmatia
Family: Ctenochasmatidae
Nopsca, 1928
Type species
Ctenochasma roemeri
Meyer, 1852
Subfamilies

Ctenochasmatinae
Gnathosaurinae

Classification

Cladogram following Andres, Clark & Xu, 2014.[2]

 Ctenochasmatidae 
 Gnathosaurinae 

Kepodactylus insperatus

Elanodactylus prolatus

Feilongus youngi

Moganopterus zhuiana

Huanhepterus quingyangensis

Plataleorhynchus streptophorodon

Gnathosaurus subulatus

Gnathosaurus macrurus

 Ctenochasmatinae 

Ctenochasma

Pterodaustro guinazui

Eosipterus yangi

Beipiaopterus chenianus

Gegepterus changi

References

  1. ^ Buffetaut, E. and Jeffrey, P. (2012). "A ctenochasmatid pterosaur from the Stonesfield Slate (Bathonian, Middle Jurassic) of Oxfordshire, England." Geological Magazine, (advance online publication) doi:10.1017/S0016756811001154
  2. ^ a b Andres, B.; Clark, J.; Xu, X. (2014). "The Earliest Pterodactyloid and the Origin of the Group". Current Biology. 24: 1011–6. doi:10.1016/j.cub.2014.03.030. PMID 24768054.
Archaeopterodactyloidea

Archaeopterodactyloidea (meaning "ancient Pterodactyloidea") is an extinct clade of pterodactyloid pterosaurs from the middle Late Jurassic to the latest Early Cretaceous (Kimmeridgian to Albian stages) of Africa, Asia and Europe. It was named by Alexander Wilhelm Armin Kellner in 1996 as the group that contains Germanodactylus, Pterodactylus, the Ctenochasmatidae and the Gallodactylidae. In 2003, Kellner defined the clade as a node-based taxon consisting of the last common ancestor of Pterodactylus, Ctenochasma and Gallodactylus and all its descendants. Although phylogenetic analyses that based on David Unwin's 2003 analysis do not recover monophyletic Archaeopterodactyloidea, phylogenetic analyses that based on Kellner's analyses, or the analyses of Brian Andres (2008, 2010, 2018) recover monophyletic Archaeopterodactyloidea at the base of the Pterodactyloidea.

Barremian

The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch (or Lower Cretaceous series). It is preceded by the Hauterivian and followed by the Aptian stage.

Beipiaopterus

Beipiaopterus is a genus of ctenochasmatid pterosaur (flying reptile) from the Lower Cretaceous Yixian Formation (Aptian) in the People's Republic of China.

The genus was named in 2003 by Lü Junchang. The generic name is derived from Beipiao City in Liaoning Province and a Latinised Greek pteron, "wing". The specific epithet honours paleontologist Professor Chen Peiji.

The type and only species is based on holotype BPM 0002, a crushed partial skeleton of a subadult individual on a slab, missing the skull. It includes four cervical, fourteen dorsal, three sacral and nine caudal vertebrae, a complete left wing and two hind limbs. Remains of the soft parts have been preserved, including partial wing membranes, a membrane attached to the tibia, a "mane" on the neck and webbing of the feet. It had a wingspan of one metre and was about fifty centimetres long if the skull had the same length as the remainder of the body: 103 millimetres for the neck, ten centimetres for the rump and 37 millimetres for the tail. In the wing finger the fourth, normally most extreme, phalanx was absent; according to Lü this was not an artefact of preservation but the normal condition of the animal, one also known from Nyctosaurus.

In 2005 a study of the wing membrane by SEM (Scanning Electron Microscope) was published, showing it had contained many blood vessels, which indicated a role in the thermoregulation.Lü assigned Beipiaopterus to the Ctenochasmatidae because of the elongation of the cervical vertebrae and the general form of the humerus. This was later affirmed by an exact cladistic analysis which showed that it was a basal member of the group.

Cathayopterus

Cathayopterus is a ctenochasmatid pterosaur from the Early Cretaceous-age Yixian Formation of Liaoning, China. It is a member of the group of pterosaurian filter-feeders. The type species is C. grabaui, described in 2006 by Wang Xiaolin and Zhou Zhonghe.

Ctenochasmatoidea

Ctenochasmatoidea is a group of early pterosaurs within the suborder Pterodactyloidea. Their remains are usually found in what were once coastal or lake environments. They generally had long wings, long necks, and highly specialized teeth.

Eosipterus

Eosipterus is an extinct genus of pterosaur from the Early Cretaceous of Liaoning, China.

The genus was named in 1997 by Ji Shu'an and Ji Qiang. The type species is Eosipterus yangi. The genus name is derived from Greek eos, "dawn" and Greek pteron, "wing" with a Latin ending; and a grammar error: normally the combination would have resulted in "eopterus". The "dawn" element refers to its age but also to China being "in the east". The specific name honours paleontologist Yang Daihuan.

The genus is based on holotype GMV2117, found near Jinggangshan in western Liaoning Province, in the Yixian Formation. It was the first pterosaur discovered in that region. It consists of a partial crushed skeleton of a subadult individual on a slab, lacking skull and neck. Most vertebrae have been severely damaged and even their number cannot be determined. The authors state that eighteen detached belly ribs are present in the matrix.

The wings are robust and elongated. The wing finger has the standard four phalanges, a difference from the possibly related Beipiaopterus which has lost the fourth phalanx. Total wingspan was about 1,2 metres. The pelvis is not well preserved. The femur has a length of six centimetres; the tibia of 96 millimetres. The fibula is strongly reduced. The foot claws are slightly curved; the fifth toe has been reduced to a single claw.

The authors placed Eosipterus in a general Pterodactyloidea incertae sedis; in 1999 a placement within Pterodactylidae was suggested and even a synonymy with Pterodactylus within a hypothesis that the lower Yixian Formation dated from the late Jurassic. A cladistic study in 2006 found that it was a member of the Ctenochasmatidae — David Unwin thought it more precisely belonged to the Ctenochasmatinae — but a later study showed that it was basal to the Germanodactylidae.

Euctenochasmatia

Euctenochasmatia is an extinct group of pterodactyloid pterosaurs. It was named by David Unwin in 2003 as the group that contains the most recent common ancestor of Pterodactylus kochi and Ctenochasma, and all its descendants.

Gallodactylidae

Gallodactylidae is a group of pterosaurs within the suborder Pterodactyloidea.Gallodactylids differed from other related pterosaurs in several distinct features, including fewer than 50 teeth present only in the jaw tips, and rounded crests present on the rear portion of the skull and jaws but not near the ends of their snouts. At least some species possessed jaw flanges, possibly used to bissect hard-shelled prey.

Gegepterus

Gegepterus was a genus of ctenochasmatid pterosaur from the Early Cretaceous-age Yixian Formation of Liaoning, China.

The genus was named in 2007 by Wang Xiaolin, Alexander Kellner, Zhou Zhonge and Diogenes de Almeida Campos. The type species is Gegepterus changi. The genus name is derived from Manchu ge ge, the title of a princess, in reference to the dainty gracility of the specimen, and a Latinised Greek pteron, "wing". The specific name honours female paleontologist Chang Meemann, who over the years established a cordial relationship between the Chinese and Brazilian authors. In 2008 Wang emended the epithet to changae, but such changes are no longer allowed by the ICZN.

It is known from two specimens. The first is holotype IVPP V 11981, which was in 2001 found in grey shales from the lower part of the formation (estimated at 125 million years old), near the city of Beipiao. It consists of a crushed and damaged partial skeleton of a subadult including skull, lower jaws, cervical and sacral vertebrae, ribs, gastralia ("belly ribs"), shoulder girdle and hindlimb remains, along with dark soft tissue remains near the skull and gastralia and in the orbit; unfortunately, the soft tissue remains show no structure except for some small, unbranched fibers at the back of the head. The jaws are very elongated; the snout is flat and concave on top, with a low and thin crest. The forehead slightly projects to the front. The cervicals are elongated.The authors assigned it to the Ctenochasmatidae on the basis of its long rostrum and numerous needle-like teeth, about 150 in total. This is the first uncontroversial report of the Ctenochasmatidae from the Yixian Formation, as the fossils of other assumed ctenochasmatids have not preserved the dentition. It was at first suspected to be the juvenile of some known species.In 2011 a second, smaller specimen was described, IVPP V 11972, which increased the known skeletal elements and showed a more extensive covering of hair-like structures.

Gladocephaloideus

Gladocephaloideus is a genus of gallodactylid ctenochasmatoid pterosaur from the Early Cretaceous of western Liaoning, China.

Huanhepterus

Huanhepterus is an extinct genus of ctenochasmatid pterodactyloid pterosaur from the Late Jurassic-age Huachihuanhe Formation of Qingyang, Gansu, China.

The genus was named by Dong Zhiming in 1982. The type species is Huanhepterus quingyangensis. The genus name refers to the Huang Jian (not the Yellow River or "Huang He", but a smaller tributary of the Jinghe River in Gansu), and combines it with a Latinized Greek pteron, "wing". The specific name refers to Qinyang County.

It is based on holotype IVPP V9070, a partial articulated skeleton consisting mostly of impressions of the left half of the body and the beak-end of the skull. The fossil was in May 1978 found in a quarry operated by the Sanshilipu-commune, when an explosion exposed a vertebra. Its force obliterated the right half of the specimen.

Huenhepterus had a long, low skull, with a low crest running along the midline that was higher toward the tip of the snout and became smaller toward the eyes. The teeth, about 26 pairs in the upper and 25 in the lower jaws, were slender and numerous, and became shorter farther from the 11th pair, both to the front as to the back, where they become absent completely in posterior part of the snout. The cervical vertebrae were long, as were the toes, and there was no fused complex of the front dorsal vertebrae (notarium), as seen in other pterosaurs. The wingspan of the type individual was estimated at 2.5 m (8.2 ft). This genus was described as most like Gnathosaurus. David Unwin later referred it the Gnathosaurinae, a subgroup of the Ctenochasmatidae.

Like Gnathosaurus, it may have used its tightly-packed, slender teeth to filter food from water.

Liaodactylus

Liaodactylus is a genus of filter-feeding ctenochasmatid pterosaur from the Jurassic of China. The genus contains one species, L. primus, described by Zhou et al. in 2017. As an adaptation to filter-feeding, Liaodactylus had approximately 150 long, comb-like teeth packed closely together. It is both the earliest known ctenochasmatid and the first filter-feeding pterosaur from the Jurassic Tiaojishan Formation. Later and more specialized ctenochasmatids differ from Liaodactylus in having longer snouts, smaller openings (or fenestrae) in the skull, and more teeth. Within the Ctenochasmatidae, Liaodactylus was most closely related to the European Ctenochasma.

Monofenestrata

The Monofenestrata are an unranked group of pterosaurs that includes the family Wukongopteridae and the suborder Pterodactyloidea.The clade Monofenestrata was in 2009/2010 defined as the group consisting of Pterodactylus and all species sharing with Pterodactylus the synapomorphy, shared derived trait, of an external nostril confluent with the antorbital fenestra, the major skull opening on the side of the snout. The name is derived from Greek monos, "single", and Latin fenestra, "window". The concept was inspired by the discovery of Darwinopterus, a species combining a pterodactyloid-type skull with a more basal build of the remainder of the body. The Darwinoptera, a primitive subgroup of monofenestratans showing this transitional anatomy, was also named for Darwinopterus and defined as all descendants of its common ancestor with Pterorhynchus.The earliest known monofenestrate fossils have been found in the Stonesfield Slate formation of the United Kingdom, which dates to the Bathonian stage of the Middle Jurassic, dated to about 166 million years ago. Identified elements include cervical vertebrae, fourth metacarpals and a possible pterodactyloid synsacrum. Below is a cladogram showing the results of a phylogenetic analysis presented by Andres, Clark & Xu, 2014. This study found the two traditional groupings of ctenochasmatoids and kin as an early branching group, with all other pterodactyloids grouped into the Eupterodactyloidea.

Ningchengopterus

Ningchengopterus is a genus of pterodactyloid pterosaur from the Early Cretaceous (Aptian) Yixian Formation of China.

It is known from a juvenile specimen, holotype CYGB-0035, an almost complete articulated skeleton of a hatchling also showing soft parts, such as the flight membrane and pycnofibres, compressed on a plate and counterplate. It was in 2009 the smallest toothed pterosaur specimen even found in China. The type species Ningchengopterus liuae was in 2009 named and described by Lü Junchang. The genus name combines a reference to the Ningcheng district in Inner Mongolia with a Latinised Greek pteron, "wing". The specific name honours Ms Liu Jingyi who collected the fossil and donated it to science.Ningchengopterus was typified by the possession of about fifty teeth, twelve in each upper jaw and thirteen in each lower jaw. The teeth are curved, conical and pointed. The skull has a length of thirty-eight millimetres. The snout is elongated and tapering. The lower jaws show an incipient crest.The specimen could not be more precisely determined than Pterodactyloidea. It shared the relative proportions of the first and second phalanx of the flight finger with the Ctenochasmatidae, and especially Eosipterus found in the same formation, but showed no further synapomorphies of that group, so that Lü abstained from placing it in that clade.The teeth suggested that Ningchengopterus was a fish eater. The fully formed flight membrane was seen as confirmation of a hypothesis by Mark Unwin that pterosaurs displayed little parental care, their "babies" being able to fly shortly after hatching.

Phylogeny of pterosaurs

This phylogeny of pterosaurs entails the various phylogenetic trees used to classify pterosaurs throughout the years and varying views of these animals. Pterosaur phylogeny is currently highly contested and several hypotheses are presented below.

Plataleorhynchus

Plataleorhynchus was a genus of ctenochasmatid pterodactyloid pterosaur from the Tithonian-Berriasian-age Upper Jurassic or Lower Cretaceous Purbeck Limestone of Dorset, England.

The genus was named in 1995 by Stafford Howse and Andrew R.C. Milner|Andrew Milner. The type species is Plataleorhynchus streptophorodon. The genus name is derived from Platalea, the spoonbill, and Greek rhynchos, "snout", in reference to the distinctive form of the front of the skull. The specific name is derived from Greek streptophoros, "collared", and odon, "tooth", referring to the tooth form.

It is based on holotype NHML R.11957 (earlier BMNH R.11957), an incomplete anterior upper jaw with teeth found in a chalkstone quarry near Langton Matravers. The fossil is present on a plate; its underside is visible. This jaw is notable because it expands to form a circular, spatula-like shape at the front, holding 22 narrow teeth that point sideways. Forty other teeth (sockets) were present in the preserved remainder of the snout; the total for the upper jaws was estimated at 76.

The authors classified Plataleorhynchus as a member of the Ctenochasmatidae, a group containing many filter feeders. David Unwin in 2005 placed it in the subgroup of the Gnathosaurinae.

Although Plataleorhychus would have been similar in size to large gnathosaurines like Gnathosaurus; its skull length was estimated at a minimum of forty centimetres (15.75 in), the different shape of its spoonbill, presence of an apparently horn-covered pad on the palate, and smaller teeth suggest it did not feed in the same way, perhaps stirring up water-dwelling animals from muddy or weedy environments.

Pterodactyloidea

Pterodactyloidea (derived from the Greek words πτερόν (pterón, for usual ptéryx) "wing", and δάκτυλος (dáctylos) "finger" meaning "winged finger", "wing-finger" or "finger-wing") is one of the two traditional suborders of pterosaurs ("wing lizards"), and contains the most derived members of this group of flying reptiles. They appeared during the middle Jurassic Period, and differ from the basal (though paraphyletic) rhamphorhynchoids by their short tails and long wing metacarpals (hand bones). The most advanced forms also lack teeth, and by the late Cretaceous, all known pterodactyloids were toothless. Many species had well-developed crests on the skull, a form of display taken to extremes in giant-crested forms like Nyctosaurus and Tupandactylus. Pterodactyloids were the last surviving pterosaurs when the order became extinct at the end of the Cretaceous Period, together with the non-avian dinosaurs and most marine reptiles.

"Pterodactyl" is also a common term for pterodactyloid pterosaurs, though it can also be used to refer to Pterodactylus specifically or (incorrectly) to pterosaurs in general. Well-known examples of pterodactyloids include Pterodactylus, Pteranodon, and Quetzalcoatlus.

In 2014, fossils from the Shishugou Formation of China were classified as the most basal pterodactyloid yet found, Kryptodrakon. At a minimum age of about 161 my, it is about 5 million years older than the oldest previously known confirmed specimens. Previously, a fossil jaw recovered from the Middle Jurassic Stonesfield Slate formation in the United Kingdom, was considered the oldest known. This specimen supposedly represented a member of the family Ctenochasmatidae, though further examination suggested it belonged to a teleosaurid stem-crocodilian instead of a pterosaur. O'Sullivan and Martill (2018) described a partial synsacrum from the Stonesfield Slate identified as possibly pterodactyloid based on the number of incorporated sacrals although they commented that the morphology was perhaps closer to that of wukongopterids. If correctly identified, it would be the oldest pterodactyloid fossil known.

Pterodaustro

Pterodaustro is a genus of Cretaceous pterodactyloid pterosaur from South America, which lived 105 million years ago.

Pterofiltrus

Pterofiltrus is a genus of ctenochasmatid pterosaur from the Early Cretaceous of western Liaoning, China.

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