Coelurosauravus

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Coelurosauravus
Temporal range: Lopingian
~260.4–251  Ma
Coelurosauravus.svg
Skull reconstruction
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Family: Weigeltisauridae
Genus: Coelurosauravus
Piveteau 1926
Type species
Coelurosauravus elivensis
Piveteau, 1926
Synonyms
  • Daedalosaurus madagascariensisCarroll 1978

Coelurosauravus (meaning "hollow lizard grandfather") is an extinct genus of gliding reptile, known from the Late Permian of Madagascar. Like other members of the family Weigeltisauridae, members of this genus possessed long, rod-like ossifications projecting outwards from the body. These bony rods were not extensions of the ribs but were instead a feature unique to weigeltisaurids. It is believed that during life, these structures formed folding wings used for gliding flight, similar to living gliding Draco lizards. [1]

Contents

Coelurosauravus is solely known from the type species, C. elivensis, which was named by Jean Piveteau in 1926 based on fossils from the Lower Sakamena Formation of Madagascar. The species Weigeltisaurus jaekeli from Europe was formerly considered a species of Coelurosauravus, but is now placed in its own genus.

History of discovery

The only known specimens of Coelurosauravus were collected in 1907-1908 by J.-M. Colcanap, a captain of the French colonial infantry, in southwest Madagascar. The precise location is not known, but it is likely from Mount Eliva near the upstream part of the Sakamena River, a tributary of the Onilahy River. [2] In 1926, the specimens were described by Jean Piveteau as Coelurosauravuselivensis. In 1930 Weigeltisaurus jaekeli was described from specimens Germany. This European species is now known from numerous specimens found in Germany (and one in England), of which some were very well preserved. In 1987, Weigeltisaurus jaekeli was synonymized with Coelurosauravus as a second species, Coelurosauravus jaekeli. [1] However, a 2015 study reinstated Weigeltisaurus as a separate genus for "Coelurosauravus" jaekeli, which has been retained by subsequent authors. [3] In 1979 Robert L. Carroll placed one of the C. elivensis specimens into the new genus and species Daedalosaurus madigascariensis, based on supposed differences with the holotype specimen, [4] but it has subsequently been regarded as not distinct from C. elivensis. [5]

List of specimens

Description

The skull of Coelurosauravus is the smallest of the weigeltisaurids, with a mature skull length of 3.5 centimetres (1.4 in) around half those of other weigeltisaurids. [2] The total combined head and torso length is 18 centimetres (7.1 in), reaching a length of at least 35 centimetres (14 in) including the preserved length of the tail. [6] Like other weigeltisaurids, the skull bones are covered in cranial ornamentation, consisting of low tubercles and spikes, including a horned frill present on the squamosal bone. In contrast to Weigeltisaurus, only tubercles, rather than spikes, are present on the parietal bone, which is also shared with Glaurung . The teeth are simple and conical in shape and packed into a dense row. The teeth sequentially decrease in size posteriorly. [2] Compared to Weigeltisaurus, Coelourosauravus has a shorter neck and longer thorax (which is also flattened), and like other weigeltisaurids the tail is elongate. Like other weigeltisaurids, the penultimate phalanges are elongated, which in combination with their recurved unguals indicative of claws were likely an adaption to cling to tree bark. [6] At least 29 pairs of long, elongate rod-shaped bones project from the sides of the body, dubbed "patagials". These are roughly equally spaced along the trunk. The first nine patagials show a rapid increase in size, with the ninth being the longest of all of the patagials, with the remaining pairs gradually decreasing in size posteriorly. When fully opened, each patagial membrane would have had a wingspan of 35 centimetres (14 in). [6]

Paleobiology

Though no stomach contents have been found, Coelurosauravus and other weigeltisaurids have been interpreted as arboreal insectivores. The simple conical teeth of Coelurosauravus are well adapted to the piercing of arthropod cuticle. The cranial ornamentation may have served a display purpose. [2]

Gliding

Life restoration of Weigeltisaurus jaekeli, a close relative of Coelurosauravus and formerly considered a member of the genus Weigeltisaurus reconstruction.png
Life restoration of Weigeltisaurus jaekeli , a close relative of Coelurosauravus and formerly considered a member of the genus

The rods originate from the lower-lateral surface of the body. The furling and unfurling of the gliding membrane were likely controlled by the abdominal muscles. Preserved fossils of Weigeltisaurus show that the bony rods had a high degree of flexibility, similar to the ribs of living gliding lizards. Due to the low-wing configuration, it is likely that the gliding surface was angled upwards to increase stability. [7] In living gliding lizards, it has been found that the forelimbs grab hold of the membrane during flight, suggesting that the forelimbs are used to control the patagium while in flight. Similar behaviour has been proposed for weigeltisaurids. [8] This is supported the presence of an additional phalange in the fourth digit of the hands of weigeltisaurids, which would have allowed them to more effectively grasp the wing. [6] In a 2011 study comparing Coelurosauravus elivensis and other extinct gliding reptiles to modern Draco species, Coelurosauravus was found to be a less efficient glider than modern Draco due to its larger body size, with a wing loading around 107.9 N/m2, 4.5 times than higher than Draco, with a substantial drop in height per glide, corresponding with a steep descent angle of more than 45 degrees. [9] However, some authors have considered that the unique configuration and aspect ratio of the wings of weigeltisaurids means that the comparison needs to be tested experimentally. [6]

Paleoenvironment

The Lower Sakamena Formation was deposited in a wetland environment situated within a North-South orientated rift valley, perhaps similar to Lake Tanganyika. The climate at the time of deposition was temperate, warm, and humid, with seasonal rainfall and possible monsoons [2] Flora from the formation includes the equisetalean Schizoneura , the glossopterid gymnosperm Glossopteris , and seed fern Lepidopteris. Other vertebrates known from the Lower Sakamena Formation include the palaeoniscoid fish Atherstonia , the procolophonid parareptile Barasaurus , the neodiapsids Hovasaurus, Claudiosaurus, Thadeosaurus , and Acerosodontosaurus , fragments of rhinesuchid temnospondyls, an indeterminate theriodont therapsid and the dicynodont Oudenodon. [10]

See also

Related Research Articles

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<i>Youngina</i> Extinct genus of reptiles

Youngina is an extinct genus of diapsid reptile from the Late Permian Beaufort Group of the Karoo Red Beds of South Africa. This, and a few related forms, make up the family Younginidae, within the Order Eosuchia. Eosuchia, having become a wastebasket taxon for many probably distantly-related primitive diapsid reptiles ranging from the Late Carboniferous to the Eocene, Romer proposed that it be replaced by Younginiformes.

<i>Protorosaurus</i> Extinct genus of reptiles

Protorosaurus is an extinct genus of reptile. Members of the genus lived during the late Permian period in what is now Germany and Great Britain. Once believed to have been an ancestor to lizards, Protorosaurus is now known to be one of the oldest and most primitive members of Archosauromorpha, the group that would eventually lead to archosaurs such as crocodilians and dinosaurs.

<span class="mw-page-title-main">Avicephala</span> Extinct clade of neodiapsid reptiles

Avicephala is a potentially polyphyletic grouping of extinct diapsid reptiles that lived during the Late Permian and Triassic periods characterised by superficially bird-like skulls and arboreal lifestyles. As a clade, Avicephala is defined as including the gliding weigeltisaurids and the arboreal drepanosaurs to the exclusion of other major diapsid groups. This relationship is not recovered in the majority of phylogenetic analyses of early diapsids and so Avicephala is typically regarded as an unnatural grouping. However, the clade was recovered again in 2021 in a redescription of Weigeltisaurus, raising the possibility that the clade may be valid after all.

<i>Claudiosaurus</i> Extinct genus of reptiles

Claudiosaurus is an extinct genus of diapsid reptiles from the Late Permian Sakamena Formation of the Morondava Basin, Madagascar. It has been suggested to be semi-aquatic.

<i>Hovasaurus</i> Extinct genus of reptiles

Hovasaurus is an extinct genus of basal diapsid reptile. It lived in what is now Madagascar during the Late Permian and Early Triassic, being a survivor of the Permian–Triassic extinction event and the paleontologically youngest member of the Tangasauridae. Fossils have been found in the Permian Lower and Triassic Middle Sakamena Formations of the Sakamena Group, where it is amongst the commonest fossils. Its morphology suggests an aquatic ecology.

<span class="mw-page-title-main">Araeoscelidia</span> Extinct clade of reptiles

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<i>Weigeltisaurus</i> Extinct genus of reptiles

Weigeltisaurus is an extinct genus of weigeltisaurid reptile from the Late Permian Kupferschiefer of Germany and Marl Slate of England. It has a single species, originally named as Palaechamaeleo jaekeli in 1930 and later assigned the name Weigeltisaurus jaekeli in 1939, when it was revealed that Palaeochamaeleo was a preoccupied name. A 1987 review by Evans and Haubold later lumped Weigeltisaurus jaekeli under Coelurosauravus as a second species of that genus. A 2015 reassessment of skull morphology study substantiated the validity of Weigeltisaurus and subsequent authors have used this genus. Like other Weigeltisaurids, they possessed long rod-like bones that radiated from the trunk that were likely used to support membranes used for gliding, similar to extant Draco lizards.

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Sakamena is a village near Betroka in the region of Anosy in Madagascar.

<i>Lazarussuchus</i> Extinct genus of reptiles

Lazarussuchus is an extinct genus of amphibious reptile, known from the Cenozoic of Europe. It is the youngest known member of Choristodera, an extinct order of aquatic reptiles that first appeared in the Middle Jurassic. Fossils have been found in Late Paleocene, Late Oligocene, Early Miocene and Late Miocene deposits in France, Germany, and the Czech Republic. Two species have been named: the type species L. inexpectatus ("unexpected") from the late Oligocene of France. and L. dvoraki from the early Miocene of the Czech Republic. It was not a large animal; with the total preserved body and tail length of L. inexpectatus being just over 30 centimetres. A complete specimen of Lazarussuchus with preserved soft tissue was found from the Late Paleocene of France, but has not been assigned to a species.

<i>Acerosodontosaurus</i> Extinct genus of reptiles

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<span class="mw-page-title-main">Kuehneosauridae</span> Extinct family of reptiles

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<i>Acleistorhinus</i> Extinct genus of reptiles

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<span class="mw-page-title-main">Weigeltisauridae</span> Extinct family of reptiles

Weigeltisauridae is a family of gliding neodiapsid reptiles that lived during the Late Permian, between 259.51 and 251.9 million years ago. Fossils of weigeltisaurids have been found in Madagascar, Germany, Great Britain, and Russia. They are characterized by long, hollow rod-shaped bones extending from the torso that probably supported wing-like membranes. Similar membranes are also found in several other extinct reptiles such as kuehneosaurids and Mecistotrachelos, as well as living gliding lizards, although each group evolved these structures independently.

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Glaurung is an extinct genus of weigeltisaurid reptile from the Upper Permian of Germany. The only known species is Glaurung schneideri. Originally considered a specimen of Coelurosauravus, a later study named it as a new genus after noting that it had several unique characteristics relative to other weigeltisaurids. These characteristics included a low skull, small eyes, smooth parietal and squamosal bones, and spiny jugal bones.

<i>Parasaurus</i> Extinct genus of reptiles

Parasaurus is a genus of pareiasaur known from fossils collected in the Kupferschiefer in Germany, dating to the Late Permian (Wuchiapingian). The type species, Parasaurus geinitzi, described by Hermann von Meyer in 1857, was the first pareiasaur ever described. The seven known specimens were redescribed in 2008.

References

  1. 1 2 Evans, Susan E.; Haubold, Hartmut (1 July 1987). "A review of the Upper Permian genera Coelurosauravus, Weigeltisaurus and Gracilisaurus (Reptilia: Diapsida)". Zoological Journal of the Linnean Society. 90 (3): 275–303. doi:10.1111/j.1096-3642.1987.tb01356.x. ISSN   0024-4082.
  2. 1 2 3 4 5 Buffa, Valentin; Frey, Eberhard; Steyer, J.-Sébastien; Laurin, Michel (2021-07-12). "A new cranial reconstruction of Coelurosauravus elivensis Piveteau, 1926 (Diapsida, Weigeltisauridae) and its implications on the paleoecology of the first gliding vertebrates". Journal of Vertebrate Paleontology. 41 (2): e1930020. Bibcode:2021JVPal..41E0020B. doi:10.1080/02724634.2021.1930020. ISSN   0272-4634. S2CID   237517962.
  3. Bulanov, V.V.; Sennikov, A.G. (2015). "Substantiation of Validity of the Late Permian Genus Weigeltisaurus Kuhn, 1939 (Reptilia, Weigeltisauridae)". Paleontological Journal. 49 (10): 1101–1111. doi:10.1134/S0031030115110039. S2CID   85660972.
  4. R. L. Carroll. 1978. Permo-Triassic "lizards" from the Karoo System. Part II. A gliding reptile from the Upper Permian of Madagascar. Palaeontologia Africana21:143-159
  5. Evans, S. E. (October 1982). "The gliding reptiles of the Upper Permian". Zoological Journal of the Linnean Society. 76 (2): 97–123. doi:10.1111/j.1096-3642.1982.tb01496.x. ISSN   1096-3642.
  6. 1 2 3 4 5 Buffa, Valentin; Frey, Eberhard; Steyer, J.-Sébastien; Laurin, Michel (2022-09-08). "The postcranial skeleton of the gliding reptile Coelurosauravus elivensis Piveteau, 1926 (Diapsida, Weigeltisauridae) from the late Permian Of Madagascar". Journal of Vertebrate Paleontology. 42 (1): e2108713. Bibcode:2022JVPal..42E8713B. doi: 10.1080/02724634.2022.2108713 . ISSN   0272-4634.
  7. Pritchard, Adam C.; Sues, Hans-Dieter; Scott, Diane; Reisz, Robert R. (2021-05-20). "Osteology, relationships and functional morphology of Weigeltisaurus jaekeli (Diapsida, Weigeltisauridae) based on a complete skeleton from the Upper Permian Kupferschiefer of Germany". PeerJ. 9: e11413. doi: 10.7717/peerj.11413 . ISSN   2167-8359. PMC   8141288 . PMID   34055483.
  8. Dehling, J. Maximilian (2017-12-13). "How lizards fly: A novel type of wing in animals". PLOS ONE. 12 (12): e0189573. Bibcode:2017PLoSO..1289573D. doi: 10.1371/journal.pone.0189573 . PMC   5728497 . PMID   29236777.
  9. McGuire, Jimmy A.; Dudley, Robert (2011-12-01). "The Biology of Gliding in Flying Lizards (Genus Draco) and their Fossil and Extant Analogs". Integrative and Comparative Biology. 51 (6): 983–990. doi: 10.1093/icb/icr090 . ISSN   1540-7063. PMID   21798987.
  10. Smith, R. M. H. 2000. Sedimentology and taphonomy of Late Permian vertebrate fossil localities in Southwestern Madagascar. Paleontologia Africana 36:25–41

Further reading