Gwyneddosaurus

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Gwyneddosaurus
Temporal range: Late Triassic, Norian
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Family: Tanystropheidae
Genus: Gwyneddosaurus
Bock, 1945
Species:
G. erici
Binomial name
Gwyneddosaurus erici
Bock, 1945

Gwyneddosaurus is a possibly invalid genus of extinct aquatic tanystropheid reptile. The type species, G. erici was described in 1945 by Wilhelm Bock, who identified it as a coelurosaurian dinosaur related to Podokesaurus (at the time, "podokesaurids" were thought to be coelurosaurians). Its remains were found in the Upper Triassic Lockatong Formation of Montgomery County, eastern Pennsylvania, and the holotype includes skull fragments, several vertebra, ribs, gastralia, partial shoulder and hip bones, and several forelimb and hindlimb elements found in soft shale, while the paratype includes a femur and a tibia. The type specimen is ANSP  15072 and it was discovered by Bock's four-year-old son [1] while the paratype is only listed as ?(ASNP coll.). It was not a large animal; the type skeleton was estimated by Bock as 18 centimetres (7.1 in) long, [1] and its thigh bone was only 23 millimeters long (0.91 in). [2]

Friedrich von Huene assigned the animal to Protorosauria in 1948 as the smallest known member of the group, finding it to be most like Macrocnemus . [2] Steel (1970) classified it as a theropod dinosaur, [3] whereas Olsen and Baird (1986) identified it as a chimera of mixed remains from a coelacanth and possibly the tanystropheid Tanytrachelos ; [4] Olsen and Flynn (1989) later modified this interpretation, describing the type specimen of Gwyneddosaurus as a "gastric ejection" (regurgitation) composed of Tanytrachelos bones and possibly scraps of a coelacanth. They noted that this would make Gwyneddosaurus a senior synonym of Tanytrachelos, and recommended conserving the younger but better-represented genus. [5]

Related Research Articles

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Tanystropheus is an extinct genus of archosauromorph reptile which lived during the Triassic Period in Europe, Asia, and North America. It is recognisable by its extremely elongated neck, longer than the torso and tail combined. The neck was composed of 13 vertebrae strengthened by extensive cervical ribs. Tanystropheus is one of the most well-described non-archosauriform archosauromorphs, known from numerous fossils, including nearly complete skeletons. Some species within the genus may have reached a total length of 6 meters (20 ft), making Tanystropheus the longest non-archosauriform archosauromorph as well. Tanystropheus is the namesake of the family Tanystropheidae, a clade collecting many long-necked Triassic archosauromorphs previously described as "protorosaurs" or "prolacertiforms".

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

Mecistotrachelos is an extinct genus of gliding reptile believed to be an archosauromorph, distantly related to crocodylians and dinosaurs. The type and only known species is M. apeoros. This specific name translates to "soaring longest neck", in reference to its gliding habits and long neck. This superficially lizard-like animal was able to spread its lengthened ribs and glide on wing-like membranes. Mecistotrachelos had a much longer neck than other gliding reptiles of the Triassic such as Icarosaurus and Kuehneosaurus. It was probably an arboreal insectivore.

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

Stegomosuchus is an extinct genus of small protosuchian crocodylomorph. It is known from a single incomplete specimen discovered in the late 19th century in Lower Jurassic rocks of south-central Massachusetts, United States. It was originally thought to be a species of Stegomus, an aetosaur, but was eventually shown to be related to Protosuchus and thus closer to the ancestry of crocodilians. Stegomosuchus is also regarded as a candidate for the maker of at least some of the tracks named Batrachopus in the Connecticut River Valley.

Protanystropheus is an extinct genus of archosauromorph from the Middle Triassic of Poland, Germany, Austria and the Netherlands. It was named by Sennikov in 2011 and the type species is Protanystropheus antiquus, first described in 1908 by German paleontologist Friedrich von Huene under the name Tanystropheus antiquus. Sennikov (2011) referred to Protanystropheus several vertebrae, including those belonging to "Thecodontosaurus" primus, but such a referral has later been questioned, because these specimens may represent other basal archosauromorphs.

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

Cosesaurus is a genus of archosauromorph reptiles likely belonging to the family Tanystropheidae. It is known from fossil imprints of a single small skeleton, MGB V1, which was found in Muschelkalk outcrops near the municipalities of Mont-ral and Alcover in Spain. These outcrops are dated to the Ladinian age of the middle Triassic about 242 to 237 million years ago. The specimen is stored at the Museu Martorell, which is now part of the Museu de Ciències Naturals de Barcelona. The poor preservation and likely juvenile nature of the specimen has led to the anatomy of Cosesaurus being misidentified by several different sources. For example, Paul Ellenberger claimed that it was an ancestor to birds in the 1970s, while David Peters claimed that it was a pterosaur ancestor in 2000. Both of these claims contrast with mainstream scientific theories on the origins of either group, and other paleontologists who study the specimen are unable to find the features which Ellenberger or Peters reported to be present. The Ellenberger and Peters hypotheses are thus considered fringe theories with questionable scientific soundness due to their low reproducibility. Mainstream hypotheses for the relations of Cosesaurus generally agree that it is a "protorosaur", specifically a tanystropheid closely related to long-necked reptiles such as Macrocnemus, Tanytrachelos, Tanystropheus, or Langobardisaurus.

Tanystropheidae is an extinct family of mostly marine archosauromorph reptiles that lived throughout the Triassic Period. They are characterized by their long, stiff necks formed from elongated cervical vertebrae with very long cervical ribs. Some tanystropheids such as Tanystropheus had necks that were several meters long, longer than the rest of their bodies.

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

Tanytrachelos is an extinct genus of tanystropheid archosauromorph reptile from the Late Triassic of the eastern United States. It contains a single species, Tanytrachelos ahynis, which is known from several hundred fossil specimens preserved in the Solite Quarry in Cascade, Virginia. Abundant fossils of Tanytrachelos are found in a series of lakebed sediments that were deposited over the course of about 350 thousand years in a lake which existed approximately 230 million years ago. Some fossils are very well-preserved and include the remains of soft tissues. Tanytrachelos is the most likely trackmaker of the ichnogenus Gwyneddichnium.

Saurosphargis is an extinct genus of a basal marine reptile, saurosphargid, known from the Middle Triassic of southwestern Poland and eastern Netherlands. It contains a single species, Saurosphargis volzi.

<i>Ozimek volans</i> Extinct species of reptile

Ozimek is a genus of sharovipterygid archosauromorph reptile, known from Late Triassic deposits in Poland and closely related to the Kyrgyzstani Sharovipteryx. It contains one species, O. volans, named in 2016 by Jerzy Dzik and Tomasz Sulej. Like Sharovipteryx, Ozimek had long, slender limbs with the hindlimbs longer than the forelimbs; the hindlimbs likely supported gliding membranes as fossilized in Sharovipteryx. Another unusual characteristic was the shoulder girdle, where the massive coracoids formed a shield-like structure covering the bottom of the shoulder region that would have limited mobility. In other respects, such as its long neck, it was a typical member of the non-natural grouping Protorosauria. Phylogenetic analysis has indicated that it, possibly along with Sharovipteryx, may have been an unusual member of the protorosaur group Tanystropheidae, although further study of its anatomy is needed to resolve its precise relationships.

Megacnemus is an extinct genus of archosauromorph reptile. Megacnemus is an enigmatic and poorly described genus, known from a single bone. The type species of Megacnemus, Megacnemus grandis, was named by Friedrich von Huene in 1954. The holotype of Megacnemus is a limb bone, believed to be a femur. Although the exact locality from which this bone was unearthed is unknown, it is believed to have come from Middle Triassic deposits near Gogolin, in southwest Poland. As the bone is more than 20 centimeters long, Megacnemus may have been quite large, similar to Vritraminosaurus in size.

Boreopricea is an extinct genus of archosauromorph reptile from the Early Triassic of arctic Russia. It is known from a fairly complete skeleton discovered in a borehole on Kolguyev Island, though damage to the specimen and loss of certain bones has complicated study of the genus. Boreopricea shared many similarities with various other archosauromorphs, making its classification controversial. Various studies have considered it a close relative of Prolacerta, tanystropheids, both, or neither. Boreopricea is unique among early archosauromorphs due to possessing contact between the jugal and squamosal bones at the rear half of the skull.

Gwyneddichnium is an ichnogenus from the Late Triassic of North America and Europe. It represents a form of reptile footprints and trackways, likely produced by small tanystropheids such as Tanytrachelos. Gwyneddichnium includes a single species, Gwyneddichnium major. Two other proposed species, G. elongatum and G. minore, are indistinguishable from G. major apart from their smaller size and minor taphonomic discrepancies. As a result, they are considered junior synonyms of G. major.

References

  1. 1 2 Bock, Wilhelm (1945). "A new small reptile from the Triassic of Pennsylvania". Notulae Naturae of the Academy of Natural Sciences of Philadelphia. 154.
  2. 1 2 von Huene, Friedrich (1948). "Notes on Gwyneddosaurus". American Journal of Science. 246 (4): 208–213. doi: 10.2475/ajs.246.4.208 .
  3. Steel, R. (1970). "Part 14. Saurischia. Handbuch der Paläoherpetologie/Encyclopedia of Paleoherpetology". Gustav Fischer Verlag, Stuttgart: 1–87.
  4. Olsen, P. E.; Baird, D. (1986). "The ichnogenus Atreipus and its significance for Triassic biostratigraphy". In Padian, K. (ed.). In The Beginning of the Age of Dinosaurs: Faunal Change across the Triassic-Jurassic Boundary. Cambridge: Cambridge University Press. pp. 61–87. ISBN   0-521-36779-4.
  5. Olsen, P. E.; Flynn, J. (1989). "Field guide to the vertebrate paleontology of Late Triassic rocks in the southwestern Newark Basin (Newark Supergroup, New Jersey and Pennsylvania)". The Mosasaur. 4: 1–35.