Thoosuchus

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Thoosuchus
Temporal range: Early Triassic
Thoosuchus.jpg
Life restoration of Thoosuchus yakovlevi
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Order: Temnospondyli
Suborder: Stereospondyli
Family: Thoosuchidae
Genus: Thoosuchus
Efremov, 1940
Species
  • T. acutirostrisEfremov, 1940 (type)
  • T. yakovlevi(Ryabinin 1926)
  • T. tardusGetmanov, 1989
  • T. tuberculatusGetmanov, 1989

Thoosuchus (meaning "active crocodile") is an extinct genus of basal trematosauroid trematosaurian temnospondyl. Fossils have been found from Russia and date back to the Early Triassic. It is the type genus of the family Thoosuchidae, formerly called the subfamily Thoosuchinae and placed within Benthosuchidae. [1] [2] [3] The benthosuchids were originally composed of the majority of basal trematosaurian forms regarded as the ancestors of the trematosaurids. [4] [5] [6] [7] [8]

Contents

Discovery and naming

Although the genus was first named in 1940, material from one species, E. yakovlevi, was originally tentatively referred to Trematosuchus in 1926. [9] Russian paleontologist Ivan Yefremov [Efremov] named it Thoosuchus "active crocodile" (from Ancient Greek θοός (thoos) "nimble, active" and σοῦχος (soukhos) "crocodile") in 1940, "in view of its obviously more active mode of life in water than the mode of life of Benthosuchus " (page 13). [1]

Description

Thoosuchus jakovlevi skull Thoosuchus jakovlevi.JPG
Thoosuchus jakovlevi skull

For its family, Thoosuchus was fairly small, reaching a little over 60 cm with a 15 cm skull. [10]

Thoosuchus superficially resembles the more derived trematosaurids, but can be distinguished from them on the basis of a deep, narrowing otic notch. [11] [12] It had widely spaced orbits and a moderately elongated skull roof that was well ornamented with ridges and grooves, especially on the parietals. [13] This ornamentation is also a characteristic of trematosaurids and has been described as representing a "zone of intensive growth". [14] [15] The well developed lateral line system of Thoosuchus is indicative of its presumed aquatic lifestyle.

Phylogeny

Thoosuchus in a cladogram after Novikov (2018) with only Early Triassic Eastern Europe taxa included: [16]

Temnospondyli

See also

Related Research Articles

<span class="mw-page-title-main">Temnospondyli</span> Ancestors of modern amphibians adapted to life on land

Temnospondyli or temnospondyls is a diverse ancient order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian and Triassic periods, with fossils being found on every continent. A few species continued into the Jurassic and Early Cretaceous periods, but all had gone extinct by the Late Cretaceous. During about 210 million years of evolutionary history, they adapted to a wide range of habitats, including freshwater, terrestrial, and even coastal marine environments. Their life history is well understood, with fossils known from the larval stage, metamorphosis and maturity. Most temnospondyls were semiaquatic, although some were almost fully terrestrial, returning to the water only to breed. These temnospondyls were some of the first vertebrates fully adapted to life on land. Although temnospondyls are amphibians, many had characteristics such as scales and large armour-like bony plates (osteoderms) that generally distinguish them from the modern soft-bodied lissamphibians.

<i>Mastodonsaurus</i> Extinct genus of temnospondyls

Mastodonsaurus is an extinct genus of temnospondyl from the Middle Triassic of Europe. It belongs to a Triassic group of temnospondyls called Capitosauria, characterized by their large body size and presumably aquatic lifestyles. Mastodonsaurus remains one of the largest amphibians known, and may have exceeded 6 meters in length.

<i>Rhinesuchus</i> Extinct genus of temnospondyls

Rhinesuchus is a large temnospondyl. Remains of the genus are known from the Permian of the South African Karoo Basin's Tapinocephalus and Cistecephalus assemblage zones, both belonging to the Beaufort Group. The skull of Rhinesuchus had a flat triangular shape with blunt snout similar to some of the other large temnospondyls, and had a palate filled with small sharp teeth, suggesting that it hunted fish. Also, the small eyes were on top of the head suggesting that it approached its prey from below.

<span class="mw-page-title-main">Stereospondyli</span> Extinct suborder of amphibians

The Stereospondyli are a group of extinct temnospondyl amphibians that existed primarily during the Mesozoic period. They are known from all seven continents and were common components of many Triassic ecosystems, likely filling a similar ecological niche to modern crocodilians prior to the diversification of pseudosuchian archosaurs.

<i>Eryosuchus</i> Extinct genus of temnospondyls

Eryosuchus is an extinct genus of capitosauroid temnospondyl from the Middle Triassic of northern Russia. It was a very large predator: the largest specimen known could reach up to 3.5 m (11.5 ft) in length, with a skull over 1 m long.

<i>Intasuchus</i> Extinct genus of amphibians

Intasuchus is an extinct genus of temnospondyl amphibian from the Middle Permian of Russia. It is known from a single species, Intasuchus silvicola, which was named in 1956. Intasuchus belongs to the family Intasuchidae and is probably its sole member, although other taxa such as Syndyodosuchus and Cheliderpeton have been assigned to the family in the past. Intasuchus most likely belongs to the group Archegosauroidea, Permian relatives of the large, mostly Mesozoic temnospondyl clade Stereospondyli.

<i>Trematosaurus</i> Extinct genus of amphibians

Trematosaurus is an extinct genus of trematosaurid temnospondyl amphibian found in Germany and Russia. It was first named by Hermann Burmeister in 1849 and the type species is Trematosaurus brauni.

<i>Dvinosaurus</i> Extinct genus of amphibians

Dvinosaurus is an extinct genus of amphibious temnospondyls localized to regions of western and central Russia during the middle and late Permian, approximately 265-254 million years ago. Its discovery was first noted in 1921 by Russian paleontologist Vladimir Prokhorovich Amalitskii in a posthumously published paper that documents the findings of a site in Russia's Arkhangelsk District. Its name is derived from the proximity of this site to the Northern Dvina River.

<i>Konzhukovia</i> Genus of amphibians (fossil)

Konzhukovia is an amphibian genus that belongs to an extinct family Konzhukoviidae of temnospondyls, the largest clade of basal tetrapods including about 198 genera, 292 species, and more than half of which were alive during the early Mesozoic period. The animal was a predator that lived about 260 million years ago, and could get up to about three meters in length. Specifically, Konzukovia lived during the Permian, between 252 and 270 million years ago according to the type of rock the fossil was found in. There are three species within this genus, K. vetusta, K. tarda, and K. sangabrielensis, the first two originating from Russia while the latest originating from Southern Brazil. The discovery of this specimen in Southern Brazil provided more evidence to support the idea that during this animals existence, there was a “biological corridor” because of the supercontinent Pangea, allowing these species to be found so far apart from each other. Konzhukovia belongs to the family Archegosauridae, a family consisted of large temnospondyls that most likely compare to modern day crocodiles. Since the discovery of the latest species, K. sangabrielensis, Pacheco proposes that there must be the creation of a new family, Konzhokoviidae, a monophyletic group in a sister-group relationship with Stereospondlyi in order to accommodate the three species. Konzhukovia skulls usually exhibit typical rhinesuchid features including an overall parabolic shape, small orbits located more posteriorly, and the pterygoids do not reach the vomer. These animals were long-snouted amphibians that had clear adaptations made for fish catching, as well as exemplifying aquatic features.

<i>Benthosuchus</i> Extinct genus of amphibians

Benthosuchus is an extinct genus of temnospondyl amphibian from the Early Triassic of Russia. It was primarily aquatic, living in rivers and lakes. Multiple species are known, with the largest reaching about 2.5 meters in length.

<span class="mw-page-title-main">Lydekkerinidae</span> Extinct family of temnospondyls

Lydekkerinidae is a family of stereospondyl temnospondyls that lived in the Early Triassic period. During this time period, lydekkerinids were widely distributed, with putative remains reported from Russia, Greenland, India, South Africa, Madagascar, Australia, and Antarctica. In contrast to most other stereospondyls, lydekkerinids were relatively small-bodied. The type genus is Lydekkerina, the namesake of the family and the best-known lydekkerinid.

<span class="mw-page-title-main">Limnarchia</span> Extinct clade of temnospondyls

Limnarchia is a clade of temnospondyls. It includes the mostly Carboniferous-Permian age Dvinosauria and the mostly Permian-Triassic age Stereospondylomorpha. The clade was named in a 2000 phylogenetic analysis of stereospondyls and their relatives. Limnarchia means "lake rulers" in Greek, in reference to their aquatic lifestyles and long existence over a span of approximately 200 million years from the Late Carboniferous to the Early Cretaceous. In phylogenetic terms, Limnarchia is a stem-based taxon including all temnospondyls more closely related to Parotosuchus than to Eryops. It is the sister group of the clade Euskelia, which is all temnospondyls more closely related to Eryops than to Parotosuchus. Limnarchians represent an evolutionary radiation of temnospondyls into aquatic environments, while euskelians represent a radiation into terrestrial environments. While many euskelians were adapted to life on land with strong limbs and bony scutes, most limnarchians were better adapted for the water with poorly developed limbs and lateral line sensory systems in their skulls.

Bukobaja is an extinct genus of mastodonsaurid temnospondyl from the middle Triassic of Russia. It contains a single species, Bukobaja enigmatica. Bukobaja mainly occurs in the Bukobay Svita as part of the Ladinian?-age "Mastodonsaurus fauna", a section of Russian Triassic biostratigraphy characterized by "Mastodonsaurus" torvus. It was also present in the underlying Donguz Svita. Bukobaja appears to be a valid genus similar to, yet distinct from, Mastodonsaurus. Despite appearing to possess several unique features, Bukobaja is still known from very few remains. This has led to difficulties in determining its relations more precisely than "Mastodonsauridae incertae sedis". It has also been compared to trematosaurids.

<i>Bothriceps</i> Extinct genus of amphibians

Bothriceps is an extinct genus of stereospondyl temnospondyl. It is a member of the infraorder Trematosauria and is the most basal brachyopomorph known. It may be the only brachyopomorph that lies outside the superfamily Brachyopoidea, which includes the families Brachyopidae and Chigutisauridae. It shares several similarities to Keratobrachyops, another basal brachyopomorph, and may be closely related to or even synonymous with it.

<i>Lydekkerina</i> Extinct genus of temnospondyls from the Early Triassic

Lydekkerina is an extinct genus of stereospondyl temnospondyl. It is the type genus of the family Lydekkerinidae. Fossils have been collected from Early Triassic deposits in South Africa and Australia. The type species is L. huxleyi, first described in 1889. While most other stereospondyls were semiaquatic, Lydekkerina was exclusively terrestrial.

Luzocephalus is an extinct genus of temnospondyl from the Early Triassic of Russia and Greenland. It is usually regarded as a member of the family Lydekkerinidae, although it has also been placed in the family Trematosauridae.

<i>Lapillopsis</i> Extinct genus of temnospondyls

Lapillopsis is an extinct genus of stereospondyl temnospondyl within the family Lapillopsidae. Fossils belonging to the genus have been found in the Arcadia Formation of Queensland, Australia.

<i>Keratobrachyops</i> Extinct genus of amphibians

Keratobrachyops is an extinct genus of trematosaurian temnospondyl found in the Arcadia Formation of Queensland, Australia. It had been thought to be a basal chigutisaurid but is now thought to be a basal brachyopomorph closely related to the genus Bothriceps, and may even be a synonym of it.

<i>Trematosuchus</i> Extinct genus of amphibians

Trematosuchus is an extinct genus of trematosaurian temnospondyl within the family Trematosauridae from South Africa. The type species was first named by Haughton in 1915 as Trematosaurus sobeyi. It was assigned to its own genus, Trematosuchus, by D.M.S. Watson in 1919.

Selenocara is an extinct genus of mastodonsauroid temnospondyl. The type species is Selenocara groenlandica, described by Gunnar Säve-Söderbergh in 1935 on the basis of skull bones from the Lower Triassic Wordie Creek Formation of Greenland. Säve-Söderbergh originally described it as a new species of Wetlugasaurus.

References

  1. 1 2 Efremov, I. A. (1940). Preliminary description of the new Permian and Triassic Tetrapoda from U.S.S.R. Trudy Paleontologicheskogo Instituta10:1–140.
  2. Getmanov, S.N. (1982). A labyrinthodont from the Lower Triassic of the Obshchiy Syrt Region. Paleontological Journal1982:102-106.
  3. Damiani, R. J. and Yates, A. M. (2003). The Triassic Amphibian Thoosuchus yakovlevi and the Relationships of the Trematosauroidea (Temnospondyli: Stereospondyli). Records of the Australian Museum55:331–342.
  4. Hartmann-Weinberg, A. and Kuzmin, F. M. (1936). Untertriadische Stegocephalen der UdSSR Lyrocephalus acutirostris nov. sp. Problems of Paleontology1:63–84.
  5. Shishkin, M. A. (1964). Stereospondyli. In: Orlpv, I. A., ed. Fundamentals of Palaeontology: amphibians, reptiles and birds Moscow: Nauka. pp. 83–122.
  6. Shishkin, M. A. (1980). The Luzocephalidae, a new Triassic labyrinthodont family. Paleontological Journal1980:88–101.
  7. Getmanov, S. N. (1989). Triassic amphibians of the East European platform (family Benthosuchidae Efremov). Trudy Paleontologicheskogo Instituta236:1–102.
  8. Shishkin, M. A. and Welman, J. (1994). A new find of Trematosuchus (Amphibia, Temnospondyli) from the Cynognathus Zone of South Africa. Palaeontologia africana31:39–49.
  9. Riabinin, A. N. (1926). Trematosuchus (?) yakovlevi nov. sp. from the Lower Triassic deposits in the surroundings of Rybinsk. Izvestiya Geologicheskago Komiteta45:519–527.
  10. http://www.angellis.net/Web/PDfiles/amphs.pdf [ bare URL PDF ]
  11. Yates, A. M. and Warren, A. A. (2000). The phylogeny of the 'higher' temnospondyls (Vertebrata: Choanata) and its implications for the monophyly and origins of the Stereospondyli. Zoological Journal of the Linnean Society128:77-121.
  12. Damiani, RJ (2001). A systematic revision and phylogenetic analysis of Triassic mastodonsauroids (Temnospondyli: Stereospondyli). Zoological Journal of the Linnean Society133:379-482.
  13. Shishkin, M. A., Novikov, I. V. and Gubin, Y. M. (2000). Permian and Triassic temnospondyls from Russia. In: Benton, M. J., Shishkin, M. A., Unwin, D. M. and Kurochkin, E. N. (eds.), The Age of Dinosaurs in Russia and Mongolia. Cambridge University Press, pp. 35-59.
  14. Säve-Söderbergh, G. (1937). On the dermal skulls of Lyrocephalus, Aphaneramma, and Benthosaurus, labyrinthodonts from the Triassic of Spitsbergen and N. Russia. Bulletin of the Geological Institution of the University of Uppsala27:189–208.
  15. Bystrow, A. P. (1935). Morphologische Untersuchungen der Deckknochen des Schädels der Wirbeltiere. Acta Zoologica16:65–141.
  16. Novikov A.V. (2018). Early Triassic amphibians of Eastern Europe: evolution of dominant groups and peculiarities of changing communities (PDF) (in Russian). Moscow: RAS. p. 138. ISBN   978-5-906906-71-7. Archived from the original on December 8, 2023. Retrieved February 8, 2024.{{cite book}}: CS1 maint: bot: original URL status unknown (link)