| Bystrowianidae Temporal range: Late Permian - Middle Triassic | |
|---|---|
 | |
| Life restoration of Bystrowiana permira | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | † Chroniosuchia |
| Family: | † Bystrowianidae Vyushkov, 1957 |
| Subgroups | |
Bystrowianidae is a family of chroniosuchian tetrapods from the Permian and Triassic periods. [1]
Below is the cladogram from Buchwitz et al. (2012) showing the phylogenetic relations of bystrowianids: [2]
Cladogram from Novikov (2018) showing internal relationships of bystrowianids based on differences in their osteoderms: [3]
| Bystrowianidae | |
Aetosaurs are heavily armored reptiles belonging to the extinct order Aetosauria. They were medium- to large-sized omnivorous or herbivorous pseudosuchians, part of the branch of archosaurs more closely related to crocodilians than to birds and other dinosaurs. All known aetosaurs are restricted to the Late Triassic, and in some strata from this time they are among the most abundant fossil vertebrates. They have small heads, upturned snouts, erect limbs, and a body ornamented with four rows of plate-like osteoderms. Aetosaur fossil remains are known from Europe, North and South America, parts of Africa, and India. Since their armoured plates are often preserved and are abundant in certain localities, aetosaurs serve as important Late Triassic tetrapod index fossils. Many aetosaurs had wide geographic ranges, but their stratigraphic ranges were relatively short. Therefore, the presence of particular aetosaurs can accurately date a site in which they are found.
Chroniosuchidae is a family of semi-aquatic tetrapods found in sediments from the upper Permian and the upper Triassic periods, most in Russia. They were generally rather large animals, with long jaws similar to those found in modern crocodiles, and probably lived a similar life style as riverside piscivores and ambush predators. Like all Chroniosuchians, they bore extensive osteoderm armour on their backs, possibly as protection against terrestrial predators such as the Permian therapsids and the Triassic Rauisuchians.
Chroniosuchus is an extinct genus of chroniosuchid from the upper Permian period. The genus was first named by Vjuschkov in 1957.
Bystrowiana is an extinct genus of bystrowianid chroniosuchian from upper Permian deposits of Vladimir Region, Russia and Jiyuan, China. Chroniosuchians are often thought to be reptiliomorphs, but some recent phylogenetic analyses suggest instead that they are stem-tetrapods. The genus is named in honour of the Russian paleontologist Alexey Bystrow. It was first described by Vyushkov in 1957 and the type species is Bystrowiana permira. Two species—B. permira and B. sinica—are known.
Kotlassia extinct genus of kotlassiine seymouriamorph from the Late Permian of Russia. The type, and currently only, species is K. prima.
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.
Trematosauridae is a family of large marine temnospondyl amphibians with several included genera.
Chroniosuchia is a group of tetrapods that lived from the Middle Permian to Late Triassic in what is now Eastern Europe, Kyrgyzstan, China and Germany. Chroniosuchians are often thought to be reptiliomorphs, but some recent phylogenetic analyses suggest instead that they are stem-tetrapods. They were all rather short limbed with a strong tail and elongated snout, somewhat resembling modern crocodiles. The group is traditionally considered to be a suborder or order of labyrinthodonts. Chroniosuchians likely had ecological niches as riverside predators, and may have been outcompeted by semiaquatic true reptiles such as phytosaurs in the late Triassic. Most forms bore a heavy armour of scutes along the back, possibly for protection against land born predators like therapsids, or to strengthen the axial skeleton for terrestrial locomotion. Indeed, femoral microanatomy of Chroniosaurus suggests that it was amphibious to 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.
Rhomaleosauridae is a family of plesiosaurs from the Earliest Jurassic to the latest Middle Jurassic of Europe, North America, South America and possibly Asia. Most rhomaleosaurids are known from England, many specifically from lower Blue Lias deposits that date back to the earliest Jurassic, just at the boundary with the Triassic. In fact, to date only two undisputed rhomaleosaurids were named from outside Europe - the closely related Borealonectes russelli and Maresaurus coccai from Canada and Argentina, respectively. These two species are also the only Middle Jurassic representatives of the family. Rhomaleosauridae was formally named by Kuhn in 1961, originally proposed to include Rhomaleosaurus cramptoni and its relatives, which have short necks and large heads relatively to plesiosauroids like Elasmosaurus and Plesiosaurus, but longer necks and smaller heads relatively to advanced pliosaurids like Pliosaurus and Kronosaurus.
Madygenerpeton is an extinct genus of chroniosuchid reptiliomorph from the Late Triassic Madygen Formation of Kyrgyzstan. It was first named by paleontologists Rainer R. Schoch, Sebastian Voigt and Michael Buchwitz in 2010 from a nearly complete skull and associated osteoderms. The type species is M. pustulatus.
Bystrowiella is an extinct genus of bystrowianid chroniosuchians from upper Middle Triassic deposits of Kupferzell and Vellberg, northern Baden-Württemberg, Germany.
Vladlenosaurus is an extinct genus of capitosaurian temnospondyl from Russia. It lived during the late Vetlugian. Based on the type of deposits it was found in, Vladlenosaurus probably inhabited lacustrine, or lake, habitats. The type species is V. alexeyevi, named in 2000.
Axitectum is an extinct genus of bystrowianid chroniosuchians from lower Triassic deposits of Nizhni Novgorod and Kirov Regions, Russia. It was a rather large animal judging by the size of its vertebrae. The back was covered in bands of highly ornamented osteoderm plates, similar to those found in modern crocodiles. The bands overlapped with the next band at the posterior end.
Synesuchus is an extinct genus of bystrowianid chroniosuchians from middle Triassic deposits of Komi Republic, northern Fore-Ural of Russia. It is known from the holotype PIN 4466/12, which consists of armor scute and from the referred materials PIN 4466/10, 4466/11, 4466/13 and 4466/14. It was found in the Nadkrasnokamenskaya Formation of the Bukobay Horizon. It was first named by I.V. Novikov and M.A. Shishkin in 2000 and the type species is Synesuchus muravjevi. The generic name comes from Syne, from Bolshaya Synya river, and “crocodile”, and the specific name honors the Russian geologist Ivan Stepanovich Murav'ev.
Vonhuenia is an extinct genus of proterosuchid, a basal archosauriform from the Early Triassic of Russia. Fossils have been found in the Vokhminskaya Formation, along the Vetluga River that are Induan in age, making Vonhuenia one of the earliest archosauriforms.
Laosuchus is an extinct genus of chroniosuchian known from the Permian-Triassic boundary of Asia. Two species have been named.
Counillonia is an extinct genus of dicynodont therapsid from the area of Luang Prabang in Laos, Southeast Asia that lived at around the time of the Permian-Triassic boundary and possibly dates to the earliest Early Triassic. Its type and only known species is C. superoculis. Counillonia was related to the Triassic dicynodonts such as Lystrosaurus and the Kannemeyeriiformes that survived the Permian mass extinction, but it was more closely related to the Permian genus Dicynodon than to either of these lineages. Counillonia may then possibly represent another line of dicynodonts that survived the Permian mass extinction into the Triassic period, depending on its age. The discovery of Counillonia in Laos and its unexpected evolutionary relationships hint at the less well understood geographies of dicynodont diversity across the Permo-Triassic boundary outside of well explored regions like the Karoo Basin in South Africa.
Repelinosaurus is an extinct genus of dicynodont from the Purple Claystone Formation of Luang Prabang in Laos, Southeast Asia that lived at around the time of the Permian-Triassic boundary and possibly dates to the earliest Early Triassic. Its type and only known species is R. robustus. Repelinosaurus was originally described as the earliest known kannemeyeriiform dicynodont, supporting the idea of a more rapid radiation of the Triassic kannemeyeriiform dicynodonts during the Early Triassic following the Permian mass extinction. However, it may alternatively be more closely related to the Permian Dicynodon. The discovery of a potential early kannemeyeriiform in an understudied locality like Laos highlights the importance of such places in dicynodont research, which has been largely focused on historically important localities such as the Karoo Basin of South Africa.
This list of fossil amphibians described in 2018 is a list of new taxa of fossil amphibians that were described during the year 2018, as well as other significant discoveries and events related to amphibian paleontology that occurred in 2018.
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