''Biarmosuchus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

biarmosuchia Biarmosuchia is an extinct clade of non-mammalian synapsids from the Permian. Biarmosuchians are the most basal group of the therapsids. They were moderately-sized, lightly built carnivores, intermediate in form between basal sphenacodont " pel ...

n therapsids that lived around 267 mya during the

Middle Permian The Guadalupian is the second and middle series/epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± 0. ...

period. ''Biarmosuchus'' was discovered in the Perm region of

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. The first specimen was found in channel

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

that was deposited by

flood A flood is an overflow of water (list of non-water floods, or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant con ...

waters originating from the young

Ural Mountains The Ural Mountains ( ),; , ; , or simply the Urals, are a mountain range in Eurasia that runs north–south mostly through Russia, from the coast of the Arctic Ocean to the river Ural (river), Ural and northwestern Kazakhstan.

Description

''Biarmosuchus'' was a medium-sized predator, similar in size to a large

dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the gray wolf. Also called the domestic dog, it was selectively bred from a population of wolves during the Late Pleistocene by hunter-gatherers. ...

, grew up to to in length with a skull length (immature) to . It was a lightly built, probably agile animal that would have fed on smaller tetrapods. Their legs are quite long, and the animals were probably quite agile in spite of their size. A large opening for the eye and a small temple opening common in primitive stem-mammals, this lends to a weak bite but how it ate is pure speculation. The teeth contained eight small

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

s on the

palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sep ...

, followed by a

canine tooth In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, eye teeth, vampire teeth, or fangs, are the relatively long, pointed teeth. In the context of the upper jaw, they are also known as '' fangs''. They can appear more f ...

and a further five canine teeth. So together the species contained fourteen upper teeth and twelve lower teeth of small size.

Discovery and species

''Biarmosuchus tener'' was described by Chudinov in 1960 from the Ezhovo locality, Udmurtia, Russia. It was named for

Bjarmaland Bjarmaland (also spelled ''Bjarmland'' and ''Bjarmia'') was a territory mentioned in sagas from the Viking Age and in geographical accounts until the 16th century. The term is usually understood to have referred to the southern shores of the Whit ...

, the name for the

White Sea The White Sea (; Karelian language, Karelian and ; ) is a southern inlet of the Barents Sea located on the northwest coast of Russia. It is surrounded by Karelia to the west, the Kola Peninsula to the north, and the Kanin Peninsula to the nort ...

region in

Old Norse literature Old Norse literature refers to the vernacular literature of the Scandinavian people up to c. 1350. It mainly consists of Icelandic writings. In Britain From the 8th to the 15th centuries, Vikings and Norse settlers and their descendants colon ...

. ''Biarmosuchus tener'', known from two assorted skulls and post-cranial remains, including several complete skeletons. In 1999, ''Biarmosuchus tchudinovi'', a new species, was described by Ivakhnenko from the Sokol locality, Udmurtia, Russia.

Classification

''Biarmosuchus'' would seem to represent one of the most primitive of the Biarmosuchia, and could be taken as a good generalized model for the other, mostly later, forms. This genus is abundantly represented, but most of the specimens remain inadequately prepared and have not been used for an anatomical and functional analysis. Such details as the configuration of the palatines are unknown, as well as numerous characteristics of the postcranial skeleton. It may be that several taxa are represented, but in the present state of our knowledge, it is not possible to define them. ''Biarmosaurus antecessor'' is based on a larger (206 mm as opposed to 153 mm) skull than the holotype, representing a mature individual. This animal is similar in size to '' Phthinosuchus'', but opinions differ as to how distinct the two forms are. The large size of the orbit (eye socket) constitutes the most notable difference. Three monospecific genera, ''Biarmosuchus'', ''

Eotitanosuchus ''Eotitanosuchus'' ("dawn giant crocodile") is an extinct genus of biarmosuchian therapsids whose fossils were found in the town of Ochyor in Perm Krai, Russia. It lived about 267 million years ago. The only species is ''Eotitanosuchus olsoni' ...

'', and '' Ivantosaurus'', are known from the Ocher locality, differing dramatically in size. Ivakhnenko (1999) argues that these represent different growth stages of the same animal but it is now believed the three forms appear to be quite distinct.

References

* Chudinov, P. K. 1965, "New Facts about the Fauna of the Upper Permian of the USSR", ''

The Journal of Geology ''The Journal of Geology'' publishes research on geology, geophysics, geochemistry, sedimentology, geomorphology, petrology, plate tectonics, volcanology, structural geology, mineralogy, and planetary sciences. Its content ranges from planetary ev ...

'', 73:117-30 * Olsen, E. C., 1962,

Late Permian Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudonym used by Dave Groh ...

terrestrial vertebrates, USA and USSR '' Transactions of the American Philosophical Society'', new series, 52: 1–224. *

Patricia Vickers-Rich Patricia Arlene Vickers-Rich (born 11 July 1944), also known as Patricia Rich, is an Australian Professor of Palaeontology and Palaeobiology, who researches the environmental changes that have impacted Australia (including the ancient super ...

and Thomas H. Rich 1993, ''The Great Russian Dinosaurs'', Guntar Graphics, p. 27 * Kemp, TS 1982. ''Mammal-like Reptiles and the Origin of Mammals''.

Academic Press Academic Press (AP) is an academic book publisher founded in 1941. It launched a British division in the 1950s. Academic Press was acquired by Harcourt, Brace & World in 1969. Reed Elsevier said in 2000 it would buy Harcourt, a deal complete ...

, New York, 363 pp

External links

Biarmosuchidae
at Kheper

at Palaeos

at Palaeos * ttp://www.ga.gov.au/paleo/2005_1/jacobs28/system.htm Systematic Palaeontology {{Taxonbar, from=Q2187191 Biarmosuchia Prehistoric therapsid genera Wordian genera Guadalupian synapsids of Europe Permian Russia Fossils of Russia Fossil taxa described in 1960

Description

Discovery and species

Classification

See also

References

External links