Biarmosuchidae

Kingdoms of Life > Animalia > Vertebrata > Tetrapoda > Sauropsida > Therapsida

Family Biarmosuchidae Olson 1962

Biarmosuchus life reconstruction (unfortunately I do not remember where I copied this image from)

Family Biarmosuchidae

Ecological niche: medium-sized terrestrial carnivores
Guild: medium carnivore (large dog or large monitor lizard?)
Time: middle Permian (Wordian) epoch
Distribution: although so far fossil remains are known only from eastern Russia it is likely these animals had a much wider, probably worldwide (Pangea) distribution
preferred food: smaller tetrapods
length: 1.5 meters (skull: about 20 cm in adult forms)
weight: about 30 kg
Metabolism: partially endothermic
Predators: Eotitanosuchids and Brithopodids
Ancestor: Basal Therapsid (Tetraceratops like ancestor?)
Replaced: Medium-sized Sphenacodontid, and Varanopseid pelycsaurs
Replaced by: Theriodonts
Descendents: maybe the Hipposauridae, Ictidorhinidae, and Burnetiidae
Taxonomic status - Family

Technical Diagnosis
Note - the following diagnosis is from Denise Sigogneau-Russell, "Theriodontia part 17 B I "Encyclopedia of Paleoherpetology, p.19

Diagnosis: Ventral sinuosity of the skull. Very narrow interorbital roof. Long dorsal premaxillary. Short lateral postorbital bone, not reaching the level of the ventral border of the orbit. Paroccipital process still reaches the quadrate. Long palatal dentigerous tuberosities. Parasphenoid keeled ventrally. Mandibular symphysis not sloping. Incisors perhaps without a heel. Short cervical vertebrae, but longer than the dorsals, and with a ventral keel. Long neural apophyses. ShghtIy divergent zygapophyses. Interclavicle very wide anteriorly. Humerus with a feeble torsion and with an entepicondylar foramen; humerus wide distally. Ilium scarcely wider anteriorly. Pubis very developed. Slender limbs. Phalangeal formula 2 3 4 5 4.

Biarmosuchus Chudinov 1960

Biarmosuchus tener, top and side views of skull
image from Denise Sigogneau-Russell, "Theriodontia" Encyclopedia of Paleoherpetology

Diagnosis: Snout higher than wide. Temporal fossa slightly less high than the orbit and narrower. Intertem- poral roof much wider than interorbital roof. Cranial bars slender. Long lacrymal. Frontal participates widely in the supraorbital rim. Occiput high. Interparietal very narrow. Mandible slender. Well marked chin. 5 or 6 upper incisors. Strong ungucal phalanges

There is only one species:

Biarmosuchus tener Chudinov 1960

(= Biarmosaurus antecessor Chudinov 1960)
Meaning of Name: "Crocodile from Biarmia, an ancient country in the Perm region."
Age: Late Permian, Zone I (Ocher Faunal Assemblage), Upper Kazanian, Late Permian, approx. 267 million years ago Wordian epoch).
Locality: Ezhovo, Ocher locality, Fore-Urals, Perm Region, Russia
Size: Size of a large dog (skull length 15 cm (immature) to 21 cm - overall length about 2 meters).
Remains: assorted skull and post-cranial remains, including several complete skeletons, all from the same locality.

Discussion: 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 similiar 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. For a long time Biarmosuchus was placed in the same family as Eotitanosuchus, but it is now believed the two forms appear to be quite distinct (see however M. F. Ivakhnenko for the opposing opinion). Biarmosuchus would seem to represent one of the most primitive of the Biarmosuchian therapsida, and could be taken as a good generalised ancestor for the other, mostly later, forms. In 1999, Biarmosuchus tchudinovi, a new species, was described by M. F. Ivakhnenko, , from the Sokol locality, Udmurtia, Russia.

Half skeleton encased in sediment, as found in the field. Replica by Gonswana Studios

some Links and References

Denise Sigogneau-Russell, "Theriodontia I - Phthinosuchia, Biarmosuchia, Eotitanosuchia, Gorgonopsia" Part 17 B I, Encyclopedia of Paleoherpetology, Gutsav Fischer Verlag, Stuttgart and New York, 1989

Everett C. Olson, "Late Permian Terrestrial Vertebrates, USA and USSR", Transactions of the American Philosophical Society, Philadelphia, vol 52 part 2, 1962

Stars of the Show - includes Biarmosuchus

Therapsida (cladogram)

M. F. Ivakhnenko, Biarmosuches from the Ocher Faunal Assemblage of Eastern Europe, Paleonotological Journal - Vol. 33, No. 3, 1999

Permian Period

Therapsida

Biarmosuchia

Palaeos Page (incorporates some of this material, plus a lot of additional material)

Kingdoms of Life > Animalia > Vertebrata > Tetrapoda > Sauropsida > Therapsida

Unless otherwise attributed or quoted, all text is licensed under
the Creative Commons License 1.0 and a 2.0. This licence does not cover quoted material, and images, which are copyright their respective owners.
images not loading? | error messages? | broken links? | suggestions? | criticism?
contact me

page by M.Alan Kazlev
page uploaded 1 August 2000. Reposted and last modified 1 September 2005