''Scalopodon'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of therocephalian

therapsid Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented mor ...

s from the

Late Permian Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eigh ...

. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

''Scalopodon tenuisfrons'' was named in 1999 from the

Kotelnichsky District Kotelnichsky District (russian: Коте́льничский райо́н) is an administrativeLaw #387-ZO and municipalLaw #284-ZO district (raion), one of the thirty-nine in Kirov Oblast, Russia. It is located in the west of the oblast. The area ...

Kirov Oblast Kirov Oblast (russian: Ки́ровская о́бласть, ''Kirovskaya oblast'') is a federal subject of Russia (an oblast) in Eastern Europe. Its administrative center is the city of Kirov. Population: 1,341,312 ( 2010 Census). Geography N ...

. ''Scalopodon'' is known from a single fragmentary

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

specimen including the back of the skull, the left side of the lower jaw and isolated

postorbital The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some v ...

and

prefrontal bone The prefrontal bone is a bone separating the lacrimal and frontal bones in many tetrapod skulls. It first evolved in the sarcopterygian clade Rhipidistia, which includes lungfish and the Tetrapodomorpha. The prefrontal is found in most modern ...

s. The skull was found in the ''Deltavjatia'' Assemblage Zone, which dates back to the early

Wuchiapingian In the geologic timescale, the Wuchiapingian or Wujiapingian (from in the Liangshan area of Hanzhong, Shaanxi Province) is an age or stage of the Permian. It is also the lower or earlier of two subdivisions of the Lopingian Epoch or Series. ...

about 260 million years ago. Distinguishing features of ''Scalopodon'' include narrow

frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, pa ...

s and a distinctive

sagittal crest A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull (at the sagittal suture) of many mammalian and reptilian skulls, among others. The presence of this ridge of bone indicates that there are exceptiona ...

along the

parietal region The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integrates sensory inform ...

at the back of the skull. ''Scalopodon'' was originally classified in the family

Scaloposauridae Baurioidea is a superfamily of therocephalian therapsids. It includes advanced therocephalians such as ''Regisaurus'' and ''Bauria''. The superfamily was named by South African paleontologist Robert Broom in 1911. Bauriamorpha, named by D. M. S. ...

, and was the first scaloposaurid found in Russia (scaloposaurids are also known from southern Africa and Antarctica). More recent studies of therocephalians have found scaloposaurids like ''Scalopodon'' to be juvenile forms of larger therocephalians and do not consider Scaloposauridae to be a valid group. ''Scalopodon'' and most other scaloposaurids are now classified as

basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

members of Baurioidea.

References

Baurioids Therocephalia genera Lopingian synapsids of Europe Fossils of Russia Fossil taxa described in 1999 {{paleo-therapsid-stub