''Phthinosuchus'' is an extinct
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
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 more ...
s from 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. ...
of Russia. ''Phthinosuchus'' is the sole member of the family Phthinosuchidae. ''Phthinosuchus'' may have been one of the most primitive therapsids, meaning that its ancestors may have branched off early from the main therapsid line.
Discovery
''Phthinosuchus'' was named in 1954 by
Ivan Yefremov. It is currently only known from the back of the skull, as the front of the skull was lost after description. Two species, ''P. discors'' and ''P. horissiaki'', have been described.
Description
''Phthinosuchus'' was 1.5 m (5 ft) long with a 20 cm skull, and looked much like the
Sphenacodontids
Sphenacodontidae (Greek: "wedge point tooth family") is an extinct family of small to large, advanced, carnivorous, Late Pennsylvanian to middle Permian pelycosaurs. The most recent one, ''Dimetrodon angelensis'', is from the late Kungurian or e ...
, such as ''
Dimetrodon
''Dimetrodon'' ( or ,) meaning "two measures of teeth,” is an extinct genus of non-mammalian synapsid that lived during the Cisuralian (Early Permian), around 295–272 million years ago (Mya). It is a member of the family Sphenacodontid ...
'' and ''
Sphenacodon
''Sphenacodon'' (meaning "wedge point tooth") is an extinct genus of synapsid that lived from about 300 to about 280 million years ago (Ma) during the Late Carboniferous and Early Permian periods. Like the closely related '' Dimetrodon'', ''Sphen ...
''. Its
temporal fenestra
An infratemporal fenestra, also called the lateral temporal fenestra or simply temporal fenestra, is an opening in the skull behind the orbit in some animals. It is ventrally bordered by a zygomatic arch. An opening in front of the eye sockets, ...
e were larger than those of the Sphenacodontids.
Its jaw was slender, unlike other predatory therapsids,
but like the other
early therapsids, it was probably sprawling and
carnivorous
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...
.
Classification
''Phthinosuchus'' is a member of the suborder
Phthinosuchia, which was made specifically for ''Phthinosuchus'' given that it did not fit into any other suborder.
See also
*
List of therapsids
*
Evolution of mammals
The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the Pennsylvanian sub-period of the late Carboniferous period. By the mid-Triassic, there were many synapsid species that looked l ...
*
Dinocephalians
References
Dinocephalians
Prehistoric therapsid genera
Prehistoric synapsids of Europe
Fossil taxa described in 1954
Taxa named by Ivan Yefremov
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