Monotypic prehistoric vertebrate genera

Trucidocynodon is an extinct genus of ecteniniid cynodonts from the Upper Triassic (Carnian) of Brazil. It is a monotypic genus that contains a single species, Trucidocynodon riograndensis. Fossils of Trucidocynodon were discovered in outcrops of the Upper Santa Maria Formation in Paleorrota Geopark, Agudo. Trucidocynodon is one of the most completely known Triassic cynodonts, as its holotype is a nearly complete and fully articulated skeleton.

Lycosuchus is a genus of early therocephalian (an extinct type of therapsid, the group that modern mammals belong to) that lived roughly 260–258 million years ago, straddling the boundary of the Middle and Late Permian period, from what is now the Karoo Basin of South Africa. The type and only species is L. vanderrieti, named by paleontologist Robert Broom in 1903. Lycosuchus is known from a handful of well-preserved specimens mostly preserving the skull and lower jaw; the holotype specimen itself being a nearly complete and undistorted occluded skull and jaws. Other specimens have revealed mo

Niaftasuchus is an extinct genus of therapsids. Its type and only named species is Niaftasuchus zekkeli.

Simorhinella is an extinct genus of therocephalian therapsids from the Guadalupian, or Middle Permian, of South Africa. It is includes only a single species, Simorhinella baini, named by South African paleontologist Robert Broom in 1915. Broom named Simorhinella on the basis of a single small fossil from the British Museum of Natural History collected in 1878 that includes the skull and jaws from the eye sockets forward of a young juvenile. The skull is unusual in that it has an extremely short and broad snout, unlike the longer and narrower snouts of most other early therocephalians. Because

Eucritta (meaning "true creature") is an extinct genus of stem-tetrapod from the Viséan epoch in the Carboniferous period of Scotland. The name of the type and only species, E. melanolimnetes ("true creature from the black lagoon") is a homage to the 1954 horror film Creature from the Black Lagoon.

Brithopus is an extinct genus of dinocephalian therapsids. It contains a single species, Brithopus priscus, known from fragmentary remains found in the Copper Sandstones near Isheevo, Russia.

Dinosaurus is an extinct genus of therapsid of controversial affinities. Its type and only species is Dinosaurus murchisonii. It is only known from a partial snout from the Permian of Russia. Its taxonomic history is intertwined with several other poorly-known Russian therapsids, particularly Rhopalodon, Brithopus, and Phthinosuchus.

Arisierpeton is an extinct genus of synapsids from the Early Permian Garber Formation (Sumner Group) of Richards Spur, Oklahoma. It contains a single species, Arisierpeton simplex.

Gorgodon is an extinct genus of basal synapsids. The genus is monotypic, known only from the type species Gorgodon minutus from the Early Permian of the southwestern United States. The only known remains of Gorgodon are two fossils consisting of fragments of the skull. Gorgodon was described and named by paleontologist Everett C. Olson in 1962 from the San Angelo Formation in Knox County, Texas. Based on what is known of Gorgodon—the squamosal, quadrate, and pterygoid bones of the back of the skull, the maxilla and premaxilla bones that make up the front of the skull, and several teeth—Gorgodo