Nominosuchus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of protosuchia

Protosuchia

Protosuchia is a group of extinct Mesozoic crocodyliforms. They were small in size and terrestrial. In phylogenetic terms, Protosuchia is considered an informal group because it is a grade of basal crocodyliforms, not a true clade....

n-grade

Evolutionary grade

In alpha taxonomy, a grade refers to a taxon united by a level of morphological or physiological complexity. The term was coined by British biologist Julian Huxley, to contrast with clade, a strictly phylogenetic unit.-Definition:...

 crocodylomorph

Crocodylomorpha

The Crocodylomorpha are an important group of archosaurs that include the crocodilians and their extinct relatives.During Mesozoic and early Tertiary times the Crocodylomorpha were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. These were...

. It is known from several specimens discovered in ancient lake deposits of the Tithonian

Tithonian

In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...

-age Upper Jurassic Tsagaantsav Formation, southwestern Mongolia

Mongolia

Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

. The type specimen

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

 is PIN 4174/4, a partial skull. Nominosuchus was not large; its skull length is estimated at 60 millimetres (2.4 in). It was similar to Shartegosuchus

Shartegosuchus

Shartegosuchus is a genus of protosuchian-grade crocodylomorph. It is known primarily from PIN 4174/2, the partial deformed skull and jaws of a juvenile. This specimen was discovered in ancient lake deposits of the Tithonian-age Upper Jurassic Tsagaantsav Formation, southwestern Mongolia. ...

, and is assigned to the same family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 (Shartegosuchidae

Shartegosuchidae

Shartegosuchidae is an extinct family of Late Jurassic and Early Cretaceous crocodylomorphs. The family is named after the Late Jurassic Shar Teeg Beds in southwestern Mongolia, from which most shartegosuchid remains have been found. Four genera are currently assigned to Shartegosuchidae:...

). Nominosuchus was described in 1996 by Mikhail Efimov, and the type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

is N. matutinus.