Sphenosuchus is an extinct 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 sphenosuchia

Sphenosuchia

Sphenosuchia is a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Late Jurassic. Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral to crocodyliforms, which include all living crocodilians.-Stratigraphic...

n from the Elliot Formation (Early Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

) of South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, discovered and described early in the 20th century. The skull is excellently preserved but other than elements of the forelimb and isolated parts of the hind limb, the Sphenosuchus material is incomplete. It was probably quadrupedal, but may have been a facultative biped

Facultative biped

A facultative biped is an animal that is capable of walking or running on two legs, often for only a limited period of time, in spite of normally walking or running on four limbs or more. Well-known examples include many lizards such as the Basilisk lizard, and even some cockroaches when running...

.

Sphenosuchus was first thoroughly described in 1972 by the British palaeontologist Alick Walker

Alick Walker

Alick Donald Walker was a British palaeontologist, after whom the Alwalkeria genus of dinosaur is named....

, in a paper in the journal Nature. Walker suggested, based on detailed (but still preliminary at that time) studies of the skull of Sphenosuchus and modern birds, that crocodylomorphs and birds might share an immediate common ancestor. Walker recanted his hypothesis in 1985, but restated and elaborated on it (in essence 'de-recanting') in a monograph published in 1990, which provided the most comprehensive description and discussion of Sphenosuchus yet published.

Species

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...

, Sphenosuchus acutus is the only described species in this genus.