Hylaeochampsa 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 eusuchia

Eusuchia

Eusuchia is a clade of crocodylomorphs that first appears in the Early Cretaceous with Hylaeochampsa. All living crocodilian species are eusuchians, as are many extinct forms.-Description:...

n 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 only from a partial skull recovered from Barremian

Barremian

The Barremian is an age in the geologic timescale between 130.0 ± 1.5 Ma and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch...

-age rocks of the Lower Cretaceous Vectis Formation

Vectis Formation

The Vectis Formation is a geological formation on the Isle of Wight, England whose strata date back to the Early Cretaceous . The Vectis Formation is composed of three geological members: the Shepherds Chine member, the Barnes High Sandstone member, and the Cowleaze Chine member...

 (Wealden Group

Wealden Group

The Wealden Group is a group in the lithostratigraphy of southern England. The Wealden group consists of paralic to continental facies sedimentary rocks of Valanginian to Barremian age and thus forms part of the English Lower Cretaceous. It is composed of alternating sands and clays...

) of the Isle of Wight

Isle of Wight

The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...

. This skull, BMNH R 177

Natural History Museum

The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...

, is short and wide, with a eusuchian-like palate

Palate

The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...

 and inferred enlarged posterior

Anatomical terms of location

Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...

 teeth that would have been suitable for crushing. Hylaochampsa was described by Richard Owen

Richard Owen

Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...

 in 1874, with H. vectiana as 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...

. It may be the same genus as the slightly older Heterosuchus

Heterosuchus

Heterosuchus is an extinct genus of crocodylomorph that may have been an eusuchian. It is known only from neck and back vertebrae recovered from Early Cretaceous-age rocks of the Hastings Beds Heterosuchus is an extinct genus of crocodylomorph that may have been an eusuchian. It is known only...

, inferred to have been of similar evolutionary 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:...

, but there is no overlapping material as Heterosuchus is known only from vertebrae. If the two could be shown to be synonyms, Hylaeochampsa would have priority because it is the older name. Hylaeochampsa is the type genus

Type genus

In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...

 of the family Hylaeochampsidae

Hylaeochampsidae

Hylaeochampsidae is an extinct family of basal eusuchian crocodylomorphs thought to be closely related to the order Crocodylia. It was first constructed by Charles William Andrews in 1913 to include just one member: Hylaeochampsa...

, which also includes Iharkutosuchus

Iharkutosuchus

Iharkutosuchus is an extinct genus of basal eusuchian crocodyliform. It fossils have been found in the Santonian-age Upper Cretaceous Csehbánya Formation in the Bakony Mountains of western Hungary...

from the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 of Hungary

Hungary

Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...

. James Clark and Mark Norell positioned it as the sister group

Cladistics

Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 to Crocodylia. Hylaeochampsa is currently the oldest known eusuchian.