Brevirostres is a group of

crocodilian Crocodilia () is an Order (biology), order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorp ...

s that, as originally formulated, included alligatoroids and crocodyloids, but not gavialoids. Results of molecular phylogenetic analysis uniformly draw gavialoids and crocodyloids into a close relationship; in that case, Brevirostres becomes redundant with

Crocodilia Crocodilia () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchia ...

. Members of brevirostres are crocodilians with small snouts, and are distinguished from the long-snouted

gharial The gharial (''Gavialis gangeticus''), also known as gavial or fish-eating crocodile, is a crocodilian in the family (biology), family Gavialidae and among the longest of all living crocodilians. Mature females are long, and males . Adult males ...

s. It is defined

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

ally as the

last common ancestor A most recent common ancestor (MRCA), also known as a last common ancestor (LCA), is the most recent individual from which all organisms of a set are inferred to have descended. The most recent common ancestor of a higher taxon is generally assu ...

of '' Alligator mississippiensis'' (the American alligator) and ''

Crocodylus niloticus The Nile crocodile (''Crocodylus niloticus'') is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. It is widely distributed in sub-Saharan Africa, occurring mostly in the eastern, southern, and ce ...

'' (the Nile crocodile) and all of its descendants. This classification was based on morphological studies primarily focused on analyzing skeletal traits of living and extinct fossil species, and placed the gharials outside the group due to their unique skull structure, and can be shown in the simplified

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below: However, recent molecular studies using

DNA sequencing DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, thymine, cytosine, and guanine. The ...

render Brevirostres redundant with Crocodylia upon finding the crocodiles and gavialids to be more closely related than the alligators. The new clade Longirostres was defined by Harshman ''et al.'' in 2003, and can be shown in the cladogram below:

History

Brevirostres was first named by Karl Alfred von Zittel in 1890. Von Zittel considered ''

Gavialis ''Gavialis'' is a genus of crocodylians that includes the living gharial ''Gavialis gangeticus'' and one known extinct species, '' Gavialis bengawanicus.'' ''G. gangeticus'' comes from the Indian Subcontinent, while ''G. bengawanicus'' is know ...

'', the gharial, to be closely related to ''

Tomistoma ''Tomistoma'' is a genus of gavialid crocodilians. They are noted for their long narrow snouts used to catch fish, similar to the gharial. ''Tomistoma'' contains one extant (living) member, the false gharial (''Tomistoma schlegelii''), as well ...

'', the false gharial, and excluded them from the group. ''Tomistoma'', as its name implies, is traditionally not considered closely related to ''Gavialis'', but instead classified as a crocodylid. Under this classification, all members of Brevirostres are brevirostrine, or short-snouted. Recent molecular analyses support von Zittel's classification in placing ''Tomistoma'' as a close relative of ''Gavialis''. If this classification is accepted, Brevirostres can be considered redundant with

Crocodylia Crocodilia () is an Order (biology), order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorp ...

, as the two names would refer the same clade. Brevirostres would not, however, be a

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

of Crocodylia, as the two names have different definitions.

References

Crocodilia Enigmatic crocodilian taxa Paraphyletic groups {{Archosaur-stub