''Smilosuchus'' (meaning "chisel crocodile") is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus of

leptosuchomorph Leptosuchomorpha is a clade of phytosaurs. It is a node-based taxon defined as the last common ancestor of '' Leptosuchus studeri'' and '' Pseudopalatus pristinus'' and all of its descendants. Phylogeny Below is a cladogram A cladogram (fr ...

parasuchid Parasuchidae is a clade of phytosaurs more derived than ''Diandongosuchus'', a basal phytosaur. It encompasses nearly all phytosaurs, include early ''Parasuchus''-grade forms as well as a more restricted clade of more specialized phytosaurs. This ...

from the Late Triassic of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

History

The type species was first described in 1995 as a replacement generic name for ''Leptosuchus gregorii''. Because of the large rostral crest it possessed, it was considered to be distinct enough from other species of ''

Leptosuchus ''Leptosuchus'' is an extinct genus of leptosuchomorph phytosaur with a complex taxonomical history. Fossils have been found from the Dockum Group and lower Chinle Formation outcropping in Texas, New Mexico, and Arizona, USA, and date back to th ...

'' (all of which had smaller and more restricted crests) to be within its own genus. Some studies seem to suggest that ''Smilosuchus'' is congeneric with ''Leptosuchus'', as the enlarged crest could have been independently developed in ''Leptosuchus''. However, newer studies support the idea that ''Smilosuchus'' is distinct from the type species of ''Leptosuchus'', ''Leptosuchus crosbiensis''. Phylogenetic analyses suggest that ''Smilosuchus'' is more closely related to

mystriosuchin Mystriosuchini, historically known as Pseudopalatinae, is an extinct tribe (formerly subfamily) of derived phytosaurs in the clade Leptosuchomorpha. As with all other phytosaurs, mystriosuchins lived during Late Triassic. The name is derived from ...

s than to ''Leptosuchus'' species.

Description

Smilosuchus-reconstructions-Jeff-Martz-600-px-tiny-Oct-2014-Tetrapod-Zoology

Like all phytosaurs, ''Smilosuchus'' had the nostrils close to the top of its

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals may ...

. The rostral crest and nasal bulge supporting these raised nostrils was larger in ''Smilosuchus'' than in many other phytosaurs. Its skull was extremely large, up to 155 cm long, although estimates for the overall length vary from to . The

jaws Jaws or Jaw may refer to: Anatomy * Jaw, an opposable articulated structure at the entrance of the mouth ** Mandible, the lower jaw Arts, entertainment, and media * Jaws (James Bond), a character in ''The Spy Who Loved Me'' and ''Moonraker'' * ...

are very short and broad and the teeth are

heterodont In anatomy, a heterodont (from Greek, meaning 'different teeth') is an animal which possesses more than a single tooth morphology. In vertebrates, heterodont pertains to animals where teeth are differentiated into different forms. For example, ...

, with large tusks at the anterior of the

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

for impaling prey and more blade-like teeth for slicing flesh closer to the back of the mouth. The tusks are mounted on a bulge at the tip of the snout present in nearly all phytosaurs. Its squamosal processes are short and deep, indicating a powerful bite. This coupled with its large size (it is one of the largest known phytosaurs) suggests that it hunted large prey such as '' Placerias.''

Phylogeny

Below is a cladogram from Stocker (2012):

References

Phytosaurs Prehistoric reptile genera Late Triassic reptiles of North America Fossil taxa described in 1995 {{triassic-reptile-stub