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

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of leptosuchomorph parasuchid from the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

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'' (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 mystriosuchins than to ''Leptosuchus'' species.

Description

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

Like all phytosaurs, ''Smilosuchus'' had the

nostril A nostril (or naris , : nares ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbinates ...

s 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 ani ...

. The

rostral Rostral may refer to: Anatomy * Rostral (anatomical term), situated toward the oral or nasal region * Rostral bone, in ceratopsian dinosaurs * Rostral organ, of certain fish * Rostral scale The rostral scale, or rostral, in snakes and other sca ...

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

jaw The jaws are a pair of opposable articulated structures at the entrance of the mouth, typically used for grasping and manipulating food. The term ''jaws'' is also broadly applied to the whole of the structures constituting the vault of the mouth ...

s are very short and broad and the

teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

are

heterodont In anatomy, a heterodont (from Greek, meaning 'different teeth') is an animal which possesses more than a single tooth morphology. Human dentition is heterodont and diphyodont as an example. In vertebrates, heterodont pertains to animals wher ...

, with large

tusk Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine tooth, canine teeth, as with Narwhal, narwhals, chevrotains, musk deer, water deer, muntjac, pigs, ...

s at the anterior of the

mouth A mouth also referred to as the oral is the body orifice through which many animals ingest food and animal communication#Auditory, vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity (or in Latin), is also t ...

for impaling

prey Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not ki ...

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 The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestra ...

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 ''Placerias'' (meaning 'broad body') is an extinct genus of dicynodonts that lived during the Carnian to the Norian age of the Triassic Period (geology), Period (230–215 million years ago). ''Placerias'' belongs to a group of dicynodonts called ...

.''

Phylogeny

Below is a

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 ...

from Stocker (2012):

References

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