Kingdom Animalia
Phylum Chordata
Superclass Tetrapoda
Class Reptilia
Subclass Diapsida
Order Phytosauria
Family Phytosauridae
Genus Smilosuchus
1st Species Smilosuchus gregorii
2nd Species Smilosuchus adamanensis
3rd Species Smilosuchus lithodendrum
Other attributes
Time Range 221.5-205.6 mya
Location United States of America
Name Meaning Knife crocodile
Physical Dimensions 6.8 meters long for S.gregorii; 5 meters long for S.adamanensis
Dietary Classification Carnivore

Smilosuchus is a phytosaurid phytosaurian reptile from the Late Triassic of the United States of America. It was officially named in 1995 by R. A. Long and P. A. Murry. It was one of the biggest phytosaurs to exist, and its remains were thought to be those of another phytosaur, right before it was discovered that those remains were different enough to be their own genus.


Like any other phytosaur, Smilosuchus resembled a crocodile, with a bulky body, 4 semi-erect legs, a long, muscular tail, a large head with massive jaws, and eyes on the top of its head. However, it had a few major differences, like nostrils situated near its eyes, a slightly downturned snout, and serrated teeth; there was even some differences between species, as Smilosuchus gregorii had a deeper and broader snout and big, fang-like teeth, while Smilosuchus adamanensis had a shallower and thinner snout and small, conical teeth. Its body would have been covered in scaly skin, with a row of osteoderms running down its back and tail.


Smilosuchus was a predator; specific diet depends on the species. Due to its deeper snout and more robust teeth, the aforementioned S.gregorii would have been able to prey on small dinosaurs, small-midsized paracrocodylomorphs, and large anomodonts; the aforementioned S.adamanensis, on the other hand, would have preyed on fish, using its small, thin teeth and its slender snout to catch them.


Smilosuchus had a semi-aquatic lifestyle, being at home both in the water and on the land; despite its crocodilian physiology and tendency to spend 50% of its time in the water, it was a competent terrestrial animal as well, and was able to perform a "high walk" similar to those of modern crocodiles. Unlike modern crocodiles, however, its teeth were serrated, and were able to slice the flesh of prey items; due to this, it may not have been able to perform the dismembering spin that modern crocodiles were able to do when ripping prey apart, and may have used another type of movement in order to rip apart its food. In fact, only the larger species, S.gregorii would have been able to attack large terrestrial animals to sustain itself, due to its big teeth and deep snout; the smaller S.adamanensis would have preferred to prey on small aquatic animals, using its slender snout and small teeth to snag any small fish that swam by. An interesting thing to note is that Smilosuchus may have been superprecocial (requiring very little to no parental care), and adults may have laid their eggs in a safe place before abandoning them; newly-hatched Smilosuchus would have had to fend for themselves, possibly hiding in vegetation in order to hide from predators such as the large amphibian Koskinonodon, the small dinosaur Coelophysis, and the large paracrocodylomorphs Poposaurus and Postosuchus.

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