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Temporal range: Late Triassic
Leptosuchus gregorii skull.jpg
Skull of Smilosuchus gregorii
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Phytosauria
Family: Phytosauridae
Node: Leptosuchomorpha
Genus: Smilosuchus
Long & Murry, 1995
Type species
Smilosuchus gregorii
(Camp, 1930)
  • S. adamanensis (Camp, 1930) Stocker, 2010
  • S. gregorii (Camp, 1930) Long & Murry, 1995
  • S. lithodendrorum (Camp, 1930) Stocker, 2010
Restoration of Smilosuchus gregorii
S. gregorii and S. adamanensis compared to a human

Smilosuchus (meaning "chisel crocodile") is an extinct genus of leptosuchomorph phytosaurid from the Late Triassic of North America. The type species was first described in 1995 as a replacement generic name for Leptosuchus gregorii.[1] 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.[2] 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 pseudopalatines than to Leptosuchus species.[3][4]


Below is a cladogram from Stocker (2012):[4]


"Paleorhinus" scurriensis

Paleorhinus bransoni

"Paleorhinus" sawini


Brachysuchus megalodon


Rutiodon carolinensis

"Machaeroprosopus" zunii

Protome batalaria


"Phytosaurus" doughtyi

TMM 31173-120

Leptosuchus crosbiensis

Leptosuchus studeri

Smilosuchus lithodendrorum

Smilosuchus adamanensis

Smilosuchus gregorii

Pravusuchus hortus


Pseudopalatus mccauleyi

Mystriosuchus westphali

Pseudopalatus pristinus

List of synonyms[edit]

Placerias and Smilosuchus

Synonyms of S. adamanensis:
Machaeroprosopus adamanensis Camp, 1930
Rutiodon adamanensis (Gregory, 1962)
Leptosuchus adamanensis (Long & Murry, 1995)

Synonyms of S. gregorii:
Machaeroprosopus gregorii Camp, 1930
Phytosaurus gregorii (Gregory, 1962)
Nicrosaurus gregorii (Gregory, 1962)
Rutiodon gregorii (Ballew 1989)
Leptosuchus gregorii (Irmis, 2005)

Synonyms of S. lithodendrorum:
Machaeroprosopus lithodendrorum Camp, 1930
Rutiodon adamanensis (Gregory, 1962)


  1. ^ Long, R. A., and Murry, P. A. (1995). Late Triassic (Carnian and Norian) tetrapods from the southwestern United States. New Mexico Museum of Natural History and Science Bulletin 4:1-254.
  2. ^ Irmis, R. B. (2005). The vertebrate fauna of the Upper Triassic Chinle Formation in Northern Arizona. In: Nesbitt, S. J., Parker, W. G. and Irmis, R. B., eds., Guidebook to the Triassic Formations of the Colorado Plateau in northern Arizona: Geology, Paleontology, and History. Mesa Southwest Museum, Bulletin No. 9.
  3. ^ Michelle R. Stocker (2010). "A new taxon of phytosaur (Archosauria: Pseudosuchia) from the Late Triassic (Norian) Sonsela Member (Chinle Formation) in Arizona, and a critical reevaluation of Leptosuchus Case, 1922". Palaeontology. 53 (5): 997–1022. doi:10.1111/j.1475-4983.2010.00983.x. 
  4. ^ a b Stocker, M. R. (2012). "A new phytosaur (Archosauriformes, Phytosauria) from the Lot's Wife beds (Sonsela Member) within the Chinle Formation (Upper Triassic) of Petrified Forest National Park, Arizona". Journal of Vertebrate Paleontology. 32 (3): 573–586. doi:10.1080/02724634.2012.649815.