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Gracilisuchus stipanicicorum

Gracilisuchus is an extinct genus of crurotarsan archosaur, a group that includes the ancestors of crocodilians; it was about 50cm in length. Gracilisuchus was identified at one time to be a dinosaur due to its long tail and dinosaur-like snout; it was believed to be a fast two legged runner, although it would have often walked on all fours. A reassessment of the skull, spine and ankle of Gracilisuchus identified it as an archosaur rather then a dinosaur. Gracilisuchus bones were discovered in the 1970s, it lived during the Middle Triassic Period in what is now South America and it probably had a diet of several animals.



Gracilisuchus stipanicicorum


Romer, 1972

Meaning of the generic name

Latin gracilis "slender, gracile" + Greek soukhos "crocodile".
  Meaning of the specific name

  In honor of Drs. Pedro  and Maria Stipanicic.


Skull length: 95 mm, Length: 30 cm


Holotype (La Plata Museum No. 64-XI-14-11): A slab with a skull in dorsal view, much  of the presacral column and scattered limb and girdle material. The slab also contains the holotype of of Lagosuchus talampayensis.
Referred materials: MCZ 4117 (nearly complete skull) ; MCZ 4118 (partial skull and poscranial skeleton); MCZ 4116 (A slab with skull and postcranial elements).

Age and Distribution

Horizon: Chañares Formation, Middle Triassic (Ladinian).
Locality: 2 km North of Rio Chañares, La Rioja Province, Argentina.


Archosauromorpha Crurotarsi Paracrocodylomorpha

  Further Reading

  A. S. Romer. 1972. The Chañares (Argentina) Triassic reptile fauna. XIII. An early ornithosuchid pseudosuchian, Gracilisuchus stipanicicorum, gen. et sp. nov. Breviora 389:1-24.
J. M. Parrish. 1993. Phylogeny of the Crocodylotarsi, with reference to archosaurian and crurotarsan monophyly. Journal of Vertebrate Paleontology 13(3):287-308


With short forelimbs and a dermal armor consisting of two rows of dorsal scutes, this small animal was found in the same slab that contains the remains of the dinosaur ancestor, Lagosuchus (now Marasuchus) It was originally described as an ornithosuchid by Romer in 1972, before being placed amongst the rauisuchids (Parrish, 1988). It may in fact be more related to the ancestry of crocodiles.

Life reconstruction of Gracilisuchus stipanicocorum (© N. Tamura)