Genus: Calsoyasuchus TYKOSKI, ROWE, KETCHAM & COLBERT, 2002
Etymology: In honor of Dr. Kyril Calsoyas, former of Seba Dalkai Navajo Tribal School, our friend and gracious host in the Navajo Nation and a great champion of education, and Greek, sauchos, from the Egyptiona word for "crocodile."

Species: valliceps TYKOSKI, ROWE, KETCHAM & COLBERT, 2002
Etymology: Combination of Latin, valles, "valley" and Greek, cephale, "head," in reference to the deep median valley present on the dorsal surface of nasals and frontal bones.

Holotype: TMM 43631-1

Locality: TMM 43631 (“Calsoyasuchus hill”), field number TR 97/09, northern part of the Gold Spring Drainage basin, Adeii Eechii Cliffs, Navajo Nation, Coconino County, Arizona.

Horizon: Kayenta Formation, Glen Canyon Group, middle third of the silty facies of that unit.


Age: ?Sinemurian-Pliesbachian Stage, Middle Lias Epoch, Middle Early Jurassic.

Maaterial: Incomplete skull of a medium-sized crocodyliform, missing the occiput, braincase, most of the suspensorium, posterior portions of the palate, and jaws.