Genus: Vigilius WARREN & MARISCANO, 2000
Etymology: Latin, vigilia, "keeping watch." Referes to the large orbits of Welles’ original name and also to the fact that the skull was keeping vigil over the Grand Canyon, Arizona.

Species: wellesi WARREN & MARISCANO, 2000
Etymology: In honor of the late Dr. Samuel Welles who first named the genus and described the skull with the late Dr. Richard Estes.
= Taphrognathus bradyi WELLES, 1947 (referred material)
= Hadrokkosaurus bradyi (WELLES, 1947) WELLES & ESTES, 1969 (referred material)

Holotype: UCMP 31699

Locality: Geronimo (Holbrook) quarry, UC V-3922, on Highway 66, 6 miles west of Holbrook, immediately west of Geronimo Trading post, Apache County, Arizona.

Horizon: Holbrook Member, Moenkopi Formation.

Biostratigraphy:

Age: Ansian Stage, Lower Mid Triassic Epoch, Early Middle Triassic.

Material: Skull.

Referred material:

Locality: Holbrook quarry, UC V-3922, on Highway 66, 6 miles west of Holbrook, immediately west of Geronimo Trading post, Apache County, Arizona.

Horizon: Holbrook Member, Moenkopi Formation.

Biostratigraphy:

Age: Ansian Stage, Lower Mid Triassic Epoch, Early Middle Triassic.

Material:

UCMP 36836: 36250, 36837, 36840: Fragmentary skull elements.

UCMP 25431:

UCMP 37771, 76478, 76477, 75432: Left palatines.

UCMP 75432: Exoccipital.

UCMP 75431: Right vomer.

UCMP 75433, 75435, 76479: Fragments of left maxillae.

UCMP 80855: Atlas.

UCMP 36841: Right clavicle.

UCMP 36247: Left pterygoid.

UCMP 37770: Humerus.

 

Locality: UCMP V-4207, west end of western most butte on south side of Cameron-Grand Canyon highway, 4.5 miles west of turnoff from Cameron-Flagstaff highway, NE 1/4, sec. 26, T29N, R8E, Coconino Point SE Quadrangle, Coconino County, Arizona.

Horizon: Holbrook Member, Moenkopi Formation.

Biostratigraphy:

Age: Ansian Stage, Lower Mid Triassic Epoch, Early Middle Triassic.

Material:

UCMP 38165: Skull.