Species: durus (COPE, 1866) COPE, 1868 (nomen dubium)
Etymology:
= Mastodonsaurus durus COPE, 1866 (nomen dubium)
= Metoposaurus durus (COPE, 1866) CHOWDHURY, 1965 (nomen dubium)

Holotype: Not definitely determinable

Locality: Phonixville, Montgomery County, Pennsylvanian.

Horizon: Newark Group.

Biostratigraphy:

Age: Late Triassic.

Material:

AMNH 1850: Left clavicle.

AMNH 1863: Portion of an interclavicle.

AMNH 1868: Fragments

AMNH 3927: Fragment of a clavicle and some possible impressions in rock. It is possible that the type is included among these specimens.

AMNH 2333: Tooth.

AMNH 2324: Fragmentary clavicular plate.