Genus: Microcoelus LYDEKKER, 1893
Etymology: Greek, mikros, "small" and Greek, koilos,"hollow": “Small Hollow”.
= Microsarops KUHN, 1963 (sic)
= Microsaurus HATCHER, 1900 vide LULL, 1910/DEJEAN, 1833 (sic)

Species: patagonicus LYDEKKER, 1893
Etymology: In reference to the province of Patagonia in Argentina.

Holotype: MLP LY 23

Locality: Right bank of the Rio Neuquen, between 2 and 4 km upstream from the railroad bridge which crosses the river, very close to the city of Neuquen, Neuquen Province, Argentina.

Horizon: Bajo de la Carpa Formation, Lower Rio Colorado Subgroup, Upper Neuquen Group.
(was Bajo de LA Carpa Member? Rio Colorado Formation, Neuquen Group.)

Biostratigraphy:

Age: Coloradoan Tetrapoda Assemblage, Santonian-Campanian Stage, Senonian Subepoch, Gulf Epoch, Late Cretaceous.

Material: Anterior dorsal and caudal vertebrae.