Genus: Macrocephalosaurus TUPI-CALDAS, 1933 non GILMORE, 1943
Etymology: Latin, macro, "big, long," Greek, kephale, "head" and Greek, sauros, "lizard."

Species: mariensis TUPI-CALDAS, 1933
Etymology:
= Hyperodapedon mariensis (TUPI-CALDAS, 1933)

Holotype: MCN 1867

Locality: Cerro da Alemoa Stie, near the town of Santa Maria, Rio Grande Do Sul State State, Brazil.

Horizon: Upper Santa Maria Member, Santa Maria Formation.

Biostratigraphy:

Age: Ladinian Stage, Upper Mid Triassic Epoch, Middle Triassic.

Material: Skull and nearly complete skeleton.

Referred material:

MORAIS, MULLER, KERBER & PRETTO, 2025

Locality: Buriol ravine, 29°39'30.7"S, 53°26'09.8"W, Sao Joao do Polesine, Rio Grande do Sul, Brazil.

Horizon: Alemoa Member, Santa Maria Formation, Candelaria sequence, Parana Basin.

Biostratigraphy: Hyperodapedon Assemblage Zone.

Age: Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

CAPPA/UFSM 0295: A parital skull of a post hatchling.

_____________________________________________________________________________________