Rhynchonellata - Rhynchonellida - Petasmariidae

Full reference: G. A. Cooper. 1953. Sponges, Brachiopoda, Pelecypoda, and Scaphopoda. Permian fauna at El Antimonio, western Sonora, Mexico. Smithsonian Miscellaneous Collections 119(2):21-80

Belongs to Leiorhynchoidea according to G. A. Cooper 1953

Sister taxa: Leiorhynchoidea amygdaloidea, Leiorhynchoidea laevis, Leiorhynchoidea rotundidorsa, Leiorhynchoidea scelesta, Leiorhynchoidea schucherti, Leiorhynchoidea sulcata, Leiorhynchoidea variabilis

Type specimen: USNM 115549b. Its type locality is USNM806i, Cerros de los Monos, El Antimonio, Sonora, which is in a Wordian marine shale in the Antimonio Formation of Mexico.

Ecology: stationary epifaunal suspension feeder

Average measurements (in mm): shell 26.0 x 26.8