Plaesiomyidae

Classification
Phylum: Brachiopoda
Class: Rhynchonellata
Order: Orthida
Family: Plaesiomyidae
Cincinnatian Genera: Austinella, Plaesiomys, Retrorsirostra

Geologic Range
Early Ordovician – Late Ordovician

Common Paleoecology
Plaesiomyidae is an extinct genus of stationary epifaunal suspension feeders

Description of the Family

• Costelalte orthoids with receding or subparallel dental plates
• Ventral muscle scar subquadrate to bilobate, variable enclosure by elongate diductor scars of lanceolate to oval adductor track
• Notothyrial platform supporting large cardinal process and divergent brachiophores
• Saccate ventral mantle canal system with divergent vascula media
• Dorsal system sporadically preserved