Ordovician – Recent
Pterioida is an extant order of stationary low-level epifaunal suspension feeders.
Characteristics of the Order
- Generally inequivalve and pleurothetic
- Heteromyarian or monomyarian
- Ligament opisthodetic or amphidetic, and either alivincular , multivincular or duplivincular
Treatise on Invertebrate Paleontology, Part N, Vol. 1 of 3 (1969):
- Generally inequivalve and pleurothetic; inequilateral or secondarily nearly equilateral; heteromyarian or monomyarian; ligament opisthodetic or amphidetic, alivincular, multivincular, or duplivincular, generally extended by secondary fusion layer; prismatonacreous, crossed-lamellar or foliate; pallial line not sinupalliate