Productida is an extinct order of brachiopods in the extinct class Strophomenata. Members of Productida first appeared during the Silurian.[1] They represented the most abundant group of brachiopods during the Permian period, accounting for 45-70% of all species. The vast majority of species went extinct during the Permian-Triassic extinction event, though a handful survived into the Early Triassic.[2] Many productids are covered in hollow tubular spines, which are characteristic of the group. A number of functions for the spines have been proposed, including as a defensive mechanism against predators.[3]
^Williams, Alwyn; Brunton, C.H.C.; Carlson, S.J.; et al. (1997–2007). Kaesler, Roger L.; Selden, Paul (eds.). Part H, Brachiopoda (Revised). Treatise on Invertebrate Paleontology. Boulder, Colorado; Lawrence, Kansas: Geological Society of America; University of Kansas.
