†order Orthopsida Mortensen 1942 (sea urchin)
Alternative spelling: Orthopsina
Full reference: T. Mortensen. 1942. New Echinoidea (Camarodonta). Preliminary notice. Videnskabelige Meddelelsar Dansk Naturhistoriske Forening i Kjøbenhavn 106:225-232
Parent taxon: Acroechinoidea according to A. B. Smith 1995
See also Fell and Pawson 1966 and Sepkoski 2002
Sister taxa: Aspidodiadematoida, Carinacea, Diadematoida, Micropygoida, Nicolleaumatidae, Pedinoida, Pedinopsidae
Subtaxa: none
Ecology: slow-moving low-level epifaunal grazer
Distribution: there are no occurrences of Orthopsida in the database