Order Thecideida Pajaud 1970 (lamp shell)
Parent taxon: Rhynchonellata according to C. C. Emig et al. 2013
See also Sepkoski 2002 and Williams et al. 2006
Sister taxa: Athyridida, Atrypida, Cadomelloidea, Cardiarinidae, Dentatrypa, Mongolellidae, Orthida, Pentamerida, Protorthida, Rhynchonellida, Spiriferida, Spiriferinida, Terebratulida, Tropidoleptidae
Subtaxa: Thecideoidea Thecospiroidea
Ecology: stationary epifaunal suspension feeder