Triassic Echinoids

Abstract

Although 142 species of Triassic echinoids have been reported, only 24 are based on sufficient material to permit reliable generic identification. These species are redescribed and illustrated. Twelve of them are from the St. Cassian Beds in the Italian Dolomites. A large collection of specimens from these beds is described, from which are erected two new species, <I>Megaporocidaris mariana</I> and <I>Levicidaris zardinia</I>, and five new genera: <I>Zardinechinus</I>, a miocidarid, <I>Paurocidaris</I> and <I>Leurocidaris</I>, cidarids, and the psychocidarids, <I>Levicidaris</I> and <I>Megaporocidaris</I>. A new pedinoid, <I>Hemipedina hudsoni</I>, is described from the Norian of Arabia. During the Early and Middle Triassic, only flexible miocidarids were present. Apparently all Mesozoic echinoids are descended from them. The first cidarids occur in the Late Triassic (Karnian) together with the first psychocidarids. The first certain pedinoid appears in the Norian. Finally at the close of the Triassic, in the Rhaetian, the first hemicidaroid appears.