The Echinoid Directory

Order Pedinoida Mortensen, 1939, p. 547

Diagnosis	Acroechinoids with: dicyclic apical disc firmly bound to corona test rigid; plating tesselate primary tubercles perforate and non-crenulate perignathic girdle of paired peg-like auricles which remain separate lantern aulodont, with deep, V-shaped foramen magnum; teeth U-shaped in cross-section spines cylindrical and smooth, without cortex or thorns. Primary spines solid, secondary spines may have a hollow lumen.
Range	Late Triassic (Norian) to Recent; widespread.
Species Included	Only the family Pedinidae is included. However, there are also two other genera that possibly also belong here and which are quite different from the Pedinida: Orthocidaris Cotteau, 1862, and Zardinechinus Kier, 1977.
Classification and/or Status	Euechinoidea, Acroechinoidea
Remarks	The following genus remains too poorly known to be placed with certainty into the following key, but probably belongs here: Engelia Tornquist, 1908 Mortensen, T. 1939. New Echinoida (Aulodonta). Preliminary Notice. Videnskabelige Meddelelser fra Danks naturhistorisk Forening i Kobenhavn 103, 547-550. Mortensen, T. 1940. A Monograph of the Echinoidea. III, 1. Aulodonta, with Additions to Vol. II (Lepidocentroida and Stirodonta). C. A. Reitzel, Copenhagen, 370 pp.