The Echinoid Directory

Prymnechinus Koehler, 1927, p. 109

Diagnostic Features	Test small; profile inflated with rounded ambitus. Apical disc relatively large, hemicyclic with ocular I insert. A single tubercle on each genital plate bordering the periproct. Periproct subcircular; suranal plate large and distinct. Ambulacra trigeminate, plate compounding echinid-style. Pore-pairs uniserial to peristome. Each triad with a primary tubercle occupying much of the available space. Perradial triple suture points with pits, larger on oral surface. Interambulacral plates relatively tall, each with a primary tubercle and a few surrounding secondaries. Plates rather naked in appearance. Horizontal interambujlacral sutures with elongate pits on either side of the primary tubercle. Primary tubercles imperforate and non-crenulate. Peristome small, with almost no bucal notches. Spines relatively long, up to test diameter in length.
Distribution	Recent; Indo-West Pacific.
Name gender	masculine
Type	Prymnechinus proctalis Koehler, 1927, p. 109 (=Genocidaris apodus Agassiz & Clark, 1906, p. 126), by original designation.
Classification and/or Status	Euechinoidea; Camarodonta; Temnopleuroida; Temnopleuridae. Subjective junior synonym of Temnopleurus Agassiz.
Remarks	Clark (1912) and Mortensen (1943) describe the type species. Clark, H. L. 1912. Hawaiian and other Pacific Echini. Memoirs of the Museum of Compasrative Zoology, Harvard College 34(4), 180 pp, 32 pls. Mortensen, T. 1943. A monograph of the Echinoidea Part III.2, Camarodonta 1. C. A. Reitzel, Copenhagen.