The Echinoid Directory

Contributed by Andrew Smith, August 2007

Prionechinus A. Agassiz, 1879, p. 202

Diagnostic Features	Test low with rounded ambitus. Apical disc large; with marked sexual dimorphism in gonopore size and position. Dicyclic. Periproct subcircular, covered in fine platelets with distinct suranal plate. Ambulacra trigeminate. Plating in triads with echinid-style plate compounding. Pore-pairs arranged uniserially throughout; no crowding adorally. Single primary tubercle to each compound ambulacral plate. Narrow perradial zone with only a few miliaries. Interambulacral plates wider than tall, with a single central primary tubercle surrounded by a few miliaries on upper and lateral sides. * Primary tubercles imperforate and non-crenulate. No trace of pitting or sculpture on test. Peristome large with almost no buccal notches.
Distribution	Recent, Indo-Pacific.
Name gender	masculine
Type	Prionechinus sagittiger Agassiz, 1879, p. 202, by monotypy.
Species Included	P. sagittiger Agassiz, 1879; Recent, Indo-West Pacific. P. forbesianus (Agassiz, 1881); Recent, Pacific. P. agassizi Wood-Mason & Alcock, 1891; Recent, Indian Ocean. P. sculptus Agassiz 7 Clark, 1907; Recent, Hawaii.
Classification and/or Status	Camarodonta; Temnopleuroida; Trigonocidaridae
Remarks	Agassiz, A. 1879. Proceedings of the American Academy 14, p. 202. Mortensen, T. 1943. A monograph of the Echinoidea Part III.2, Camarodonta 1. C. A. Reitzel, Copenhagen.