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.