The Echinoid Directory

Aporocidaris Agassiz & Clark, 1907, p. 36

Diagnostic Features
  • Test relatively thin and fragile; none exceeding 30 mm in test diameter.
  • Apical disc very large (65-75% test diameter); raised; strongly dicyclic; covered in tubercles, but with a bare edge to the plates. Relatively few periproctal plates. Ocular pores surrounded by a distinct rim.
  • Interambulacral tubercles perforate and non-crenulate; areole not sunken. Scrobicular tubercles hardly differentiated from other granulation.
  • Median interradial suture zone rather bare and slightly sunken; small pits at adradial end of horizontal interambulacral sutures.
  • Ambulacra narrow; composed of relatively few plates. Pore-pairs very narrow with only a thin interporal partition, or the two pores coalesced; strongly oblique to the plate suture.
  • Peristome about half test diameter; relatively few ambulacral plates in each series (less than 10).
  • Primary spines long, cylindrical and slender with short collar and distinct neck; terminating in a simple point. Shaft of spine with semiregular rows of thorns with scattered fine hairs in between.
  • Oral spines spear-shaped and with serrated margins.
  • Secondary spines erect and cylindrical, not adpressed around the base of the primary spines.
Recent, Antarctic and Pacific deep sea.
Name gender feminine
Porocidaris milleri Agassiz, 1898, p. 74, by original designation.
Species Included
  • A. milleri (Agassiz, 1898); Recent, East Pacific.
  • A. fragilis Agassiz & Clark, 1907; Recent, North Pacific.
  • A. antarctica Mortensen, 1909; Recent, Antarctic.
  • A. incerta (Koehler, 1902); Recent, southern tip of South America.
  • A. eltaniana Mooi et al. 2000; Recent, Antarctic.
  • A. usarpi Mooi et al. 2000; Recent, Antarctic.
Classification and/or Status

Cidaroida, Ctenocidaridae


Differs from Ctenocidaris by the larger size of its apical disc and its adoral interradial sutures which are rather bare.

Agassiz, A. & Clark, H. L.  1907. Hawaiian and other Pacific Echinoids. Memoirs of the Museum of Comparative Zoology at Harvard College  34(1), 1-42, pls 1-44.

Mortensen, T. 1928. A monograph of the Echinoidea. 1, Cidaroidea. C. A. Reitzel, Copenhagen.

Caso, M. E. 1979. Los equinoideos del Pacifico de Mexico. Parte Primera - Ordenes Cidaroidea y Aulodonta. Publicaciones especiales Centro de Ciencias del Mar y Limnologia, Universidad Nacional Autonoma de Mexico 1, 1-103.

Mooi, R., David, B., Fell, F. J. & Chone, T. 2000. Three new species of bathyal cidaroids (Echinodermata: Echinoidea) from the Antarctic region. Proceedings of the Biological Society of Washington 113, 224-237.