The Echinoid Directory

Centrocidaris Agassiz, 1904, p. 32

Diagnostic Features
  • Tests generally small (< 30 mm diameter).
  • Apical disc dicyclic; about half the test diameter. Genital plates similar in size. Periproct area small. Plates sparsely tuberculate.
  • Interambulacra with large primary tubercle; tubercles perforate and non-crenulate with incised areoles (traces of crenulation may be present adapically).
  • Scrobicular tubercles not much differentiated but forming continuous circles on ambital plates; areoles coalesced on adoral plates; contiguous on ambital plates. Extrascrobicular zones narrow and interradial zone rather naked.
  • Ambulacra almost straight-sided. Pore-pairs oblique and non-conjugate with interporal partition about as large as a single pore. Marginal tubercle on each plate plus a smaller secondary tubercle; the rest of the narrow perradial zone is naked.
  • Ambulacral width almost half that of interambulacral zone.
  • Peristome narrower in diameter than apical disc; interradial plates confined to outer part of membrane.
  • Primary spines long and cylindrical, tapering to a blunt point. In aboral spines the shaft is more or less smooth but shows traces of longitudinal ribs. Ribbing, formed of rows of stubby thorns, is more evident on adoral spines. Cortical hairs dense and well developed forming a glabrous crust.
  • Secondary spines club-shaped, not adpressed.
Distribution
Recent, East Pacific.
Name gender feminine
Type
Cidaris (Discocidaris?) hirsutispinus de Meijere, 1904, p. 20, by original designation.
Species Included
  • Only the type species.
Classification and/or Status

Cidaroida, Cidaridae, Cidarinae.

Monotypic.

Remarks

The secondary club-like spines are distinctive, as are the relatively broad ambulacra and the rather strongly dicyclic apical disc.

Agassiz, A. 1904. The Panamic deep sea echini. Memeoirs of the Museum of Comparative Zoology, Harvard, 31, p. 32.

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