The Echinoid Directory

Echinodiadema Verrill, 1867, p. 580

Diagnostic Features
  • Test plating rather fragile, although plating effectively sutured throughout.
  • Apical disc hemicyclic with ocular plates II and III exsert. Large circular periproct without enlarged periproctal plates. Genital plates projecting interradially; ocular plates almost as large as genital plates.
  • Ambulacral narrow and straight; pore-pairs non-conjugate; uniserial but crowded adorally to form phyllodes.
  • Ambulacral plating trigeminate with single large primary tubercle per plate.
  • Interambulacral zone with ambital plates rather pentagonal with a single primary tubercle.
  • Primary tubercles on ambital plates flanked by interradial row of small secondary tubercles; all tubercles perforate and crenulate.
  • Peristome much larger than apical disc, with deep, rounded buccal notches associated with adradial tags.
  • Spines very long and slender; hollow, with verticillate ornament.
Recent; Gulf of California.
Name gender neuter
Echinodiadema coronata Verrill, 1867, by original designation.
Species Included
  • Only the type species.
Classification and/or Status

Diadematoida; Diadematidae.

Subjective junior synonym of Centrostephanus Peters, 1855.


Differs from Centrostephanus longispinus, the type of Centrostephanus, only in having primary ambulacral and interambulacral tubercles better developed adapically and in having a smaller apical disc.

Mortensen, T. 1940. A monograph of the Echinoidea. Volume III. 1, Aulodonta. C.A. Reitzel, Copenhagen.

Verrill, 1867-1871. Notes on the Radiata in the Museum of Yale College, with description of new genera and species. Transactions Conn. Acad. 1-9.