The Echinoid Directory

Crassiholaster Smith & Wright, 2003, p. 556

Diagnostic Features
  • Test ovate with weak anterior sulcus. Lower surface strongly convex.
  • Test thick-shelled.
  • Apical disc with four gonopores.
  • Paired ambulacra subpetaloid with small circumflexed pore-pairs. Columns of pore-pairs similar in width.
  • Frontal groove absent adapically, developing only towards the ambitus and continuing adorally.
  • Peristome small and circular, typically facing somewhat anterior.
  • Plastron plating meridosternous: plating biserial after the first sternal plate.
  • No enlarged primary tubercles aborally.
  • No fascioles.
Distribution
Lower Cretaceous (Albian) to Upper Cretaceous (Cenomanian).
Name gender masculine
Type
Spatangus subglobosus Leske, 1778, p. 240, by original designation.
Species Included
  • C. bischoffi (Renevier, 1868); Albian and Cenomanian, Europe.
  • C. subglobosus (Leske, 1778); Cenomanian, Europe.
  • C. sulciproctus Smith & Wright, 2003; Cenomanian, UK.
  • C. sphaericus (Schluter, 1869): Cenomanian, UK, Germany.
Classification and/or Status

Holasteroida, basal Meridosternata.

Possibly paraphyletic by exclusion of the stegasterids.

Remarks

Differs from Holaster primarily in its rotund form, thicker shell and more forward-facing peristome. Differs from Echinocorys in having a much more convex base and a distinct sulcus leading from the ambitus to peristome (in G. sphaericus the periproct is very low and inframarginal like that of Echinocorys). Differs from Lampadocorys in having the peristome much closer to the anterior margin.

Smith, A. B. & Wright, C. W. 2003. British Cretaceous echinoids. Part 7, Atelostomata, 1. Holasteroida. Palaeontographical Society Monographs, London. Pp. 440-568, pls 139-182.