The Echinoid Directory

Fournierechinus Jackson, 1929, p. 67

Diagnostic Features
  • Test very large, up to 500 mm in diameter; shape flattened, discoidal; plating imbricate.
  • Apical disc unknown; relatively small.
  • Ambulacra wide throughout, composed of very many columns of small polygonal plates, each with a pore-pair; plates imbricate adorally. Aboral ambulacra as wide as interambulacra. 18-20 columns of plates in each ambulacrum; pore-pairs small and unspecialized aborally.
  • Adoral ambulacra with 18-20 columns of plates but ambulacral zones greatly expanded and making up almost entire oral surface. Adoral pore-pair large and circular, with prominent rim.
  • Interambulacral zones much narrower than ambulacral zones on oral surface, where they are reduced of just a single column of narrow plates; expanding at ambitus and formed of up to 14 columns of polygonal plates above the ambitus. Narrowing adapically but never much narrower than ambulacra.
  • Interambulacral plates each with a small perforate primary tubercle.
  • Lantern present; structure unknown; teeth grooved and denticulate at tip.
  • Spines unknown.
Distribution
Lower Carboniferous (Visean), Belgium.
Name gender masculine
Type
Fournierechinus deneensis Jackson, 1929, p. 67, by original designation.
Species Included
  • Only the type species.
Classification and/or Status

Stem group Echinoidea; Proterocidaridae.

Monotypic.

Remarks

Kier (1962) provided a new and detailed description of the type species which led him to synonymize this genus with Proterocidaris. It differs from the type species of Proterocidaris, however, in having a much less marked change in the width of ambulacral zones between oral and aboral surfaces, and in having interambulacral zones reduced to a single column adorally that ends well before the peristome. This seems sufficient to merit retaining the two as separate genera.

Kier, P. M. 1962. Redescription of some Lower Carboniferous echinoids from Belgium. Institut royal des Sciences naturelles de Belgique, Bulletin 38(5), 1-12, pls 1-6.