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The Echinoid Directory

Proterocidaris de Koninck, 1882, p. 514

[=Eupholidocidaris Kier, 1956, p. 15, type species Eupholidocidaris brightoni Kier, 1956; =Jacksonechinus Lambert, 1936, p. 39, type species Jacksonechinus andrewi Lambert, 1936 ]

Diagnostic Features	Test up to 250 mm in diameter; flattened and discoidal in shape with marked change between aboral and oral plating. Apical disc small, monocyclic; genital plates larger than ocular plates. One genital plate pierced by hydropores; all genital plates have multiple gonopores arranged as an arc. Ambulacra on aboral surface relatively narrow and straight; composed of 4 columns of small hexagonal plates in the type species, each with a pore-pair; no tubercles. On the oral surface ambulacral zones greatly expanded, with up to 9 columns of hexagonal plates; pore-pairs large and circular with pronounced peripodial rim. Ambulacral plate imbricate adorally. Interambulacra with up to 13 columns of hexagonal plates, imbricating adapically. A small perforate primary tubercle, without pronounced areole, occurs on interambulacral plates.
Distribution	Carboniferous, Europe, North Africa.
Name gender	feminine
Type	Proterocidaris giganteus de Koninck, 1882, p. 514, by monotypy.
Species Included	P. giganteus Koninck, 1882; Lower Carboniferous, Belgium. P. brightoni Kier, 1956; Lower Carboniferous, Ireland. P. belli (Kier, 1959); Upper Carboniferous (Lower Westphalian), USA. P. andrewi (Lambert, 1936); Upper Carboniferous, Egypt.
Classification and/or Status	Stem group Echinoidea; Proterocidaridae. Presumed paraphyletic by exclusion of Pronechinus.
Remarks	The type species was described in detail by Kier (1962). Fournierechinus was treated by Kier (1962) as a junior synonym, but it differs from the type species in having ambulacral columns widened on both apical and oral surfaces, and in having adoral interambulacral zones reduced to a single column of plates. Pronechinus is more pentagonal in outline, though with a similar test architecture, but is most readily distinguished by its mixture of small, normal pore-pairs and large circular pore-pairs adorally. 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. de Koninck, L. G. 1882. Compte Rendu Assoc. Francais Adv. Sci. 10, [for 1881] p. 514.