The Echinoid Directory

Diplocidaris Desor, 1855, p. 44

[=Alternocidaris Quenstedt, 1873, p. 219 (objective); =Diplotiaris Quenstedt, 1872, p. 36 (objective); Rolliericidaris Vadet, 1991, p. 160, type species Diplocidaris etallon (Desor, in Desor & de Loriol, 1869); = Smithicidaris Vadet, 1991, p. 156, type species Diplocidaris jacquemonti Lambert, in Lambert & Thiery, 1910 ]

Diagnostic Features
  • Test large with coarse tuberculation.
  • Apical disc small, ca 40% test diameter; plates generally firmly bound to corona; dicyclic.
  • Interambulacral plates relatively few and large, each plate dominated by a single perforate, crenulate tubercle; the areole circular and incised; areoles widely separated on ambital plates.
  • Scrobicular tubercles not or only weakly differentiated; extrascrobicular zones wide and well developed, covered in scattered tubercles; best developed adradially and interradially.
  • Ambulacra narrow, weakly sinuous; pore-pairs alternately offset. The interporal partition distinctly raised, not conjugate.
  • Ambulacral plating pseudobigeminate; elements alternately tall and short but all reaching the perradius; a large marginal tubercle on every other plate, alternating with a smaller inner tubercle.
  • Peristome larger than apical disc; ca. 50% test diameter.
  • Spines - none definitely associated with tests of type species. Cylindrical spines with densely and irregularly tuberculate shaft present in same beds.
Lower Jurassic (Pliensbachian) to Lower Cretaceous (Valanginian), Europe, North Africa, Madagascar.
Name gender feminine
Cidaris gigantea Agassiz, 1840, p. 66, by subsequent designation of Savin, 1903, p. 181.
Species Included
  • Lambert & Thiery (1910, p. 138) list numerous specimens of which the following are confirmed:
  • D. gigantea (Agassiz, 1840); Oxfordian, Europe, Madagascar.
  • D. besairiei Lambert, 1936; Bajocian, Madagascar.
  • D. jacquemonti Lambert, 1910; Pliensbachian-Toarcian, France.
  • D. desori Wright, 1858; Toarcian, western Europe.
  • D. dumortieri Cotteau, 1863; Bathonian, France.
  • D. gevreyi Lambert in Savin 1902; Valanginian, France.
Classification and/or Status

Cidaroida; Diplocidaridae.

Presumed monophyletic.


The highly distinctive ambulacral structure makes these species immediately recognizable. Vadet (1991) subdivided the genus on the basis of scrobicular tubercle size relative to the areole diameter and on the width of the interradial zones of extrascrobicular tubercles (see remarks under Rolliericidaris Vadet, 1991; Smithicidaris Vadet, 1991).

Desor, E. 1855-1858. Synopsis des échinides fossiles, lxviii + 490 pp., 44 pls. Reinwald, Paris.

Vadet, A. 1991. Revision des "Cidaris" du Lias et du Dogger Europeens. Memoires de la Societe academique du Boulonnais 10, 1-176.