The Echinoid Directory

Nudicidaris Vadet, 1991, p. 113

[=Guittonicidaris Vadet, 1991, p. 151, type species Rhabdocidaris bigoti Mercier, 1930; = Remycidaris Vadet, 2004, p. 12, type species Remycidaris largiporus Vadet, 2004]

Diagnostic Features
  • Test rigid with ambulacra firmly sutured to interambulacra.
  • Apical disc and peristome about the same size; both ca. 50% test diameter; plating of apical disc just dicyclic, plating of peristome unknown.
  • Primary interambulacral tubercles perforate and crenulate with weakly incised areoles; areoles discrete and separate except adorally.
  • Scrobicular tubercles forming a well-marked raised ring around the areoles; extrascrobicular zones with rather few scattered granules.
  • Ambulacra weakly sinuous; pore zones weakly incised; pore-pairs non-conjugate to subconjugate.
  • Ambulacral tuberculation at ambitus and adapically uniform with wide, rather naked perradial zone; adorally with enlarged tubercles on every second plate.
  • Spines not definitely known; possibly long, slender and cylindrical; neck short and shaft ornamented with beaded ribs.
Middle Jurassic (Bathonian) to Lower Cretaceous (Albian); Europe.
Name gender feminine
Cidaris sublaevis Cotteau, 1861, p. 341, by original designation.
Species Included
  • N. sublaevis (Cotteau, 1867); Callovian, France.
  • N. elegans (Munster, in Goldfuss, 1829); Oxfordian-Kimmeridgian, Europe.
  • N. bigoti (Mercier, 1930); Bathonian-Callovian, France.
  • N. loryi (Cotteau, 1861); Valanginian, France.
  • N. sp.; Albian, France.
Classification and/or Status

Cidaroida, Polycidaridae.

Presumed monophyletic.


Vadet (2004) emphasised the wide and naked perradial zone as the distinguishing feature of this genus. An undescribed species comes from the Albian of France. The relative development of pore-pairs seems variable within this genus: the type species has subconjugate pore-pairs whereas N. elegans has non-conjugate pore-pairs. Radwanska (2003) provides a description of elegans.

Vadet, A. 1991. Revision des "Cidaris" du Lias et du Doggers Europeens. Memoires de la Societe academique du Boulonnais 10, 1-167, pls 1-9.

Vadet, A. 2004. Echinides fossiles du Boulonnais. Du Bajocien au Tithonien: les "Cidaris". Annales de la Societe d'Histoire Naturelle du Boulonnais 3, 1-35.

Radwanska, U. 2003. The Kimmeridgian echinoids of Poland. Acta Geologica Polonica 53, 143-165.