The Echinoid Directory

• Test relatively small; known from fragments only.
• Apical disc unknown.
• Interambulacra composed of 5 or possibly 6 plates per series. Interambulacral plates only slightly wider than tall at ambitus. Primary tubercle with relatively small mamelon which is perforate and with a distinctly crenulate platform, and which increases in size adapically. Areoles circular; strongly incised; only the most adoral two plates with confluent areoles.
• Scrobicular tubercles undifferentiated. Extrascrobicular tubercles of same size as those surrounding areole; best developed interradially; with scattered granulation in between. Plates depressed towards interradial and adoral/adapical sutures.
• Adradial suture of interambulacral plates oblique and denticulate.
• Ambulacra with non-conjugate pore-pairs.
• A primary tubercle to every second plate at ambitus and adorally (pseudobigeminate); the perradial zone very narrow with just the occasional granule. All elements reaching the perradius but alternately taller and shorter.
• Perignathic girdle of apophyses.
• Spines not definitely associated with test fragments; those from same bed cylindrical to weakly fusiform, with shaft ornamented by ribs of thorns.

Lower to Middle Jurassic (Pliensbachian- Bajocian) western Europe.

Cidaris moorei Cotteau, 1875, p. 24, by original designation.

• C. moorei (Cotteau, 1875); Pliensbachian - Lower Bajocian, France, ?England.
• Vadet (1991) included a second species in his genus, C. couvelardi Vadet, 1991; Toarcian-Hettangian, England and France, based on fragments.

Cidaroida; miocidarid (stem group).

Possibly a subjective junior synonym of Miocidaris Doderlein, 1887

Although Wright's original material of Cidaris moorei has imbricate plate margins, Vadet (1991) deemed this indeterminate and based his genus on material from the Toarcian of May, France, described by Cotteau (1875) under the same name.

Interambulacral plate morphology is like that of Miocidaris. Isolated plates figured by Vadet & Chesnier (2003) have slightly deeper areoles and rather coarser secondary tuberculation, but are otherwise similar to material of Miocidaris cassiani Bather 1909 illustrated here. Spines of species historically assigned to Miocidaris are quite variable and may eventually form a sound basis for subdividing this genus. Those of Couvelardicidaris have a well developed ornamentation of dense thorned ribs distinct from those of Miocidaris pakistanensis Link, and Eotiaris verneuiliana. Unfortunately, the spines of the type species of Miocidaris are as yet unknown. Until they are, Couvelardicidaris is retained in preference to the less well known and basically indeterminate Miocidaris.

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

Vadet, A. & Chesnier, M. 2003. Echinides fossiles de Normandie du Sinemurien au Bajocien inferieur. Annales de la Societe d'Histoire naturelle du Boulonnais 3, 1-48.