The Echinoid Directory

Caenocidaris Thiery, 1928, p. 180

[=Besairiecidaris Lambert, in Besairie, 1936, p. 117, type species Besairiecidaris ankarensis Lambert, 1936; =Chesniericidaris Vadet, 2004, p. 27, type species Cidaris wrightii Desor, 1855.]

Diagnostic Features	Test depressed (height less than 50% diameter). Apical disc large, about 50% test diameter; plating unknown. Interambulacra composed of ca. five plates per series; one small rudimentary plate in each zone adapically. Interambulacral plates approximately as wide as tall, with large primary tubercle. Mamelons large and increasing in size adapically; with small perforation on ambital and adapical tubercles only (adoral tubercles imperforate); platform narrow, smooth on adoral side but distinctly crenulate around adapical margin of ambital and adapical tubercles. Areoles circular; hardly incised. Scrobicular tubercles coarse and strongly differentiated. Extrascrobicular granules also rather coarse and only really developed interradially. Ambulacra narrow, sinuous, the pore zones a little depressed and about as wide as the perradial tuberculate zone. Pore-pairs non-conjugate, the two pores separated by a partition that is narrower than an individual pore. A primary tubercle to every plate from the ambitus adapically, but adorally every second tubercle enlarged; the perradial zone very narrow with just the occasional granule. All ambulacral elements reaching the perradius but alternately taller and shorter adorally. Perignathic girdle of apophyses. Spines short, stout and fusiform with distinct neck and distally tapering point. Shaft ornamented by beaded ribs proximally, and more irregular pustules distally.
Distribution	Middle Jurassic (Aalenian, Bajocian); Europe, Madagascar.
Name gender	feminine
Type	Cidaris cucumifera Agassiz, 1840, p. 70, by original designation.
Species Included	C. cucumifera (Agassiz, 1840); Aalenian, Bajocian, western Europe. C. pacomei (Cotteau, 1884); Aalenian, western Europe [possibly just a spine variant]. C. wrightii (Desor, 1857); Aalenian, UK. C. ankarensis Lambert, 1936; Bajocian, Madagascar. C. yeovilensis Wright, 1858; Aalenian, England
Classification and/or Status	Cidaroida, Psychocidaridae. Probably paraphyletic.
Remarks	Balanocidaris differs only in having finer scrobicular tubercles and more incised areoles but is otherwise very similar; possibly only worth distinguishing at subgenus level. Thiery, P. 1928. Considerations phylogenetiques sur les Cidaridae (postumously published by Coenot & Lambert). Archives de Zoologie experimental et generale 67. Notes et Revue 4, 179-181. Vadet, A. 1991. Revision des "Cidaris" du Lias et du Dogger Europeens. Memoires de la Societe du Bolognnais 10, 1-167, pls 1-9.