The Echinoid Directory

Contributed by Andrew Smith, January 2008

Asterocidaris Cotteau, 1859, p. 14

Diagnostic Features	Test hemispherical, flattened beneath. Apical disc small, less than one-quarter test diameter; plating dicyclic, with posterior oculars closer to periproct than anterior oculars. Genital plates large, with one or two large tubercles. Periproct with smooth edges. Ambulacra narrow, slightly sinuous above. Plating trigeminate aborally, quadrigeminate at ambitus; compounded in diadematid style with all elements extending to perradius. Pore-pairs uniserial above and at ambitus, expanded adorally to form phyllodes. Primary tubercles large on oral surface, sharply decreasing in size at ambitus but continuing to apex. Interambulacral plates a little wider than tall, dominated by a large primary tubercle. Ring of small secondaries surrounds each tubercle forming a scrobicular circle. The top two or three plates with primary tubercle very much reduced - not much larger than scoribicular tubercles, these plates also taller than wide. Primary tubercles at ambitus and adorally with small, rudimentary perforate and with feeble crenulation only on their adoral side. On the aboral surface tubercles imperforate and non-crenulate. Those of the ambulacra very much smaller than those of the interambulacra. Peristome large, more or less flush, with deep, open buccal notches giving the peristome edge a crenulate appearance. No sphaeridial pits and no basicoronal interambulacral plate in adult. Spines and lantern not known for certain.
Distribution	Middle to Upper Jurassic (Bajocian-Oxfordian), Europe.
Name gender	feminine
Type	Asterocidaris nodoti Cotteau, 1859, p. 14, by subsequent designation of Lambert & Thiery, 1910, p. 169.
Species Included	A. nodoti Cotteau,1859; Oxfordian, Europe. A. granulosa (Wright, 1857); Bajocian, France. A. minor Cotteau, 1863; Bathonian, France.
Classification and/or Status	Carinacea, Hemicidaridae, Hemicidarinae.
Remarks	Distinguished from all other hemicidarids by its imperforate and non-crenulate aboral ambulacral tubercles. Cotteau, G. 1859 [April]. Échinides nouveaux ou peu connus (2). Revue et Magazin de Zoologie 11, p. 159.