The Echinoid Directory

 Cidaridae with:

• Apical disc larger than peristomial opening; generally monocyclic.
• Interambulacra with single large primary tubercle that is perforate and non-crenulate (traces of crenulation may be present adapically, on adapical side).
• Scrobicular circle clearly differentiated and extrascrobicular granulation dense and uniform.
• Ambulacra simple throughout.
• Pore-pairs narrow and non-conjugate.
• Distinct sutural pits and grooves developed; best developed adjacent to perradial and interradial sutures.
• Spines stout; fusiform, with cortex and typically flanged.

?Upper Cretaceous, Europe; Miocene to Recent, Indo-Pacific.

The presence of generally well-defined sutural grooves in this group makes them readily recognizable. Stereocidarinae are closely related but differ in having at least one fully formed adapical plate in each interambulacral zone with only a rudimentary tubercle.

Mortensen, T. 1928. A Monograph of the Echinoidea. I. Cidaroidea. C. A. Reitzel, Copenhagen.  551 pp.