The Echinoid Directory

 Cidaridea with:

• Interambulacra with single large primary tubercle that is perforate and non-crenulate (traces of crenulation may be present adapically, on adapical side).
• Scrobicular circle undifferentiated; granulation dense and uniform over interambulacral plates; no sutural pits or grooves.
• Ambulacra simple throughout; no enlarged primary tubercles.
  
• Pore-pairs narrow and non-conjugate; the two pores commonly confluent and set rather strongly oblique to the horizontal suture.
• Spines mostly cylindrical and thorned.

?Upper Cretaceous, Europe; Recent, Antarctic, sub-Antarctic and deep Pacific.

Mortensen (1928) based his classification of cidaroids primarily on the structure of the pedicellariae, separating Goniocidarinae and Ctenocidarinae on the presence or absence of an end tooth on the small globiferous pedicellariae. The lack of clearly differentiated scrobicular circles and the dense uniform granulation on interambulacral plates together with their lack of naked sutural zones characterise tests of this taxon.

Mortensen, T. 1928. A monograph of the Echinoidea. 1. Cidaroida. C. A. Reitzel, Copenhagen.