The Echinoid Directory

Suborder Pygasterina Durham & Melville, 1957

[ex Order Pygasteroida; =Pileatoida Lambert, 1900]

Diagnosis	Holectypoida with: periproct on aboral surface, either in direct contact with apical disc plates or separated by interambulacral plates; apical disc compact with four genital plates, the posterior being absent (or at least not forming an integral part of the remainder of the disc).
Range	Middle Jurassic (Bajocian) to Late Cretaceous (Maastrichtian); Europe, Middle East, North America and the Caribbean.
Remarks	Readily distinguished from Holectypina by the aboral rather than oral periproct

Diagnosis

Holectypoida with:

periproct on aboral surface, either in direct contact with apical disc plates or separated by interambulacral plates;
apical disc compact with four genital plates, the posterior being absent (or at least not forming an integral part of the remainder of the disc).

Range

Middle Jurassic (Bajocian) to Late Cretaceous (Maastrichtian); Europe, Middle East, North America and the Caribbean.

Remarks

Readily distinguished from Holectypina by the aboral rather than oral periproct