The Echinoid Directory

Family Stegasteridae Duncan, 1889, p. 211

Diagnosis	Stegasterine holasteroids with: thick test with flat base Periproct marginal with distinct subanal bulge meridosternous to orthosternous plastron small circular peristome facing forward into deep oral groove marginal fasciole generally present (may be absent in adults of some taxa).
Range	Upper Cretaceous (Coniacian) to Maastrichtian; worldwide

Diagnosis

Stegasterine holasteroids with:

Range

Upper Cretaceous (Coniacian) to Maastrichtian; worldwide