The Echinoid Directory

Family Toxasteridae Lambert, 1920, p. 16

[=Palaeostominae Zittel, 1879, p. 539, non Meissner]


 Spatangoids with:

  • apical disc ethmophract with four gonopores;
  • labral plate elongate; subtriangular with concave base;
  • sternal plates asymmetric with oblique median suture;
  • episternal plates biserially offset;
  • fascioles generally absent (peripetalous fasciole begining to develop in Washitaster and Pseudowashitaster).
Cretaceous (Valanginian to Maastrichtian); worldwide.

Currently a paraphyletic assemblage but with some well defined constituent clades. The lack of fascioles is primitive, as is the oblique median suture separating the sternal plates and ethmophract apical disc.  Two taxa with partially developed peripetalous fascioles - Washitaster and Pseudowashitaster -  are included here on account of their clear close overal similarity to Heteraster, a form lacking fascioles.

The following taxa may be toxasterids but are too poorly known to be determinate:

Allotoxaster Nisiyama, 1968
Somalechinus Checchia-Rispoli, 1945