The Echinoid Directory

Family Holasteridae Zittel, 1879, p. 532


 Basal Meridosternata with:

  • apical disc of standard holasteroid structure, with four gonopores;
  • frontal groove present from ambitus to peristome as shallow furrow; usually also extending adapically;
  • plastron plating meridosternous with sternal plate similar in size to episternal plates and with episternals biserially offset. In some taxa episternals reaching opposite adradial suture making plastron metasternous;
  • pores in anterior ambulacrum small and differentiated from those in the paired ambulacra aborally.
Cretaceous (Hauterivian to Maastrichtian); northern hemisphere.