The Echinoid Directory

Key to the families of Temnopleuroida


1a. Apical disc dicyclic.
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1b. Apical disc hemicyclic.

2a. Ornament consists of sharp-edged sutural pits.

Temnopleuridae

2b. Ornament consists of raised epistroma or tuberculation with irregular depressions, some of which are sutural.

Trigonocidaridae