clypeasteroid

Definitions

Any echinoderm of the order Clypeasteroida of sand dollars.

Examples

“Their living representatives include⟳ the sea urchins or 'true' echinoids, the heart-urchins or spatangoids and allied forms, the sand-dollars or clypeasteroids, and the slate-pencil-urchins, or cidaroids.”

“At ordinal levels, in cassiduloids and holectypoids, ambitus is circular, elliptical or oval, while clypeasteroids have⟳ a pentagonal to circular type⟳.”

“Their traditional taxonomy, based on skeletal characters, has been largely corroborated by recent molecular phylogenetic analyses with one marked exception: clypeasteroids are not found to be monophyletic.”

CEFR level