English

A clypeasteroid, Mellita quinquiesperforata

Noun

clypeasteroid ‎(plural clypeasteroids)

1. Any echinoderm of the order Clypeasteroida, of sand dollars.
   • 2006, Robert Wynn Jones, Applied Palaeontology, page 181,

     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.

   • 2008, Anis Kumar Ray, Fossils in Earth Sciences, page 217,

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

   • 2009, Andrew B. Smith, Sea urchins (Echinoidea), S. Blair Hedges, Sudhir Kumar (editors), The Timetree of Life, page 302,

     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.

Synonyms

• (any species of Clypeasteroida): pansy shell, sand dollar, sea cookie, snapper biscuit

Hyponyms

• (species of Clypeasteroida): sea biscuit