clypeasteroid
English
A clypeasteroid, Mellita quinquiesperforata
Noun
clypeasteroid (plural clypeasteroids)
- 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.
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Synonyms
- (any species of Clypeasteroida): pansy shell, sand dollar, sea cookie, snapper biscuit
Hyponyms
- (species of Clypeasteroida): sea biscuit