[=Perinatus A. Agassiz, 1872, p. 119, nomen nudum; =Raphidechinus Lambert & Thiery, 1914, p. 241, type species Echinus molaris de Blainville, 1815]
|Distribution||Recent; tropical Indo-Pacific.|
|Type||Echinostrephus aciculatus A. Agassiz, 1863, by original designation.|
|Classification and/or Status||Camarodonta; Echinoida; Echinometridae.
|Remarks||The high ambitus makes this genus instantly identifiable. It lives in reefal environments where it bores a living chamber for itself. It uses its aboral spines for defence and its aboral tube-feet to capture drift algae. Larger individuals may become trapped within their hole as they grow.
Although the two species differ in the number of pore-pairs incorporated into a compound plate (E. aciculatus has four, E. molaris three), they are similar in other respects and thus treated as congeneric.