Digitate thorny oyster

Spondylus tenuis

Family Spondylidae - oysters, thorny

Bivalve (2 shells); shell ovate, slightly inflated, small wings; color brick red to reddish purple, white spot on beaks, internally whitish or yellowish with reddish margins on upper valve, lower (attached) valve with red and yellow blotches internally; radial ribs, some thicker ribs interspaced by narrower ribs; ribs may have short spatulate or finger-like spines or may have no spines, just little knobs, most spines will be found on periphery of shell; lower attached shell with flat exterior; interlocking teeth on hinges, teeth on upper shell spread apart, teeth on lower shell together.
Similar Species
May be confused with the Atlantic thorny oyster, S. americanus. The Atlantic thorny oyster is more whitish, has longer spines and occurs in deeper water than the digitate thorny oyster. The digitate thorny oysters usually occur in 50 ft or less of water.
Gulf, attached to hard substrates
Maximum Size
6.4 cm (2 1/5 in)
Other Common Names
Previous Scientific Names
S. ictericus