Spheciospongia vesparium, commonly known as the loggerhead sponge, is a species of sea sponge belonging to the family Clionaidae. While it is highly toxic to many fish, this sponge is eaten by certain angelfish and is known to form part of the diet of the hawksbill sea turtle (Eretmochelys imbricata).

Description This massive sponge has varying forms in different locations. One common form is barrel-shaped or cake-shaped with a flattened top, but it may also be roughly globular or amorphous. The texture is firm, tough and dense. The surface is broadly undulating and rough, with a mixture of large and small osculi surrounded by groups of fine pores, each 1 to 2 mm (0.04 to 0.08 in) in diameter. The color of the sponge both inside and out is purplish, gray or brownish-black, and the surface is often partly obscured by sediment or by algae growing on it.

Distribution and habitat This sponge is native to the Caribbean Sea and around the coasts of the Bahamas and Florida. It occurs on patch reefs and in lagoons; when growing on soft sediment it often has a wider and deeper base than when growing on rock. Its depth range is 5 to 15 m (16 to 49 ft).