Spheciospongia vesparium Lamarck 1815

Spheciospongia vesparium (Lamarck, 1815)

Synonymy and references. de Laubenfels, 1950: Rützler (1974): 29, figs. 24–26; Spheciospongia vesparium (Lamarck, 1815): Vicente et al. (1991): 215, figs. 2a, 3a.

Material. USNM 1228938, 1228939, Carrie Bow Cay back reef, near crest, inside and underside of Acropora palmata coral rubble, 0.3 m; K. Ruetzler col. 23 Apr 1974. USNM 1228940, 1228941, Carrie Bow Cay forereef slope, coral-rock underside, 30 m; K. Ruetzler col. 26 Apr 1974.

External morphology. Only some low, hollow cushions, 10 x 10 mm, with 2–5 mm oscula, were visible at the substratum surface. A narrow tunnel leads into 8–14 mm cavities inside the substratum, some apparently excavated, some taken over from previous occupants. The exposed ectosomal tissue is blackish, the choanosome filling the endolithic cavities is grayish yellow.

Skeleton structure. Megascleres (tylostyles) are scattered throughout the tissue, partly bundled in tracts, particularly in the ectosome where they tend to run perpendicularly to the surface. Microscleres (spirasters) are tiny and scattered throughout.

Spicules. Tylostyles are straight or bent about one third of their length below the head; tyles are spherical, in a few spicules they are reduced to oval swellings: 240–340 x 10–15 (304 x 12) Μm. Spirasters are very delicate, with thin shafts making 2–5 turns and clusters of spines prominent at either end and on the convex parts of the turns; some are amphiasters and transitions between the two forms: 10–18 (14) Μm in length (the overall width does not exceed 10 Μm).

Ecology. Massive and early-stage excavating specimens are found on shallow reef and lagoon rock pavements, the latter also cryptic on the forereef; 0.3– 20 m.

Distribution. Bermuda, United States Atlantic coast, Bahamas, Gulf of Mexico, and the Caribbean.