Phorbas aurantiacus new species

(Figures 4 b, 36)

Synonymy and references. Phorbas Duchassaing & Michelotti, 1864: van Soest (2002b): 585, fig. 6 (for generic assignment).

Material. Holotype: USNM 1229060, Curlew Bank, forereef slope, framework cave, 21 m; C. Piantoni and M. Parrish col. 23 Aug 2012.

Paratype: USNM 1229061 Carrie Bow Cay, forereef slope, coral rock underside, 30 m; K. Ruetzler col. 26 Apr 1974.

External morphology. Fleshy crust extending over about 30 cm 2, 1– 4 mm thick. Soft consistency, surface covered by low bumps (conules) with 2–4 mm diameter oscules in between, alternating with ostial sieves of about the same size. Live color deep orange red.

Skeleton structure. Tracts of styles echinated by acanthostyles run from the base of the sponge toward the surface; very thin styles fan out from the end of the tracts, giving them a brush-like appearance.

Spicules. Smooth, slender styles with gradually narrowing points; of great size range without falling into distinct categories: 155–590 x 2–10 (221 x 4) Μm; acanthostyles in three size categories, I: 223–410 x 13–21 (324 x 15) Μm; one was observed deformed as a centrotylote acanthoxea; II: 140–190 x 10–15 (151 x 13) Μm; III: 75– 98 x 8–13 (87 x 10) Μm.

Ecology. Forereef cave and on lower surface of coral rubble, 21– 30 m.

Distribution. Belize.

Etymology. The species name reflects the vivid color of the sponge in life, aurantiacus (Latin) = orange.

Comments. In this species the smooth styles replace the tornotes usually encountered in species of Phorbas; the absence of microscleres is within the generic definition.