Mycale (Carmia) microsigmatosa Arndt, 1827

Rützler, Klaus, Piantoni, Carla, Van, Rob W. M. & Díaz, Cristina, 2014, Diversity of sponges (Porifera) from cryptic habitats on the Belize barrier reef near Carrie Bow Cay, Zootaxa 3805 (1), pp. 1-129 : 68

Mycale (Carmia) microsigmatosa Arndt, 1827

Synonymy and references. Mycale (Carmia) microsigmatosa Arndt, 1827 : van Soest (1984a): 24, fig. 7, pl. 2: 6; Hajdu & Rützler (1998): 758, figs. 12, 13, 17f.

Material. USNM 1229066, Carrie Bow Cay, south back reef, lower surface of platy coral rubble, 1 m; K. Ruetzler col. 17 Aug 2012.

External morphology. A thin (2–4 mm) incrustation over about 25 cm 2 of rock surface. Soft consistency, scattered oscula (1–2 mm) at the ends of subectosomal canals. The base color is a light orange, but enhanced by clusters of dark orange pigment grains throughout the tissue.

Skeleton structure. No ectosomal specialization, mostly single megascleres and sigmas. Dendritic tracts of megascleres lead from the sponge base toward the surface, with microscleres scattered among them.

Spicules. Subtylostyles with oval heads not much wider than the center of the shaft: 221–310 x 4–6 (294 x 5) Μm; anisocheles I: 17–20 (18) Μm; anisocheles II: 8–13 (1) Μm; sigmas, a small percentage s-shaped: 25–80 (51) Μm.

Ecology. Occurrence on the wave-exposed back reef is rare, the species is mostly found in lagoon and mangrove habitats; 0.5–1.5 m.

Distribution. Bermuda, Bahamas, Gulf of Mexico, and throughout the Caribbean.

Comments. The clusters of dark orange pigment grains in pale, translucent tissue are unique to this species.