Amphimedon erina

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 : 83

Amphimedon erina (de Laubenfels, 1936)

Synonymy and references. Haliclona erina de Laubenfels, 1936a: 457; Hechtel (1965): 19, pl. 1 (2, 3).

Material. USNM 1229112, 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 1191333, Carrie Bow Cay, lagoon, under concrete dock, 0.5 m; K. Ruetzler, col. 12 May 1978. Carrie Bow Cay, lagoon, under concrete dock, 0.5 m; K. Ruetzler, col. 12 May 1978.

External morphology. Encrusting or cushion-shaped, with repent branches extending from the base; 1–1.5 cm thick, including elevated oscula, covering about 100 cm 2. Color deep green, consistency crumbly.

Skeleton structure. Irregular reticulum of fibers cored by spicules, or tracts of 2–8 spicules in parallel. Some tangential fiber meshes at the surface.

Spicules. Robust oxeas with acerate tips, except for a few styloid modifications: 130–200 x 7–10 (167 x 8) Μm. A small percentage of thinner and slightly shorter, fusiform oxeas (130–170 x 3–5 (143 x 4) Μm) can be considered developmental stages.

Ecology. Common in the lagoon, hidden among seagrass and under coral rubble, and in mangroves in deep shade, 0.5– 2 m.

Distribution. Jamaica and western Caribbean ( Panama and Belize); may be more abundant but has often been confused with another green (non-symbiotic) species, Amphimedon viridis Duchassaing & Michelotti.

Comments. Although not a typical cave species, its distribution extends to the lower surfaces of coral rock and similar shaded habitats. The green color is proper to the sponge, not a photosynthetic pigment from a symbiont. We separate this species from Amphimedon viridis by its brittle, “dry-feeling” consistency and more robust oxeas. A. viridis has soft and limp consistency and is slightly mucous when rubbed, and its oxeas are thin and fusiform, not more than 150 x 3 Μm in dimensions; the latter species is found in the shallow lagoon west of Carrie Bow Cay, in fully light-exposed habitats.