Hymeniacidon caerulea Pulitzer-Finali, 1986

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 : 75

Hymeniacidon caerulea Pulitzer-Finali, 1986

Synonymy and references. Hymeniacidon caerulea Pulitzer-Finali, 1986: 117 , fig. 37.

Material. USNM 1229084, Carrie Bow Cay north back reef near crest, inside and underside of Acropora palmata coral rubble, 0.3 m; K. Ruetzler col. 23 Apr 1974. USNM 1229085, Carrie Bow Cay south back reef, behind reef crest, under coral rock, 1 m; K. Ruetzler col. 17 Jun 1977. USNM 1229086, Carrie Bow Cay reef flat, in dead conch shells, 1 m; K. Ruetzler and C. Piantoni col. 23 Feb 2006. USNM 1229087, Curlew Bank forereef cave, 20 m; C. Piantoni col. 29 Jun 2007. USNM 1229088, Curlew Bank forereef cave, 20 m; C. Piantoni and M. Parrish col. 23 Aug 2012.

External morphology. Crusts of 1-3 mm thickness, up to 6 cm 2 horizontal extension. Surface smooth; color deep blue, which barely changes in alcohol, even after years of storage.

Skeleton structure. Some spicules are arranged in tracts but most occur disorganized throughout the tissue

Spicules. Slender styles, the larger ones are generally thickest in the upper third of their length (toward the rounded end): 300–600 x 5–12 (443 x 9) Μm.

Ecology. Common in shaded habitats, 0.3–20 m

Distribution. Florida, Bahamas, and the entire Caribbean.

Comments. In the field this species is easily confused with Terpios fugax , which occurs in similar habitats and is also encrusting and of similar color. In both species, this conspicuous, deep blue color is caused by the same micro-symbiont, a blue-pigmented, multicellular, filamentous bacterium ( Rützler & Smith, 1993).