Amorphinopsis

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 : 74-75

Amorphinopsis sp.

Synonymy and references. Nailondria de Laubenfels, 1954: 182, fig. 121. Amorphinopsis Carter, 1887 : Erpenbeck and van Soest (2002): 790, fig. 1.

Material. USNM 1229083, Curlew Bank forereef cave, ceiling, 1 m from entrance, 20 m; C. Piantoni and M. Parrish col. 22 Aug 2012.

Comparative material studied: USNM 23083 Nailondria maza de Laubenfels, 1954 (holotype, West-Central Pacific).

External morphology. Filling cavities and crevices in coral rock, 3–15 mm below the substratum surface. No epilithic structures were seen except small, white tubules and fistules that turned out to belong to a co-occurring Siphonodictyon . From calcareous fragments and pitting of the substratum it seems that the sponge is excavating. Color white.

Skeleton structure. Cavernous tissue filling the rock cavities, including densely packed spicules without orientation (criss-cross). No spongin visible on a histological section, only a variety of cells, including small (18 µm) choanocyte chambers.

Spicules. Strongyles of great size range but may be lumped into three size classes. Most are bent more or less sharply, once, twice, or three times in the same or in opposing directions (wavy). Some of the thinner ones show oxeote modifications, but are rare and assumed to be developmental stages rather than a different spicule type. Strongyles I: 430–1020 x 20–48 (789 x 29) µm; II: 440–940 x 6–15 (620 x 10) µm; III: 240–420 x 5–10 (343 x 7) µm.

Ecology. Inhabiting and (possibly) excavating cavities in coral rock of a framework cave ceiling, 20 m. The sponge is closely associated with other sponges, that is, specimens of Agelas sventres and Siphonodictyon coralliphagum .

Distribution. Belize.

Comments. Our material does not show ectosomal differentiation, but the choanosomal skeleton agrees with the definition of Amorphinopsis and the type species of its synonym Nailondria , N. maza de Laubenfels, which however has oxeas or strongyloxeas and styles for spicules (Erpenbeck and van Soest, 2002). The only other Amorphinopsis known from the Atlantic Ocean is A. atlantica Carvalho, Hajdu, Mothes and van Soest, which is usually grayish green and has oxeas and styles as spicules.