Topsentia bahamensis Diaz

Ugalde, Diana, Gómez, Patricia & Simões, Nuno, 2015, Marine sponges (Porifera: Demospongiae) from the Gulf of México, new records and redescription of Erylus trisphaerus (de Laubenfels, 1953), Zootaxa 3911 (2), pp. 151-183 : 166-167

Topsentia bahamensis Diaz , van Soest & Pomponi, 1993

( Fig. 12 A–C)

Synonymy: Topsentia bahamensis Diaz , van Soest & Pomponi, 1993:290.

Material examined. CNPGG –586 Sisal Banks reefs (21°26'21.50”N 90°17'7.9”W), depth 15 m 02/XII/2011.

Description. Encrusting to massive sponge (3.5 × 2.5 cm long per width, 2.5 cm thick) with one solid fistular growth on top 4 cm in height, 10 mm in diameter ( Fig. 12 A). An oscule along the fistula is visible, that splits at the base. Color is white when alive and in alcohol; surface is smooth although micro-hispid at places, consistency is firmly compressible but easily crumbled.

Skeleton. The ectosome is a layer of tangentially placed oxeas strewn in confusion, with many of the larger oxeas protruding beyond the surface. The choanosomal skeleton exhibits a vague reticulation in all directions, produced by ill-defined multispicular tracts with no trace of spongin, intermingled with single oxeas, also oriented in all directions, assembling a condensed mass ( Fig. 12 B).

Spicules. Fusiform and slightly curved oxeas ( Fig. 12 C), in two size categories I: 196–507 × 5.2–14 µm, II: 556–820 × 13.5–28 µm.

Distribution and ecology. Bahamas ( Díaz et al. 1993). The present specimen was found inhabiting shallower waters (15 m depth) than those of the original description, which stated 40 to 160 m. It is the first record for México and the Gulf of Mexico.

Remarks. The present material matches the original description exactly, even for spicule sizes. Apparently it is not a common species around the Caribbean Sea. It probably inhabits Jamaica ( Lehnert & Soest 1996), but the specimen recorded there, lacks fistular growth, which is one of the main features of T. bahamensis . A species similar to the present one is the widespread T. ophiraphidites (de Laubenfels de 1934), but it differs in lacking an ectosomal tangential skeleton, together with a gray, brown or pink color alive and the presence of two or three category sizes of oxeas and strongyloxeas. These traits separate both species.

Figures

FIGURE 12: Topsentia bahamensis Diaz, van Soest & Pomponi, 1993: A. Specimen preserved in alcohol; broken at half in lateral view. B. Longitudinal section of skeleton, with a wide choanosomal channel (centre down). C. Common oxeas in two size categories (LM).