Aplysina orthoreticulata sp.n. (Figs. 21, 22 A)

Holotype: MNRJ 4651 (BA, 16º07'30'' S - 38º10'52'' W), 40 m depth, Programme REVIZEE Central V coll., 30/VI/2001.

Diagnosis: This is the only digitiform Aplysina with a surface covered by shallow depressions and having a skeleton made of an orthogonal reticulation of stout spongin fibres. The colour is beige with purple spots in vivo, turning into purple when preserved in ethanol.

Description

The specimen is a digitiform projection, 16 cm long and 1 cm in diameter (Fig. 21A), covered by shallow irregular depressions. It possesses many small oscula (0.1 cm across) restricted to the sides of the sponge. The diameter of the projections is mostly regular, with the exception of a constriction in the upper portion that reduces the sponge diameter to 0.5 cm. Fibers are observed projecting themselves perpendicularly from the surface of the sponge. The colour is beige with purple spots in vivo, turning completely purple when preserved in ethanol. Consistency very hard, incompressible.

Skeleton: Choanosome with an orthogonal reticulation of spongin fibers, resulting in small meshes (average 550 Μm) in which the fibers are organized perpendicularly to each other (Fig. 21B). The fibers possess a laminated bark with reddish colour and thickness of 100–307 Μm (average 184 Μm) and fine black or reddish pith, with thickness between 10 and 40 Μm (average 22 Μm; Fig. 21C).

Bathymetry: The only specimen was dredged at 40 m depth.

Distribution: Provisionally known only from the type locality off the State of Bahia (Brazil; Fig. 22 A). Etymology: The specific name orthoreticulata is derived from the new species’ orthogonal reticulation. Remarks: Aplysina orthoreticulata sp.n. presents a superficial resemblance to A. cauliformis (cf. above), both comprising digitiform branches of regular diameter. However, none of the currently recognized morphotypes of the latter (see above) possess their surface excavated by shallow depressions and the orthogonal reticulation, which is unique within the genus.