Desmanthus levii, Van Soest & Hajdu, 2000

Van Soest, Rob W. M. & Hajdu, Eduardo, 2000, New species of Desmanthus (Porifera, Demospongiae) with a discussion of its ordinal relationships, Zoosystema 22 (2), pp. 299-312 : 304

Desmanthus levii n. sp.

( Fig. 1 F-I)

HOLOTYPE. — NW side of Uva Island . W side of bay, Contreras Islands, Gulf of Chiriqui , Pacific coast of Panama, on boulders, 5 m, coll. W. H. de Weerdt, # 12-XII-90 -1-1 ( ZMA POR13398 ).

PARATYPE. — NW side of Uva Island . Rocky Point, Contreras Islands , Gulf of Chiriqui , Pacific coast of Panama, on fishing net, 3 m, coll. W. H. de Weerdt, # 10-XII-90 -1-1 (on verongid) ( ZMA POR13399 ).

ETYMOLOGY. — Named in honor of Prof. Claude Lévi in recognition of a lifetime devoted to sponge biology.

DISTRIBUTION. — Pacific coast of Panama, shallow water, 3- 5 m.

DESCRIPTION

Thin crusts, up to 1 mm in thickness, covering up to 20-25 cm 2 in area (only a few cm 2 were collected). Colour bright orange. Surface smooth, fine-grained, no special markings were noted. Structure compact.

Skeleton

In dehydrated sections ( Fig. 1F ), the surface appears pierced by the numerous curved styles which stand erect between the rhabdomes of desmas II. Some styles may lie loosely, tangentially to the surface. The choanosomal skeleton is composed of a thin basal layer of desmas I with moderate zygosis. On top of this layer is a thick continuous layer or alternatively several layers of desmas II. The upper layer or most proximally situated desmas II have some of the rhabdomes (see arrows in Fig. 1F ) protruding beyond the surface among the styles. All cladomes are facing down.

Spicules

Smooth desmas I ( Fig. 1H ), with thin multiply branched cladi, dimensions: 90-112 × 5-10 µm (n = 12). Smooth, more robust desmas II ( Fig. 1G ), with cladomes strongly concave and strongly tuberculate, dimensions: 94-136 × 12- 20 µm. Rhabdomes conical and fairly straight, mostly smooth, dimensions: 47-141 × 15-23 µm. Smooth, curved, relatively thin styles ( Fig. 1I ), thicker at the base, with sharp points, most often slightly bent on the basal part, dimensions variable but in single size category, dimensions: 136- 460 × 4-12 µm.

REMARKS

This species resembles D. rhabdophorus ( Hentschel, 1912 as Lophacanthus ) and D. meandroides n. sp. in many morphological aspects, and it is likely they are closely related. Its specific characters are the distinctly smaller desmas I which are concentrated in an unusually thin layer at the base, and the rhabdomes of desmas II which are on average shorter than those of the other two species. In view of this, it is unlikely that D. levii n. sp. constitutes a disjunct population of either of these.

Figures

FIG. 1. — A-E, Desmanthus meandroides n. sp.; A, habit of holotype, MNRJ 341, photographed in situ; B, from holotype, partly cleaned section of desma II skeleton showing forest of outward-pointing rhabdomes; C, from holotype, desma II showing prominent rhabdome; D, from holotype, desma I; E, from holotype, style; F-I, Desmanthus levii n. sp.; F, from holotype ZMA 13398, uncleaned section shown sideways. Arrows indicate desma II rhabdomes protruding into the surface membrane among the styles; G, from holotype, desma II showing prominent rhabdome and concave cladome; H, from holotype, desma I; I, from holotype, style (scale bar: bar shared with Fig. 1E = 100 µm). Scale bars: A, 1 cm; B-I, 100 µm.