Characella poecillastroides Van Soest, Meesters & Becking, 2014

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 101-102

Characella poecillastroides Van Soest, Meesters & Becking, 2014

Figures 62 a–g

Characella poecillastroides Van Soest et al., 2014: 410 , figs 6a–d, 7a–e.

Material examined. RMNH Por. 9822, Suriname, ‘Luymes’ Guyana Shelf Expedition, station 1, 7.1667°N 53.5833°W, depth 104–130 m, bottom sandy calcarenite, 24 August 1970 .

Description. Two fragments of a flattened sponge ( Fig. 62 a), overall size 11 x 7 x 2 cm. Surface smooth where not overgrown by a other sponges, but rough and hard in exposed places. Color in alcohol yellowish beige.

Skeleton. Ectosomal skeleton with a crust of acanthomicroxeas, carried by bundles of long oxeas and confusedly arranged plagiotriaenes. Choanosome with confused mass of spicules. The surface bears a crust of Parahigginsia cf. strongylifera (see above).

Spicules. ( Figs 62 b–g) Oxeas, plagiotriaenes, amphiasters, acanthomicroxeas.

Oxeas ( Figs 62 b,b1) fusiform, curved, rather abruptly pointed, quite variable in length, 1350– 1943 –2450 x 34 – 55.2 –71 µm.

Plagiotriaenes ( Fig. 62 c), short-shafted, but usually the rhabd and the cladi are distinct, rhabdomes 294– 397 –520 x 24 – 29.5 –36 µm, cladomes 288– 334 –390 µm, cladi 126– 185 –234 x 23 – 26.2 –30 µm,

Amphiasters ( Fig. 62 d), with relatively robust and finely spined rays, overall diameter 16– 18.2 –21 µm.

Acanthomicroxeas ( Figs 62 e–g), in two to three size categories, (1) larger ( Figs 62 e,e1) 210–256–282 x 5 – 6.0 –6.5 µm, (2) intermediate ( Fig. 62 f), rare (n=4) 76–172 x 2–3 µm and (3) small ( Fig. 62 g) 34– 43 – 51 x 2.5– 3.1 –3.5 µm.

Distribution and ecology. Guyana Shelf, Bonaire, sandy and rocky bottoms at 104–168 m depth.

Remarks. The fragments reported here are closely similar in habit and spicules to the type. The plagiotriaenes are slightly smaller and there is a rare middle-sized acanthomicroxea (70–170 µm), which is not reported from the type.

The surface is encrusted by what appears to be a Parahigginsia rather similar to what was recently described as P. strongylifera , because of the possession of the characteristic acanthomicroxeas with thin erect spines. See above for a description and discussion. Remarkably, instead of strongyles, the spicules are thickly fusiform oxeas arranged in a confused reticulation. These spicules are also shorter, 171–204 x 9–14 µm than the strongyles of the type (290–370 x 10–18 µm). It remains to be decided whether the present encrustation falls within the variation of P. strongylifera .

Puerto Rican Characella enae ( De Laubenfels, 1934) (as Neothenea , p. 5), (type specimen USNM 22321, slide re-examined), shows a general similarity to C. poecillastroides . It has a flabellate shape, but its megascleres are consistently much longer and thicker than those of C. poecillastroides : oxeas up to 12 mm x 106 µm, plagiotriaenes and dichotriaenes (not found in C. poecillastroides ) with cladi similarly up to 100 µm in thickness, amphiasters are 25–30 µm and acanthomicroxeas show less differentiation in size categories.

Figures

FIGURE 62. Characella poecillastroides Van Soest, Meesters & Becking, 2014, a, habitus of RMNH Por. 9822 (scale bar = 1 cm), b – g, SEM images of spicules, b, oxea, b 1, details of b, c, plagiotriaene, d, amphiaster, e, large acanthomicroxea, e 1, details of e, f, intermediate acanthomicroxea, g, small acanthomicroxea.