Penares chelotropa Boury-Esnault, 1973

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 90-91

Penares chelotropa Boury-Esnault, 1973

Figures 56 a–g

Penares chelotropa Boury-Esnault, 1973: 271 , text-fig. 10; Muricy et al. 2011: 41, fig. 5E.

Material examined. RMNH Por. 9368, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 107, 7.7°N 57.5°W, depth 65 m, bottom muddy sandy with shells, 5 September 1970 .

Description. ( Fig. 56 a) Reddish brown (in alcohol), finger-shaped, or fused and then flattened erect lobes, with smooth surface without visible openings. Length of ‘fingers’ up to approximately 2 cm, diameter of individual fingers 0.5 cm, fused ones about 1 cm or slightly thicker. Internal color yellow. Consistency firm, choanosome crumbly.

Skeleton. At the surface there is a dense crust of crowded microrhabds, forming an outer layer of about 250–350 in thickness, carried by the cladomes of a subsurface layer of orthotriaenes. The dense crust is pierced regularly by small rounded openings at distances of about 200 µm, presumably these are oscules, diameter 50–120 µm. Choanosomal skeleton consisting mostly of oxeas, which form axial bundles verging toward the surface. Euasters are strewn among the bundles and loose oxeas.

Spicules. ( Figs 56 b–g) Oxeas, short-shafted orthotriaenes, oxea-like microrhabds, euasters.

Oxeas ( Figs 56 b–d), in two size categories, all fusiform and slightly curved, (1) larger ( Figs 56 b,b1), 544– 604 –712 x 9 – 13.0 –16 µm, (2) smaller ( Figs 56 c,c1,d,d1), 127–196–249 x 3.5–6.4–10 µm.

Orthotriaenes ( Figs 56 e), in a large size range, calthrops-like because rhabds and cladi are approximately equally long, but distinguishable because the rhabds are straight, and the cladi often have their ends curved or sometimes slightly crooked; rhabdomes, 112– 223 –354 x 8 – 13.4 –18 µm, cladomes 192– 316 –452 µm, cladi 84– 181 –256 x 7 – 11.6 –15 µm.

Microrhabds/microxeas ( Figs 56 f), curved, sharply pointed, oxea-like, but occasionally with a swollen central part, in a large size range but not easily divisible in size categories, 42– 68 – 99 x 1.5– 2.4 –3.5 µm.

Euasters ( Figs 56 g), quite variable in size and shape, rays thin and lightly spined, resembling strongylasters or occasionally tylasters, but are best classed as oxyasters because the ray apices are mostly pointed, 9– 16.9 –23 µm, ray number 4–12.

Distribution and ecology. Guyana Shelf, Northeast Brazil, soft bottom, at 42–65 m depth.

Remarks. The present specimens are quite similar in shape, size, and spicule details, to the holotype of P. chelotropa , so this identification is made with confidence. Boury-Esnault (1973, p. 272, left hand column) names the asters tylasters, but as stated above, the endings of the spicules under SEM are pointed, even though the spines of the rays are more concentrated at the ends causing the spicules to look sometimes like tylasters in light microscopy.

Figures

FIGURE 56. Penares chelotropa Boury-Esnault, 1973, a, habitus of RMNH 9368 (scale bar = 1 cm), b – g, SEM images of spicules, b, large oxea, b 1, details of b, c – d, small oxeas, c 1 and d 1, details of c and d, e, orthotriaenes, f, microrhabds / microxeas, g, oxyasters.