Mycale (Zygomycale) angulosa (Duchassaing & Michelotti, 1864)

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 162-163

Mycale (Zygomycale) angulosa (Duchassaing & Michelotti, 1864)

Figures 101 a–j

Restricted synonymy:

Pandaros angulosa Duchassaing & Michelotti, 1864: 89 , pl. IX fig. 4.

Zygomycale parishi ; De Laubenfeld 1956: 3 (Not: Rhaphiodesma parishi Bowerbank, 1875 ) Mycale (Aegogropila) angulosa ; Van Soest 1984: 16, pl. I figs 5–6, text-fig. 3 (with additional synonyms). Mycale (Zygomycale) angulosa ; Van Soest & Hajdu 2002: 688; Muricy et al. 2011: 158.

Material examined. RMNH Por. 9947, Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station F46, 6.312°N 56.57°W, depth 25–29 m, bottom sand, 7 May 1966 .

Description. Irregularly ramose ( Fig. 101 a), with shorter or longer partially creeping branches, 3 cm or more in length, 0.5–1 cm in diameter, forming masses of up to 4 x 4 x 2 cm. Color in alcohol pale brown. Surface irregular, covered with small lobes occasionally bearing small oscules (<1 mm). Consistency soft to slightly firm.

Skeleton. The surface skeleton ( Fig. 101 b) is of the Aegogropila type, with tangentially intercrossing spicule tracts of 30–90 µm in diameter containing 7–12 spicules in cross section. Anisochelae I form rosettes. Choanosomal skeleton irregularly reticulate, with strong spicule tracts of 150–200 µm in diameter.

Spicules. ( Figs 101 c–j) Styles, anisochelae, isochelae, sigmas, toxas, trichodragmas.

Styles ( Figs 101 c,c1), fusiform, tapering gradually to rounded and pointed opposite ends, no obvious constriction or tyle, size 294– 316 –342 x 8 – 9.3 –11 µm.

Anisochelae, in two distinct size categories, (1) anisochelae I ( Fig. 101 d), robust, with long free shaft and short lower alae, 47– 51.1 –59 µm, and (2) anisochelae II ( Fig. 101 e), robust, with short free shaft and long upper alae, 18– 21.7 –26 µm.

Isochelae ( Fig. 101 f), uniform in shape and size, thin, elongate, 11– 12.2 –14 µm.

Sigmas in two size categories, (1) large, robust ( Fig. 101 g), 74– 82.2 –92 µm, and (2) small, thin (rare) ( Fig. 101 h), 30– 34.0 –36 µm.

Toxas ( Fig. 101 i), with shallow curve and upturned apices, occurring in toxodragmas ( Fig. 101 i1), length 25– 63.8 –84 µm, dragmas 5–7 µm in thickness.

Trichodragmas ( Fig. 101 j), 24– 33.1 – 42 x 6 – 7.7 –9 µm.

Distribution and ecology. Guyana Shelf, Virgin Islands, Cuba, Jamaica, Curaçao, NE Brazil, in mangroves, bays and on soft bottoms at 1–58 m depth ( Guyana Shelf 25–29 m).

Remarks. Shape and spicule sizes match closely with previous descriptions of this common species. A similar sister species, M. (Z.) sierraleonensis Van Soest, Beglinger & De Voogd, 2014 , was recently described from Sierra Leone in the East Atlantic. It spicules are almost identical in shape and size, but it has a third size category of sigmas. The present specimen confirms this difference.

Figures

FIGURE 101. Mycale (Zygomycale) angulosa (Duchassaing & Michelotti, 1864), a, habitus of RMNH Por. 9947 (scale bar = 1 cm), b, light microscopic image of surface skeleton, c – j, SEM images of the spicules, c, style, c 1, details of c, d, anisochela I, e, anisochela II, f, palmate isochela, g, large sigma, h, small sigma, i, toxa, i 1, toxodragma, j, trichodragma.