Amphimedon complanata ( Duchassaing 1850 )

Ugalde, Diana, Gómez, Patricia & Simões, Nuno, 2015, Marine sponges (Porifera: Demospongiae) from the Gulf of México, new records and redescription of Erylus trisphaerus (de Laubenfels, 1953), Zootaxa 3911 (2), pp. 151-183 : 174-175

Amphimedon complanata ( Duchassaing 1850)

( Fig. 18 A–C)

Selected synonymy: Spongia complanata Duchassaing, 1850:26 .

Haliclona (Amphimedon) complanata ; Wiedenmayer 1977:86.

Amphimedon complanata ; van Soest 1980:31; Alcolado 2002:68; Lehnert & van Soest 1998:91.

Material examined. CNPGG –1207 Sisal Banks reefs (21º26'28.3”N, 90º17'34.0”W), depth 10.5 m, 10/IX/2011. CNPGG –1208 Sisal Banks reefs (21° 26' 24”N 90° 28' 25.39”W), depth 6 m, 13/IX/2011. CNPGG –1285 Sisal Banks reefs (21º26'17''N 90º16'38''W), depth 9 m, 7/XI/2011.

Description. Mainly flabellate forms but flabellate-shape specimens with branches are also found ( Fig. 18 A). Dimensions up to 23 cm high and 12 cm in its widest width. Numerous oscules scattered on the surface, 1–3 mm in diameter. The surface is smooth to microhispid, and its consistency is very compressible and flexible when alive. The color is all white when alive, and creamy or beige in alcohol.

Skeleton. The ectosomal skeleton is a poorly developed paratangential reticulum. The choanosomal skeleton is a fibro-reticulum with a tendency to become fasciculate, composed by thin ascending fibres cored by 0–8 spicules per cross section. Primary fibres are 100–170 µm in diameter. These are interconnected by secondary fibres 8–25 µm in diameter, cored by 0–2 spicules. Rectangular to round meshes are 70–500 µm ( Fig. 18 B).

Spicules. Thin strongylotes 60–97 × 1–2.6 µm tapering towards the ends, approaching the shape of hastate oxea ( Fig.18 C). In places authentic hastate oxeas are seen.

Distribution and ecology. Bahamas ( Dendy 1890), Lesser Antilles (van Soest 1980); Jamaica (Lehnert & van Soest 1998), Florida ( Storr 1964); Cuba (Alcolado 2002). Amphimedon complanata inhabits particularly shallow coral reef environments. The specimens were collected in reef areas where the coral rubble and sea grass were abundant, in depths from 6 to 11 m. This finding is a new record for Mexico and the southern Gulf of Mexico.

Remarks. Amphimedon complanata exhibited a consistently white color when alive, but purple or black specimens may also occur ( Duchassaing & Michelotti 1864). Unfortunately van Soest (1980) and Wiedenmeyer (1977) did not recorded live color and they only cite the color reported by previous authors. Regarding the sponge habit, a massive encrusting shape is cited for Jamaica specimens ( Lehnert & Soest 1998), different from the massive-to-flabellate and the massive-to-ramose (with upright branches) shape, with a strong tendency towards flabelliform habit reported in Duchassaing & Michelotti (1864) and van Soest (1980) respectively, as well as in the presently described material. A different surface structure with deep depressions connected by ridges is described from the Jamaican specimen, contrasting with the smooth to microhispid surface described by Duchassaing & Michelotti (1864), van Soest (1980) and the present work.

Figures

FIGURE 18. Amphimedon complanata (Duchassaing 1850): A. Specimen with flabellate habit preserved in alcohol. B. Skeletal arrangement, ascending and connective fibres with a tendency to become fasciculate. C. Common thin strongylotes.