Dysidea variabilis ( Duchassaing & Michelotti, 1864 )

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 : 177-178

Dysidea variabilis ( Duchassaing & Michelotti, 1864)

( Fig. 20 C–D; 22D)

Selected synonymy: Amphimedon variabilis Duchassaing & Michelotti, 1864:80 . Dysidea variabilis ; Wiedenmayer 1977:146; van Soest 1978:52.

Material examined. CNPGG –1217, CNPGG –1405 Alacranes reef (22º23’42.7”N, 89º42’20”W) depth 9 m, 1/ VIII/2009. CNPGG –1289 Alacranes reef (22º23’12.89”N, 89º40’44.72”W) depth 18 m, 13/XII/2011.

Description. It is a massive-globular sponge with several lobes of different sizes scattered over entire sponge ( Fig. 22 D). Lobules collapse when the sponge is out of the water. Overall size 10 cm high, 8.7 cm in width. Enveloped by a white ectosomal veil, and covered by a lot of sediment when alive. Oscules only on top of the sponge, 0.5–1.5 cm in diameter, surrounded by a thin and delicate membrane, which collapses in alcohol ( Fig. 20 C). The conules are not obvious under water but displayed when the sponge is out of the water; 1–4 mm in height. The consistency is compressible but crumbly. The color is light orange when alive, beige in alcohol.

Skeleton. The ectosome consists of a dense and irregular reticulation of fibres containing foreign material like sand and spicules. The choanosomal skeleton is made up by fibres 45–85 µm in diameter, stuffed with sand and spicules; it forms rectangular meshes ( Fig. 20 D), 120–170 µm in width.

Distribution and ecology. St. Thomas ( Duchassaing & Michelotti 1864); Florida (de Laubenfels 1936). The specimens were collected in coral reef environments, associated with dead coral, gorgonians and sponges, such as A plysina fistularis and A. cauliformis , between 9 and 18 m depth. This is the first record of the species in Mexico and the southern Gulf of Mexico.

Remarks. Dysidea variabilis was originally recorded red in color when alive ( Duchassaing & Michelotti 1864). Nevertheless, two colors have to be taken into account for the present species, the originally red and the orange color cited by de Laubenfels (1936), van Soest (1978), and the one described here. Rützler et al. (2009) register this species within the waters of the GMx, and attribute such information to de Laubenfels (1953). However, de Laubenfels does not mention this species in its work of 1953.

Figures

FIGURE 20. Hyatella cavernosa (Pallas, 1766): A. Specimen preserved in alcohol. B. Irregular polygonal reticulation of spongin fibres in choanosomal skeleton. Dysidea variabilis (Duchassaing & Michelotti, 1864): C. Specimen preserved in alcohol. D. Choanosomal arrangement consisting of an irregular reticulation made of foreign material like sand or spicules bound by spongin.

FIGURE 22. Sponges in situ: A. Dragmacidon reticulatum. B. Agelas tubulata. C. Chalinula molitba. D. Dysidea variabilis.