Ephydatia facunda Weltner, 1895

Pinheiro, U. S., Hajdu, E. & Correa, M. D., 2004, First description of gemmules of Ephydatia facunda Weltner, 1895 (Porifera, Haplosclerida, Spongillidae) by scanning electron microscopy, with underwater observations of a large population from north-eastern Brazil, Journal of Natural History 38 (9), pp. 1071-1080 : 1072-1074

Ephydatia facunda Weltner, 1895

(figures 3–11)

Ephydatia facunda Weltner, 1895: 140 ; Gee, 1930: 98, 1931: 38, 1932: 28; De-Rosa-Barbosa, 1979: 28; Volkmer-Ribeiro et al., 1981: 13; De-Rosa-Barbosa, 1984: 130; Volkmer-Ribeiro et al., 1988: 88; Volkmer-Ribeiro and Tavares, 1990:171.

Meyenia facunda: Penney, 1960: 48 .

Ephydatia ramsayi var. talaensis: Weltner, 1898: 331 ; Gee, 1931: 50, 1932: 32.

Meyenia ramsayi var. talaensis: Penney, 1960: 53 .

Ephydatia fluviatilis ramsayi (Haswell, 1882) ; Ezcurra-De-Drago, 1975: 168.

H   (not re-examined). ZMB 1773 , Ephydatia facunda type ‘ Zoologisches Museum, Berlin’ , 8 November 1892, Brazil, Rio Grande do Sul .

Studied material. Brazil, Alagoas, Barra de São Miguel, Rio Niquim ( River Niquim ; figure 1) . Coll. A. G. A. Borba Jr; MNRJ 2961 , 5 December 1999 ; MNRJ 4087 , 24 March 2001 . Coll. E. Hajdu; MNRJ 5194 , 5195 , 5196 , 5197 , 5198 , 7 September 2001 .

Description. Living specimens can be incrusting, cushion-like or globose (figures 3–5). Their surface can be nearly flat, or bear variably shaped projections. Most often these are irregularly volcaniform, but slightly digitiform ones were also seen; ridges, pits and grooves are very common, thus rendering their overall appearance very irregular. Largest specimens seen were around 20×20× 10 cm (width+depth+height). All specimens were very soft and fragile, easily crumbling down to several small pieces upon collection. Colour alive ranged between whitish, yellowish (more often) or greenish. A highly conspicuous dermal membrane was seen in every specimen, protruding in chimney-like oscules (up to 2–3 cm in diameter; figures 3, 5). Preserved specimens are light brown. Gemmules (388–442 Mm in diameter, seen in MNRJ-5196 only; figures 6–8) are rare and appear spread near the base of the sponges. They are roundish, with a relatively well-developed gemmular theca; where a palisade of erect gemmuloscleres is embedded (figure 8), their distal rotules nearly always pierce the outer gemmular membrane (figures 6, 7), a trait probably related to the shrinkage undergone through the drying process. For the same reason, no data can be furnished for the micropyle. Abundant whitish and roundish basal structures seen in situ in many specimens, at first thought to be gemmules, turned out to be concentrations of rectangular diatoms.

Skeleton: there is no sign of an ectosomal skeletal specialization in dried preserved specimens. The choanosomal architecture is an isodictyal reticulation of paucispicular tracts of oxeas and single oxeas, with a considerable amount of the same spicules strewn at random. Spicules: megascleres ( table 1): smooth or, more often, microspined oxeas (figure 9) with spines equally distributed over most of the surface of the spicule, absent from the extremities only (figure 10), slightly curved (normally), variably bent (less commonly) or straight (rare), length 262–470 Mm (mean 318 Mm), thickness 7–18 Mm (mean 12.3 Mm); microscleres: absent. Gemmuloscleres (figure 11): birotules with abundant spines (13–35) equally distributed over the whole shaft, spines with varied dimensions, all appearing to be simple, with a small basis, and pointing in various directions, length of the spicule 47–62 Mm (mean 53 Mm), thickness of the shafts 5–7.5 Mm (mean 5.5 Mm), diameter of the rotules 17–27 Mm (mean 23 Mm).

Ecology. Specimens occurred both on soft sediments (rare) as well as on every piece of hard substratum available (normally). The main concentration of specimens, hundreds in some 25–30 m 2, was observed on a sunken wood platform (figure 4) at 7–9 m depth, used as support for diving courses. Specimens occurred both on the wood substrata, as well as on the ropes and tyres used for flotation (keeping the platform slightly above the muddy floor). Water temperature was near 25°C, and visibility around 3– 5 m. The water was yellowish brown, thus indicating a considerable amount of dissolved organic matter. The surrounding area had small patches of Atlantic rain forest, but sugar cane and coconut plantations, as well as extensive farming for beef or dairy products predominate.