Clathrina Gray, 1867

Klautau, Michelle & Borojevic, Radovan, 2001, Sponges of the genus Clathrina Gray, 1867 from Arraial do Cabo, Brazil, Zoosystema 23 (3), pp. 395-410 : 398-400

Genus Clathrina Gray, 1867

TYPE SPECIES. — Grantia clathrus Schmidt, 1864 by monotypy.

DIAGNOSIS. — Clathrinidae in which the choanoderm is flat or occasionally raised up into conuli by the apical actines of large tetractines, but it never forms true folds, at least when the sponge is in the extended state. The cormus is composed of anastomosed tubes. The skeleton contains regular, equiangular and equiradiate triactines and/or tetractines, to which diactines or tripods may be added ( Borojevic et al. 1990).

Clathrina ascandroides Borojevic, 1971 ( Fig. 2 ; Table 1)

Clathrina ascandroides Borojevic, 1971: 527 , figs 6; 7.

TYPE MATERIAL. — Holotype, attached to Laminaria brasiliensis , coll. by H. de Souza Lima, Museu Nacional do Rio de Janeiro ( MNRJ 2096 ).

TYPE LOCALITY. — Cabo de São Tomé, Rio de Janeiro, Brazil.

MATERIAL EXAMINED. — Oasis Coralino. Harbour, Forno and Pedra Vermelha, several specimens collect- ed in crevices or under rocks held together by the soft coral Palythoa sp. , 1 to 3 m depth.

DESCRIPTION

Specimens of this species are white in life but become brown in alcohol or when frozen. The cormus is composed of large, loosely anastomosed tubes, which are free in the apical region. Oscula are spread through the tubes and there are no water-collecting tubes. The histological sections showed no special characteristics.

The skeleton is composed of triactines and two populations of tetractines ( Fig. 2 ), the triactines being the most abundant spicules. Spicules ( Table 1) are equiangular and equiradiate, but parasagittal spicules can also be found. The triactines and the smaller tetractines are of the same size. Their actines are cylindrical or slightly conical with a sharp end. These small spicules are localised outside the tubes, giving them a smooth surface. The apical actine of the tetractines is conical, smooth, thinner and shorter than the facial actines. It projects inside the tubes. The large tetractines surround the interior of the tubes, and also project their apical actines into the central lumen. Actines are conical and sharp; the apical actine is straight and smooth, shorter than the basal ones, with very sharp and thin end. The habitat of this species is sciaphilous, and it can be easily found under rocks in the Oasis Coralino, in summer.

REMARKS

Clathrina ascandroides was first described in 1971 by Borojevic, who found some specimens of this species attached to Laminaria brasiliensis , from Cabo de São Tomé (Rio de Janeiro). This species is very similar to C. atlantica , although it differs from that species in the absence of diactines. In the original description, Borojevic (1971) did not distinguish between the two populations of tetractines ( Table 2).

Later on, Borojevic and Peixinho (1976) cited this species from the Northeast of Brazil and, at that time, they distinguished between the two tetractine populations ( Table 2).

In 1987, Borojevic and Boury-Esnault widened the distribution of C. ascandroides , describing it from the Bay of Biscaye, France ( Table 2), which gave to this species an amphi-atlantic distribution.

Figures

FIG. 2. — Clathrina ascandroides Borojevic, 1971, spicules. Abbreviations: tr, triactines; te, tetractines; lte, large tetractines. Scale bar: 200 µm.