Clathrina aspina Klautau, Solé-Cava & Borojevic, 1994

Klautau, Michelle & Borojevic, Radovan, 2001, Sponges of the genus Clathrina Gray, 1867 from Arraial do Cabo, Brazil, Zoosystema 23 (3), pp. 395-410 : 401

Clathrina aspina Klautau, Solé-Cava & Borojevic, 1994

( Fig. 3 ; Table 3)

Clathrina aspina Klautau et al., 1994: 373 , tabs 1; 2, fig. 4.

TYPE MATERIAL. — Holotype, 13.VI.1987, coll. G. Muricy, The Natural History Museum, London ( BMNH 1999.9.16.3).

TYPE LOCALITY. — Arraial do Cabo (Gruta Azul), Rio de Janeiro, Brazil.

ETYMOLOGY. — From the Latin spina: spine; a, from the Greek prefix of negation. For the absence of spines in the apical actine.

MATERIAL EXAMINED. — Upwelling Area. Gruta Azul and Oasis Coralino. Forno, Enseada, several specimens collected on the walls of a cave.

DESCRIPTION

Specimens of this species have a white compact cormus in life and in alcohol. It is composed of thin, regular and tightly anastomosed tubes. Oscula are simple apertures surrounded by a thin membrane. They are localised on the top of conical projections distributed throughout the cormus and receive the excurrent water from water-collecting tubes ( Fig. 3A ). In fixed specimens it is difficult to recognise the oscula. No special characteristic was found on the histological sections.

The skeleton is composed of triactines, tetractines and tripods ( Fig. 3B ). Triactines and tetractines are equiangular and equiradiate, but parasagittal spicules are also present. They have no special organisation. Actines are conical and blunt at the end. The apical actine of the tetractines ( Fig. 3C ) is shorter and thinner than the facial ones ( Table 3), conical, sharp and smooth. It is always projected into the lumen of the tubes. Tripods are mainly large conical triactines in the holotype, however, typical tripods ( Fig. 3D ), with a raised centre and conical actines can be found in other specimens of C. aspina . They are localised on the external tubes, delimiting the cormus.

C. aspina has sciaphile habitat, being found in caves, crevices and under the soft coral Palythoa sp. It is abundant in the Oasis Coralino and in the upwelling habitat of the Gruta Azul.

REMARKS

C. aspina is very similar to another species found in Arraial do Cabo, C. brasiliensis . Both species have the same cormus organisation and the same type of spicules. However, the apical actine of the tetractines of C. brasiliensis is covered with spines, while in C. aspina the apical actine is smooth. We have already compared specimens from both populations using allozyme electrophoresis ( Klautau et al. 1994), and our results showed that, even when living in sympatry, there is no gene flow between them.

Figures

FIG. 3. — Clathrina aspina Klautau et al., 1994; A, underwater photo by E. Hajdu; B, spicules, holotype (BMNH 1999.9.16.3); C, api- cal actine of the tetractines (arrow), holotype; D, spicules, another specimen. Abbreviations: tr, triactines; te, tetractines; lte, tripods as large triactines. Scale bars: A, 1 cm; B, D, 100 µm; C, 50 µm.