Leucascandra caveolata, Borojevic & Klautau, 2000

Borojevic, Radovan & Klautau, Michelle, 2000, Calcareous sponges from New Caledonia, Zoosystema 22 (2), pp. 187-201 : 200

Leucascandra caveolata n. sp.

( Figs 9; 10 )

TYPE MATERIAL. — Holotype MNHN-LBIM-C- 1999-05.

ETYMOLOGY. — The name refers to the honeycomb appearance of the internal surface of the sponge.

MATERIAL EXAMINED. — Many large specimens.

TYPE LOCALITY. — Passe de Nakéty, stn 303.

LOCALITIES. — This sponge is common on the east and south coasts of New Caledonia. Poindimié, south coast, stn 227, 15- 30 m. – South Lagoon , coral reefs Cineria, stn 263. – Passe de Nakéty, east coast, stn 303, 20 m ; idem north coast, south of the Grande Fausse Passe, 30 m.

DESCRIPTION

The sponge forms large cormi (up to 10 cm high) of a rather loose meshwork, composed of delicate tubes, the larger ones attaining nearly 1 cm in diameter. The smaller ones (in general no more than 2 mm in diameter) rise perpendicularly from the larger ones. They are ramified at the distal part, and occasionally anastomosed, bearing a naked osculum at the end (photos in Lévi 1998: 73; 79). They are brown red in life, but the alcohol-preserved specimens are white.

The wall of the tubes ( Fig. 9) is supported by a thin cortex, composed of triactines only, and a parallel atrial skeleton composed of tetractines. In both layers, most spicules are arranged in parallel, with the unpaired angle directed towards the osculum. The thin choanosome is only supported by the unpaired actines of the subatrial triactines ( Fig. 10 ). All the spicules are of a similar thickness.

Spicules ( Fig. 10 )

Cortical triactines, with slightly curved paired actines measuring 180 (± 50) / 20 (± 2) µm, and a shorter, straight unpaired actine, measuring 105 (± 28) / 20 (± 2) µm. The small subatrial triactines have a wide unpaired angle. The paired actines are curved in order to fit into the atrial skeleton. They measure 78 (± 9) / 15 (± 1.5) µm, while the straight unpaired one measures 85 (± 12) / 18 (± 2) µm. The atrial triactines and tetractines with the unpaired straight actine measure 382 (± 68) / 20 (± 2) µm, and the paired ones, 264 (± 26) / 21 (± 2) µm.

Figures

FIG. 10. — Leucascandra caveolata n. gen. n. sp. Transverse section. Note the choanoskeleton composed only of subatrial triactines (arrow head), and atrial skeleton containing triactines and tetractines (arrow). Scale bar: 30 µm.