Kebira, Row, 1909

Van, Rob W. M. & De, Nicole J., 2018, Calcareous sponges of the Western Indian Ocean and Red Sea, Zootaxa 4426 (1), pp. 1-160 : 144-146

Kebira spec.

Figs 90a–g

Material examined. ZMA Por. 10379b, Seychelles, Mahé, E coast, N of Moyenne Island, 4.6167°S 55.5167°E, depth 1–7 m, reef, snorkeling, coll. R.W.M. van Soest, field nr. NIOP-E stat. 606, 10 December 1992.

Description. The specimen is small and tubular ( Fig. 90a ), about 1.5 cm high, 0.5 cm in diameter, with a narrow apical oscule. Color in alcohol dirty white. Surface smooth and shining, due to a thick surface armor of tangential giant diactines.

Aquiferous system. Leuconoid.

Skeleton. In cross section there is a thin cortical layer of triactines with long unpaired actines carried by a thick mass of tangentially arranged giant diactines. The choanosome is a mass of triactines traversed in places by short tracts of nail-shaped triactines. The atrial skeleton is a layer of tri- and tetractines with short unpaired actines and straight paired actines.

Spicules. ( Figs 90b–g ) Giant diactines, nail-shaped triactines, large triactines with long unpaired actines, small tri- and tetractines with short unpaired actines.

Giant and smaller diactines ( Figs 90b ), fusiform, curved, 105– 869 – 2520 x 7.5– 37.1 –84 µm.

Nail-shaped triactines ( Figs 90c,c 1 ), fusiform, with one end poined and the opposite end with two tiny actines, usually more or less symmetrical; unpaired actine 252– 503 –781 x 8.5– 9.9 –12 µm, paired actines 3– 6.8 – 15 x 2.5– 4.2 –6 µm.

Triactines with long unpaired actines and flaring paired actines ( Fig. 90d ); unpaired actines 292– 348 –384 x 10 – 17.8 –24 µm, paired actines 226– 297 –342 x 9 – 18.4 –23 µm.

Tetractines ( Fig. 90e ), with short unpaired actines and straight paired actines; unpaired actines 31– 49 – 61 x 8 – 10.3 –12 µm, paired actines 69– 192 –231 x 8 – 11.6 –14 µm, apical actines 3– 25 – 32 x 3 – 7.9 –10 µm.

Triactines ( Fig. 90f ), with short unpaired actines and straight paired actines; unpaired actines 30– 46 – 63 x 7 – 10.3 –12 µm, paired actines 71– 188 –234 x 8 – 10.9 –12 µm.

Distribution and ecology. Seychelles, shallow-reef locality.

Remarks. Although this specimen shares the possession of atrial tetractines with Kebira tetractinifera sp.nov., it shares also features with K. uteoides such as a dense layer of tangential diactines, twice as long as those of K. tetractinifera sp.nov. Further research is necessary to establish the value of these features for distinction of additional taxa in Kebira .

Unfortunately, our attempt to obtain a 28S sequence of the specimen failed.

Figures

FIGURE 1. Marine Ecoregions in the Western Indian Ocean with localities (numbered blue squares) from where the studied calcareous sponges were obtained. 1, Israelian Red Sea, Gulf of Aqaba, 2, Saudi Arabian Red Sea, off Jeddah, 3, Eritrean Red Sea, Dahlak Archipelago, 4, Oman, Gulf of Arabia, 5, Maldives, 6, India, Lakshadweep, 7, Seychelles, Mahé region, 8, Seychelles, Amirantes, 9, Mayotte, 10, Mozambique Channel, 11, Mauritius, 12, Rodrigues, 13, South Africa, Kwazulu Natal, 14. South Africa, Port Elizabeth, 15. Nosy Be, Madagascar.

FIGURE 90. Kebira spec., ZMA Por. 10379b, from the Seychelles, a, habitus (scale bar = 1 cm), b–f, SEM images of the spicules, b, giant diactine, c, nail-shaped triactines, c1, details of nail-shaped triactines, d, large triactine with long unpaired actine, e, tetractine with short unpaired actine, f, triactine with short unpaired actine.