Sponges from Clipperton Island, East Pacific Author Van, Rob W. M. Author Kaiser, Kirstie L. Author Syoc, Robert Van text Zootaxa 2011 2839 1 46 journal article 10.5281/zenodo.320220 1866626c-f527-402a-8449-b0618086da67 1175-5326 320220 Sycettusa aff. sibogae ( Burton, 1930 ) n.comb. ( Figs 19 A–H) Grantessa sibogae Burton, 1930 : 4 . Material examined. MNHN DCL 4045–D, Jean-Louis Etienne Expédition Clipperton 2005, station 13, 32 m , on dead corals, 18–01–2005 , 2 specimens . MNHN DCL 4057, Jean-Louis Etienne Expédition Clipperton 2005, station 5, 17 m , on dead corals, 10–01– 2005 , 1 specimen . ( Fig. 19 A). MNHN DCL 4064, Jean-Louis Etienne Expédition Clipperton 2005, station 40, 20 m , on dead corals, 29–01– 2005 , 1 specimen . Examined for comparison: Holotype , ZMA Por. 0 0 148, Siboga Exped. stat. 0 77, Indonesia , Borneo Bank, Makassar Strait, 3.45°S 117.6°E , depth 59 m , 10–06–1899 . Description. A clustered mass of tubes ( Fig. 19 A), the largest 5 x5x 2 cm, individual tubes up to 1 cm long and 0.5 cm in diameter. Color (alcohol) pale yellow-brown. Skeleton. Compressed syconoid without articulation ( Fig. 19 B). The thin cortex is made up of the actines of cortical equiangular triactines, the choanosome is made up of the unpaired actines of the subcortical larger sagittal triactines; atrial skeleton likewise made up of the paired actines of smaller equiangular triactines. Spicules. Triactines only ( Fig. 19 C). These are quite diversified, basically divisible in (1) equiangular triactines, large ( Fig. 19 D), with actines up to 530 x 47 µm, and small ( Fig. 19 E) up to 164 x 19 µm, and (2) unequiangular triactines which often have downcurved or upcurved paired actines, consisting of large triactines ( Fig. 19 F) with paired actines up to 290 x 38 and unpaired actine up to 525 x 45 µm, and small triactines ( Fig. 19 G) with paired actines up to 47 x 7 and unpaired actine 90 x 9 µm. There are also atrial intercrossing trichoxeas ( Fig. 19 H), invariably broken, largest unbroken fragment: 240 x 1.5 µm. Ecology and distribution . Encrusting dead corals in shallow reefs; if conspecific with the Indonesian material the species is known from Île Clipperton and the Makassar Strait region. Remarks. The genus Sycettusa unites former Grantessa species lacking an articulated skeleton ( Borojevic et al. 2002 ). The species Grantessa sibogae Burton (1930) was synonymised with the apparently widespread Indo- Pacific species Sycettusa sycilloides ( Schuffner, 1877 as Sycortis ) by Burton (1963) without further comments. For that reason and because Schuffner’s material was from East Africa ( Mauritius ) we prefer to retain Sycettusa sibogae n.comb. as a distinct species. The type of S. sibogae n.comb. (ZMA Por. 00148) from Makassar Strait, Indonesia , is a single tube and the large triactines have their rays somewhat more curved than in our material but spicule sizes and categories match to a large extent. The possibility that the Clipperton specimens belong to a closely related but distinct species cannot be entirely excluded. For that reason we added ‘ aff .’ to the species identification. Sycettusa tenuis Borojevic & Klautau (2000) from New Caledonia differs from the present material in possessing atrial tetractines and lacking the subdivision in larger and smaller triactines.