Clathrina passionensis, Van, Rob W. M., Kaiser, Kirstie L. & Syoc, Robert Van, 2011

Van, Rob W. M., Kaiser, Kirstie L. & Syoc, Robert Van, 2011, Sponges from Clipperton Island, East Pacific, Zootaxa 2839, pp. 1-46 : 38

Clathrina passionensis n. sp.

( Figs 18 A–E)

Holotype. CASIZ 180256, Clipperton Island Expedition 1994, E side, 9–12 m, coll. R.J. van Syoc, nr. RVS–235, 23 –04–1994, growing on a specimen of Spongia (Spongia) sweeti .

Description. Encrusting mass ( Fig. 18 A) of tightly anastomosing thin tubes, overall size 4 x 4 x 0.5 cm. The sponge encrusts a specimen of Spongia (Spongia) sweeti and it follows the irregular surface contours. Tube network forms a continuous sheet without elevations, but several larger oscules protrude slightly. Individual tubes ( Fig. 18 C) approx. 0.2 mm in diameter, meshes ( Fig. 18 B) approx. 0.5 x 0.2 mm. Water-collecting tubes are absent. Consistency fairly soft, easily damaged. Color dirty white (in alcohol).

Skeleton. Asconoid with a single layer of triactines and tetractines forming the tube walls.

Spicules. Triactines and tetractines variable in size, but not divisible in size categories, both generally of the same size. Rays conical with sharp points.

Triactines ( Fig. 18 D), equiangular, rays 27– 77.0 –117 x 4 – 8.6 –13 µm.

Tetractines ( Fig. 18 E), equiangular, facial rays 18– 67.8 – 99 x 5 – 7.8 –12 µm, apical rays shorter and sharply pointed, 27– 41 x 3–4 µm.

Etymology. Named after ‘ Isla de Pasión’, the original name for Île Clipperton.

Ecology. Encrusting sponges in shallow reef habitat.

Remarks. A recent monograph of Clathrina by Klautau & Valentine (2003) allowed us to compare the present species with descriptions of Clathrina from the Indo-Pacific. Among these are three species possessing both triactines and tetractines, and sharing the lack of diactines, trichoxeas or tripods with our new species, viz. Clathrina adusta Wörheide & Hooper, 1999 from the Great Barrier Reef, Clathrina gardineri Dendy, 1913 from the Western Indian Ocean and Clathrina africana Klautau & Valentine, 2003 from South Africa. Clathrina adusta is similar to our new species in habit, tube diameter, and tight anastomosis, but average / upper sizes of spicule rays (triactines 110 / 156, tetractines 111/192 µm) clearly exceed those of the Clipperton material. Furthermore, C. adusta changes color from white to brown in preservation, unlike our material. Clathrina gardineri likewise is similar, but its triactines are divisible in those with a smaller size category (rays 45–65 µm) and a larger size category (rays 87–137 µm). Clathrina africana has spicule characters closely similar to our new species, but it is dissimilar in habit as it is a loosely anastomosing network of coarser tubes. A further argument to keep the two distinct at the species level is the distance between Cape Town and Clipperton Island which is assumed to be too great for conspecificity.

Figures

FIGURE 18. Clathrina passionensis n. sp., holotype CASIZ 180256, A. habit encrusting a specimen of Spongia (Spongia) sweeti, scale bar = 1 cm, B and C. details of surface, scale bar = 100 µm, D. triactine, E. tetractine.