Suberea etiennei, 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 : 37-38

Suberea etiennei n. sp.

( Figs 17 A–C)

Holotype. CASIZ 180255, Clipperton Island Expedition 1994, NE side, 15 m, coll. R.J. van Syoc nr. RVS–221, 18 –04–1994.

Paratype MNHN DCL 4045–C, Jean-Louis Etienne Expédition Clipperton 2005, station 13, 32 m, on dead corals, 18–01–2005, 1 specimen.

Paratypes MNHN DCL 4049–B, Jean-Louis Etienne Expédition Clipperton 2005, station 42, 8 m, on dead corals, 31–01–2005, 2 specimens.

Paratypes MNHN DCL 4050–C, Jean-Louis Etienne Expédition Clipperton 2005, station 42, 8 m, on dead corals, 31–01–2005, 2 specimens.

Paratypes MNHN DCL 4052–C, Jean-Louis Etienne Expédition Clipperton 2005, station 42, 8 m, on dead corals, 6–01–2005, 7 specimens.

Paratypes MNHN DCL 4053–F, Jean-Louis Etienne Expédition Clipperton 2005, station and depth not recorded, on dead corals, 2 specimens. ( Fig. 17 A).

Description. Thickly encrusting to lumpy sponges with surface provided with sharp conules ( Fig. 17 A). Consistency barely compressible, tough. Size of encrusting patches up to 5 x 4 cm, lumpy parts may be elevated up to 1 cm. No apparent oscules (preserved material). Conules approx. 0.5 mm high, 1–1.5 mm apart, with supporting fiber endings often protruding. Color reddish brown to violet-black (live color unknown, likely to be altered by aerophobic reaction, as is usual for the genus).

Skeleton. Low proportion of pithed fibers compared to the soft tissue. Fibers ( Fig. 17 B) following a dendritic course, dividing dichotomously or trifold at irregular distances as much as 2 mm or more. Near the surface, fiber divisions are more frequent and the endings support the surface conules. Fibers relatively thin for the genus, 55–97 µm in diameter over much of their length but petering out to the pointed ending of approx. 30 µm diameter. Bark making up approx. 15–20 % of the fiber diameter and strongly laminated ( Figs 17 B–C).

Soft tissue. Although no properly fixed material was available, distributions of cells suggest small rounded choanocyte chambers of 20–25 µm diameter.

Etymology. Named after Jean-Louis Etienne, the leader of the 2004/5 Expedition to Île Clipperton, who brought the significant collection of Clipperton sponges to the Muséum national d’Histoire naturelle, Paris.

Ecology. Encrusting dead corals in deeper parts of the reef.

Remarks. The new species conforms in all major aspects to the genus Suberea , including sprawling conulose shape, high organic vs. fiber ratio, dendritic fiber system of pithed fibers with modest bark component, and probable aerophobic color change. Among the species of Suberea the new species stands out by its relatively thin fibers. Suberea is so far confined to the Indo-Pacific, and one species has been reported from East Pacific waters, Suberea azteca ( Gomez & Bakus, 1992 as Aplysina ). This differs clearly from our new species in having an elaborate stalked shape and occasionally anastomosing fibers forming irregular large meshes. This feature seems to exclude it from Suberea proper. Nearly all other Suberea species have much thicker fibers than our new species, usually well over 200 µm diameter. Only Suberea creba Bergquist, 1995 from New Caledonia shows some similarities, as its fibers are ‘only’ 120–250 µm diameter, approx. twice as thick as those of the Clipperton species. The surface of S. creba is described and pictured as mostly smooth, lacking the dense conulose aspect of the new species.

Figures

FIGURE 17. Suberea etiennei n. sp. A. one of the paratypes MNHN DCL 4053 – F, habit encrusting a coral, B. fiber of the same, scale bar = 100 µm, C. fiber detail of holotype CASIZ 180255, scale bar = 50 µm.