Tethya sarai Desqueyroux-Faúndez & Van Soest, 1997

Van, Rob W. M., Kaiser, Kirstie L. & Syoc, Robert Van, 2011, Sponges from Clipperton Island, East Pacific, Zootaxa 2839, pp. 1-46 : 14-15

Tethya sarai Desqueyroux-Faúndez & Van Soest, 1997

( Figs 6 A–E)

Tethya sarai Desqueyroux-Faúndez & Van Soest, 1997: 424 , figs 119–124.

Material examined. ZMA Por. 13992, Clipperton Island Expedition 1994, 10 °18’N 109°13’W, 9–18 m, coll. K. Kaiser, 14–26 April 1994, 3 specimens.

ZMA Por. 13993, same collecting data, 1 specimen.

ZMA Por. 13994, same collecting data, 1 specimen.

ZMA Por. 13995, same collecting data, 1 specimen.

ZMA Por. 13996, same collecting data, 1 specimen.

ZMA Por. 13997, same collecting data, 1 specimen.

ZMA Por. 13999, same collecting data, 1 specimen.

CASIZ 103402, Clipperton Island Expedition 1994, E side, 10°18.53’N 109°11.98’W, 13.5 m, coll. R.J. van Syoc nr. RVS–235, 23 –04–1994, 1 specimen.

CASIZ 103404, Clipperton Island Expedition 1994, SE corner, 10°17.02’N 109°12.79’W, 12 m, coll. R.J. van Syoc nr. RVS–238, 24–0–1994, 1 specimen.

CASIZ 180252, Clipperton Island Expedition 1994, aboard M/V Royal Star, 15 m, coll. R.J. van Syoc nr. RVS–242, 26 –04–1994, 3 specimens.

CASIZ 180253, Clipperton Island Expedition 1994, NE side, under coral flats, 9–10.5 m, coll. R.J. van Syoc nr. RVS–221, 18 –04–1994, 1 specimen.

CASIZ 180254, Clipperton Island Expedition 1994, NW side, 12 m, coll. R.J. van Syoc nr. RVS–225, 20 –04– 1994, 1 specimen.

MNHN DCL 4041–A, Jean-Louis Etienne Expédition Clipperton 2005, station 45, 22 m, 5–02–2005, 1 specimen.

MNHN DCL 4045, Jean-Louis Etienne Expédition Clipperton 2005, station 13, 33 m, on dead corals, 18–01– 2005, 1 specimen.

MNHN DCL 4062, Jean-Louis Etienne Expédition Clipperton 2005, station 25, 18 m, 17–01–2005, 2 specimens.

MNHN DCL 4063, Jean-Louis Etienne Expédition Clipperton 2005, station 10, 13 m, 17–01–2005, 1 specimen.

Description. Spherical sponges ( Fig. 6 A), dark grey in preserved condition, consistency hard (probably due to contraction), size up to 2 cm in diameter. Surface warty, but relatively smooth.

Skeleton ( Fig. 6 B). Consists of radiating bundles of megascleres, with a distinct peripheral cortical region of approximately 500–750 µm thick (preserved condition). The outer region of the cortex is a thin single layer of micrasters supported by a thicker layer of megasters. Below these layers is a collagenous region with a low density of microscleres traversed by megasclere bundles. The inner region of the cortex is formed by a dense layer of megasters. The choanosomal region consists of dense masses of radiating megasclere bundles, some of which end at the underside of the cortex while others traverse the cortex and fan out to form the surface warts. Numerous microscleres are dispersed among the choanosomal megasclere bundles; predominantly represented by megasters, but with a minority of strongylasters or tylasters similar in shape to the ectosomal micrasters, but slightly larger. Also found in most specimens are rare oxyasters.

Spicules. Strongyloxeas, micrasters and megasters.

Strongyloxeas ( Fig. 6 C) in two overlapping size categories, 456– 522 –624 x 4 – 7.8 –9 µm and 720– 945 – 1175 x 12–14 µm.

Megasters ( Fig. 6 D): Spherasters with a large centre and 20+ conical rays, in a large size range, but no size zonation is evident, 18– 41.7 – 66 µm, RC = 0.4 – 0.6 (index of length of rays divided by diameter of the centre).

Micrasters of the cortex, tylasters ( Fig. 6 E) 9–15 µm with approx. 8 rays; further into the interior similarly shaped asters are slightly larger than those at the surface, but appear morphologically identical. Choanosomal oxyasters ( Fig. 6 F) appear to be present but they are barely differentiated from micrasters in size and shape. They have oxyaster-like or strongylote morphology and are relatively rare, up to 28 µm, with approx. 10 rays.

Ecology and distribution. Under coral blocks and overhangs in the shallow reef down to 33 m; known from Île Clipperton and Galápagos Islands.

Remarks. The assignment of the present material to T. sarai is not without hesitation, as there are some differences in skeleton and spicule categories, and because the description of Desqueyroux-Faúndez & Van Soest (1997) is rather ambiguous. The most striking similarity is the occurrence of choanosomal micraster-like oxyasters/ strongylasters. These occur rarely in our material as well as in in Desqueyroux-Faúndez & Van Soest’s material. The Galápagos spicules are overall more robust, but overlap in size with the Clipperton spicules.

Tethya taboga ( De Laubenfels, 1936b as Taboga ) described from Panama has larger megascleres and larger choanosomal oxyasters. T. californiana de Laubenfels, 1932 described from California also has larger megascleres and lacks choanosomal oxyasters.

Bakus (1975) reported the occurrence of ‘ Tethya aurantia’ from Isla del Coco, but did not provide a description.

Sarà et al. (2001) described five new species from the Pacific coast of Mexico, all very similar to the Galápagos and Clipperton specimens, but they lack choanosomal oxyasters and four of these species differ from the present species in having strongyloxeas clearly much larger (see Table 3). Tethya deformis as reported by Desqueyroux- Faúndez (1990) from Easter Island has similar spicule sizes as T. sarai , but it lacks choanosomal oxyasters. Whether this material is conspecific with records of this species from Japan ( Thiele, 1898 as Donatia ), Chile ( Thiele, 1905 as Donatia papillosa ) and New Zealand ( Bergquist, 1968) as Desqueyroux-Faúndez (1990) suggested, remains to be further investigated.

Name Color strongyloxeas (µm) micrasters megasters oxyasters Locality

(diameter µm) (diameter µm) (diameter µm)

Tethya sarai Clip- cream or red- (1) 456–624 x 4–9 9–15 18–66 9 –28 Île Clipperton

perton material dish brown (2) 720– 1175 x 12– (RC=04–0.6) (alcohol) 14

Tethya sarai Desqu- cream (alco- 920–1500 x 20–30 8–15 38–90 21–28 Galápagos

eyroux-Faúndez & hol) (RC=not Islands

Van Soest, 1997 recorded)

Tethya socius Sara et pink (alcohol) 1700 x 30 8–12 60–118 not present Mexico

al., 2001

Tethya deformis orange (1) 9120987 x 13 – 13.5 54 (RC=not not recorded Easter Island

sensu Desqueyroux- 17 recorded)

Faúndez, 1990 (2) 1045–1386 x

21–29

Figures

FIGURE 6. Tethya sarai Desqueyroux-Faúndez & Van Soest, 1997. A. habit of specimens from sample ZMA Por. 13992, B. cross section of peripheral region showing the cortex and arrangement of megascleres and megasters, C. two sizes of strongyloxeas, D. two sizes of megasters, E. micraster of the ectosome, F. small oxyaster of the choanosome.