Tethya simi, Sarà & Bavestrello & Calcinai, 2000

Sarà, Michele, Bavestrello, Giorgio & Calcinai, Barbara, 2000, New Tethya species (Porifera, Demospongiae) from the Pacific area, Zoosystema 22 (2), pp. 345-354 : 349

Tethya simi n. sp.

TYPE MATERIAL. — Holotype ( MSNG 49676 ).

ETYMOLOGY. — After C. J. Sim, the Korean spongologist who collected the specimens.

OTHER MATERIAL. — Paratype (MSNG 49677).

TYPE LOCALITY. — Songsampo (Korea). 30.VI.1984, coll. C. J Sim.

DESCRIPTION

Morphology

Body globose, 2.5 cm in diameter, consistency firm, yellow ochre in alcohol ( Fig. 3A ). Tubercles flattened and little evident, 1.5 mm wide.

Skeleton ( Fig. 4 )

Megasclere bundles with large terminal fans. Megasters through entire cortex ( Fig. 3C ) but not in the choanosome. Micrasters represented by two different categories in the cortex and choanosome. Sponge surface covered by cortical micrasters ( Fig. 3D ).

Spicules

Strongyloxeas. ( Fig. 3B ) Main strongyloxeas, with a thin proximal rounded end, 1200-1800 × 10-20 µm. Auxiliary megascleres 300-700 × 3-11 µm. The two categories have however many intermediates.

Megasters. ( Fig. 3E, F ) Spherasters 40-80 µm in diameter, R/C = 0.2-0.5. Rays often apically bent or forked ( Fig. 3F ), about 20.

Micrasters. Cortical micrasters are generally tylasters ( Fig. 3G ) with indistinct knobs on their ray tips, being spines diffused along the ray. Several tylasters have a more or less developed centrum and shortened rays, 8-12 µm in diameter, ray number 8-14, generally 14. Choanosomal micrasters are oxyasters with conical rays, sometimes without spines ( Fig. 3J ) but generally more or less spined ( Fig. 3H, I ). Some oxyasters are spiny at the ray tips, 15-20 µm in diameter, generally 20 µm. Ray number eight to fourteen, commonly twelve to fourteen.

REMARKS

T. simi specimens were originally labelled T. aurantium . There are in fact some traits in common between the two species, both living in the northern temperate seas, as the existence of two micraster categories in the cortex and choanosome and the features of the oxyaster choanosomal category. But T. simi is distinguished clearly by the tylaster features of its cortical micrasters and by the megaster distribution in the cortex. In addition, in T. simi , the fibrous cortical inner layer, which is well developed in T. aurantium , is absent.

Figures

FIG. 3. — Tethya simi; A, holotype; B, strongyloxeas; C, the cortical region showing the megaster distribution; D, the superficial layer of tylasters; E, F, SEM views of megasters; G, SEM view of a tylaster; H-J, SEM views of oxyasters. Scale bars: A, 5 mm; B, 170 µm; C, 160 µm; D, 10 µm; E, F, 30 µm; G, 3.5 µm; H-J, 4 µm.

FIG. 4. — Tethya simi; schematic drawing of the skeletal arrangement. Scale bar: 0.7 mm.