New Tethya species (Porifera, Demospongiae) from the Pacific area Author Sarà, Michele Dipartimento per lo Studio del Territorio e delle sue Risorse, Università di Genova, Viale Benedetto XV, 5, I- 16132 Genova (Italy) sara @ dipteris. unige. it Author Bavestrello, Giorgio Istituto di Scienze del Mare dell’Università di Ancona, Via Brecce Bianche, I- 60131 Ancona (Italy) Author Calcinai, Barbara Dipartimento per lo Studio del Territorio e delle sue Risorse, Università di Genova, Viale Benedetto XV, 5, I- 16132 Genova (Italy) text Zoosystema 2000 22 2 345 354 journal article 10.5281/zenodo.5402001 1638-9387 5402001 Tethya strongylata n. sp. TYPE MATERIAL . — Syntypes ( BMNH 1938:4:8:1, slide 1938:4:8). ETYMOLOGY. — For the occurrence of many strongyles in the spicule complement some of which are very short and plump. TYPE LOCALITY. — Galapagos Islands. West side of James Island. DESCRIPTION Morphology The two specimens are globose and respectively of 2 and 3 cm in diameter. The larger specimen has a large bud of 8 mm in diameter attached to the mother sponge by a short peduncle 2 mm long. Tubercles flattened and cortex with lacunae. 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. FIG. 5. — Tethya strongylata ; schematic drawing of the skeletal arrangement. Scale bar: 1 mm. Skeleton ( Fig. 5 ) Radial megasclere bundles not branched. Spherasters throughout the whole cortex, more densely in the inner layer ( Fig. 6A ). Some small spherasters in the choanosome. Sponge surface covered by cortical micrasters. Spicules Megascleres. Strongyloxeas ( Fig. 6B ) or anisostrongyles ( Fig. 6C ) frequently shortened, 500- 2000 × 18-33 µm. Some spicules are short and plump strongyles, anisostrongyles and styles ( Fig. 6D, E, G ) 140-300 × 40-60 µm. Megasters. ( Fig. 6F ) Spherasters with short rays, in the cortex 40-85 µm and in the choanosome 35-48 µm in diameter, R/C = 0.1-0.7, frequently 0.5. Rays may be distorted, forked, spined or reduced to hemispherical outgrowths ( Fig. 6H ), often with different ray aspects in the same spicule. Ray number 24-30. Micrasters. ( Fig. 6I, J ) Tylasters 10-14 µm in diameter, generally 11-12 µm. As the rays are entirely spined the apical knob, a little more densely spined, is not distinct. Some tylasters have a small centrum. Ray number generally 12-14. REMARKS T. strongylata is characterized by the shortened megascleres which are often anisostrongyles with some short and plump strongyles and styles. The megasters are also peculiar as they are frequently reduced and irregular. The rays are unusually short and numerous. In contrast, micrasters show a great uniformity in size and shape. They differ from the T. japonica Sollas, 1888 tylasters for their greater size, number and robustness of rays, and from those of T. deformis Thiele, 1898 for the less frequent and smaller development of the centrum. T. strongylata is the second species of Tethya described for the Galapagos Islands. The other species is T. sarai Desqueroux-Faundez & Van Soest, 1997 which is distinguished from strongylata not only by the lack of the peculiar traits of this species but also in possessing a category of choanosomal strongylasters/tylasters which are well distinguished from the cortical tylasters.