Tethya samaaii Ribeiro & Muricy, 2011

Samaai, Toufiek, Gibbons, Mark J. & Muricy, Guilherme, 2017, Validation of Tethya samaaii Ribeiro & Muricy, 2011, replacement name for the sponge Tethya rubra Samaai & Gibbons, 2005 (Demospongiae, Tethyida, Tethyidae), Zootaxa 4347 (3) : -

Tethya samaaii Ribeiro & Muricy, 2011

Original description. Tethya rubra Samaai & Gibbons, 2005: 31 .

Synonymy. Tethya rubra Samaai & Gibbons, 2005: 31 ; Waterworth et al. 2017: 2 (preocc. by Tethya rubra Ribeiro & Muricy, 2004: 11). Tethya samaaii Ribeiro & Muricy, 2011: 1525 (replacement name).

Material studied. Holotype. SAM–4900 (fragment BMNH 1997.5.12.124 ) ( Ts 180 ), South Paw, Oudekraal South Africa (33.93°S, 17.35°E), depth 12 m, collected by P. Coetzee, 23 April 1996 .

Material examined for comparison. Holotype Tethya rubra Ribeiro & Muricy, 2004 . MNRJ 5316 , Siriba Island , Abrolhos Archipelago, Bahia State, Brazil (17°58'12.9"S, 38°42'34.5"W), 0 4 March 2002, coll. S. Ribeiro, intertidal.

Description. Massive, sub-spherical sponge, 40 × 60 x 60 mm diameter, with disc-like attachment. Surface hispid, with tuberculate elevations separated by contractile pore-bearing grooves or channels; few oscules are visible, 2 mm in diameter. Well-pronounced cortex, ~ 5 mm thick. Texture firm, velvety to the touch, barely compressible. Colour in life, reddish-orange externally with orange choanosome; in preservative, externally pale-orange and internally yellow-beige. Yellow eggs are present in the choanosome.

Skeleton. Choanosomal skeleton radial, with compact, widely spaced tracts of anisostrongyloxeas in three size classes, 700–1500 µm wide, that arise from the base, and fan slightly just below the ectosomal region to form inverted cone-shaped brushes. Smaller anisostrongyloxeas and oxyspherasters dispersed in the choanosome between the bundles of anisostrongyloxeas. Sub-cortical region extremely collagenous and without microscleres, extending around megasclere tracts and forming a boundary, 1000 µm thick. Ectosomal skeleton ~2000 µm thick, with small oxyspherasters and tylasters forming a dermal crust. Oxyasters are abundant and occur in the upper cortex and dermal crust where expanding dermal brushes of anisostrongyloxeas are also visible.

Spicules. Megascleres. Anisostrongyloxeas, smooth, straight, thickest centrally with proximal ends strongylote, distally hastate, in two size classes: I) 2818 (2800–3273) × 91 µm, n=10; II) 757 (655–828) × 18 µm, n = 10. Anisostrongyles with distal end more stylate than proximal end, 379 (309–455) × 9 µm, n=10. Microscleres. Megasters. Oxyspherasters 199 (155–209) µm, n=10. Micrasters. Microxyspherasters with double-pointed rays, 38 (23–46) µm in diameter, n=10; tylasters with terminally spined rays, 14 (12–21) µm in diameter, n=10.

Geographical distribution. Endemic to the south-west coast of South Africa.

Remarks. Tethya rubra Ribeiro & Muricy, 2004 clearly differs from T. samaaii (= T. rubra sensu Samaai & Gibbons, 2005 ) in several characters. It has a smaller body size (1–2 cm in diamater) and its external color in life may also be yellow. The cortex is thinner (500–1500 µm thick) and has rounded lacunae, abundant spherasters and a dermal crust of tylasters. Megasclere bundles fan out in the surface, 150–300 µm wide in the choanosome and 1000–1750 µm in the cortex. The choanosome has cavities 100–625 µm in diameter, absent in T. samaaii . The spicules of T. rubra are in general smaller compared to T. samaaii (main anisostrongyloxeas 604–1426 µm; accessory strongyloxeas 291–633 µm; spherasters 18–50 µm in diameter; oxyasters with branched, straight or twisted rays, 21–42 µm; and tylasters with 4–6 cylindrical, almost isodiametric rays, 5–13 µm in diameter) ( Ribeiro & Muricy 2004, 2011). In contrast, T. samaaii has small anisostrongyles 309–455 µm long, with the tyle of distal end larger than that of proximal end; large oxyspherasters with a multitude of rays; microxyspherasters with double-pointed rays, and tylasters with terminally spined rays ( Samaai & Gibbons 2005).

We showed here that the replacement name T. samaaii given by Ribeiro & Muricy (2011) for T. rubra Samaai & Gibbons, 2005 is valid and eliminates the taxonomic confusion between two different species, allowing a better understanding of the global diversity of the genus Tethya and of the biogeography of the sponge faunas of the Western and Eastern South Atlantic Ocean.