Calcareous sponges of the Western Indian Ocean and Red Sea Author Van, Rob W. M. Author De, Nicole J. text Zootaxa 2018 2018-06-01 4426 1 1 160 journal article 29979 10.11646/zootaxa.4426.1.1 cdd567ed-ebd8-4801-a6a4-af6c9fb964fd 1175-5326 1271239 18929E20-5296-4458-8A8A-4F5316A290FD Clathrina sinusarabica Klautau & Valentine, 2003 Figures 14a–d , 15a–d Clathrina coriacea ; Row 1909 : 184 (not: Montagu 1814 ). Clathrina sinusarabica Klautau & Valentine, 2003 : 45 , fig. 37; Voigt et al. 2017 : 12 , fig. 7. Material examined. RMNH Por. 10003, Saudi Arabia, Jeddah, near Thuwal, Tahlah, 22.25725°N 38.880917°E, scuba, coll. N.J. de Voogd, field nr. THU14/JED 210, 13 November 2014 ; ZMA Por. 13414, Israel, Schuhmacher’s Pinnacle, Gulf of Aqaba, depth 6 m , scuba, coll. M. Wunsch, field nr. AQ11, 1 July 1998 ; ZMA Por. 13476, Israel, pillar container port, Gulf of Aqaba, depth 5 m , scuba, coll. M. Wunsch, field nr. AQ61, 5 July 1998 . FIGURE 14. Clathrina sinusarabica Klautau & Valentine, 2003 , a, RMNH Por. 10003, from the Saudi Arabian Red Sea, Jeddah (field nr. JED210), in situ on the reefs of Jeddah, a1, detailed view of water collecting tubes of the same (photos N.J. de Voogd), b, ZMA Por. 13414, at Aqaba, in situ on Schuhmacher’s Pinnacle, c, ZMA Por. 13476, at Aqaba’s container port (photos M. Wunsch). Description. Cushion of loosely anastomosed semi-transparent white tubuli ( Figs 14a–c ) of 0.5–1.2 mm diameter. Water collecting tubes ( Fig. 14a 1 ) are common at the upper and lateral sides, but are less prominent in the Aqaba specimens ( Figs 14b–c ). Preserved material is now fragmented and has pinkish color in alcohol. Size of the entire Jeddah specimen is 5 x 3 x 2 cm, the Aqaba specimens are slightly smaller. FIGURE 15. Clathrina sinusarabica Klautau & Valentine, 2003 , a, light microscopic view of part of the cormus and tubuli of RMNH Por. 10003 from Jeddah, b–d, SEM images of spicules, b, of Jeddah specimen RMNH Por. 10003, c, of Aqaba specimen ZMA Por. 13414, d, of Aqaba specimen ZMA Por. 13476. Aquiferous system. Asconoid. Skeleton. ( Fig. 15a ) Tubule walls thin, with single layer of spicules. Spicules. ( Figs 15b–d ) Equiradiate equiangular triactines with thin cylindroconical actines ending in pointed apices, 78–214 x 7.5–17.5 µm (n=75). The spicules sizes of the three specimens are: RMNH Por. 10003: 83– 164.4 –194 x 7.5– 9.04 –11 µm ZMA Por. 13414: 107– 167 –214 x 9 – 13.4 –17.5 µm ZMA Por. 13476: 78– 132 –162 x 9 – 11.2 –14.5 µm. Distribution and ecology. Saudi Arabia , Jeddah, on reefs; if correctly identified it occurs in the Sudanese Red Sea , Agig, and the Israelian part of the Gulf of Aqaba, on reefs, depth 5– 6 m . Remarks. The type of Clathrina sinusarabica Klautau & Valentine, 2003 resembles our specimens in habitus and color, but the actines of its spicules are significantly shorter, 72–103 x 8.4 µm (according to Klautau & Valentine 2003 ). We base ourselves for the identification on Voigt et al. ’s (2017) description, which gives actines of 50–166 x 8–18 µm. The partial 28S sequence obtained for the Jeddah specimen conforms to Voigt’s molecular data (cf. Fig. 2A ). The Jeddah specimen was sequenced, the Aqaba specimens were not. The Aqaba specimens appear to be morphologically similar, so we assume they are members of C. sinusarabica , but we gave separate measurements of the spicules of the three specimens, just in case. Morphologically, the present specimens resemble Rodrigues and Seychelles material described below as Clathrina rodriguesensis sp.nov. , having firm whitish tubuli and robust triactines, but molecular data do not support this similarity (cf. Fig. 2A ). The present specimens show also considerable resemblance to the Indonesian species Clathrina sororcula Van Soest & De Voogd, 2015 , which has loosely anastomosed semi-transparent white tubes, cylindrical triactines of the same average length. Differences are the presence of several water-collecting tubes (raised oscules, absent in C. sororcula ) and the greater size of the actines of the spicules. No molecular sequence data for C. sororcula could be obtained. Clathrina rowi Voigt et al. , 2017 , Clathrina luteoculcitella Wörheide & Hooper, 1999 and Clathrina chrysea Borojević & Klautau, 2000 sensu Van Soest & De Voogd 2015 are closely related in a molecular sense (cf. Fig. 2A ). The New Caledonian type material of the latter was yellow, but life color of the Indonesian material was unknown. The color in alcohol is transparent-white like the present specimen. Spicule sizes match reasonably (75–144 x 7–11 µm), but actines are more conical. C. rowi and C. luteoculcitella are treated below.