Leucetta chagosensis Dendy, 1913

Leucetta chagosensis Dendy, 1913 View in CoL

Figures 37a–f View FIGURE 37 , 38a–d View FIGURE 38

Leucetta chagosensis Dendy, 1913: 10 View in CoL , Pl. 1 fig. 6, Pl. 4 fig. 2; Gosliner et al., 1996: 16, photos 3 and 5; Lévi et al., 1998: 77; Wörheide & Hooper, 1999: 882, figs 8H–M (with additional synonyms); Borojevic & Klautau, 2000: 194, fig. 6; Wörheide et al., 2002: 1753; Baine & Harasti, 2007: 15.

Leucetta View in CoL ‘lemon’ Colin & Arneson, 1995: 60, photo 230.

Material examined. ZMA Por. 08048, Indonesia, Nusa Tenggara, N of Sumbawa, Bay of Sanggar, 8.32°S 118.24°E, depth 2–4 m GoogleMaps , SCUBA, coll. R. W.M. van Soest, Indonesian-Dutch Snellius II Expedition stat. 114/II/05, 22 September 1984 ; ZMA Por. 08513, Indonesia, Nusa Tenggara, N of Sumbawa, Bay of Sanggar, 8.32°S 118.24°E, depth 5–7 m GoogleMaps , SCUBA, coll. R. W.M. van Soest, Indonesian-Dutch Snellius II Expedition stat. 114 / III/16 , 21 September 1984 ; ZMA Por. 08694, Indonesia, Maluku, Pulau Pulau Maisel , reef edge N of Mai, 5.4667°S 125.5167°E, depth 6–13 m GoogleMaps , SCUBA, coll. R. W.M. van Soest, Indonesian-Dutch Snellius II Expedition stat. 013/ IV/22, 4 September 1984 ; ZMA Por. 08923, Indonesia, SE Sulawesi, NE Take Bone Rate, S of Tarupa Kecil, 6.5°S 121.1333°E, depth 10–15 m GoogleMaps , SCUBA, coll. R. W.M. van Soest, Indonesian-Dutch Snellius II Expedition stat. 133/ IV/42, 25 September 1984 ; ZMA Por. 10846, Indonesia, Nusa Tenggara, Bali, Pulau Menjangan , 8.1167°S 114.5167°E, depth 4 m, coll. C.C. Hofman, #11, 30 July 1991 GoogleMaps ; ZMA Por. 15947, Indonesia, Sumatera, Padang, Pandan Island , 0.3833°S 100.2167°E, depth 10 m, coll. M. Pampus, 7 November 1995 GoogleMaps ; ZMA Por. 16012, Indonesia, Sulawesi, Spermonde Archipelago, Bone Baku , 5.132°S 119.361°E, depth 6 m GoogleMaps , SCUBA, coll. B.W. Hoeksema, 14 May 1997 ; ZMA Por. 17167, Indonesia, SW Sulawesi, Spermonde Archipelago, Kapoposang Island , 4.6885°S 118.9367°E, depth 12.3 m, coll GoogleMaps . R.A. Edrada , # TM84 , 7 August 1997 ; ZMA Por. 17364, Indonesia, SW Sulawesi, Spermonde Archipelago, Barong Lompo , depth 14.4 m, coll . R.A. Edrada , # TM14 , 8 August 1997 ; ZMA Por. 17555, Papua New Guinea, 10.9561°S 150.4188°E, depth 12–18 m GoogleMaps , SCUBA, coll. Rachel Sonnenschein, #02126, 28 May 2002 ; ZMA Por. 17709, Papua New Guinea, Milne Bay, 9.1695°S 150.3012°E, depth 9 m GoogleMaps , SCUBA, coll. Karen Tenney, #03554, 17 December 2003 ; ZMA Por. 19879, Indonesia, North Sulawesi, Siladen Island , 1.63°N 124.8°E, depth 10 m, coll. S. Tsukamoto, June 2006 GoogleMaps ; RMNH Por. 1627, Palau, Koror, Siaes Reef , western barrier, 7.3116°N 134.2268°E, depth 25 m GoogleMaps , SCUBA, coll. N.J. de Voogd, # KOR07 About KOR /170505/045, 17 May 2005 ; RMNH Por. 1628, Palau, Koror, Mutremdiu, W side Uchelbeluu Reef , 7.2737°N 134.5241°E, depth 20 m GoogleMaps , SCUBA, coll. N.J. de Voogd, # KOR.03/210505/087, 21 May 2005 ; RMNH Por. 1652, Palau, Koror, Toagel Mlungi Channel, western barrier reef off Babeldaob , 7.5425°N 134.4685°E, depth 27 m GoogleMaps , SCUBA, coll. N.J. de Voogd, # KOR09 About KOR /180505/53B, 18 May 2005 ; RMNH 1792 About RMNH , Indonesia, NE Kalimantan, Berau Islands, NE-side Maratua Island , 2.2802°N 118.6029°E, depth 0–30 m GoogleMaps , SCUBA, coll. C. Fransen, #BER17/101003/092, East Kalimantan Expedition 2003, 10 October 2003 ; RMNH Por. 1880, Indonesia, NE Kalimantan Islands, off Tanjung Batu , 2.2396°N 118.0934°E, depth 0–30 m GoogleMaps , SCUBA, coll. B.W. Hoeksema, #BER19/131002/151, East Kalimantan Expedition 2003, 13 October 2003 ; RMNH Por. 1923, Indonesia, Nusa Tenggara, Bali, SE-end of Tulamben beach, 8.2778°S 115.5959°E, depth 18 m GoogleMaps , SCUBA, coll. N.J. de Voogd, #BAL22/NV/130401/183, Bali Lombok Strait Expedition 2001, 13 April 2001 ; RMNH Por. 2910, Indonesia, Nusa Tenggara, Bali, NE side of Pulau Serangan , off lighthouse, 8.7214°S 115.2586°E, depth 0–17 m GoogleMaps , SCUBA, coll. N.J. de Voogd, #BAL14/050401/073, Bali Lombok Strait Expedition 2001, 5 April 2001 ; RMNH Por. 9196 Indonesia, Halmahera , Maitara Maitara W, 0.7299°N 127.3624°E, depth 0–30 m GoogleMaps , SCUBA, coll. N.J. de Voogd, #TER09/291009/, Ternate-Halmahera Expedition 2009, 29 October 2009 ; RMNH Por. 9197, Indonesia, Halmahera, off Hiri Pulau Maka , 0.9119°N 127.3091°E, depth 0–30 m GoogleMaps , SCUBA, coll. N.J. de Voogd, #TER13/311009/, Ternate-Halmahera Expedition 2009, 31 October 2009 ; RMNH Por. 9348, Indonesia, off Halmahera mainland, Teluk Dodinga , Karang Galiasa Kecil W, 0.8525°N 127.5888°E, depth 0–30 m GoogleMaps , SCUBA, coll. N.J. de Voogd, #TER39/141109/, Ternate-Halmahera Expedition 2009, 14 November 2009 .

Description. ( Figs 37a–c View FIGURE 37 ) Yellow globular, semiglobular or massively lobate sponge with one or more prominent oscules with slightly raised rim. There is usually an ‘atrium’ or large internal cavity, while the choanosome is provided with irregularly elongate radiate canals. Size up to 12 x 8 x 8 cm. Surface optically smooth, but harsh to the touch. Consistency toughly compressible.

Histology. Leuconoid aquiferous system.

Skeleton. Ectosomal skeleton ( Fig. 37d View FIGURE 37 ) a thin layer of small triactines forming small rounded (‘alveolar’) meshes, carried by subectosomal large triactines. Choanosomal skeleton lacunose ( Fig. 37e View FIGURE 37 ), in places similar to ectosomal arrangement of small alveolae, with large lacunae. These lacunae are bordered by rare tetractines, sticking into the lumen with their apical actines. Oscular rims have a layer of sagittal triactines ( Fig. 37f View FIGURE 37 arrows).

Spicules. ( Figs 38a–d View FIGURE 38 ) Large triactines, small triactines, tetractines.

Large triactines ( Fig. 38a View FIGURE 38 ), equiangular equiactinal, 274– 480.1 –720 x 20– 32.3 –60 µm.

Small triactines ( Fig. 38b View FIGURE 38 ), equiangular equiactinal, 102– 138.9 –186 x 8– 10.9 –17 µm, rarely some triactines have crooked ‘paired’ or single actines and these may then appear sagittal ( Fig. 38d View FIGURE 38 ); these are particularly concentrated in the rims of the oscules (see arrows in Fig. 37f View FIGURE 37 ) and are of the same general size as the regular small triactines.

Small tetractines ( Fig. 38c View FIGURE 38 ), rare, with equiangular equiactinal basal radiate system, actines 104– 126.2 –135 x 9– 11.5 –13 µm, with small apical actines, 12–15 x 6–8 µm.

Ecology. Shallow-water reefs.

Distribution. Indonesia, Papua New Guinea, Palau Islands. Elsewhere reported from a.o. Northeast Australia, New Caledonia, Vanuatu, French Polynesia, the Western Indian Ocean, and the Red Sea ( Wörheide et al. 2008).

Remarks. By the bright yellow color our specimens differ clearly from the pink or whitish Leucetta microraphis (cf. below), and also by the much larger size of the triactines of that species.

L. chagosensis may be confused with small light-colored Pericharax orientalis sp.nov., but the surface of that species is supported by a layer of special cortical sagittal triactines, lacking in the present species. The oscular sagittal triactines of L. chagosensis bear a resemblance to these cortical triactines of P. heteroraphis .

Furthermore, there is considerable resemblance to Ascoleucetta sagittata (cf. above), a yellow massiveglobular species with a central atrium and strongly folded choanosome. If this species is genuinely different from L. chagosensis then they can be kept apart by the lack of oscules and oscular rims with concentrations of sagittal triactines in A. sagittata . We will await further research before it can be decided that the two must be merged.

Over its large distribution, this species was demonstrated to have considerable genetic structure with recognizable discrete geographic populations (see Wörheide et al., 2002).