Leucascus flavus Cavalcanti, Rapp & Klautau, 2013

Leucascus flavus Cavalcanti, Rapp & Klautau, 2013 View in CoL

Figures 34a–f View FIGURE 34 , 35a–d View FIGURE 35

? Leucosolenia cerebrum ; Breitfuss, 1896a: 434; Breitfuss, 1898: 172 (not Haeckel, 1872)

Leucascus flavus Calvalcanti et al., 2013: 297 View in CoL , Figs 14–15 View FIGURE 14 View FIGURE 15 .

Material examined. Holotype ZMA Por. 13145 (( Fig. 34b View FIGURE 34 ), Indonesia, SW Sulawesi, Spermonde Archipelago, Bone Baku , 5.132°S 119.361°E, depth 12 m, SCUBA, coll. N.J. de Voogd # BB /NV/160597/27, 16 May 1997. GoogleMaps

Additional specimens. RMNH 2279 About RMNH , Indonesia, Bali, Tulamben area, bay S of ‘ Emerald Hotel’ , 8.2847°S 115.6031°E, depth 20 m GoogleMaps , SCUBA, coll. N.J. de Voogd, #BAL 23/120401/151, 12 April 2001 ( Figs 34a, c–d View FIGURE 34 ) ; RMNH 9346 About RMNH , Indonesia, Ternate, Halmahera, Sulamadaha Beach , 0.8632°N 127.3345°E, depth 15 m GoogleMaps , SCUBA, coll. N.J. de Voogd, #TER.04/2661009/NV017, Ternate-Halmahera Expedition 2009, 26 October 2009 ; RMNH 9347 About RMNH , Indonesia, Halmahera, Tidore Cobo , 0.7552°N 127.4066°E, depth 15 m GoogleMaps , SCUBA, coll. N.J. de Voogd, #TER.15/0111009/, Ternate-Halmahera Expedition 2009, 1 November 2009 .

Description. The description of the holotype ( Fig. 34b View FIGURE 34 ) is here summarized from Cavalcanti et al. 2013: Yellow massive sponge, with a thin skin ( Fig. 34e View FIGURE 34 ) covering a tight mass of anastomosed tubes ( Fig. 34f View FIGURE 34 ). Large oscules, without membrane or spicule fringe. Spicules triactines 70–120 x 7.5–11 µm, tetractines with actines of the basal triradiate system 75–115 x 7.5–10 µm, apical actines 41–61 x 4–5 µm. The apical actines are rugosespined ( Fig. 35c View FIGURE 35 ) and protrude into the choanocyte tubes.

Description of additional specimens, also from in situ photos: lobate-folded massive sponges ( Figs 34a–c View FIGURE 34 ) with a pale-yellow or whitish yellow color in situ. Oscules wide, rounded or elongate, at the top of lobes.

Spicules. ( Figs 35a–d View FIGURE 35 ) Triactines and tetractines.

Triactines ( Fig. 35a View FIGURE 35 ), equiangular equiactinal, occasionally parasagittal, 96– 118.1 –141 x 7.5– 8.5 –11 µm.

Tetractines ( Fig. 35b View FIGURE 35 ), triradiate system equiangular and equiactinal, 90– 114.3 –127 x 7– 9.2 –10 µm, apical actines spined ( Figs 35c–d View FIGURE 35 ), 45– 54.7 –68 µm.

Ecology. Shallow-water reefs.

Distribution. So far known only from Indonesia, but widely distributed there (Sulawesi, Bali, Ternate).

Remarks. This species was recently described by Cavalcanti et al. (2013) on the basis of an Indonesian specimen collected by one of us (NDV). Since then, the species was found several times in localities all over the Indonesian archipelago. It may be mistaken for other yellowish massive calcineans, such as Ascoleucetta sagittata Cavalcanti et al., 2013 and Leucetta chagosensis Dendy, 1913 (cf. below), but these differ in color (more definitely brightly yellow), shape not so lobate but more massive and rounded, presence of large triactines and the lack of spined apical actines of the tetractines. The latter is not easily seen with light microscopy but it is very obvious under SEM.

There is a possibility that this species was previously reported by Breitfuss (1896a, 1898) from Ternate as Leucosolenia cerebrum , a Mediterranean species now assigned to the genus Borojevia . Although his description is quite concise and generally inadequate, he specifically mentions spined apical actines of the tetractines. It is also possible that this concerns a so far undescribed species of Borojevia .

Genus Ascoleucetta Dendy & Frederick, 1924