Ascandra crewsi, Van Soest & De Voogd, 2015

Ascandra crewsi View in CoL sp. nov.

Figures 26a–c View FIGURE 26 , 27a–e View FIGURE 27

Leucosolenia sp. ; Ralifo, et al., 2007: 7.

Material examined. Holotype ZMA Por. 17556, Papua New Guinea, Wahoo , 10.2518°S 150.758°E, depth 21 m, in cave, SCUBA, coll. R. Sonnenschein #02130, 29 May 2002. GoogleMaps

Description. ( Figs 26a–b View FIGURE 26 ) The material consists of two samples showing thin-walled tubes with extensive system of thin side branches forming a reticulation around the central tube. Size of the whole specimens in preserved condition ( Fig. 26b View FIGURE 26 ) up to 10 x 4 x 3 cm, central tubes less than 1 cm in diameter and branches of the network 1–2 mm in diameter. The network of side branches is frequently dead-ended, and these ends taper to a fine point. The central tube ends in a wide oscule. Color snow-white, but the central tubes are semi-transparent. Consistency soft, becoming limp out of the water, easily damaged.

Skeleton. The wall of the central tube and the side branches is formed by a single layer of tetractines, with the long thin apical actines protruding far out into the tubar lumen ( Fig. 26c View FIGURE 26 ). Spicules. ( Figs 27a–e View FIGURE 27 ) Predominantly tetractines, a few triactines. Large tetractines ( Figs. 27a View FIGURE 27 ) equiangular equiactinal, with actines of the basal triradiate system 159– 206.4 –246 x 15– 18.8 –21 µm, apical actines usually curved at the end ( Fig. 27d View FIGURE 27 ), 181– 226.3 –279 x 13– 15.3 –17 µm. Small tetractines ( Figs 27c View FIGURE 27 ), likewise equiangular equiactinal, with actines of the basal triadiate system 54– 90.2 –117 x 7– 7.3 –8 µm, apical actines straight and needle-sharp ( Fig. 27e View FIGURE 27 ), 62– 95.8 –114 x 2.5– 3.1 –3.5 µm.

Small triactines ( Fig. 29b View FIGURE 29 ), equiangular equiactinal, relatively robust, only a few were observed, actines 140– 150 x 10–12 µm.

Ecology. Deeper part of the reef.

Distribution. So far known only from Papua New Guinea.

Etymology. Named after Dr. Phil Crews of the University of California at Santa Cruz, who leads the research group that was responsible for collecting the present specimens, and to acknowledge his great contributions to sponge natural products detection and elucidation.

Remarks. The specimens from Papua New Guinea are considered to be a distinct species despite the overall similarity to Ascandra kakaban sp.nov. described above. The present material has a larger cormus and there are distinct differences in the spicules: triactines are virtually missing (only a few could be found and these were only small ones), while the tetractines were more definitely in two size classes with the large tetractines having much longer apical actines than those of A. kakaban sp.nov. Like in the Kakaban species, the present specimens look deceptively like Clathrinidae , but the central tube and reticulated side branches, the dominance of tetractines with their long apical actines protruding far into the atrial lumen, and the paucity of triactines, are indicative of Ascandra . There is also a resemblance with regional species of the genus Soleneiscus Borojevic, Boury-Esnault & Vacelet, 1990 like S. radovani Wörheide & Hooper, 1999 and S. stolonifer ( Dendy, 1891) , from which the new species differs in the lack of diactines and the reticulated habitus.

As discussed above, Ascandra sertularia Haeckel (1872) is distinct by having large diactines.

The present material was preliminarily identified as Leucosolenia sp. by one of us (RVS), under which name the presence of novel secondary metabolites - leucosolenamides - were reported ( Ralifo et al. 2007).

Genus Leucaltis Haeckel, 1872