Clathrina beckingae, Van Soest & De Voogd, 2015

Clathrina beckingae View in CoL sp. nov.

Figures 5a–e View FIGURE 5

? Leucosolenia clathrus ; Breitfuss, 1896a: 434; Breitfuss, 1898: 171 (not: Schmidt, 1864).

Material examined. Holotype RMNH Por. 1437, Indonesia, NE Kalimantan, Berau region, Derawan Islands, Maratua Island , depth 1 m, snorkeling, coll. L. Colin, Kalimantan-Berau Expedition 2003, 23 October 2003.

Paratype RMNH Por. 4482, Indonesia, East Kalimantan Province, Berau Region, Maratua Island, Haji Buang marine lake, 2.2044°N 118.5987°E, depth 1–2 m, snorkeling, coll. L.E. Becking GoogleMaps , # LE 177 , 11 September 2008 .

Description. ( Figs 5a View FIGURE 5 , holotype, and 5b, paratypes). Cormus forming a conical mass of loosely anastomosing tubes with several water collecting tubes ending in oscules elevated above the surface of the body. Color transparent white in situ (verging to pale cream in the holotype specimen), becoming pale greyish yellow in preserved condition ( Fig. 5c View FIGURE 5 ). Size up to 2.5 x 2 x 2 cm, individual tubes 0.5–1 mm in diameter. Consistincy soft, limp.

Skeleton. ( Fig. 5d View FIGURE 5 ) Walls of tubes having only two or three layers of partly overlapping triactines, not densely arranged.

Spicules. Triactines only.

Triactines ( Fig. 5e View FIGURE 5 ), equiangular equiactinal, with thin cylindrical actines, size of actines 48– 84.9 –106 x 4– 4.7 –6 µm.

Ecology. Marine lake inhabitant.

Distribution. Indonesia.

Etymology. Named after our colleague Leontine E. Becking, expert on marine lake biota, to acknowledge her assistance in the field and for collecting material of several of the species described in this paper, including the paratype of the present species.

Remarks. By being white and having thin semitransparent tubes the new species resembles Clathrina heronensis described above, and also occurring in the same habitat. However, there are several important and significant differences: (1) the actine length and thickness of the triactines is considerably smaller and the shape is cylindrical, not conico-cylindrical, (2) distinct water-collecting tubes are present, elevated above the cormus, and (3) the cormus is forming a conical mass elevated above the substratum, not flattened.

Although Breitfuss (1896a, 1898) did not provide adequate descriptive information or illustrations, the spicule size data make it possible that his report of Clathrina (as Leucosolenia ) clathrus from Ternate concerns the present species. C. clathrus is restricted to European waters and it is highly unlikely that it would occur in Indonesia.