Clathrina purpurea, Van Soest & De Voogd, 2015

Clathrina purpurea View in CoL sp. nov.

Figures 2a–e View FIGURE 2

Clathrina sp. Erhardt & Baensch 1998: 22.

Material examined. Holotype RMNH Por. 6625, Indonesia, N Sulawesi, Lembeh Strait, Teluk Makawide , 1.4847°N 125.2406°E, depth 15 m, SCUBA, coll. N.J. de Voogd, #LEM19/090202/064, 9 February 2012. GoogleMaps

Description. A thick, seemingly conical ( Fig. 2a View FIGURE 2 ) mass of thin, loosely anastomosed tubes of 2–3 mm in diameter, forming an undulated uneven surface. There are frequent oscules ( Fig. 2b View FIGURE 2 ), several of which are raised, but water-collecting tubes with terminal oscules are lacking. Total size in life 15 x 10 cm; the preserved specimen has shrunk to 5 x 5 x 0.5 cm ( Fig. 2c View FIGURE 2 ). Color a distinctive reddish purple in life, dark red-brown and quite limp in preserved condition. Consistency soft, easily torn.

Skeleton. The walls of the tubes ( Fig. 2d View FIGURE 2 ) consist of a thin layer of triactines.

S picules. Regular triactines only. Triactines ( Fig. 2e View FIGURE 2 ) equiangular equiactinal, with thin cylindrical actines, 78– 120.3 –153 x 5.5– 6.1 –7 µm.

Ecology. On reefs, at shallow depth.

Remarks. This specimen is assigned to Clathrina in the restricted sense of Klautau et al. (2013) on account of its habitus of anastomosed tubes and continuous choanoderm in combination with its lack of tetractines. Although there are already numerous Clathrina species decribed, the present species stands out by its distinctive color and large size, combined with numerous oscules and cylindrical triactines of intemediate size. Using the key of Klautau & Valentine (2003) we were unable to find a matching species and assume here that it is undescribed. There is some resemblance in habitus to Clathrina ceylonensis ( Dendy, 1905) , as redescribed by Klautau & Valentine (2003: 16, fig. 10) but shape of the spicules of that species (conical actines) and length of the actines (67–96 µm) are sufficiently distinct from our specimen to belong to a different species.

The photo on p. 22 of the Meeres Atlas 5 of Erhardt & Baensch is obviously this species; like our holotype it was photographed in Lembeh Strait.