Desmapsamma vervoorti van Soest, 1998

(Fig. 11 A–I) (Tab. 4)

Examined material. Sample Bugor 410 (bis1): Indonesia, North Sulawesi, Siladen Island, 27 m, September 2007; sample Carramba 1: Indonesia, Ambon Island, Pintu Kota, depth not stated, 12 October 2008; sample Carramba 2 sp. 1: Indonesia, Ambon Island, Depan Tupa, depth not stated, 12 October 2008; sample Carramba 6: Indonesia, Ambon Island, Shipwreck, depth not stated, 14 October 2008; sample Carramba 8 sp. 2: Indonesia, Ambon Island, Tanjung Sial (Semur), depth not stated, 15 October 2008.

Description. Thick (about 4 mm) encrusting sponge that completely covers Carijoa riisei colonies (Fig. 11 A), leaving only polyp openings free. Surface macroscopically reticulated by large amounts of sediment (Fig. 11 B). Consistency firm, with surface tough and compressible. Pale pink to light orange in situ; the colour persists in ethanol (Fig. 11 A, B). The collected specimens are fragments of colonies of octocoral up to 9 cm long.

Skeleton. The ectosomal skeleton is an almost regular reticulation of paucispicular (about 1–4 spicules) tracts of oxeas often reinforced by sand grains (Fig. 11 C). Sometimes foreign bodies completely substitute oxeas. The choanosomal skeleton consists of tracts of oxeas organised in a rather irregular reticulum; sometimes a more regular, isotropic skeleton is detectable (Fig. 11 D). In the ectosome these tracts open in bouquets making the surface hispid. Low quantities of sand are present in the meshes of the choanosomal reticulum.

Spicules. Oxeas with hastate points (Fig. 11 E), 105 – 240 x 1.2 – 11.2 μm. Isochelae in two categories (Fig. 11 F, G): isochelae I 15 – 21.3 μm, isochelae II 7.5 – 13.8 μm. Sigmas in two categories (Fig. 11 H, I): sigmas I 20 – 43.8 μm sigmas II 10 – 18.8 μm. Refer to Tab. 4 for complete measurements.

Distribution and remarks. Indonesia (van Soest 1998; Calcinai et al. 2004 as D. anchorata). This genus includes three species: D. anchorata (Carter, 1882) from the Tropical Western Atlantic, D. vervoorti van Soest, 1998 from Indonesia and D. turbo (Carter, 1885) from Australia (van Soest et al. 2011). Differences between D. vervoorti and D. anchorata are considered inconspicuous by van Soest (1998), but their geographical separation makes the conspecificity unlikely. The description of D. turbo is too brief to allow for any comparisons.

In contrast to D. vervoorti van Soest (1998), our samples do not have three clear categories of sigmas, and the choanosomal skeleton is less regular.

The recent discovery of the octocoral genus Carijoa being native to the Indo-Pacific (Concepcion et al. 2010) refutes the hypothesis that C. riisei and its associated fauna are introduced species to this area (Calcinai et al. 2004). Interestingly, the Caribbean Desmapsamma is also frequently associated with octocorals, particularly with C. riisei (McLean & Yoshioka 2007) .