Haliclona (Soestella) crowtheri Goodwin & Brickle 2012, sp. nov.

Haliclona (Soestella) crowtheri sp. nov.

(Figure 19)

Type material: Holotype: Sample in 95% ethanol, tissue section and spicule preparation on slides. BELUM Mc 7579. Prion Island Site 1, South Georgia (54°001.590’S, 37°15.178’W); depth 17.6m; collected by C. Goodwin, D. Poncet, and P. Brewin, 19 th November 2010.

Paratypes: Sample in 95% ethanol, tissue section and spicule preparation on slides. BELUM Mc 7587 and BELUM Mc 7594. Prion Island Site 2, South Georgia (54°001.862’S, 37° 15.032’W); depth 18m; collected by C. Goodwin, D. Poncet, and P. Brewin, 19 th November 2010. BELUM Mc 7612. Rosita Harbour Site 2, South Georgia (54°00.649’S, 37° 25.618’W); depth 11.5m; collected by C. Goodwin, J. Brown, and S. Brown, 20 th November 2010. BELUM Mc 7623. Right Whale Bay, South Georgia (54°00.173’S, 37° 40.856’W); depth 18m; collected by C. Goodwin, J. Brown and S. Brown, 21 st November 2010. BELUM Mc 7633. Bird Sound Site 1, South Georgia (54°02.058’S, 38° 00.242’W); depth 18m; collected by C. Goodwin, S. Cartwright and P. Brickle, 22 nd November 2010.

Etymology: Named for the former Head of the Department of Natural Sciences National Museums Northern Ireland, Dr Peter Crowther, who retired this year after many years of service to the museum; in recognition of his support of this work when in post.

External morphology: In situ appearance: Thickly encrusting white sponge (up to 15mm thick) forming large patches (up to 20cm in diameter) on bedrock. Smooth surface bearing numerous large oscules (up to 1cm in diameter) (Fig. 19a).

Preserved appearance: Thick crust with very hard texture. Choanosome brick red in Mc7612 but white in some specimens and patchily red in others. The ectosome is a white, easily detachable, smooth layer.

Skeleton: Confused choanosomal skeleton with primary columns of 4–7 spicules joined by unispicular secondary lines. Some rounded meshes present (Fig. 19b). Detachable white ectosome formed of hexagonal meshes of oxea, each side composed of single bundle of oxea 2–3 spicules thick (Fig. 19c).

Spicules: Measurements from Mc7579.

Oxea: 266(299)321 by 11(17)20µm—occasional very thin (<1µm oxea) of a similar length are also present (Fig. 19d).

Remarks: This species is assigned to Haliclona as it is a Chalindae with unispicular secondary lines (de Weerdt 2002). The presence of a specialised ectosomal skeleton with rounded meshes assigns it to the subgenus Haliclona (Soestella) (de Weerdt 2002).

Two other species of Haliclona (Soestella) have been recorded from this region: H. auletta (Thiele, 1905) from Calbuco, Chile and H. chilensis (Thiele, 1905). However, these both possess much smaller oxeas (150 and 130–200µm respectively).

The taxonomy of this genus is still confused so species from other sub-genera were considered. Although descriptions of other species from different genera in the family occurring in the region have been examined none can be found in which such a distinctive ectosomal skeleton is described.