Higginsia natalensis Carter, 1885

Samaai, Toufiek, Pillay, Ruwen & Janson, Liesl, 2019, Shallow-water Demospongiae (Porifera) from Sodwana Bay, iSimangaliso Wetland Park, South Africa, Zootaxa 4587 (1), pp. 1-85 : 51

Higginsia natalensis Carter, 1885

( Fig. 21 A–G)

Synonymy.

Higginsia coralloides var natalensis Carter 1885, p. 293

Material examined. SAMC–A24769 (cross-reference TS 942 & Saf 03-Sod 91), Deep-sponge reef, Sodwana Bay (27.5167°S, 32.6835°E), South Africa, 0 7 November 2003, collected by T. Samaai, depth 18 m.

Description. Thickly encrusting sponge, 300 mm diameter, with a few random oscular elevations visible ( Fig. 21A ). Surface irregular, hispid, without obvious meandering grooves, Texture firm, tough, hard, not compressible. Colour in life, golden-yellow, interior slight orange tinge; in preservative, beige. A sticky mucous is visible.

Skeleton ( Fig. 21C, D ). Choanosomal skeleton is a dense petrosid-like isotropic reticulation of robust oxeas, without spongin fibres, bounded together with sparse collagen. The subectodermal skeleton is cavernous, with multispicular bundles of small oxeas. Distinct paratangential crust of small oxeas forming a continuous palisade of spicules. Acanthoxeas scattered within the mesohyl. The ectosomal skeleton crust-like, supported by long, pillarlike tracts of large oxeas.

Spicules. Megascleres ( Fig. 21 E–G). Oxeas in two classes: I) robust, smooth, slightly curved midway, long tapering points, 546 (510–597) × 25 (25) µm n = 10; II) thin, smooth, slightly curved midway, long tapering points or hastate, 293 (234–366) × 6 (6) µm, n = 10. Acanthoxeas, thin and heavily spined, 102 (86–130) × 3 (3) µm, n = 10. Microscleres. Absent

Substratum, depth range and ecology. This genus is widely distributed in the Indo-West Pacific and WIO and found often under overhangs, in spurs and grooves, growing on dead coral rubble substrates to pristine coral reef slopes. This particular species was found in an overhang at Seven Mile reef.

Geographic distribution. Port Elizabeth, Sodwana Bay South Africa.

Remarks. Higginsia natalensis has been described by Carter (1885) from Port Elizabeth, South Africa and our specimen conforms well with the original description and in the dimensions of the spiculation. Seven other species of Higginsia have been described from the WIO. These are Higginsia fragilis Lévi, 1961 (Aldabra, Seychelles), Higginsia higgini Dendy, 1922 (Chargos) , Higginsia kenyensis Pulitzer-Finali, 1993 ( Kenya) , Higginsia lamella Pulitzer-Finali, 1993 ( Kenya) , Higginsia pulcherrima Pulitzer-Finali, 1993 ( Kenya) , Higginsia petrosioides Dendy, 1922 (Tuléar, Madagascar & Seychelles) and Higginsia robusta Burton, 1959 (Gulf of Aden).

Key diagnostic characters.

• Sponge dense petrosid-like isotropic choanosomal skeleton.

• Distinct paratangential crust of small oxeas forming a continuous palisade of spicules.

• Thin heavily spined acanthoxeas.

Figures

FIGURE 21. Higginsia natalensis Carter, 1885. A. Specimen; C & D. Skeletal architecture (C, x5; D, x 10); E & F. Oxeas; G. Acanthoxeas.