Clathria (Clathria) multiformis, Samaai & Pillay & Janson, 2019

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 : 32-34

Clathria (Clathria) multiformis sp. nov.

( Fig. 12 A–M)

Material examined. Holotype. SAMC–A24740 (cross-reference TS 837 & Saf 03-Sod 20), Ramsay reef, Sodwana Bay, South Africa (27.4466°S; 32.7152°E), 0 3 November 2003, collected by T. Samaai, depth 18 m;

Paratypes. SAMC–A24741 (cross-reference TS 842 & Saf 03- Sod 106), Ribbon reef, Sodwana Bay (27.4880°S, 32.6977°E), South Africa, 0 7 November 2003, collected by T. Samaai, depth 20 m ; SAMC–A24742 (cross-reference TS 856 & Saf 03- Sod 75), Deep-sponge reef, Sodwana Bay (27.5167°S; 32.6835°E), South Africa, 0 6 November 2003, collected by T. Samaai, depth 30 m ; SAMC–A24743 (cross-reference TS 872 & Saf 03- Sod 92), Seven Mile reef (27.4580°S, 32.7141°E), Sodwana Bay, South Africa, 0 7 November 2003, collected by T. Samaai, depth 20 m ; SAMC–A24744 (cross-reference TS 940 & Saf 03- Sod 37), Five Mile reef, Sodwana Bay (27.495°S, 32.6902°E), South Africa, 0 3 November 2003, collected by T. Samaai, depth 20 m. SAMC– A24745 (cross-reference TS 931 & Saf 03- Sod 95), Seven Mile reef, Sodwana Bay (27.4580°S, 32.7141°E), South Africa, 0 7 November 2003, collected by T Samaai, depth 20 m.

Type locality. Ramsey reef, Sodwana Bay, east coast of South Africa.

Description. Tubulo-digitate to fan-shaped sponges with massive multiple digitate lobes attached to a common base, 200 × 100 × 25 mm diameter; digits cavernous, insubstantial, composed of tight or loosely anatomising sub–branches ( Fig. 12 A–E). Surface conulose with randomly scattered oscules, 2–6 mm in diameter, raised slightly above surface with distinct membranous lip; Ostia, 0.4–2.1 mm in diameter, flush with surface. Surface with small tapering digitate or spiny processes arising from free branches; surface also grooved, striated and irregularly folded; when intact, ectosomal membrane stretched across adjacent branches. Texture hard, rubbery to the touch, fairly compressible. Colour in life deep red to pinkish red; in preservative beige.

Skeleton ( Fig. 12L, M ). Choanosomal skeleton is a regular or subrenieroid reticulation of ascending, primary spongin fibres (60–135 µm diameter) and transverse connecting fibres (25–39 µm diameter). Primary fibres cored by multispicular tracts of both choanosomal principal and subectosomal auxiliary megascleres; secondary fibres are pauspicular; echinating is abundant. The choanosomal principal styles echinate the fibre endings in the peripheral skeleton, usually forming plumose brushes; auxiliary megascleres are scattered between fibres. The subectoseome is a conspicuous palisade of tangential, paratangential and erect spicule brushes composed of smaller auxiliary subtylostyles, with choanosomal megascleres protruding through the surface, overlaying prominent plumose subectosomal spicule tracts.

Spicules. Megascleres ( Fig. 12 F–I). Styles, curved near base, thick, distally hastate or fusiform: 162 (112– 252) × 11 (11) µm, n = 10. Subtylostyles, straight, some curved near base, slightly subtylote, distally fusiform: 256 (124–312) × 6 (6) µm, n = 10. Ectosomal subtylostyles, straight, short, thin, somewhat microspined, distally fusiform 121 (65–162) × 4 (4) µm, n = 10. Acanthostyles, large recurved spines, distally fusiform: 75 (53–103) × 7 (7) µm, n = 10. Microscleres ( Fig. 12J, K ). Toxas, common, distributed throughout mesohyl, long, thin, rhapidiform, with little or no central curvature, to less commonly wing-shaped; short, thin, widely curved centrally: range 7.2–192.8 × 2 (2) µm, n = 20. Palmate isochelae in two size categories: range 7–19 µm, n = 10.

Substratum, depth range and ecology. Found on rock or dead coral reefs, sheltered between coral heads. Depth range 18– 20 m. This sponge is quite abundant in Sodwana Bay.

Etymology. Named for the variety of growth forms of this species displays.

Remarks. Clathria (Clathria) multiformis sp. nov. have 1) long, thin, rhapidiform toxas [(143 (7.2–192.8) × 2(2) µm)] with little or no central curvature; 2) a second, less common and much smaller form of wing shaped toxas; 3) a tubilo-digitate to fan shaped growth form with massive multiple digitate lobes attached to a common base; 4) oscules with a prominent raised membraneous ‘lip’; 5) short, thin, somewhat microspined ectosomal subtylostyles and 6) two categories of palmate isochelae. Although individually these distinctive characters are not unique amongst known species of Clathria , in combination they clearly differentiate C. (C.) multiformis sp. nov. from other species of Clathria (Clathria) as highlighted above in the remark section of C. (C) sodwaniensis sp. nov. The cavernous, insubstantial tubo-digitate growth form, regularly rectangular skeletal structure and deep red colouration are characteristic of the species, even though spicule geometry is unremarkable.

Key diagnostic characters.

• Sponge tubulo-digitate to fan-shaped.

• Presence long, thin, rhapidiform toxas.

• Oscules with a prominent raised membraneous ‘lip’.

• Ectosomal subtylostyles microspined.

• Two categories of palmate isochelae

Figures

FIGURE 12i, 12ii. Clathria (Clathria) multiformis sp. nov. A–E. In situ; F. Styles; G. Subtylostyles; H. terminally spined style; I. Acanthostyle; J. Palmate isochelae; K. Toxas. L & M. Skeletal architecture (L, x5; M, x10).