Cinachyra barbata Sollas, 1886

Goodwin, Claire & Brickle, Paul, 2012, Sponge biodiversity of South Georgia island with descriptions of fifteen new species, Zootaxa 3542, pp. 1-48 : 4-6

Cinachyra barbata Sollas, 1886

( Figure 2)

Synonymy: Cinochyra barbata Sollas, 1886 (misspelling of the genus). Cinachyra barbata Sollas, 1888 .

Material: All samples in 95% ethanol, tissue section and spicule preparation on slides. BELUM Mc 7577. Morraine Fjord, South Georgia (54º 18.800´S, 36º 29.600´W); depth range: 13–17.5m; collected by C. Goodwin and J. Brown, 18 th November 2010 .

Comparative material examined: BMNH 1908.2.5.52 Cinachyra barbata (Sollas) . Antarctic expedition root tuft. Dried specimen.

BMNH 08.2.5.212 and 213. Cinachyra barbata (Sollas) . National Antarctic Expedition, Hut point, winter quarters. Dried specimens.

External morphology: In situ appearance: Massive globular sponge 25cm in diameter. Exterior heavily silted and hispid with numerous circular pore fields (porocalicies), up to 1cm in diameter, fringed by rings of spicules which protrude far beyond the ectosome ( Fig. 2a).

Preserved appearance: Transverse slice of sponge. Robust, uncompressible with grey choanosome and white cortex 5mm in diameter. Fringe of brown spicules mostly ~ 1cm in length but some tufts up to 3cm.

Skeleton: The globular part has a radiate skeleton with bundles of long oxeas radiating out towards the periphery ( Fig. 2b), the peripheral bundles consist of oxeas and protrianenes, the latter protrude beyond the surface ( Fig. 2c). The cortex is reinforced by cortical oxeas, strewn at all angles, and sigmaspire microscleres. Anatriaenes only occur in the basal mass where they function as anchoring spicules, this was not sampled with this specimen.

Spicules: Choanosomal oxea: up to 8000µm, sharply pointed, straight or curved.

Protriaenes: In two distinct categories; up to 13,000 by 30µm with cladi up to 180 by 16µm and smaller hair like 130 by 4µm with cladi 16–30µm (measurements from van Soest & Rützler, 2002).

Cortical oxea: 587 (742) 897 by 26.7 (41.2) 58.5µm, fusiform, bluntly pointed.

Sigmaspires: 8.7 (10.2) 12.6µm ( Fig. 2d).

Anatriaenes (up to 40,000 by 24µm) are present in the type but not recorded here as the basal mass was not sampled.

Remarks: The presence of porocalicies (pore bearing pits) and a cortical region reinforced with short oxeas assign this specimen to the genus Cinachyra Sollas, 1886 . There are three valid species: Cinachyra barbata Sollas, 1886 ; Cinachyra antarctica ( Carter, 1872) and Cinachyra helena Rodriguez and Muricy, 2007 ; the two former have been recorded in the Antarctic but the latter is only currently known from Brazil. The size of the cortical oxeas and sigmaspires and the external form in our specimen are a good match for Cinachyra barbata , it was too difficult to extract and measure the larger spicules but in any case measurements given in the type description are not very precise and unlikely to aid diagnosis. C. barbata may be distinguished from C. antarctica by its lack of sigmaspires.

Distribution: This species was originally described from Balfour Bay, Kerguelen (from more than 60 syntypes) and is found on sediment rich bottoms from 18–549 m on Antarctic shores: Wilheim II Coast, Budd Coast, Victoria Land, South Shetlands, Lars Christensen, McMurdo Sound ( Burton 1929; Koltun 1964; van Soest and Rützler 2002) and Annenkov Island and Larsen Harbour, South Georgia ( Burton 1940).