Iophon husvikensis, Goodwin & Brickle, 2012

Goodwin, Claire & Brickle, Paul, 2012, Sponge biodiversity of South Georgia island with descriptions of fifteen new species, Zootaxa 3542, pp. 1-48 : 7-8

Iophon husvikensis sp. nov.

( Figure 4)

Type material: Holotype: BELUM Mc 7673. Sample in 95% ethanol, tissue section and spicule preparation on slides; Husvik, South Georgia (54°10.285’S, 36° 40.412’W), depth 18m; collected by C. Goodwin, D. Poncet and P. Brewin, 26 th November 2010.

Paratypes: BELUM Mc 7666. Sample in 95% ethanol, tissue section and spicule preparation on slides, Husvik, South Georgia (54°10.285’S, 36° 40.412’W); depth 18m; collected by C. Goodwin, D. Poncet and P. Brewin, 26 th November 2010 . BELUM Mc 7647. Sample in 95% ethanol, tissue section and spicule preparation on slides. Bird Sound, Site 3, South Georgia (54°02.069’S, 38° 00.251’W); depth 6m; collected by J. Brown and S. Brown, 22 nd November 2010 .

Etymology: Named after the type locality, Husvik Harbour, South Georgia

External morphology: In situ appearance: Thick yellow crust with a smooth surface and occasional large, irregularly spaced, oscules, patches up to 30cm in diameter ( Fig. 4a).

Preserved appearance: Firm chocolate brown thick crust with a glassy smooth ectosome.

Skeleton: The choanosomal skeleton is an isodictyal reticulation of bundles of 2–4 styles, with some ascending columns of 3–4 styles visible. The ectosome is formed from a dense tangential layer of tornotes. Microscleres abundant throughout tissue ( Fig. 4b).

Spicules: Measurements from Mc7673.

Styles: 270(319)342 by 10.1(15.3)20.9µm, fat styles which come to an abrupt point, the majority are curved ( Fig. 4c).

Tylotes: 195(220)238 by 8.4(10.5)14.8µm with robustly spined, neatly rounded, tylote ends ( Fig. 4d, e).

Bipocoelles: 8(11)13µm aniso clawed ends, one of which bears a spur ( Fig. 4f).

Chelae: 12(16)20µm spurred anisochelae ( Fig. 4g).

Remarks: Seventeen valid species of Iophon are currently known from the Antarctic or sub-Antarctic, seven of which have smooth styles as choanosomal megascleres ( Table 2). All of these differ from this species in spicule form. Iophon abnormalis ( Ridley and Dendy, 1887) , and I. radiatum Topsent, 1901 have much larger chelae; I timidum Desqueyroux-Faúndez and van Soest, 1996 does not possess bipocoelles; I. chilense Desqueyroux- Faúndez and van Soest, 1996 has much smaller styles; and I. pluricornis var. trulliferum Hentschel,1914 has much larger styles and tylotes and smaller bipocoelles. Iophon hesperidesi Rios, Cristobo and Urgorri, 2004 has similar sized spicules but can be distinguished by the possession of unusual spoon shaped bipocoelles and also has less robustly spined ectosomal tylotes. Iophon pluricornis Topsent, 1907 can be distinguished from this and other Antarctic Iophon species by the possession of a category of entirely spined ectosomal tylotes in addition to those spined only on their ends ( Topsent 1913).