Iophon unicorne Topsent, 1907

(Fig. 2f–j)

Restricted synonymy: Iophon spatulatum Kirkpatrick, 1907, Iophon spatulatus Kirkpatrick, 1907; Iophon unicornis Topsent, 1907 .

Material examined: eight specimens collected at stations 1 (SOI; 60°28'S, 46°29'W; 139 m; 19/2/2014; MACNIn 44372; IEO-CSIC Col.), 2 (SOI; 60°53'S, 44°33'W; 218 m; 20/2/2014; MACN-In 44373), 3 (SOI; 61°31'S, 45°39'W; 308 m; 28/2/2014; MACN-In 44374; IEO-CSIC Col.), 4 (SOI; 60°55'S, 44°04'W; 256 m; 2/3/2014; MACN-In 44375), 7 (SOI; 61°00'S, 46°44'W; 609 m; 3/3/2014; IEO-CSIC Col.), 17 (SOI; 60°42,260'S, 46°01,18'W; 86 m; 8/3/2012; MACN-In 44376; IEO-CSIC Col.) and 18 (SOI; 60°47,561'S, 45°36,854'W; 96 m; 10/3/2012; MACN-In 44377; IEO-CSIC Col.) .

Description: Massive to slightly flabellate or digitiform specimens, sometimes with evident oscula, brown colour (Figure 2f). Spicules are oxeas of 400–630 µm by 20–30 µm; acanthotylotes of 270–350 µm/ 10 µm, usually mucronate at one end, rare anisochelae 17.5 µm and abundant bipocilli in many specimens, measuring 10–12.5 µm (Figure 2g –j).

Remarks: This is a common Antarctic species, well known from several locations and previously recorded by Koltun (1964), Ríos (2006), Campos et al. (2007), Göcke & Janussen (2013), Fernández et al. (2021), among others. It may be epibiotic on bryozoans, algae or ophiuroids. It was previously recorded at the SOI by Topsent (1913).