Demosponges from the sublittoral and shallow-circalittoral (<24 m depth) Antarctic Peninsula with a description of four new species and notes on in situ identification characteristics Author Goodwin, Claire E. Author Berman, Jade Author Hendry, Katharine R. text Zootaxa 2019 2019-08-23 4658 3 461 508 journal article 25927 10.11646/zootaxa.4658.3.3 c807f833-9fe4-45ec-b5d6-62c6b88979b3 1175-5326 3376028 D926CCEC-56EF-4E9A-98BE-CEB4D4D3D60A Hymedesmia ( Hymedesmia ) gaussiana Hentschel, 1914 ( Figure 10 ) Synonomy: Hymedesmia gaussiana Hentschel, 1914 Specimens. BELUM . Mc 2015.599 and BELUM . Mc 2015.609, Grotto Island , Verdansky Base ( Site 1) ( 65°14.615’S , 64° 15.019’W ), depth 14–24 m , BELUM . Mc 2015.637 and BELUM . Mc 2015.644 rocks near San Martin Island , BE- LUM. Mc 2015.657,— Detaille Island ( Site 1) ( 66°52.373’S , 66° 46.967’W ), depth 6–24 m ; collected by C. Goodwin and E. Priestley , 18/02/2015 . BELUM . Mc 2015.684 Rocks NW of Laktionov Island ( 65°45.536’S , 65° 47.319’W ), depth 6–23 m , BELUM . Mc 2015.699 and BELUM . Mc 2015.702 Vieugue Island ( 65°38.758’S , 65° 12.540’W ), depth 10– 22 m . BELUM . Mc 2015.759 Paradise Bay Wall ( 64°53.841’S , 62° 52.391’W ), depth 14–21 m ; collected by C. Goodwin and E. Priestley , 24/02/2015 . Comparative material examined. ZMB4795 slides of Holotype of Hymedesmia ( Hymedesmia ) gaussiana Hentschel, 1914 . External morphology. In situ appearance ( Figure 10A ): Rusty orange thin crust which can form large patches on bedrock (up to 30 cm in diameter). Oval pore sieves ~ 5 mm in diameter densely packed on surface. In some specimens algae in the tissues gave them a brown colour which contrasted more strongly with the red pore sieves. Preserved appearance. Thin crust (~ 1 mm thick). Firm with smooth surface. Preserving alcohol is coloured orange. Skeleton ( Figure 10B ): Hymedesmioid with a densely packed basal layer of primary and secondary acanthostyles. Ascending columns of ~15 strongyles. Spicules: Measurements from BELUM .Mc2015.599. Primary acanthostyles ( Figure 10C ): 255(353)419 by 22(28) 35 µm . Entirely spined with small spines but spines sparser towards the tip. Secondary acanthostyles ( Figure 10D ): 124(155)177 by 15(18( 20 µm . Entirely spined with small spines. Ectosomal aniso-strongyles ( Figure 10E, F ): 296(354)373 by 8(11) 14 µm often with one end slightly tylote. Arcuate chelae ( Figure 10G ): 28(34) 37 µm with a strongly curved shaft. Remarks. The spicules of our specimens were a good match in terms of size and form for the type specimen (our measurements from Holotype : Primary acanthostyles 243(282)323 by 28(30) 35 µm , secondary acanthostyles 125(148)170 by 17(22) 27 µm , strongyles 318(362)400 by 7(9) 10 µm , chelae 28(35) 41 µm . The large acanthostyles were slightly longer and more sparsely spined in some of our specimens than in the holotype . Our spicules also match those figured by Rios (2006) , although she records longer primary acanthostyles (250–390 by 25–52 µm ). Distribution. Originally recorded from 350 m depth in the Antarctic, H. gaussiana has also recently been recorded from Marguerite Bay in 355 m ( Rios 2006 ). From our survey this species also seems to be fairly common on shallow rock along the Antarctic Peninsula.