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 Homaxinella balfourensis ( Ridley & Dendy, 1886 ) ( Figure 22 ) Synonomy: Axinella balfourensis Ridley & Dendy, 1886 , Axinella supratumescens Topsent, 1907 , Homaxinella supratumescens ( Topsent, 1907 ) . Specimens. BELUM . Mc 2015.541 and BELUM . Mc 2015.546 Gøuvernoren Wreck , Enterprise Island ( 64°32.407’S , 61°59.884’W ),depth 8–18 m ; collected by C. Goodwin and E. Priestley , 13/02/2015 . BELUM . Mc 2015.559 , BELUM . Mc 2015.565 , BELUM . Mc 2015.568 , BELUM . Mc 2015.569 , BELUM . Mc 2015.575 Port Lockroy ( 64°49.572’S , 63° 29.390’W ), depth 12–17 m ; collected by C. Goodwin and E. Priestley , 14/02/2015 . BELUM . Mc 2015.681— Jenny Island ( 67°43.325’S , 68° 20.590’W ), depth 6–16 m ; collected by C. Goodwin and E. Priestley , 21/02/2015 . BE- LUM. Mc 2015.742 Rocks on west side of Pleneau Island ( 65°06.407’S , 64° 04.417’W ), depth 8–12 m ; collected by C. Goodwin and E. Priestley , 24/02/2015 . BELUM . Mc 2015.827 Diomedea Island ( 62°12.185’S , 58° 56.760’W ), depth 10–18 m ; collected by C. Goodwin and E. Priestley , 01/03/2015 . External morphology. In situ appearance ( Figure 22A ): Yellow branching sponge with branches ~ 0.5 cm in diameter. Specimens can be over 20 cm in height. Branches come abruptly to a sharp point. Some individuals have many branches, some only a few, and sometimes an individual may consist of a single branch. Branches may be undivided or divided. Dividing is sometimes dichotomous but can be very untidy and give the sponge a straggly appearance. Preserved appearance . Fairly soft pale cream branch with smooth surface. Alcohol stained pale yellow. Skeleton ( Figure 22B ): Choanosomal ascending columns of styles, up to 10 spicules thick, are joined by brush- es of ectosomal styles at the surface. Spicules ( Figure 22C ): Measurements from BELUM .Mc2015.742. Styles: 341(472)576 by 7.5(10.9) 14 µm . Thin styles, often slightly curved, heads not tylote. FIGURE 22. Homaxinella balfourensis ( Ridley & Dendy, 1886 ) . A. In situ appearance BELUM.Mc2015.575. B. Skeleton BELUM.Mc2015.742, scale bar 1000 µm. C. Styles BELUM.Mc2015.742, scale bar 200 µm. Remarks. The type locality of Axinella balfourensis Ridley & Dendy, 1886 is Kerguelen Island in 37– 110 m . Axinella supratumescens Topsent, 1907 was described from Ile Wiencke in 2–30 m and Booth Island, dead specimen on shore. Both are now placed in Homaxinella ( Topsent 1916 ) and considered synonyms ( Van Soest 2002c ). The species has been shown to be heavily impacted by anchor ice, with up to 87% being lost in a two year period ( Dayton 1989 ). Overwintering specimens may develop thinner branches and have a twiggy rather than bushy appearance (Jade Berman pers. obs.). Distribution. This species is widely distributed in the Antarctic and sub-Antarctic, in depths of between 0 and 500 m ( Koltun 1964 ; Brueggeman 1998 ). Published records include the Ross Sea ( Burton 1929 , 1934 ; Dayton 1989 ), South Georgia ( Burton 1932 ), Kerguelen ( Ridley & Dendy 1886 ), the Antarctic Peninsula ( Topsent 1907 ), and the South Shetland Islands ( Hajdu et al. 2016 ).