New records of demosponges (Porifera) from the South Orkney Islands (Antarctica) with a checklist for the region Author Schejter, Laura Author Cristobo, Javier Author Ríos, Pilar text Zootaxa 2024 2024-01-23 5403 4 401 430 http://dx.doi.org/10.11646/zootaxa.5403.4.1 journal article 10.11646/zootaxa.5403.4.1 1175-5326 10562154 C2EAB19C-07CB-4013-9C93-D25259EA2673 Mycale (Oxymycale) acerata Kirkpatrick, 1907 ( Fig 6a ) Restricted synonymy: Mycale acerata Kirkpatrick, 1907 . Material examined: 3 specimens collected at stations 1 ( SOI ; 60°28'S , 46°29'W ; 139 m ; 19/2/2014 ; MACN-In 44389; IEO-CSIC Col.), 4 ( SOI ; 60°55'S , 44°04'W ; 256 m ; 2/3/2014 ; MACN-In 44390; IEO-CSIC Col.), and 9 ( SOI ; 60°57'S , 46° 01'W ; 229 m ; 5/3/2014 ; MACN-In 44391; IEO-CSIC Col.) . Description: Massive, flexible and soft sponges, beige/light brown in colour. Verrucose surface, with a characteristic reticulate ectosome and a fibrose-reticular choanosome of thick fibers, especially in older parts of the sponge body ( Figure 6a ). One of the specimens is broken and badly preserved. Megascleres are oxeas 750–950/ 20–30 µm. Microscleres are two categories of anisochelae of 70–90 µm (this category is absent in the broken specimen) and 25–55 µm, and raphides in trichodragmata 100–210 µm. Remarks: This is a common species, very well described and frequently collected in Antarctic and subantarctic waters (e.g. Göcke & Janussen (2013) , Ríos (2006) , Desqueyroux (1989), Fernández et al. (2021)) . It was previously recorded at the SOI by Topsent (1913) , Burton (1932) and Koltun (1964) .