Additions to knowledge of the biodiversity of benthic hydroids (Cnidaria: Hydrozoa) in the Balleny Islands (Antarctica) Author Peña Cantero, Álvaro L. text Zootaxa 2021 2021-05-04 4966 3 321 336 journal article 6521 10.11646/zootaxa.4966.3.4 67f48cde-c614-4032-8c46-e21235b87124 1175-5326 4736691 F4CABF6C-1993-4112-A03E-4DBF708BB025 Staurotheca compressa Briggs, 1938 Staurotheca compressa — Peña Cantero & Vervoort, 2003: 2673–2676 , fig. 4; Peña Cantero 2009: 1749 . Material examined. E203 , a mass of stems 50 mm in diameter, with male gonothecae ( NIWA 128467); TAN 0102/ K0809 , one colony fragment 35 mm long, with female gonothecae, and one colony fragment 10 mm long, with male gonothecae ( NIWA 144358); TAN 0602/420 , a mass of stems 70 x 90 mm , with male gonothecae, basibiont of Campanularia sp. and O. bidentata ( NIWA 144251). Measurements (in µm). Hydrotheca : abcauline wall 430–450, free part of adcauline wall 150–250, adnate part of adcauline wall 350–520, adcauline wall 600–670, diameter at aperture 140–150. Ecology and distribution. In the area of study, Staurotheca compressa had been collected at depths from 55 to 234 m ( Peña Cantero & Vervoort 2003 ); present material between 103 and 292 m . Peña Cantero (2009) reported gonothecae in March; here, they are present in material collected in January and March. It has been observed as basibiont for colonies of L. longitheca ( Peña Cantero 2009 ) and Campanularia sp. and O. bidentata (present material). Previously known off Buckle Island ( Peña Cantero & Vervoort 2003 ) and Sturge Island ( Peña Cantero 2009 ). Here, found off Young and Sturge islands.