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 Halecium exaggeratum Peña Cantero, Boero & Piraino, 2013 ( Fig. 2C ) Material examined. TAN 0102/K0809 , a few stems up to 10 mm high, with putative male gonothecae, on tube of benthic organism ( NIWA 144358). Measurements (in µm). Hydrotheca : diameter at aperture 190–200, diameter at diaphragm 125, height 50. Hydrophore : adcauline length 300. Remarks. The relatively long hydrophore and the shape and size of the hydrotheca allow a certain identification. It is worth mentioning the occasional presence of a pseudodiaphragm, faintly visible in stained material ( Fig. 2C ). Ecology and distribution. The material, which represents the first record from the Balleny Islands, was collected at a depth of 292 m , off Young Island. Gonothecae present in March.