Filellum antarcticum

• Main Author: Peña Cantero, Álvaro L.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2021
• Subjects: Biodiversity; Taxonomy; Animalia; Cnidaria; Hydrozoa; Leptothecata; Lafoeidae; Filellum; Filellum antarcticum; Antarctic; Balleny Islands; Sturge Island; Antarc*; Antarctica
• Online Access: https://zenodo.org/record/4736703; https://doi.org/10.5281/zenodo.4736703

Filellum antarcticum (Hartlaub, 1904) (Fig. 1A–C) Material examined. E203, several hydrothecae and two coppiniae, on Stegella lobata (Vanhöffen, 1910) (NIWA 128467). Remarks. The presence of coppinia in the present material allows identification with confidence. The nestshaped coppinia consists of closely packed gonothecae (Fig. 1A) surrounded by a fence of distally open defensive tubes arching over them. The gonothecae are deprived of distal neck (Fig. 1B). Some of them, however, with distal part slightly raised (Fig. 1C), but never forming a distally everted neck as found in the other known Antarctic species of the genus, Filellum magnificum Peña Cantero, Svoboda & Vervoort, 2004. The gonotheca is roughly 260 µm high, 130 µm in maximum diameter, and 65–70 µm in diameter at aperture. The shape and size of the hydrothecae in the present material also match Hartlaub’s species, with a hydrothecal diameter of 100–120 µm. Ecology and distribution. The material, which represents the first record for the area, was collected at a depth of 187 m off Sturge Island, epibiotic on S. lobata. Coppiniae in January. Published as part of Peña Cantero, Álvaro L., 2021, Additions to knowledge of the biodiversity of benthic hydroids (Cnidaria: Hydrozoa) in the Balleny Islands (Antarctica), pp. 321-336 in Zootaxa 4966 (3) on page 323, DOI:10.11646/zootaxa.4966.3.4, http://zenodo.org/record/4736691