Hydractinia

• Main Author: ÁLVARO L. PEÑA CANTERO
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2017
• Subjects: Biodiversity; Taxonomy; Animalia; Cnidaria; Hydrozoa; Anthoathecata; Hydractiniidae; Hydractinia; Antarc*; Antarctic; Antarctica; Ross Sea
• Online Access: https://doi.org/10.5281/zenodo.4386768; http://treatment.plazi.org/id/C84B87CACC19FFA5E8DD06D00EBAF4DC

Hydractinia sp. (Fig. 2 D) Material examined. Stn 139, one colony fragment, 5 mm long, with a few polyps, basibiont of Campanularia hicksoni Totton, 1930 (NIWA 117481). Description. Gastrozooids 200–400 µm high and 100–200 µm in maximum diameter, with conical hypostome and distal crown of 5–8 filiform tentacles (Fig. 2 D). Each polyp usually within its own calyx delimited by perisarc ridges. No dactylozooids observed. Cnidome consisting of microbasic euryteles (10–11 x 4 µm), microbasic mastigophores (9 x 3 µm) and desmonemes (6–6.5 x 3.5 µm). Remarks. The material examined is morphologically close to H. dendritica Hickson & Gravely, 1907 by the distal position of the whorl of tentacles, the presence of perisarc ridges and spines, and the cnidome. However, H. dendritica has dactylozooids, which are not present here, although this could be related to the small colony fragment available. Peña Cantero (2015) only observed three dactylozooids in the abundant type material of H. dendritica . The infertile condition of the material also prevents me from giving a definitive identification. Ecology and distribution. The colony was collected at a depth of 236 m off Cape Hallet. Basibiont of Campanularia hicksoni . Published as part of ÁLVARO L. PEÑA CANTERO, 2017, Benthic hydroids (Cnidaria, Hydrozoa) from the Ross Sea (Antarctica) collected by the New Zealand Antarctic expedition BioRoss 2004 with RV Tangaroa, pp. 1-65 in Zootaxa 4293 (1) on pages 16-17, DOI:10.11646/zootaxa.4293.1.1, http://zenodo.org/record/828475