Halecium elegantulum Watson 2008

• Main Author: Peña Cantero, Álvaro L.
• Format: Text
• Language: unknown
• Published: Zenodo 2014
• Subjects: Biodiversity; Taxonomy; Animalia; Cnidaria; Hydrozoa; Leptothecata; Haleciidae; Halecium; Halecium elegantulum; Antarctic; The Antarctic; Australian Antarctic Territory; Mawson Coast; Antarc*
• Online Access: https://dx.doi.org/10.5281/zenodo.4630877; https://zenodo.org/record/4630877

Halecium elegantulum Watson, 2008 (Fig. 5 A–F) Halecium elegantulum Watson, 2008: 170 –171, fig. 6 A–C. Material examined. Holotype, BANZARE , Stn 103 , 67°03'S – 74 ° 29 'E (Mawson Coast), 437 m, 10.2. 31, two microslides (Hydr. 709 / 13, F 147463.1 & F 147463.2), several stems on Symplectoscyphus cf. glacialis , together with Filellum sp. and Opercularella sp. Diagnosis. Tiny, monosiphonic, unbranched stems, formed by a series of hydrothecae, each emerging from previous one far below its rim. Hydrotheca strongly widening distally; rim slightly everted. Neither diaphragm nor desmocytes present. Cnidome and gonothecae unknown. Description. Stolonal hydrorhiza. Pedicels extremely long, up to several millimetres high (Fig. 5 A, B). Stems unbranched (Fig. 5 A–C), but formed by a series of hydrothecae, each emerging from the previous hydrotheca (Fig. 5 C). Sometimes, pedicels provided with a single distal hydrotheca (Fig. 5 B). Hydrothecae strongly widening distally (Fig. 5 A–F), rim slightly everted (Fig. 5 D, F). Apparently, neither diaphragm nor desmocytes present (Fig. 5 D–F). Lower-order hydrothecae arising far below rim of previous hydrotheca, not from diaphragm as usually happens to species of Halecium . Gonothecae absent. No nematocysts could be observed. Measurements (in µm). Hydrothecae : diameter at aperture 110–130, diameter at origin of lower-order pedicel 60–70, height from origin of lower-order pedicel to hydrothecal rim 25–50. Internodes : length several millimetres, diameter 50–55. Remarks. This species is peculiar and easily recognizable by the colony structure with unbranched, delicate stems, consisting of a succession of lower-order hydrothecae, as well as by the absence of hydrothecal diaphragm. Ecology and distribution. Halecium elegantulum is only known from off Mawson Coast, where it was found at a depth of 437 m (Watson 2008). : Published as part of Peña Cantero, Álvaro L., 2014, Revision of the Antarctic species of Halecium Oken, 1815 (Cnidaria, Hydrozoa, Haleciidae), pp. 243-280 in Zootaxa 3790 (2) on pages 253-255, DOI: 10.11646/zootaxa.3790.2.2, http://zenodo.org/record/226890 : {"references": ["Watson, J. E. (2008) Hydroids of the BANZARE expeditions, 1929 - 1931: the family Haleciidae (Hydrozoa, Leptothecata) from the Australian Antarctic Territory. Memoirs of the Museum of Victoria, 65, 165 - 178."]}