Hydrodendron arboreum ( Allman, 1888 )

Soto, Joan J. & Peña, Álvaro L., 2019, Benthic hydroids (Cnidaria, Hydrozoa) from the Weddell Sea (Antarctica), Zootaxa 4570 (1), pp. 1-78 : 43

Hydrodendron arboreum ( Allman, 1888)

( Fig. 14 h–j)

Material examined. ANT XV/3: 48-36, one colony, up to 80 mm high; ANT XVII/3: 111-5, one colony, c. 40 mm high; 111-6, several stems, c. 140 mm high, on stone, with gonothecae; 111-7, several stems, up to 120 mm high, and few stems, up to 6 mm high, on O. terranovae ; 111-9, several stems, up to 110 mm high, with gonothecae; 111- 18, one colony, c. 135 mm high, with gonothecae; 111-19, one colony, c. 20 mm high; ANT XXI/2: PS65/39, a few stems, up to 33 mm high; PS65/278, one colony, c. 50 mm high; PS65/279, few stems, up to 35 mm high, on sponge; PS65/280, one colony, c. 20 mm high; PS65/281, some stems c. 80 mm high.

Ecology and distribution. Species collected between 18 ( Hickson & Gravely 1907, as Halecium arboreum ) and 1370 m depth ( Peña Cantero & Ramil 2006); present material at 62– 175 m. Pan-Antarctic species widely distributed in Antarctic and sub-Antarctic waters ( Peña Cantero & Ramil 2006). Documented in the Weddell Sea by means of remote operate vehicle ( Dimmler et al. 2001), present contribution constitutes the first verifiable record from this Antarctic region.

Figures

FIGURE 14. a Halecium incertus: colony. b–c H. secundum: b hydrophore and hydrotheca; c gonothecae. d–g H. tubatum: d stem; e detail of the basal rings of the stem; f–g hydrothecae. h–j Hydrodendron arboreum: h stem showing hydrophores arrangement; i colony; j nematophore.