Hydrodendron arboreum

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.