Eudendrium bentart Peña Cantero, 2013

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, Zootaxa 4293 (1), pp. 1-65 : 14-15

Eudendrium bentart Peña Cantero, 2013

Eudendrium bentart Peña Cantero, 2013: 125 –127, figs 2, 3A, B.

Material examined. Stn 30, three stems, up to 55 mm high (NIWA 117477).

Description. Little-branched thin stems, up to 55 mm high. Hydrocaulus slightly polysiphonic basally (e.g., 55 mm high stem slightly polysiphonic at basal 15 mm); accompanying tubes arising at base of pedicels and running downwards. Stems giving rise directly to pedicels or forming short, primary branches with up to three pedicels. Few short pedicels with hydranths. Perisarc completely ringed (from stems to pedicels). Primary branches strongly directed upwards, alternately arranged basally, but with spiral arrangement distally (one whorl every third branch). Primary branches short, usually acting as pedicels with single polyp; only few primary branches more developed, up to 5 mm long, with up to three short pedicels on upper side, forming an acute angle. Only few, well-preserved, white polyps present, 350–400 µm high, with 16–20 filiform tentacles and relatively basal little-marked groove.

Cnidome consisting of microbasic euryteles and large, putative isorhizas (not seen discharged).

Measurements (in µm). Cnidome: isorhizas [range 19.0–22.5 x 7.0–9.0, mean 21.1±1.0 x 7.8±0.4 (n=19); ratio, range 2.4–3.0, mean 2.7±0.2 (n=19)]; microbasic euryteles (7.5 x 3).

Ecology and distribution. Hitherto only known from depths between 82 and 97 m off Low Island (Peña Cantero 2013), in West Antarctica ; present material collected at a depth of 277 m, off Possession Islands , pointing to a circum-Antarctic distribution. This is the second record for the species and the first from the Ross Sea.