Eudendrium antarcticum Stechow, 1921

Soto, Joan J. & Peña, Álvaro L., 2019, Benthic hydroids (Cnidaria, Hydrozoa) from the Weddell Sea (Antarctica), Zootaxa 4570 (1), pp. 1-78 : 12

Eudendrium antarcticum Stechow, 1921

( Fig. 3g )

Material examined. ANT XV/3: 48-31, one colony, c. 15 mm high, on O. terranovae and Tubularia sp.1; 48-77, one colony, c. 15 mm high, with female gonophores; 48-197, one colony, c. 50 mm high; 48-276, one colony, 20 mm high, on B. subrufa ; ANT XVII/3: 111-19, one colony, c. 4 mm high, on H. interpolatum ; ANT XXI/2: PS65/ 292, one colony, c. 7 mm high.

Remarks. Non-reproductive material was attributed based on the cnidome, consisting of microbasic euryteles of only one size category [range 7.0–8.0 x 1.5–2.5 µm, mean 7.8±0.3 x 2.3±0.3 µm (n=23)], in agreement with previous material examined by Peña Cantero & Gili (2006) and Peña Cantero & Vervoort (2009). In the material examined here, unlike previous reports of the species (e.g. Puce et al. 2002), the female gonophores originated from partially atrophied hydranths with a reduced number of tentacles ( Fig. 3g ), probably due to the complete maturation of the gonozooid, as known to occur in other species of the genus, a process known as reproductive exhaustion (see Schuchert 2008b).

Ecology and distribution. In Antarctic waters, the species is known from depths between 240 ( Peña Cantero & Vervoort 2009) and 260 m ( Peña Cantero & Gili 2006); material examined collected at depths between 64 and 598 m, considerably extending its bathymetric range. Species previously reported from off South Africa, Bouvet, the Bransfield Strait area and doubtfully from Peter I Island [cf. Peña Cantero & Vervoort (2009) and literature therein]. Present contribution constitutes the first evidence of E. antarcticum from the Weddell Sea.

Figures

FIGURE 3. a–f Hydractinia dendritica: a–b general view of the colony; c detail of spines; d gastrozooids and dactylozooid (arrow); e gonozooid with gonophores; f dactylozooid (arrow). g Eudendrium antarcticum: female gonophore. h Eudendrium generale: female gonophore. i, k Eudendrium scotti: i gonozooid with male gonophores; k colony. j Eudendrium sp.2: gonozooid with male gonophores.