Antarctoscyphus gruzovi ( Stepanjants, 1979 )

Peña Cantero, Álvaro L., Roig Ferrer, Estela & Miranda, Thais P., 2017, Species of Antarctoscyphus Peña Cantero, García Carrascosa and Vervoort, 1997 (Cnidaria: Hydrozoa: Symplectoscyphidae) collected by US Antarctic expeditions: biogeographic implications, Journal of Natural History (J. Nat. Hist.) 51 (25 - 26), pp. 1437-1477 : 1463

Antarctoscyphus gruzovi ( Stepanjants, 1979)

( Figure 11 )

Sertularella gruzovi Stepanjants, 1979, p. 67 , pl. 12, fig. 1, pl. 25, fig. 5.

Antarctoscyphus gruzovi – Peña Cantero et al., 1997, p. 26; 1999, p. 1756–9, figs 6, 7D; Soto Àngel and Peña Cantero, 2015, p. 993, fig. 6c–e.

Material examined

Eltanin: 6/418, stem fragment, c. 9 mm long, and branch fragment, c. 8 mm long.

Diagnosis

Stems polysiphonic, unbranched, up to 65 mm high. Cauline internodes distinctly arranged in zigzag fashion. Cauline apophyses alternately arranged in one plane. Paired branch re-branching at second and fifth internodes, giving rise to branches of second order; succeeding branches at every third internode (branches up to the third order). Branch internodes long and slender; decreasing in length distally. Hydrothecae alternately arranged in two planes making an acute angle; strong tendency to unilateral disposition. Hydrothecae cylindrical, long and roughly straight; adcauline hydrothecal wall free. Hydrothecal aperture cusps of similar development and separated by shallow embayments. Gonothecae long and thin, almost cylindrical.

Ecology

Found with gonothecae in February ( Stepanjants 1979).

Bathymetric and geographic distribution

Antarctoscyphus gruzovi was reported at depths from 276 m ( Soto Àngel and Peña Cantero 2015) to 414 m (Peña Cantero et al. 1999); present material from 311– 426 m.

Species with a known distribution limited to a small area. It had only been recorded for the Elephant Island area ( Stepanjants 1979; Peña Cantero et al. 1999; Soto Àngel and Peña Cantero 2015). Our material was collected off the nearby d’ Urville Island (Antarctic Peninsula).

Figures

Figure 11. Antarctoscyphus gruzovi (Stepanjants, 1979): (a) fragment of lateral branch showing branching and hydrothecal arrangement; (b) cauline apophysis showing axillary hydrotheca and basal part of paired branches; (c, d) hydrocladial branching; (e) hydrotheca; (f) detail of distal part of hydrotheca showing opercular flaps. Scale bars: 1 mm (a), 350 µm (c), 200 µm (b, d), 150 µm (e), 50 µm (f).