Oswaldella tottoni Peña Cantero & Vervoort, 1996

Soto, Joan J. & Peña, Álvaro L., 2019, Benthic hydroids (Cnidaria, Hydrozoa) from the Weddell Sea (Antarctica), Zootaxa 4570 (1), pp. 1-78 : 49

Oswaldella tottoni Peña Cantero & Vervoort, 1996

( Fig. 17 g–m)

Material examined. ANT XV/3: 48-194, few stems, up to 120 mm high, with gonothecae; ANT XXI/2: PS65/121, several stems, up to 150 mm high, with gonothecae; PS65/276, few stems, up to 120 mm high, with gonothecae.

Remarks. Only known with female gonothecae from its type locality in the Ross Sea ( Peña Cantero & Vervoort 1996), although no sex was attributed by the authors. Material examined here let us confirm a patent sexual dimorphism ( Fig. 17m ). Male gonotheca, 1.3–1.7 mm high x 0.7–0.8 mm maximum width, cylindrical with rounded end, fusiform in lateral view, with distal, circular aperture. Female gonotheca larger, 2.4–3.0 mm high x 1.2 mm maximum width, inverted cone-shaped, flattened in lateral view, with subterminal, oval aperture.

Ecology and distribution. Species reported from depths between 256 ( Peña Cantero & Vervoort 1996) and 400 m ( Peña Cantero et al. 1997a); present material from 244 to 277 m. Circum-Antarctic species ( Peña Cantero & Vervoort 2004).

Figures

FIGURE 17. a–f Oswaldella terranovae: a hydrotheca in lateral view; b hydrotheca in frontal view; c–d cauline apophysis showing nematophores; e hydrocaule with apophyses in triseriate arrangement; f male gonotheca in frontal view. g–m O. tottoni: g hydrotheca in lateral view; f hydrotheca in frontal view; i colony; j detail of the stem showing hydrocladial arrangement; k female gonootheca in lateral view; l male gonotheca in lateral view; m female gonotheca in frontal view (left) and male gonotheca in frontal view (right).