Oswaldella rigida Peña Cantero, Svoboda & Vervoort, 1997

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 : 59-60

Oswaldella rigida Peña Cantero, Svoboda & Vervoort, 1997

( Fig. 19 A)

Oswaldella rigida — González Molinero & Peña Cantero, 2015: 416 –419, 437–438, figs 11, 16K, 18C, 20C (synonymy).

Material examined. Stn 88, stem 68 mm high (NIWA 117342).

Remarks. The material studied agrees with this species. The stem is unbranched and undivided. There is no node between cauline apophyses and hydrocladia. These are perpendicular to the stem and bifurcated. Finally, there are two axillary nematophores on cauline apophyses. The length of the hydrothecal abcauline wall is 260–320 µm. See González Molinero & Peña Cantero (2015) for a SEM study on this material.

Ecology and distribution. Recently revised by González Molinero & Peña Cantero (2015). Shelf and slope species ( González Molinero & Peña Cantero 2015), found at depths between 80 ( Peña Cantero et al. 1997b) and 1157 m ( Peña Cantero 2014a); present material at 515 m.

Circum-Antarctic distribution ( Peña Cantero et al. 1997b). Present material is the first record from the Ross Sea, collected off Cape Hallet.

Figures

FIGURE 19. Oswaldella rigida Peña Cantero, Svoboda & Vervoort, 1997: A, hydrocladial internode with hydrotheca, mesial superior nematophore and mesial inferior nematotheca. Oswaldella stepanjantsae Peña Cantero, Svoboda & Vervoort, 1997: B, hydrocladial internode with hydrotheca and mesial inferior nematotheca. Oswaldella sp.: C, hydrocladial internode with hydrotheca, mesial superior nematophore and mesial inferior nematotheca. (A from Stn 88; B from Stn 17; C from Stn 178). Scale bar: 250 µm.