Halecium interpolatum Ritchie, 1907

Peña Cantero, Álvaro L. & Marzal, Marina Fresneda, 2018, Benthic hydroids (Cnidaria: Hydrozoa) from off George V Coast (East Antarctica), Zootaxa 4441 (1), pp. 121-136 : 128

Halecium interpolatum Ritchie, 1907

( Fig. 3F )

Halecium interpolatum —watson, 2008: 171–172, fig. 7A, B; Peña Cantero, 2014c: 261 –263, figs 5G–J, 8A–B (synonymy).

Material examined. 48EV194, a few tiny stems up to 2 mm high, on S. glacialis (IK–2012–10437).

Remarks. Incipient stems with up to two hydrothecae. Species easily recognizable by the characteristic long and straight basal part of internodes ( Fig. 3F ) and the size of the microbasic eurytele nematocysts (10 X 5 µm).

Ecology and distribution. Our material was collected at depths from 325 to 409 m, epibiotic on Symplectoscyphus glacialis . Watson’s (2008) material was found at a depth of 4–13 m, in Commonwealth Bay. Circum-Antarctic distribution ( Peña Cantero 2014c).

Figures

FIGURE 3. Staurotheca antarctica Hartlaub, 1904: A, hydrothecae. Staurotheca nonscripta Peña Cantero, Svoboda & Vervoort, 1997: B, hydrotheca. Staurotheca pachyclada (Jäderholm, 1904): C, hydrotheca. Antarctoscyphus spiralis (Hickson & Gravely, 1907): D, internode with hydrotheca showing intrathecal cusps (arrow). Symplectoscyphus glacialis (Jäderholm, 1904): E, internode with hydrotheca. Halecium interpolatum Ritchie, 1907: F, incipient stem with distal hydrotheca (arrow pointing to characteristic long and straight basal part of internode). Abietinella operculata (Jäderholm, 1903): G, hydrotheca (arrow pointing to disc-shaped operculum) and nematotheca (arrow). Schizotricha nana Peña Cantero, Svoboda & Vervoort, 1996: H, unforked hydrocladial internodes showing hydrothecae and nematothecae. Oswaldella erratum Peña Cantero & Vervoort, 1997: I, hydrocladial internode showing hydrotheca and mesial inferior nematotheca (arrow). Scale bars: 200 µm.