Schizotricha nana Peña Cantero, Svoboda & Vervoort, 1996

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 : 133

Schizotricha nana Peña Cantero, Svoboda & Vervoort, 1996

( Fig. 3H )

Schizotricha nana —Peña Cantero & Vervoort, 1999: 367 (synonymy).

Material examined. 63EV314, several stem fragments up to 250 mm long, with gonothecae (IK–2009–0483).

Remarks. Species easily distinguishable amongst the Antarctic species of the genus by the low, as high as wide, hydrothecae ( Fig. 3H ). Only Schizotricha falcata Peña Cantero 1998 also has low hydrothecae, but in this species stems are unbranched and there are no ahydrothecate internodes; S. nana is characterized by having branched stems and ahydrothecate internodes.

Measurements (in µm). Hydrotheca: height 145.2±26.8 (n=21), range 110–200; diameter at aperture 137.1±23.2 (n=17), range 100–180.

Ecology and distribution. Our material was collected at depths from 423 to 433 m, with gonothecae in January. Circum-Antarctic distribution ( Peña Cantero et al. 1996).

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.