Symplectoscyphus cumberlandicus ( Jäderholm, 1905 )

Peña Cantero, Álvaro L., 2021, Additions to knowledge of the biodiversity of benthic hydroids (Cnidaria: Hydrozoa) in the Balleny Islands (Antarctica), Zootaxa 4966 (3), pp. 321-336 : 327-329

Symplectoscyphus cumberlandicus ( Jäderholm, 1905)

( Fig. 2A–B )

Material examined. TAN 0602/420, three stems up to 10 mm high ( NIWA 144240); TAN 0602/448, one stem 100 mm high, with gonothecae ( NIWA 144241).

Measurements (in µm). Hydrotheca: length abcauline wall 350–450, length free part of adcauline wall 140– 200, length adnate part of adcauline wall 370, length adcauline wall 510–570, diameter at aperture 160–200.

Remarks. The polysiphonic stem, branched in one plane, and the shape and size of hydrothecae ( Fig. 2A ) and gonothecae ( Fig. 2B ), the latter with about 13 spirally arranged rings, make certain the identification of the material from TAN 0602/448. The material from TAN 0602/420, although consisting of small stems up to 10 mm high, also agrees in the shape and size of the hydrothecae. One of the stems has, in addition, a basal 3-mm-long stolon, pointing to the polysiphonic condition found in larger stems.

Ecology and distribution. Present material, the first record of Symplectoscyphus cumberlandicus from the Balleny Islands, was collected at depths between 63 and 108 m off Young and Sturge islands. Gonothecae in material collected in March.

Figures

FIGURE 2. Symplectoscyphus cumberlandicus (Jäderholm, 1905): A, hydrothecae; B, gonotheca. Halecium exaggeratum Peña Cantero, Boero & Piraino, 2013: C, distal part of internode with hydrophore (arrow pointing to pseudodiaphragm) and hydrotheca. Schizotricha falcata Peña Cantero, 1998: D, forked hydrocladial internode and ahydrothecate internode (arrow); E, unforked hydrocladial internode showing hydrotheca and nematothecae; F, gonotheca; G–H, forked hydrocladial internodes from holotype (arrows pointing to perisarc indentations). Scale bar: 200 µm.