Halecium exaggeratum Peña Cantero, Boero & Piraino, 2013

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 : 329

Halecium exaggeratum Peña Cantero, Boero & Piraino, 2013

( Fig. 2C )

Material examined. TAN 0102/K0809, a few stems up to 10 mm high, with putative male gonothecae, on tube of benthic organism ( NIWA 144358).

Measurements (in µm). Hydrotheca: diameter at aperture 190–200, diameter at diaphragm 125, height 50. Hydrophore: adcauline length 300.

Remarks. The relatively long hydrophore and the shape and size of the hydrotheca allow a certain identification. It is worth mentioning the occasional presence of a pseudodiaphragm, faintly visible in stained material ( Fig. 2C ).

Ecology and distribution. The material, which represents the first record from the Balleny Islands, was collected at a depth of 292 m, off Young Island. Gonothecae present 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.