Sertularella valdiviae Stechow, 1923

Cantero, Álvaro Luis Peña, 2023, On some benthic hydroids from New Zealand deep waters, with the description of a new species, Zootaxa 5389 (2), pp. 241-252 : 247

Sertularella valdiviae Stechow, 1923

( Fig. 4c–d )

Sertularella valdiviae Stechow, 1923: 11 ; 1925: 471, fig. 31; Galea et al., 2017: 306–307 , figs. 12G, H, 17I–L, 18A–D (synonymy).

Material examined. TRIP 2832/30, a few stems up to 15 mm high, without gonothecae, on tube of benthic organism ( NIWA 65573).

Description. Monosiphonic stems up to 15 mm high and with up to three incipient lateral branches; only one with a hydrotheca. Stems divided into relatively long and thin internodes arranged in a marked zigzag. Perisarc of internodes smooth.

Hydrothecae alternately arranged in one plane, widely separated. Hydrotheca flask-shaped, slightly curved outwards. Maximum diameter where hydrotheca becomes free; diameter gently decreasing distally and more markedly basally. Adcauline wall adnate to internode for less than half its length; free part slightly convex, with three weakly-marked undulations; adnate part straight or somewhat convex. Most abcauline wall slightly convex, becoming concave at distal part. Rim of hydrothecal aperture with four equally-developed cusps separated by shallow embayments.

Measurements (in µm). Internodes: length 950–2200, diameter at hydrothecal base 220–230. Hydrotheca: abcauline length 430–510, free adcauline length 360–410, adnate adcauline length 230–280, adcauline length 590– 680, diameter at aperture 210−240, diameter at diaphragm 130, maximum diameter 270–290.

Remarks. The present material is in complete agreement with Stechow’s species in the long and geniculate internodes and in the shape and size of the hydrotheca.

Ecology and distribution. The material studied was collected at depths between 977 and 1037 m, southeast off Stewart Island, epibiotic on tube of benthic organism. This constitutes the first record of the species from New Zealand waters.

Figures

FIGURE 4. (a–b) Clytia gigantea (Hincks, 1866): a, hydrotheca; b, cusps of hydrothecal aperture. (c–d) Sertularella valdiviae Stechow, 1923: c, part of stem showing hydrotheca and incipient branch; d, hydrotheca. (e–h) Cryptolaria prima Busk, 1857: e, part of stem showing hydrothecal arrangement; f–g, hydrothecae; h, nematotheca. Scale bar: 100 µm (b, h), 200 µm (a, c−g).