Schizotricha turqueti Billard, 1906

ÁLVARO L. PEÑA CANTERO, 2017, Benthic hydroids (Cnidaria, Hydrozoa) from the Ross Sea (Antarctica) collected by the New Zealand Antarctic expedition BioRoss 2004 with RV Tangaroa, Zootaxa 4293 (1), pp. 1-65 : 57-58

Schizotricha turqueti Billard, 1906

Schizotricha turqueti — Peña Cantero & Vervoort 1999: 371–372 (synonymy); 2005: 812–814; 2009: 85–86; Peña Cantero, 2006: 937–938, fig. 3d; 2008: 456; 2013: 129; Galea & Schories, 2012: 13–15, fig. 3g –k.? Schizotricha cf. turqueti — Soto Àngel & Peña Cantero, 2015: 992, fig. 5n–o.

? Schizotricha unifurcata — Totton, 1930: 231, fig. 65a–f, pl. 3 fig. 4.

Material examined. Stn 7, stem 225 mm high, basibiont of Sympletoscyphus sp. 1, and fragmented stem (largest fragment 80 mm long) (NIWA 117332); Stn 8, 45 stems up to 280 mm high, with male gonothecae, basibiont of Symplectoscyphus curvatus (NIWA 117333); Stn 13, six stems up to 220 mm high on gravel and pebbles (MNCN 2.03/668); Stn 15, ten stems up to 260 mm high, with male and female gonothecae, on shell fragments, stones and pebbles (NIWA 117334); Stn 17, ca. 30 stems up to 230 mm high on pebbles and stones, basibiont of Abietinella operculata and Symplectoscyphus sp. 1 (MNCN 2.03/669); Stn 18, two stems 220 and 110 mm high, and distal stem fragment 45 mm long (NIWA 117335); Stn 25, stem 180 mm high, with gonothecae, basibiont of Rhizorhagium antarcticum (NIWA 117336); Stn 37, stem 250 mm high, with male gonothecae (MNCN 2.03/670); Stn 67, stem 170 mm high, basibiont of A. operculata (NIWA 117337); Stn 96, stem 100 mm high (MNCN 2.03/ 671); Stn 105, basally truncated stem 65 mm long (NIWA 117338); Stn 150, three stems, 210, 130, and 190 mm high (NIWA 117339); Stn 178, nine stems up to 270 mm high, with gonothecae (MNCN 2.03/672); Stn 194, fragmented stem 150 mm high (NIWA 117340).

Remarks. Species characterized by having unbranched stems, although secondary stems are sometimes observed ( Peña Cantero & Vervoort 2005; Peña Cantero 2013). I also observed this in the material studied, but it seems to be associated to regeneration following fracture of the original stem ( Peña Cantero & Vervoort 2005). A particular case is observed in the 180 mm high stem from Stn 25, in which first branching was clearly caused by breaking of the main stem, as both “secondary stems” are of similar development. However, it is noteworthy that one of the secondary stems gives rise to three third-order stems and the other forms a third-order stem. Anyway, as Peña Cantero & Vervoort (2005) indicated, branching in S. turqueti clearly differs from the branching pattern found in typically branched species of Schizotricha .

Contrasting with previous knowledge on the species, it is noticeable the presence of up to eightieth-order hydrocladia, and up to two nematothecae on cauline apophyses. In addition, there are up to three infrathecal nematothecae on forked hydrocladial internodes; the species has usually been reported with one or two, although Peña Cantero & Vervoort (2009) already observed up to four. Finally, double unforked hydrocladial internodes have been repeatedly reported (cf. Peña Cantero & Vervoort 2005, 2009; Peña Cantero 2013).

Ecology and distribution. Eurybathic species ( Peña Cantero & Vervoort 2005), recorded from the intertidal level ( Billard 1906) to a depth of 1890 m ( Peña Cantero & Vervoort 2005); present material from 110 to 736 m, on shell fragments, gravel, pebbles and stones, basibiont of colonies of Rhizorhagium antarcticum , Abietinella operculata , Symplectoscyphus curvatus and Symplectoscyphus sp. 1, and with gonothecae in February.

Circum-Antarctic species ( Peña Cantero & Vervoort 2005). Recently reported from off Elephant Island and Bransfield Strait ( Peña Cantero & Vervoort 2009), off Livingston Island (Peña Cantero 2006, 2008), off Deception Island and Trinity Island ( Peña Cantero 2008), off Low Island (Peña Cantero 2013), and off King George Island ( Galea & Schories 2012), all in West Antarctica . See Peña Cantero & Vervoort (2005) for previous records. In the Ross Sea, already known from off Franklin Island and off Cape Adare ( Peña Cantero & Vervoort 2005). Present material collected off Cape Adare, Adare Peninsula, Possession Islands, Moubray Bay and Cape Hallet.