Symplectoscyphus exochus Blanco, 1982

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 : 42-44

Symplectoscyphus exochus Blanco, 1982

( Fig. 12 F)

Symplectoscyphus exochus— Peña Cantero, 2010a: 36 (synonymy); 2012: 861, fig. 7b; 2013: 133, fig. 4C; 2014a: 1724, fig. 6c.

Material examined. Stn 53, incipient stem with three hydrothecae on Staurotheca nonscripta (NIWA 117577)—material doubtfully assigned to this species; Stn 67, two stems up to 7 mm high on Staurotheca nonscripta (MNCN 2.03/637)—material doubtfully assigned to this species; Stn 148, stem fragment 10 mm long, with incipient gonothecae (NIWA 117578).

Measurements (in µm). Hydrothecae: length of abcauline wall 230, length free part of adcauline wall 200, length adnate part of adcauline wall 200, length adcauline wall 400, diameter at aperture 120.

Remarks. Despite the scarcity of material from Stn 148, the species could be undoubtedly identified because of the presence of incipient gonothecae with ringed walls, which undoubtedly separates it from S. glacialis . However, the remaining material is doubtfully assigned to S. exochus due to its infertile condition. It is difficult to separate this species from S. glacialis in the absence of gonothecae (cf. Peña Cantero & Vervoort 2009) because both species may have very similar hydrothecae.

Ecology and distribution. Eurybathic species, collected at depths from 15 ( Vervoort 1972b) to 1958 m ( Peña Cantero 2012); present material from 389 to 397 m.

Circum-Antarctic ( Peña Cantero 2014a). Recently reported from the Bellingshausen Sea ( Peña Cantero 2012) and off Low Island (Peña Cantero 2013), in West Antarctica , and off Queen Mary Coast ( Peña Cantero 2014a), in East Antarctica . See Peña Cantero (2010a) for previous records. Present material is the first record from the Ross Sea, off Moubray Bay .

Figures

FIGURE 12. Antarctoscyphus admirabilis Peña Cantero, Svoboda & Vervoort, 1999: A, branch internode with hydrotheca. Symplectoscyphus aggregatus (Jäderholm, 1917): B, fragment of branch with hydrothecal arrangement and shape. Symplectoscyphus anae Peña Cantero, Svoboda & Vervoort, 2002: C, internode with hydrotheca. Symplectoscyphus densus sp. nov.: D – E, fragment of branch with hydrothecal arrangement and shape; Symplectoscyphus exochus Blanco, 1982: F, internode with hydrotheca. Symplectoscyphus liouvillei (Billard, 1914): G, internode with hydrotheca. Symplectoscyphus vanhoeffeni Totton, 1930: H, internode with hydrotheca. Symplectoscyphus weddelli Peña Cantero, Svoboda & Vervoort, 2002: I, internode with hydrotheca. Symplectoscyphus sp. 1: J, internode with hydrotheca. Symplectoscyphus sp. 2: K, internode with hydrotheca. (A from Stn 17; B from Stn 112; C from Stn 126; D from Stn 7 (holotype); E from Stn 97 (paratype); F from Stn 67; G from Stn 150; H from Stn 130; I, from Stn 53; J from Stn 7; K from Stn 25). Scale bar: 250 µm.