(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.