Antarctoscyphus grandis ( Blanco, 1977a )

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 : 38

Antarctoscyphus grandis ( Blanco, 1977a)

Sertularella biformis — Totton, 1930: 199 –200, fig. 45, pl. 2 fig. 8.

Antarctoscyphus grandis —Peña Cantero et al., 1999: 1750–1756, figs 4, 5, 7B–C (synonymy); Peña Cantero 2008: 458; 2010b: 768; 2013: 130; Peña Cantero & Vervoort, 2009: 87–87.

Material examined. Stn 7, two stem fragments up to 55 mm long, basibiont of Halecium interpolatum Ritchie, 1907 (NIWA 117549); Stn 8, two stems up to 90 mm high (MNCN 2.03/620); Stn 13, stem 100 mm high (NIWA 117550); Stn 17, five stems up to 110 mm high on pebbles (NIWA 117551); Stn 23, old stem 190 mm long, basally and distally truncated, giving rise to two secondary stems, basibiont of Hydractinia sp. (MNCN 2.03/621); Stn 39, four stems up to 300 mm high, with gonothecae (NIWA 117552); Stn 48, stem 280 mm high, with gonothecae (MNCN 2.03/622); Stn 52, two stems, 185 and 135 mm high, one basally truncated, other distally truncated (NIWA 117553); Stn 67, stem ca. 280 mm high, other stem 240 mm high (in two fragments), fragment 80 mm long, with gonothecae (MNCN 2.03/623); Stn 102, stem fragment 12 mm long (NIWA 117554); Stn 108, stem 130 mm high (NIWA 117555); Stn 124, colony with two stems, up to 210 mm high (one distally broken and without branches), with female gonothecae, basibiont of Staurotheca nonscripta and Billardia subrufa (MNCN 2.03/624); Stn 125, three stem fragments up to 11 mm long, belonging to two stems (NIWA 117556); Stn 130, basally truncated stem 105 mm high, with gonothecae (NIWA 117557); Stn 132, stem 170 mm high, with gonothecae (MNCN 2.03/625); Stn 143, basally broken stem 120 mm high, with gonothecae (NIWA 117558); Stn 150, two stems, 190 and 280 mm high, with gonothecae, basibiont of Symplectoscyphus sp. (NIWA 117559); Stn 178, three stems up to 180 mm high, with gonothecae (MNCN 2.03/626); Stn 179, stem 210 mm high (60 mm as hydrorhiza), stolons on pebbles (NIWA 117560); Stn 192, stem 19 mm long (NIWA 117561); Stn 197, four stems, 280, 240, 240 and 130 mm high, with gonothecae (NIWA 117562); Stn 198, stem fragment 18 mm long (NIWA 117563); Stn 206, distal stem fragment 65 mm long, with gonothecae (NIWA 117564).

Remarks. Distally broken stems frequently regenerate, giving rise to new stems at the end, sometimes even originating two stems of the same entity, as in the material from Stn 48. In the stem from Stn 143, three paired branches were becoming secondary stems.

Ecology and distribution. Revised by Peña Cantero et al. (1999) and Peña Cantero (2008). Hitherto considered a shelf species (Peña Cantero et al. 1997), found at depths between 15 ( Naumov & Stepanjants 1972) and 380 m (Peña Cantero et al. 1999); present material from 120 to 975 m, widely extending its bathymetric range to bathyal depths. Epilithic on pebbles, basibiont for colonies of Billardia subrufa , Halecium interpolatum , Hydractinia sp., Staurotheca nonscripta , and Symplectoscyphus sp. and with gonothecae in February and March.

Circum-Antarctic distribution (Peña Cantero et al. 1997). Recently recorded from off Deception and Livingston islands ( Peña Cantero 2008), off Elephant Island, Bransfield Island and the Bransfield Strait ( Peña Cantero & Vervoort 2009), off Peter I Island ( Peña Cantero 2010b), and off Low Island (Peña Cantero 2013), all in West Antarctica . See Peña Cantero et al. (1999) for earlier records. In the Ross Sea, already known from off Cape Adare ( Totton 1930). Present material from Robertson Bay and off Cape Adare, Adare Peninsula, Possession Islands , Moubray Bay and Cape Hallett.