Antarctoscyphus spiralis

Antarctoscyphus spiralis (Hickson and Gravely, 1907)

(Figure 13)

Sertularella spiralis Hickson and Gravely, 1907, p. 19, pl. 3, figs 19–20; Totton, 1930, p. 197, fig. 44b–d, pl. 1, fig. 7, pl. 3, fig. 5; Broch, 1948, p. 10, fig. 2; Naumov and Stepanjants, 1972, p. 42, fig. 5c; Stepanjants, 1972, p. 69, fig. 15; 1979, p. 68, pl. 12, fig. 2.

Sertularella bifurca Billard, 1914, p. 22, fig. 13.

Symplectoscyphus spiralis – Briggs, 1938, p. 34; Blanco, 1967, p. 270, pl. 3, figs 3–5, 9; 1968, p. 41, figs 1–23; 1984, p. 31, pl. 27, fig. 62, pl. 28, fig. 63; Vervoort, 1972, p. 139; Peña Cantero, 1991, p. 143–7, pls 24, 53, figs a–e, 67, fig. b; Peña Cantero and García Carrascosa, 1994, p. 124, fig. 6g; 1995, p. 79, figs 32d–e, 33a–e, 64a.

Antarctoscyphus spiralis – Peña Cantero et al., 1997, p. 27; 1999, p. 1759–60, fig. 2G–H; Peña Cantero, 2006, p. 939, fig. 3K; 2008, p. 459; 2010, p. 768; 2012, p. 858; 2013, p. 130; Peña Cantero and Gili, 2006, p. 767; Peña Cantero and Vervoort, 2009, p. 87; Galea and Schories, 2012, p. 9, fig. 2N–P; Soto Àngel and Peña Cantero, 2015, p. 993, fig. 6a–b.

Material examined

Eltanin: 6/418, several fragments, up to 30 mm long, with male gonothecae; 6/445, numerous fragments, up to 60 mm long; 7/484, three stem fragments, up to 35 mm long; 12/1002, a few stem fragments, up to 23 mm long; 12/1003, several stem fragments, up to 45 mm long; 27/1877, one stem fragment, c. 26 mm long; 27/1896, several stem fragments, up to 80 mm long; 27/1937, one stem, c. 70 mm high, basibiont of Hebella sp.; 32/1995, several fragments, up to 20 mm long; 32/1996, numerous fragments, up to 40 mm long; 32/1997, several stem fragments, up to 17 mm long; 32/2018, one stem, c. 30 mm high; 32/2021, a few stem fragments, up to 65 mm long; 32/2080, one stem, c. 35 mm high, on hydrocoral; 32/2082, numerous stem fragments, up to 70 mm long; 32/2083, one stem, c. 35 mm high; 32/2125, several stem fragments, up to 35 mm long, with gonothecae. Glacier: GLD-13, a few stem fragments, up to 130 mm long; SOSC-L 80, several fragments, up to 25 mm long; SOSC-L 101, two fragments, c. 18 and 13 mm long, with one female? gonotheca; SOSC-L 113, two fragments, up to 15 mm long; 766, one fragment, c. 18 mm long, with gonothecae; 767, several stem fragments, up to 80 mm long, with gonothecae; 768, one fragment, c. 12 mm long. Hero: 691/020, four incipient stems, up to 15 mm high, on Staurotheca frigida Peña Cantero, Svoboda and Vervoort, 1997a; 691/026, one stem fragment, c. 45 mm long; 691/031, a few stem fragments, up to 30 mm long; 702/464, three stem fragments, up to 45 mm long; 702/ 465, one stem fragment, c. 45 mm long; 721/805, one stem, c. 80 mm high; 721/938, one stem, c. 8 mm high, and one fragment, c. 30 mm long; 721/1063, one stem fragment, c. 23 mm long, and two branch fragments; 731/1756, one stem, c. 80 mm high, and several branch fragments; 731/1938, two fragments, c. 5 and 20 mm long; 731/1944, one branch fragment, c. 23 mm long; 824/022–1, two fragments, up to 17 mm long; 824/ 040–1, one stem, c. 60 mm high, and one fragment, c. 20 mm long. Islas Orcadas: 575/ 031, several fragments, up to 60 mm long; 575/066, several stem fragments, up to 100 mm long; 575/069, numerous colonies, up to 170 mm high, with gonothecae, basibiont of Sertularella sp.; 575/070, a few stem fragments, up to 115 mm high; 575/ 073, several stems, up to 115 mm high; 575/095, two stem fragments, c. 30 and 15 mm long; 575/097, two fragments, up to 10 mm long. Wilkes Station: 000AZ, one stem, up to 190 mm high.

Diagnosis

Monosiphonic stems up to 180 mm high. Stem internodes in distinct zigzag arrangement. Paired branches ramifying recurrently, alternately in one plane and at each third internode. Hydrothecae alternately arranged in two planes forming an obtuse angle. Hydrotheca nearly straight or slightly curved abcaudally; adnate to internode at least one-third of its length. Hydrothecal aperture cusps usually of similar development and separated by shallow embayments; sometimes an abcauline cusp distinctly more developed; one internal cusp at each embayment. Female gonotheca elongate-ovate, without pedicel and with circular, distal aperture. Male gonotheca fusiform, with circular, distal aperture.

Remarks

Part of the material from Stn 575/070, collected at a depth of 161–210 m off Visokoi Island (South Sandwich Islands), has no intrathecal cusps. However, it can be recognized because the hydrothecal aperture is triangular with straight sides, in contrast to what happens in A. asymmetricus, where the aperture is triangular with convex sides and, consequently, wider.

Ecology

Collected on bottoms of mud (Totton 1930; Briggs 1938; Broch 1948; Naumov and Stepanjants 1972; Peña Cantero et al. 1999), gravel (Naumov and Stepanjants 1972), animal debris (Totton 1930), stones (Peña Cantero et al. 1999), rocks (Stepanjants 1979), mud and gravel (Naumov and Stepanjants 1972), and hydroids and sponges (Naumov and Stepanjants 1972). Found epilithic on stones (Peña Cantero 2006, 2008), pebbles (Peña Cantero 2013) and gravel (Peña Cantero 2008), and epibiotic on algae, hydroids, molluscs (Naumov and Stepanjants 1972; Stepanjants 1979), bryozoans (Naumov and Stepanjants 1972; Stepanjants 1979; Peña Cantero et al. 1999; Peña Cantero 2008, 2013; Galea and Schories 2012), tubes of polychaetes (Naumov and Stepanjants 1972; Stepanjants 1979; Peña Cantero et al. 1999; Peña Cantero 2006, 2008), ascidians (Peña Cantero 2008, 2013) and dead gorgonians (Peña Cantero 2013); we found it epibiotic on the hydroid Staurotheca frigida and on a hydrocoral. Used as substratum by the hydrozoans Phialella belgicae (Peña Cantero 2008), Hebella sp. and Sertularella sp. (present material). Gonothecae found in January (Stepanjants 1979), February (Stepanjants 1979; Peña Cantero 2008, 2013; Peña Cantero and Vervoort 2009; Galea and Schories 2012), June (Stepanjants 1979), July (Hickson and Gravely 1907) and December (Stepanjants 1979; Blanco 1984); gonothecae in our material recorded in January, February and June.

Bathymetric and geographic distribution

Eurybathic species, found at depths from 6 m (Naumov and Stepanjants 1972) to 1958 m (Peña Cantero 2012); present material from 15 to 2143 m, slightly increasing its lower bathymetric limit.

Circum-Antarctic distribution (Stepanjants 1979). In East Antarctica, found in the Ross Sea (Hickson and Gravely 1907; Totton 1930), off Oates Coast (Totton 1930), George V Coast (Briggs 1938), Adélie Coast (Naumov and Stepanjants 1972), and in the Davis Sea and the Cosmonauts Sea (Stepanjants 1979). In West Antarctica, known for the South Shetland Islands (Broch 1948; Stepanjants 1979; Blanco 1984; Peña Cantero and García Carrascosa 1995; Peña Cantero 2006, 2008; Galea and Schories 2012), the Weddell Sea (Blanco 1967; Peña Cantero et al. 1999), the South Orkney Islands (Peña Cantero and García Carrascosa 1995), off Bouvet (Peña Cantero and Gili 2006), Deception and Trinity Island (Antarctic Peninsula) (Peña Cantero 2008), Low Island (Peña Cantero and Vervoort 2009; Peña Cantero 2013), Peter I Island (Peña Cantero 2010), the Bellingshausen Sea (Peña Cantero 2012) and off Elephant Island (Soto Àngel and Peña Cantero 2015). Our material comes from both East and West Antarctica. In the latter, it was collected off South Georgia, off Visokoi and Zavodovski Islands (the South Sandwich Islands), north of the South Orkney Islands, off Elephant Island, off Livingston, King George and Nelson Islands (the South Shetland Islands), off Deception and Low Islands, and off Joinville, d’ Urville, Renaud, Anvers and Trinity Islands (Antarctic Peninsula). In East Antarctica, it was found off Budd Coast (Wilkes Land), off Buckle Island (the Balleny Islands), off Cape Hallett, Cape Adare, Franklin Island (Victoria Land) and off Pennell Bank.