Aulactinia sulcata

Aulactinia sulcata (Clubb, 1902)

(Figs. 3–5; Table 2; Appx. 1, 2)

Urticina sulcata Clubb, 1902.

Urticina carlgreni Clubb, 1902.

Bunodactis sulcata: Carlgren 1924 a; Carlgren 1927; Carlgren 1928; Carlgren & Stephenson 1929; Carlgren 1949.

Bunodactis carlgreni: Carlgren 1924; Carlgren 1949.

Aulactinia sulcata: Dunn 1983.

MATERIAL EXAMINED

Polarstern ANT XVII/3: stn. PS56/165 (BEIM: ANT-4551, 1 specimen).

Polarstern ANT XIX/3: stn. PS61/068-1 (AMNH-4090, 1 specimen); stn. PS61/072-1 (AMNH-4032, 1 specimen); stn. PS61/101-1 (AMNH-4029, 1 specimen); stn. PS61/126-1 (BEIM: ANT-4008, 1 specimen).

ADDITIONAL MATERIAL EXAMINED

Aulactinia sulcata (Clubb, 1902). BEIM: ANT-3297. “VLT-2004 (Italica XIX), stn. A-2, Cape Adare, Victoria Land, 71°17.1’S 170°38.4’E, 416–421 m, 14/02/2004, Agassiz” (1 specimen).

DIAGNOSIS

Pedal disc well developed, to 29 mm in diameter; distinct limbus. Column cylindrical to dome shaped in preserved specimens, to 39 mm height and 37 mm diameter. Column with 48 longitudinal rows of simple verrucae with small stones and foreign debris attached, each row coinciding with one endo- or exo-coel. Distal column of female specimens with a deep fold that forms brooding cavity. No marginal pseudospherules. Deep fosse. Oral disc usually completely covered in preserved specimens by 48 digitiform tentacles, each with terminal pore. Column and tentacles dark pink in preserved specimens, sometimes colour obscured by adhered material. More mesenteries proximally than distally, to three cycles, regularly arranged; all cycles fertile but only first and second cycles perfect. Retractor muscles restricted, parietobasilar muscles with thin, detached pennons. Marginal sphincter muscle endodermal, strong, and circumscribed. Cnidom: spirocysts, basitrichs, and microbasic b- and p - mastigophores. For a complete description of Aulactinia sulcata, see Dunn (1983).

GEOGRAPHIC AND BATHYMETRIC DISTRIBUTION

Aulactinia sulcata is known in three separated areas in Antarctica: McMurdo Sound, off the tip of Antarctic Peninsula, and in the Davis Sea (off Queen Mary coast). The known bathymetric range of the species is 51– 1,120 m depth (Clubb 1902; Dunn 1983).

The material of this study confirms the presence of Aulactinia sulcata north of the Antarctic Peninsula: in the Bransfield Strait, South Shetland Islands, Elephant Islands, and the Drake Passage, between 151–911 m depth. Furthermore, the additional material confirms the presence of A. sulcata in McMurdo Sound (Victoria Land), between 416–421 m depth.

Aulactinia sulcata is an Antarctic, circumpolar species inhabiting continental shelf and bathyal depths (Fig. 3c).

TABLE 2. Size ranges of the cnidae of Aulactinia sulcata (Clubb, 1902); for comparative cnidae data of the species see Dunn (1983). Χ: mean. SD: standard deviation. S: ratio of number of specimens in which each cnidae was found to number of specimens examined. N: total number of capsules measured. F: Frequency, +++ = very common, ++ = common, + = rather common, --- = sporadic. Abbreviations: Mc, Microbasic. (*) Mean values based on fewer than 40 capsules.

REMARKS

Specimens studied by Clubb (1902), Carlgren (1927), and Dunn (1983) were described as having sterile directives whereas in the specimens studied by Carlgren and Stephenson (1929) directives were either sterile or fertile. In our specimens the directives are fertile. We attribute the discrepancy in the fertility of the directives to intraspecific variability and low numbers of studied specimens.

Genus Bolocera Gosse, 1860