Isotealia antarctica Carlgren, 1899

Rodríguez, Estefanía & López-González, Pablo J., 2013, <strong> New records of Antarctic and Sub-Antarctic sea anemones (Cnidaria, Anthozoa, Actiniaria and Corallimorpharia) from the Weddell Sea, Antarctic Peninsula, and Scotia Arc </ strong>, Zootaxa 3624 (1), pp. 1-100 : 27-30

Isotealia antarctica Carlgren, 1899

( Figs. 12–14 ; Table 6; Appx. 1, 2)

? Leiotealia badia McMurrich, 1893 .

Isotealia antarctica Carlgren, 1899 ; McMurrich 1901; (?) Pax 1923; (?) Pax 1926; Carlgren 1927; Carlgren 1945; Carlgren 1949; Carlgren 1959; Sebens & Paine 1978; Riemann-Zürneck 1980; Riemann-Zürneck 1986a

.

MATERIAL EXAMINED

Polarstern ANT XXI/2 : stn. PS65/344-1 ( BEIM: ANT-4858, 4 specimens; BEIM: ANT-4859, 2 specimens;

BEIM: ANT-4950, 1 specimen ).

DIAGNOSIS

Pedal disc well developed, wider than oral disc, with cuticle. Column cylindrical, smooth, to 37 mm diameter and 27 mm height in preserved specimens, divided into scapus and scapulus; margin with 48 imperforate (?) pseudoacrorhagi. Small fosse. Living specimens light pink or orange, with mesenterial insertions visible, preserved specimens brown; tentacles of the same colour as the column but lighter. Tentacles to 168, inner longer than outer ones. Marginal sphincter muscle endodermal, circumscribed. More mesenteries proximally than distally. Mesenteries arranged in five cycles, first three cycles perfect (plus some pairs of the fourth cycle); third and fourth cycles fertile. Retractor muscles diffuse; parietobasilar muscles well developed, with short and thick mesogleal pennon. Cnidom: Spirocysts, basitrichs, and microbasic b - and p -mastigophores. For a complete description of Isotealia antarctica , see Riemann-Zürneck (1980).

GEOGRAPHIC AND BATHYMETRIC DISTRIBUTION

The type locality of Isotealia antarctica is in the west of the south Atlantic Ocean, on the Argentinean coast ( Carlgren 1899). Other records ( McMurrich 1893; Carlgren 1959) extend the distribution of the species to the Chilean and Patagonian coast within the Sub-Antarctic region. Riemann-Zürneck (1980) extended the geographic distribution of the species in the north, off Rio de la Plata (34ºS). The known depth range of the species is 25– 600 m.

The material of this study extends the distribution of Isotealia antarctica to the south and east, in the Antarctic region, close to Bouvet Island, between 574– 567 m depth.

Isotealia antarctica is an Antarctic and Sub-Antarctic species, inhabiting continental shelf and bathyal depths ( Fig. 14a ).

REMARKS

According to Riemann-Zürneck (1980), this species has yet to be confirmed in Antarctica, Patagonia, and Chile. Most specimens identified as I. antarctica (Carlgren 1927, 1945) were poorly preserved and thus their identity is not reliable. Other records of the species in the Ross Sea ( Dayton et al. 1974; Amsler et al. 1999) also need to be verified.

TABLE 6. Size ranges of the cnidae of Isotealia antarctica Carlgren, 1899 ; for comparative cnidae data of the species see Riemann-Zürneck (1980). 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.

Family CAPNEIDAE Gosse, 1860

Genus Capnea Forbes, 1841

Figures

FIGURE 12. External anatomy of Isotealia antarctica Carlgren, 1899. a) Lateral view of living specimen [BEIM(ANT-4859)]. b) Detail of distal margin of the column showing marginal pseudoespherules. c) Lateral view of living specimen [BEIM(ANT- 4950)]. d) Detail of distal margin of the column showing marginal pseudoespherules. e) Oral view of preserved specimen [BEIM(ANT-4950). f) Detail of oral view in preserved and contracted specimen. Scale bars: a, b, e, 20 mm; c, 25 mm; d, f, 10 mm.

FIGURE 13. Cnidae of Isotealia antarctica Carlgren, 1899. a–c, e–g, i) Basitrichs. d) Spirocyst. h, j) Microbasic p- mastigophores. k) Microbasic b-mastigophore.

FIGURE 14. Distribution map of species. a) Isotealia antarctica Carlgren, 1899. b) Capnea georgiana (Carlgren, 1927). c) Stephanthus antarcticus Rodríguez & López-González, 2003. d) Liponema multiporum Hertwig, 1882. e) Dactylanthus antarcticus (Clubb, 1908). f) Actinostola crassicornis (Hertwig, 1882). Green triangles, type locality; green circles, previous localities; red circles, localities from this study; yellow circles, localities from this study from underwater photography survey; dark line, Subtropical Front; light line, Polar Front.