Eltaninactis infundibulum Dunn, 1983

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 : 67-70

Eltaninactis infundibulum Dunn, 1983

( Figs. 27 , 37–38 ; Table 15; Appx. 1, 2)

Eltaninactis infundibulum Dunn, 1983 ; Dawson 1992.

MATERIAL EXAMINED

Polarstern ANT XVII/3 : stn. PS56/178-2 ( BEIM: ANT-4258, 1 specimen; AMNH-4259, 1 specimen; BEIM: ANT-4260, 1 specimen; AMNH-4261, 7 specimens) .

TABLE 15. Size ranges of the cnidae of Eltaninactis infundibulum Dunn, 1983 ; 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 in fewer than 40 capsules.

DIAGNOSIS

Pedal disc well developed with well-developed basilar muscles; slightly convex, to 33 mm diameter, with a deciduous cuticle. Column thick, firm, conical to more or less rounded in preserved specimens, to 41 mm height; column divisible into scapus and scapulus, scapus with stratified cuticle and tenaculi, scapulus smooth. Oral disc flat, to 14 mm diameter. Living specimens with oral disc and actinopharynx orange, tentacles with three orange bands alternate with two lighter ones; column and pedal disc brownish due to cuticle and tenaculi; preserved specimens with scapulus, oral disc and tentacles pale pink. Tentacles relatively tough, to 24, pointed and short (to 11 mm). Marginal sphincter muscle mesogleal, very weak. More mesenteries proximally than distally. Mesenteries hexamerously arranged in two cycles; first cycle perfect and fertile (macrocnemes), second imperfect and sterile (microcnemes); third cycle only present proximally. Retractor muscles strong and restricted; parietobasilar muscles well developed, strong. Longitudinal muscles of tentacles ectodermal. No acontia. Cnidom: Spirocysts, basitrichs, and microbasic p -mastigophores. For a complete description of Eltaninactis infundibulum , see Dunn (1983).

GEOGRAPHIC AND BATHYMETRIC DISTRIBUTION

Eltaninactis infundibulum is known from two widely separated areas: off the Antarctic Peninsula (between 769– 1,230 m depth) and from the northwest of the Chatham Islands (east of New Zealand), between 2,610– 2,668 m depth ( Dunn 1983) .

The material from this study represents the second record for this species, confirming its distribution off the Antarctic Peninsula, west off Deception Island, between 804–930 m depth.

Eltaninactis infundibulum is an Antarctic species distributed also within the limits of the sub-Antarctic region (Subtropical Front) in bathyal depths; however, in the proximity of the Antarctic continent E. infundibulum reaches continental shelf depths ( Fig. 27f ).

REMARKS

According to the original description, Eltaninactis infundibulum has a third cycle of mesenteries proximally, very weak basilar muscles, and the longitudinal muscles of the tentacles are meso-ectodermal ( Dunn 1983). Although the material from this study has similar sizes (25–45 mm column height) to that in the original description, we found only two cycles of mesenteries, the basilar muscles are well-developed, and the longitudinal muscles of the tentacles are ectodermal. We also found slight differences in the cnidae of the specimens examined in this study compared to the material upon which the original description was based. However, we attribute these differences to intraspecific variability.

Family HORMATHIIDAE Carlgren, 1925

Genus Actinauge Verrill, 1883

Figures

FIGURE 27. Distribution map of species. a) Actinostola georgiana Carlgren, 1927. b) Hormosoma scotti Stephenson, 1918. c) Stomphia selaginella (Stephenson, 1918). d) Galatheanthemum profundale Carlgren, 1956. e) Actinoscyphia plebeia (McMurrich, 1893). f) Eltaninactis infundibulum Dunn, 1983. Green triangles, type locality; green circles, previous localities; red circles, localities from this study; dark line, Subtropical Front; light line, Polar Front.

FIGURE 37. External anatomy of Eltaninactis infundibulum Dunn, 1983. a) Lateral view of living specimen [BEIM(ANT- 4260)]. b) Lateral view of specimen preserved [AMNH-4261]. c) Lateral view of a contracted and preserved specimen [AMNH-4261]. d) Detail of the pedal disc of preserved specimen [AMNH-4261]. Scale bars: a–b, 30 mm; c, 20 mm; d, 5 mm.

FIGURE 38. Cnidae of Eltaninactis infundibulum Dunn, 1983. a, c, e, g, h, k) Basitrichs. b, d, i, j, l–n) Microbasic p- mastigophores. f) Spirocyst.