Actinauge verrillii McMurrich, 1893

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 : 70-75

Actinauge verrillii McMurrich, 1893

( Figs. 39–41 ; Table 16; Appx. 1, 2)

Actinauge verrillii McMurrich, 1893 (part.); Hargitt 1914; Carlgren 1949; Dunn 1983.

non Actinauge verrillii: Riemann-Zürneck 1973 .

MATERIAL EXAMINED

Polarstern ANT XVII/3 : stn. PS56/178–2 ( BEIM: ANT-4584, 2 specimens) .

Polarstern ANT XIX/3 : stn. PS61/64–1 (AMNH-4000, 1 specimen) ; stn. PS61/92–1 (AMNH-4135, 1 specimen); stn. PS61/114–10 (AMNH-4007, 1 specimen; AMNH-4031, 1 specimen; AMNH-4165, 32 specimens; BEIM: ANT-4166, 2 specimens) .

DIAGNOSIS

Pedal disc with well-developed basilar muscles, shape depends on substratum: most specimens attached to gastropod shell, cylindrical object (such as worm tube or sponge spicules), or bolus of mud. Column very thick and firm, cylindrical, to 60 mm diameter and 77 mm height in preserved specimens, divisible into scapus and scapulus. Scapus reticulate, covered in irregular tubercles more pronounced distally, with cuticle often eroded. Scapulus smooth, usually never completely retracted, without cuticle. Scapulus with 24 longitudinal endocoelic mesogleal thickenings more or less prominent. Oral disc wider than column. Living specimens with scapulus, tentacles and oral disc salmon in colour; column and pedal disc brownish due to cuticle; preserved specimens similar in colour to living ones but lighter. Tentacles rarely visible, to 96, tapered and relatively short, with strong aboral mesogleal thickenings. Marginal sphincter muscle mesogleal reticulate, long. Equal numbers of mesenteries proximally and distally. Mesenteries hexamerously arranged in four cycles, only first cycle perfect and sterile. Retractor muscles diffuse; parietobasilar muscles well developed but not forming mesogleal pennon. Longitudinal muscles of tentacles ectodermal, more developed in oral side. Acontia with only basitrichs. Cnidom: Spirocysts, basitrichs, and microbasic p -mastigophores. For detailed information on Actinauge verrillii , see McMurrich (1893) and Dunn (1983).

TABLE 16. Size ranges of the cnidae of Actinauge verrillii McMurrich, 1893 ; 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.

GEOGRAPHIC AND BATHYMETRIC DISTRIBUTION

Actinauge verrillii sensu str. has been reported in the southern hemisphere, in the sub-Antarctic region and in northerner latitudes (Pacific, Galapagos Islands, Tasmania, and Chile) between 584– 3,001 m depth ( Dunn 1983).

The material of this study extends the geographic distribution of this species to the south, to the Antarctic region, in the Drake Passage, the South Shetland and Elephant islands, between 123– 2,856 m depth; the bathymetric range of the specimens in this study is the shallowest known for the species.

Actinauge verrillii sensu str. is a wide spread species in the southern hemisphere, inhabiting continental shelf and bathyal depths ( Fig. 41a ).

REMARKS

We considered Actinauge verrillii sensu str. to be restricted to the southern hemisphere until more detail studies address the disjunct distribution of the species of this genus in both hemispheres (see Riemann-Zürneck 1973, 1986b; Dunn 1983)

Genus Hormathia Gosse, 1859

Figures

FIGURE 39. External anatomy of Actinauge verrillii McMurrich, 1893. a–b) Lateral view of living specimens [AMNH-4007], [BEIM(ANT-4584)]. c) Detail of the scapulus in a living specimen [AMNH-4007]. d) Oral view of preserved specimen [BEIM(ANT-4007)]. g) Detail of pedal disc rapping bolus of mud [AMNH-4007]. e) Lateral view of preserved specimen [AMNH-4007)]. f) Oral view of preserved specimen [BEIM(ANT-4166)]. h) Pedal disc of preserved specimen [AMNH-4007]. Scale bars: a, c, e–f, 20 mm; b, 30 mm; d, g–h, 15 mm.

FIGURE 40. Cnidae of Actinauge verrillii McMurrich, 1893. a, b, c, d, g, h, k, l, n, o, q, s, t) Basitrich. c, f, i, m, p, r) Microbasic p-mastigophore. j) Spirocyst.

FIGURE 41. Distribution map of species. a) Actinauge verrillii McMurrich, 1893. b) Hormathia armata Rodríguez & López- González, 2001. c) Hormathia lacunifera (Stephenson, 1918). d) Corallimorphus profundus Moseley, 1877. e) Corallimorphus rigidus Moseley, 1877. Green triangles, type locality; green circles, previous localities; red circles, localities from this study; dark line, Subtropical Front; light line, Polar Front.