Stomphia selaginella (Stephenson, 1918a)

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 : 55-59

Stomphia selaginella (Stephenson, 1918a)

( Figs. 27 , 31–32 ; Table 12; Appx. 1, 2)

Cymbactis selaginella Stephenson, 1918a : Carlgren 1921.

Stomphia selaginella: Stephenson 1920b ; Pax 1923; Pax 1926; Carlgren 1928; Carlgren & Stephenson 1929; Carlgren 1939; Carlgren 1949; Grebelny 1975; Fautin 1984.

Cymbactis frigida Pax, 1922 : Pax 1926.

MATERIAL EXAMINED

Polarstern ANT XV/3: stn. PS48/044 ( BEIM: ANT-4271, 1 specimen) ; stn. PS48/050 ( BEIM: ANT-4300, 3 specimens) ; stn. PS48/071 ( BEIM: ANT-4297, 4 specimens) ; stn. PS48/082 (AMNH-4372; BEIM: ANT-4375, 3 specimens) ; stn. PS48/084 ( BEIM: ANT-4275, 1 specimen) ; stn. PS48/097 (AMNH-4787, 5 specimens); stn. PS48/ 100 ( BEIM: ANT-4333, 4 specimens) ; stn. PS48/154 ( BEIM: ANT-4335, 1 specimen) ; stn. 48/189 ( BEIM: ANT- 4267, 1 specimen; BEIM: ANT-4288, 3 specimens) ; stn. PS48/220 (AMNH-4326, 20 specimens; BEIM: ANT-4327, 19 specimens) ; stn. 48/222 ( BEIM: ANT-4328, 36 specimens; AMNH-4334, 6 specimens) ; stn. PS48/322 ( BEIM: ANT-4269, 7 specimens) ; stn. PS48/336 ( BEIM: ANT-4376, 9 specimens; BEIM: ANT-4377, 5 specimens) .

Polarstern ANT XVII/3 : stn. PS56/102 ( BEIM: ANT-4496, 1 specimen; BEIM: ANT-4561, 1 specimen); stn. PS56/119-1 (AMNH-4642, 35 specimens; AMNH-4554, 3 specimens); AMNH-4556, 1 specimen); stn. PS56/124- 1 (AMNH-4641, 21 specimens; BEIM: ANT-4643, 21 specimens); stn. PS56/135-1 ( BEIM: ANT-4578, 7 specimens; AMNH-4579, 6 specimens); stn. PS56/135-6 ( BEIM: ANT-4558, 1 specimen) ; stn. PS56/136-1 ( BEIM: ANT-4569, 1 specimen; BEIM: ANT-4574, 1 specimen; AMNH-4575, 2 specimens; BEIM: ANT-4576, 4 specimens); stn. PS56/165-1 (AMNH-4531, 2 specimens) ; stn. PS56/166-1 (AMNH-4268, 20 specimens; BEIM:

ANT-4270, 1 specimen; BEIM: ANT-4468, 1 specimen ; AMNH-4477, 3 specimens; AMNH-4478, 2 specimens; BEIM: ANT-4479, 6 specimens ; AMNH-4506, 2 specimens; BEIM: ANT-4514, 1 specimen ; BEIM: ANT-4532, 1 specimen ; AMNH-4597, 3 specimens; AMNH-4599, 15 specimens); stn. PS56/167-1 ( BEIM: ANT-4505, 2 specimens); stn. PS56/178-2 ( BEIM: ANT-4600, 15 specimens); stn. PS56/183-1 (AMNH-4549, 3 specimens) .

TABLE 12. Size ranges of the cnidae of Stomphia selaginella (Stephenson, 1918) ; for comparative cnidae data of the species see Fautin (1984) and Häussermann (2004). 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.

Polarstern ANT XIX/3 : stn. PS61/061-1 ( BEIM: ANT-4988, 2 specimens) .

Polarstern ANT XXI/2 : stn. PS65/028-1 (AMNH-4798, 15 specimens; AMNH-4799 1 specimen; AMNH- 4853, 2 specimens); stn. PS65/029-1 (AMNH-4796, 3 specimens) ; stn. PS65/039-1 (AMNH-4811, 1 specimen).

DIAGNOSIS

Pedal disc well developed, flat, to 50 mm diameter, often with slight central protuberance. Column smooth, firm or delicate, thick or thin, cylindrical in expanded specimens or dome-shaped in contracted specimens, to 32 mm diameter and 40 mm height in preserved specimens, not divisible into regions but sometimes with distal margin marked. Oral disc wide, flat, to 37 mm diameter in expanded specimens, mesenterial insertions visible. Distinct chromatic pattern in living specimens: white column with irregular orange spots, usually more abundant proximally but variable in distribution and intensity of colour; oral disc light red or orange with dark orange radial lines coinciding with mesenterial insertions; tentacles light orange with two more or less distinct darker orange bands; mouth and actinopharynx light orange; preserved specimens pale orange, only actinopharynx and bands in the tentacles maintain orange colouration. Tentacles relatively thick and pointed, to 12 mm long in preserved specimens, between 64–68, restricted to column margin, inner longer than outer ones. Marginal sphincter muscle mesogleal, strong, diffuse and long, longitudinally striated. More mesenteries proximally than distally. Mesenteries arranged in four cycles: 16 pairs of mesenteries (first and second cycles) perfect and sterile, third and forth cycles imperfect and fertile; fourth cycle present only proximally. Mesenteries of last cycle might follow Actinostola rule. Retractor muscles strong, diffuse; parietobasilar muscles well developed, with thin and long mesogleal pennon often fused to the mesentery. Longitudinal muscles of tentacles mesogleal. Juveniles with conical base internally brooded in coelenteron. Cnidom: Spirocysts, basitrichs, and microbasic b- and p -mastigophores. Large microbasic b -mastigophores in base of outer tentacles, to 55 µm long. For a complete description of Stomphia selaginella , see Stephenson (1918a) and Fautin (1984).

GEOGRAPHIC AND BATHYMETRIC DISTRIBUTION

Stomphia selaginella is a circumpolar species collected in the Scotia Sea, Antarctic Peninsula, Ross Sea, and Wilkes Land, between 16– 1,674 m depth ( Fautin 1984).

The material from this study confirms the presence of the species in the Drake Passage, Antarctic Peninsula, eastern Weddell Sea, and Bouvet Island, between 122– 1,227 m depth.

Stomphia selaginella is a circumpolar endemic Antarctic species, inhabiting continental shelf and bathyal depths ( Fig. 27c ).

REMARKS

Stomphia selaginella has two different morphotypes (thin and delicate or thick and robust); however, we found no significant differences separating them apart from column consistency and maybe the abundance of the basitrichs in the mesenterial filament (delicate morphotype with sporadic basitrichs whereas in the robust morphotype basitrichs are common to abundant).

Family GALATHEANTHEMIDAE Carlgren, 1956

Genus Galatheanthemum Carlgren, 1956

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 31. External anatomy of Stomphia selaginella (Stephenson, 1918). a) Oral view of living specimens brooding juveniles [BEIM(ANT-4505)]. b–c) Oral view of living and expanded specimens [AMNH-4798]. d) Lateral view of preserved specimen [BEIM(ANT-4269)]. e) Oral view of preserved specimen [BEIM(ANT-4269)]. f) View of the pedal disc showing the central protuberance [BEIM(ANT-4275)]. g) Lateral view of several juveniles in different stages of development found brooded in the coelenterons of adult specimens [AMNH-4372]. h) Detail of a brooded juvenile; note its conical shape and the prolonged proximal end [AMNH-4506]. Scale bars: a, d–e, 30 mm; b–c, f, 20 mm; g–h, 10 mm.

FIGURE 32. Cnidae of Stomphia selaginella (Stephenson, 1918). a, b, d, f, h) Basitrichs. c) Spirocyst. e) Microbasic b- mastigophore. g, i) Microbasic p-mastigophores.