Sigmodota magnibacula ( Massin and Hétérier, 2004 ),

O’Loughlin, P. Mark & VandenSpiegel, Didier, 2010, A revision of Antarctic and some Indo-Pacific apodid sea cucumbers (Echinodermata: Holothuroidea: Apodida), Memoirs of Museum Victoria 67, pp. 61-95 : 82-84

Sigmodota magnibacula ( Massin and Hétérier, 2004)

Figure 1e , 11 ; tables 2, 3

Taeniogyrus contortus .— Ekman, 1927: 416–417.— Cherbonnier, 1974: 610.— Gutt, 1988: 24.— Gutt, 1991: 324. (all or part probably non Taeniogyrus contortus ( Ludwig, 1875)) Taeniogyrus cf. contortus . — O’Loughlin et al., 1994: 553, 554. Taeniogyrus magnibaculus Massin and Heterier, 2004: 441–444 , figs 1, 2, table 1.

Material examined. Scotia Sea , South Orkney Is, 60.82°S 46.49°W, 216 m, BAS stn PB–EBS–4, 2006, NMV F168629 (1) ; NMV F168639 (1 specimen as tissue sample MOL AF 798 ); NHM 2010.1 – 4 (4) ; RBINS IG 31 459 (1, SEM figures); 60°50'S 44°30'W, 172 m, US AMLR 2009 stn 16–31, NMV F168840 (13) ; 61°13'S 45°56'W, 240 m, US AMLR stn 41–46, NMV F168841 (8).

Eastern Antarctica, Ross Sea , McMurdo Sound, 366 m, Terra Nova stn 348, 13 Feb 1912, NHM 1932.8.11.216–217 (2); NHM 1932.8 . 11.218 (1); Cape Adare , 71°53'S 170°11'E, 220 m, BIOROSS stn TAN0402/94, NIWA 61060 (2) ; Ross Sea , 74°43'S 164°08'E, 140 m, MNA 2440 (1) ; 74°43'S 164°07'E, 120 m, MNA 2446 (10) ; 74°45'S 164°15'E, 219 m, MNA 2462 (1) ; IPY–CAML stn TAN0802/26, 74°58'S 170°27'E, 285 m, NIWA 35724 (4) ; stn TAN0802/31, 74°59'S 170°27'E, 283 m, NIWA 35776 (1).

Wilkes Land, 66°18'S 110°32'E, 101 m, USARP 1961 , USNM E33725 (25).

Prydz Bay , ANARE 1987 , stn 51, 525 m, NMV F76847 (1) ; stn 22, 165 m, NMV F168862 (1) ; stn 38, 312 m, NMV F168863 (3) ; N end of Fram Bank , 67°05'S 68°59'E, 216 m, ANARE AA93–131 , NMV F69100 (2).

MacRobertson Shelf, 67°16'S 65°25'E, 121 m, ANARE AA93– 127 , NMV F68691 (20) ; 66°55'S 62°32'E, 113 m, AA93–124, NMV F69099 (2) ; Mawson Base, 8 m, ANARE 1972 , NMV F168839 (1).

Diagnosis. Sigmodotid species up to 105 mm long (preserved); 12 peltato-digitate tentacles, 6 pairs of digits per tentacle, apical pair largest, decreasing in size towards base of tentacle trunk; rows of interradial off-white papillae comprising clusters of chiridotid wheels; wheels 56–200 µ m diameter; hooks scattered in body wall, 128–216 µ m long, blunt spines on outer surface of hook variably present and of variable size; tentacle rods irregularly straight, slightly swollen mid-rod, tapered, short branches distally, 170–320 µ m long; calcareous ring and ossicles sometimes absent in largest specimens; 3 polian vesicles.

Colour (preserved). Body wall and tentacles dark red-brown to violet-brown epidermally, dark grey underneath.

Distribution. Antarctic, Weddell Sea, 72°29'S 26°57'W, 226 m ( Massin and Hétérier 2004); South Orkney Is, 172–240 m; Ross Sea, 120–366 m; Terre Adélie, 170–250 m ( Cherbonnier 1974); Wilkes Land, 101 m; Prydz Bay, 165–525 m; MacRobertson Shelf, 8– 121 m.

Remarks. As can be seen in Table 3 the maximum size of specimens, and length and form of the tentacle rods, are good diagnostic characters for Sigmodota magnibacula (Massin and Hétérier) .Diameter of wheels and length of hooks are comparable, but tentacle rods much larger.As discussed above in the Remarks under Sigmodota contorta (Ludwig) , the eastern Antarctic material of Cherbonnier (1974) is judged to be Sigmodota magnibacula , as is some or all of the Weddell Sea material of Gutt (1988, 1991). In discussing Taeniogyrus contortus (Ludwig) from the “Winterstation”, Ekman (1927) made mention of what is probably this species. Massin and Hétérier (2004) noted that this species was “living on the spines of cidarid echinoids”. We have not seen evidence of such an association. The US AMLR specimens were found inside Demospongiae.

Figures

Figure 1. Colour photos of preserved specimens of apodid species. a, Prototrochus linseae sp. nov. (7 mm long; S Shetland Is; holotype, NMV F168631); b, Kolostoneura griffithsi sp. nov. (12 mm long; insert drawings of tentacle rods, 96–112 µm long; S Orkney Is; holotype, NMV F168634); c, Scoliorhapis biopearli sp. nov. (6 mm long; insert drawing of tentacle rod, 115 µm long; S Shetland Is; holotype, NMV F168633); d, Scoliorhapis massini sp. nov. (20 mm long; Shag Rocks; holotype, NMV F168635); e, Sigmodota magnibacula (Massin and Hétérier, 2004) (15 mm long; S Orkney Is; NMV F168629); f, Taeniogyrus antarcticus Heding, 1931 (15 mm long; S Orkney Is; NMV F168630).

Figure 11. SEM images for specimens of Sigmodota magnibacula (Massin and Hétérier, 2004). a, b, plates from calcareous ring (Prydz Bay; RBINS IG 31 459 ex NMV F68691); c, wheels from body wall (S Orkney Is; RBINS IG 31 459 ex NMV F168842); d, hooks from body wall (S Orkney Is; RBINS IG 31 459); e, rods from tentacles (S Orkney Is; RBINS IG 31 459 ex NMV F168842).