Subantarctorchestia aucklandiae (Spence Bate, 1862)

(Figs. 29–39, 68)

Orchestia aucklandiae Spence Bate, 1862: 17, pl. 1a, fig. 3.— Miers, 1876: 121.— Thomson, 1881: 208.— Thomson & Chilton, 1886: 145.— Della Valle, 1893: 498, pl. 57, figs. 61–62.— Thomson, 1899: 201.— Walker, 1908: 36.— Chilton, 1909: 634.— Stephensen, 1927: 347.— Hurley, 1957: 152, figs. 1–23.— Bousfield, 1964: 54, fig. 5.

Orchestia ornata Filhol, 1885: 463, pl. 53, fig. 2.

Orchestia serrulata .— Stebbing, 1906: 535.— Chilton, 1909: 632, figs. 4, 5.—Chilton, 1920: 83.— Stephensen, 1927: 347.— Stephensen, 1935: 9.— Stephensen, 1938: 247.

Notorchestia aucklandiae .— Webber et al., 2010: 151, 220.

Type material. Auckland Islands, coll. Filhol, Astrolabe Expedition. Originally deposi,ed in the Jarden des Plantes, Paris, material not located (Paula Martin-Lefevre, pers. comm. 2019). Presumed Lost .

Material examined. Male, SEM preparation, 40 mm, AM P.90747; female, unmeasured, SEM preparation, AM P.90748; many specimens, P.90746, The Snares, (48°7′S, 166°36′E), New Zealand, Coll. D.S. Horning , 6 October 1972, stn SA 3223; 28 specimens, including 4 males and one female in a size range representative of the group (males 24 mm, 20.6 mm, 19.8 mm, 16 mm, female 15.5 mm) AM P.100688, Rima Islet, The Snares, (48°7′S, 166°36′E), 26 November 1974 ; 1 specimen, AM P.100691, Rima Islet, The Snares, (48°7′S, 166°36′E), 21 November 1976 ; male, dissected, 4 slides, 13.5 mm, AM P.105569, Sink Hole Gut, The Snares, New Zealand, 11 December 1974, coll. Charlotte E. Holmes; male, dissected, 4 slides, 25 mm, AM P.105570, Sink Hole Gut, The Snares, New Zealand, 11 December 1974, coll. Charlotte E. Holmes ; female, dissected, 4 slides, 25 mm, AM P.105571, Sink Hole Gut, The Snares, New Zealand, 11 December 1974, coll. Charlotte E. Holmes ; male, dissected, 4 slides, 26 mm, AM P.105572, Sink Hole Gut, The Snares, New Zealand, 11 December 1974, coll. Charlotte E. Holmes ; male, dissected, 4 slides, 17.5 mm, AM P.105573, Sink Hole Gut, The Snares, New Zealand, 11 December 1974, coll. Charlotte E. Holmes ; male, dissected, 4 slides, 18 mm, AM P.105574, Sink Hole Gut, The Snares, New Zealand, 11 December 1974, coll. Charlotte E. Holmes ; many specimens, AM P.100941, Sink Hole, The Snares, New Zealand, 11 December 1974, coll. Charlotte E. Holmes ; 1 specimen, AM P.100693, Sinkhole, The Snares (48°7′S 166°36′E), washed-up kelp, February 1971, coll. H.A. Best ; 7 specimens, AM P.100694, Sinkhole Gut, The Snares (48°7′S 166°36′E) 11 November 1976, coll. G.D. Fenwick ; 1 specimen, AM P.100695, Sinkhole Gut, The Snares (48°7′S 166°36′E), 11 December 1974 ; 10 specimens, AM P.100687, Sinkhole Gut, The Snares (48°7′S 166°36′E), rotting Durvillaea sp. in upper eulittoral zone, 11 December 1974, coll. Charlotte E. Holmes, (SA 3041) ; 8 specimens, AM P.100689, Penguin Creek, The Snares (48°7′S 166°36′E), on dead Sooty Shearwater bird, 15 February 1972, coll. D.S. Horning ; 3 specimens, AM P.100690, northwest side of North Promontory, The Snares (48°7′S 166°36′E) lichen, 29 November 1974, coll. D.S. Horning ; many specimens, AM P.100692, Skua Point, The Snares (48°7′S 166°36′E) 12 November 1976, coll. G.D. Fenwick (SA 3398) ; 2 specimens, AM P.100696, Tern Point, The Snares (48°7′S 166°36′E), 1972, no further data ; several specimens, AM P.100697, head of Windlass Bay, Campbell Island (52°33′S 169°4′E) under Durvillaea antarctica wrack , 23 January 1980, coll. J.K. Lowry & S. Lowry, Australian Museum Campbell Island Expedition (CA 199); several specimens, AM P.100698, head of Southeast Harbour, Campbell Island (52°36′S 169°9′E), rotting kelp, 1 February 1980, coll. J.K. Lowry, Australian Museum Campbell Island Expedition (CA 261) ; several specimens, AM P.100699, east side of Shoal Point, Perseverance Harbour, Campbell Island, (52°33′S 169°9′E), 4 February 1980, coll. J.K. Lowry & S. Lowry, Australian Museum Campbell Island Expedition (CA 269) ; several specimens, AM P.100700, eastern side of Vire Point, Campbell Island (52°33′S 169°9′E), 4 February 1980, coll. J.K. Lowry & S. Lowry, Australian Museum Campbell Island Expedition (CA 270) ; 1 female [whole animal illustration], AM P. 100580, Ocean Island, Auckland Islands, (50° 31′ 40″ S, 166° 15′ E), boulder beach, 5 February 1973, coll. D.S. Horning ; 9 specimens (including photography image A male 51 mm, B male 35 mm, rugose and smooth cuticle specimens), AM P.500981, Ocean Island, Auckland Islands, (50° 31′ 40″ S, 166° 15′ E), boulder beach, 5 February 1973, coll. D.S. Horning ; 5 specimens (all rugose cuticle), AM P.100686, Ewing Island, Port Ross, Auckland Islands, (50° 32′ S, 166° 18′ E), upper supralittoral boulder beach, 9 February 1873, coll. D.S. Horning ; 1 specimen, BMNH 1907.12.2.78, New Zealand, Donor D’Arcy Wyville Thomson; 9 Specimens, BMNH 1908.7.15.6–15, Enderby Island, Auckland Islands, HMS Discovery, Donor University of Dundee, Scotland; 7 specimens, BMNH 1925.9.8.1221, 1226, 1227, Enderby Island, ‘ Antarctica’, A.O. Walker collection (re-determined from Orchestia serrulata by LEH 2021) ; 3 specimens, BMNH 1908.7.15.16-18, Auckland Island, HMS Discovery, (original identified Orchestia chiliensis by A.O. Walker) ; 1 male, NHM UK 2021.1, Bench (Ruapuke) Island, March 1949, coll. A. Lysaght ; 2 specimens, (1 male, 1 female), NHM UK 2021.2, no location or date for collection, (original identification Alfred O. Walker); 7 specimens (males 24 mm, 20 mm, 17 mm; females 14 mm, 14 mm, 13 mm; 10 mm damaged specimen no head or urosome), BMNH 1928.12.1.2403–2407, no locality or date, coll. G.M. Thomson, Stebbing Collection (re-identified, original label Orchestia serrulata).

Type locality. Auckland Islands, New Zealand.

Diagnosis. Gnathopod 2 propodus palm with large distal sinus; dactylus lies inside defining distal spine. Gnathopod 2 coxa and pereopods 3, 4 subrectangular, as deep as or deeper than wide. Pereopod 7 with large distally acute posterodistal lobe reaching into merus. Epimeron 1 without robust setae along anterior margin.

Variation. The corrugations on the pereon range from weakly to well-developed and is not related to growth stage or gender when viewed across the hundreds of specimens examined here. The corrugations were first noted by Hurley (1957) and could range from genetic to parasitic, causes which are presently unknown (see Fig. 29). The largest male in AM P.105574 had a 6 dentate lacinia mobilis.

Size. Adult males and females 16 to 24 mm from The Snares and up to 40 mm from the Auckland Islands. In a checklist of New Zealand fauna Webber et al. (2010) notes specimens of S. aucklandiae greater than 50 mm in length.

Remarks. Hurley (1957) outlines the history of S. aucklandiae and the various synonymies with Trans. serrulata (Dana, 1852a), and concluded that all records except the original description of Dana (1852a) should be considered as S. aucklandiae . Notably Trans. serrulata sensu stricto was considered as a junior synonym of T. chiliensis (Milne Edwards, 1840) (type locality Chile), but recently Serejo & Lowry (2008: 200) re-established Trans. serrulata as a distinct and valid taxon. Subantarctorchestia aucklandiae is currently the largest known terrestrial amphipod, in samples at hand, a large male, greater than 25 mm, has a six dentate lacinia mobilis which further supports the previous statement that the number of cusps on the lacinia mobilis is a function of specimen size. Bousfield (1982) has previously used this character to classify genera, however the material here clearly shows this character is not stable within species and it is not an appropriate morphometric character for classification within the talitroids.

Habitat. Under boulders above bull kelp Durvillaea antarctica and Durvillaea sp. (Hurley 1957), in association with intertidal in association with a dead bird carcass (current study).

Distribution. New Zealand: Auckland (Spence Bate 1862). South Island: Otago Peninsula (Hurley 1956). Bench (Ruapuke) Island. Enderby Island, Ocean Island; Campbell Island: Windlass Bay, Southeast Harbour, Perseverance Harbour, Vire point. The Snares: Rima Island, Sink Hole, Penguin Creek, North Promontory, Skua Point, Tern Point (current study).