Andaniotes linearis K. H. Barnard, 1932

Berge, JØrgen, 2001, Revision of the Amphipod (Crustacea: Stegocephalidae) genera Andaniotes Stebbing, 1897 and Metandania Stephensen, 1925, Journal of Natural History 35 (6), pp. 787-832 : 796-798

Andaniotes linearis K. H. Barnard, 1932

Andaniotes linearis K. H. Barnard, 1932: 80 .

Andaniotes corpulenta: Chevreux, 1906: 22 .

? Andaniotes corpulentus: Schellenberg, 1931: 51 .

? Andaniotes linearis: Nicholls, 1938: 41 .

Andaniotes linearis: Watling and Holman, 1981: 221 .

Andaniotes corpulentus: Watling and Holman, 1981: 219 .

Material examined

Type material. NHM: 17 specimens, from` Discovery’ stations: 39, 42, 144, 148, 149, 156, 175 and 190, South Georgia and South Shetlands, 90±236 m.

Maine:`Islas Orcada’ Ðone specimen, Cruise 575, st. 89, 54 ss 44.2 ¾ S, 37 ss 11.2 ¾ W, 225±265 m, 7 June 1975; eight specimens , Cruise 575, st 90, 54 ss 50 ¾ S, 37 ss 23 ¾ W, 223± 337 m; 11 specimens , Cruise 575, st 91, 55 ss 00 ¾ S, 37 ss 42 ¾ W, 494±501 m; seven specimens , Cruise 575, st. 95, 54 ss 11.08 ¾ S, 37 ss 41.01 ¾ W, 68±80 m, 9 June 1975; 18 specimens , Cruise 876, st. 108, 60 ss 25.9 ¾ S, 46 ss 23.6 ¾ W, 152±159 m, 16 February 1976 .

`Eltanin’ Ð 12 specimens, Cruise 9, st 684, 54 ss 55 ¾ S, 38 ss 05 ¾ W, 595±677 m; three specimens, Cruise 9, st 740, 56 ss 06 ¾ S, 66 ss 19 ¾ W, 384±494 m; 10 specimens, Cruise 22, st 1593, 54 ss 43 ¾ S, 56 ss 37 ¾ W, 339±357 m, 14 March 1966.

Berlin:`Polarstern’ ANT XIV/2 Ð 11 specimens , st 20, 61 ss 22 ¾ S, 56 ss 7 ¾ W, 316; 15 specimens, st 24, 61 ss 5 ¾ S, 55 ss 56 ¾ W, 174 m; two specimens, st 31, 60 ss 54 ¾ S, 55 ss 45 ¾ W, 235 m; one specimen, st 78, 60 ss 57 ¾ S, 55 ss 33 ¾ W, 80 m; one specimen, st 130, 61 ss 13 ¾ S, 55 ss 58 ¾ W, 146 m; one specimen, st 162, 61 ss 46 ¾ S, 57 ss 30 ¾ W, 322 m.

Berlin A30Ð one specimen, 62 ss 38 ¾ S, 55 ss 45 ¾ W, 277 m.

VictoriaÐJ38731: one specimen, 66 ss 55.51 ¾ S, 62 ss 32.72 ¾ E, 113 m; J38732 : four specimens , 66 ss 53.69 ¾ S, 63 ss 06.34 ¾ E, 367 m; J38734 : one specimen , 67 ss 05.03 ¾ S, 68 ss 58.80 ¾ E, 204 m; J45339 : one specimen , 67 ss 01.3 ¾ S, 70 ss 07.6 ¾ E, 339 m; J45340 : one specimen , 67 ss 01.3 ¾ S, 70 ss 07.6 ¾ E, 339 m.

Paris MNHN 5105 : one specimen, Port Charcot (det Chevreux, 1906: Andaniotes corpulentus ) .

IRScNB: WED 96 ANT XII/3 : st 11, ten specimens , 73 ss 22 ¾ S, 21 ss 10 ¾ W, 333± 338 m (three specimens found in the sponge Mycale acerata ); st 15, ®ve specimens, 73 ss 42 ¾ S, 22 ss 30 ¾ W, 428±446 m.

WED 89 ANT VII/4 : st. 245, one immature , 74 ss 40 ¾ S, 29 ss 42 ¾ W, 483±484 m; st. 271, three specimens, 73 ss 17 ¾ S, 21 ss 00 ¾ W, 352±399 m.

Distribution Antarctic circumpolar (but see Remarks), 68± 677 m.

Description

Rostrum very small.

Antennae short. Antenna 1 shorter than antenna 2; ¯agellum four-articulate; accessory ¯agellum article 2 absent. Antenna 2 peduncle (articles 3±5) longer than ¯agellum; article 3 short, about as long as broad; article 4 longer than article 5.

Epistome produced laterally; rectangular, with a long ridge on each side; epistomal plate (medial keel) produced into a small elongate medial ridge covering the entire epistome.

Mouthparts not elongate or pointed.

Mandible incisor transverse, smooth; left lacinia mobilis present, reduced, laterally straight, conical.

Maxilla 1 palp uni-articulate, rectangular, setae long, simple, slender; apex not reaching above the apex of outer plate; outer plate distally rounded; ST in two parallel rows, ®rst marginal and second submarginal, ST ®rst row with six setae (ST1±5, ST7), ST 1 ordinary (similar to ST 2±4), gap between ST 5 and ST 7; ST A±C present, part of second row; inner plate without a well developed shoulder, setae pappose.

Maxilla 2 ordinary; outer plate setae without distal hooks or cleft; inner plate setae row A covering the entire margin, clearly separated from row B, row A setae pappose; ®rst three or four setae diOEerentiated from the other setae (weakly pappopectinate), row B setae proximally simple, distally with cusps; row C present; row D absent.

Maxilliped palp four-articulate; article 2 distally unproduced; dactylus distally simple (pointed); inner plate not exceeding base of palp article 1, with three nodular setae; medial setae-row present, reduced to one or two setae but diOEerentiated from distal row, transverse, setae simple; distal setae-row present; inner setae-row present, row not reduced (more than two setae), setae conspicuously large and strong; outer plate outer setae-row present, marginal, setae attached normally, long, robust; straight; inner setae-row present but strongly reduced, setae long, robust, slender, parallel but not appressed to outer setae-row; distal setae-group absent.

Labrum very short, lobes symmetrical and reduced.

Labium distally broad, oval.

Coxal plates and basis on the pereopods smooth. Coxae 1±3 contiguous.

Pereopod 1 coxal plate not as deep as basis; propodus subovate.

Pereopod 2 longer and thinner than pereopod 1; ischium elongate, ratio length: breadth exceeding 1.5; ischium distal posterior margin with plumose setae; propodus subrectangular; palm absent.

Pereopod 4 coxa posteroventral lobe medium sized, not reaching the base of pereon segment 7; basis anterior margin without long setae, posterior margin with long setae, plumose setae on distal anterior margin, no plumose setae on distal posterior margin; ischium with plumose setae on posterior distal margin.

Pereopod 6 basis posteriorly expanded, expansion conspicuous, concave, without a row of long plumose setae, with a row of long robust slender setae.

Pereopod 7 basis anterior margin straight, distally rounded, medial row of setae present, setae short and robust.

Oostegites on pereopods 2±5. Gills on pereopods 2±7.

Pleonites 1±3 dorsally smooth.

Urosomites 2 and 3 fused. Uropod 1 peduncle longer than rami, outer ramus longer than inner. Uropod 2 peduncle longer than rami, outer ramus as long as inner. Uropod 3 peduncle longer than half the length of rami, outer ramus twoarticulate, outer ramus shorter than inner.

Telson longer than broad; shorter than uropod 3 peduncle; no submarginal setae on apex of each lobe; cleft, apically rounded.

Males. Unknown.

Remarks

When K. H. Barnard (1932) ®rst described this species, he did so mainly on the linear (versus rounded) basis on pereopod 6. Examination of many immature and small female specimens, including (!) three females from the paratype series (st 42, see above), has revealed that this character state most probably is subject to allometric growth: young specimens possess a basis on pereopod 6 that is conspicuously rounded, very similar to that of e.g. A. corpulentus and A. abyssorum , whereas the basis becomes less expanded and slightly concave as the animals grow older.

This was probably the main reason why Watling and Holman (1981) identi®ed some of their material as A. corpulentus: K. H. Barnard (1932) did not mention this apparent allometry in his original description. However, even young specimens of the present species are distinguishable from its congeners by the basis of pereopod 6, as the row of long robust simple setae (versus setae absent or setae narrow and plumose) is unique within this genus.

Watling and Holman (1981:22 2) identi®ed ten male specimens of this species, but examination of their material showed that these in fact were immature specimens. Until the present, there have been no known male specimens of this species, despite the fact that none of its congeners has been captured at so many diOEerent localities or in such high numbers (except for A. wallaroo , see below).

Andaniotes linearis was extensively ®gured by Watling and Holman (1981: ®gs 24±26), and is thus not ®gured herein.