Andaniotes pseudolinearis, Berge, 2001

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 : 814-819

Andaniotes pseudolinearis n.sp.

(®gures 18±22)

HOLOTYPE: Female A, IRScNB WED 96 ANT XIII/4 , station 16.

PARATYPES: two females, IRScNB WED 96 ANT XIII/4 , station 16, 73 ss 53 ¾ S, 22 ss 26 ¾ W, 242± 246 m .

Additional material: Berlin AIII/44 , four specimens , 72 ss 53.10 ¾ S, 19 ss 29.33 ¾ W, 421±429 m; VictoriaÐJ38733, two females, 66 ss 53.69 ¾ S, 63 ss 06.34 ¾ E, 367 m; J45338 , one male , 67 ss 10.9 ¾ S, 69 ss 14.8 ¾ E, 307 m; IRScNB: WED 96 ANT XIII/3 : st 11, one female , 73 ss 22 ¾ S, 21 ss 10 ¾ W, 333±338 m; st. 16, three specimens (one male, two females), 73 ss 53 ¾ S, 22 ss 26 ¾ W, 242± 246 m. WED 89 ANT VII/4 : st. 272, one male , 73 ss 27 ¾ S, 21 ss 34 ¾ W, 406±409 m; st. 275, one female, 71 ss 40 ¾ S, 12 ss 35 ¾ W, 303± 330 m. EABN 67 : st 236, three specimens , 70 ss 19 ¾ S, 24 ss 14 ¾ E, 200 m. EAB 61: st. 134, two specimens, 70 ss 20 ¾ S, 24 ss 13 ¾ E, 240 m; st. 136, two specimens, 70 ss 20 ¾ S, 24 ss 13 ¾ E, 240 m; st. 199, one specimen, 70 ss 20 ¾ S, 24 ss 13 ¾ E, 240 m.

Distribution

Appears to be Antarctic circumpolar, restricted to true polar areas (66±73 ss S), 242± 429 m.

Description

Length of females: 15±18 mm, male: 18 mm.

Rostrum very small.

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

Epistome produced laterally; broad and round; epistomal plate (medial keel) produced into a small elongate medial ridge covering the entire epistome.

Mouthparts not elongate or pointed.

Mandible incisor transverse; toothed; 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 pappose, distally with cusps absent; 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 two nodular setae; medial setae-row present, not reduced, transverse, setae simple; distal setaerow present; inner setae-row present, not reduced (more than two setae), not conspicuously large; outer plate outer setae-row present, marginal, setae attached normally, long, robust, straight; inner setae-row present but strongly reduced, setae long, robust, slender, 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 subovate; 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 and posterior margins present; ischium plumose setae on posterior distal margin present.

Pereopod 6 basis posteriorly expanded, expansion conspicuous, rounded posteriorly, without a row of long plumose setae.

Pereopod 7 basis anterior margin straight, distally rounded; without medial row of setae.

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

Pleonites 1±3 dorsally smooth.

Urosomites 2 and 3 free. Uropod 1 peduncle longer than rami, outer ramus as long as inner. Uropod 2 peduncle longer than rami, outer ramus shorter than inner. Uropod 3 peduncle longer than half the length of rami, outer ramus two-articulate, outer ramus longer than inner.

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

Males. Pereopod 2 propodus equally sized in males and females. Urosome conspicuously larger than in females; uropod 1 outer ramus ordinary; uropod 2 outer ramus enlarged, curved upwards; uropod 3 rami not reduced.

Etymology The name of the species refers to its general similarity to A. linearis . Remarks

At ®rst glance, this species seems to represent just large specimens of A. linearis . However, on closer examination, the two species diOEer in some major aspects: the present species has a broad and rounded basis on pereopod 6, and also lacks the conspicuous row of large robust slender setae found in A. linearis . Furthermore, the long article 2 and the short and narrow article 3 of the maxilliped palp and the somewhat elongate telson are obvious diOEerences between the two species. The present species also has strong a nities to A. poorei , but the two species can easily be separated on the large size of the present species, and by article 2 and 3 of the maxilliped palp as described above.