Andaniotes corpulentu

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 : 794-796

Andaniotes corpulentu s ( Thomson, 1882)

Anonyx corpulentus Thomson, 1882 .

Andaniotes corpulentus: Stebbing, 1906: 96 (part).

Andaniotes corpulentus: Hurley, 1955: 196 .

Not Andaniotes abyssorum: Stebbing, 1888: 739 .

? Not Stegocephalus abyssorum: Della Valle, 1893: 629 .

? Not Andaniotes corpulentus: Schellenberg, 1931:51 .

Not Andaniotes corpulentus: Watling and Holman, 1981: 219 .

Not Metandania islandica: Stephensen, 1925: 136 .

Type material Two specimens, 46 ss 56 ¾ S, 168 ss 5 ¾ E, ~ 15 m. Not examined.

Material examined NHM (London);` Terra Nova’ Station 90, one immature , 34 ss 9 ¾ S, 172 ss 8 ¾ E, 183 m.

Additional unexamined material

Male ®gured by Stebbing (1897); ~ 40 ss S, ~ 170 ss E, unknown depth. Stebbing received this specimen from Thomson (the author of A. corpulentus ) from a location close to its type locality ( Patterson Inlet , New Zealand) .

Distribution

Known only from around New Zealand (the four specimens, above, are the only reported material of this species) .

Description

Rostrum very small.

Antennae short. Antenna 1 longer than antenna 2; ¯agellum four-articulate. 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; epimeral plate (medial keel) produced into an 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 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, 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, not reduced, transverse, setae cuspidate; distal setaerow present; inner setae-row present, 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 short and simple, slender, parallel but not appressed to outer setaerow; 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 small, reaching about the base of pereon segment 6; basis anterior margin without long setae, posterior margin with long setae, plumose setae on distal anterior and posterior margins; ischium with plumose setae on posterior distal margin.

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 fused. Uropod 1 peduncle longer than rami, outer ramus longer than inner. Uropod 2 peduncle longer than rami, outer ramus longer than inner. Uropod 3 peduncle longer than half the length of rami, outer ramus twoarticulate, outer ramus longer than inner.

Telson as long as 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 enlarged, curved upwards; uropod 2 outer ramus ordinary; uropod 3 rami reduced.

Remarks

The present species is not ®gured herein, due to lack of suitable material. Examination of the`Terra Nova’ specimen (see above) does, however, seem to ®t very well with Stebbing’s ®gure of a male. This is the only species in this genus, and one of only two species in the entire family, that is known from the littoral zone. The`Terra Nova’ specimen, however, was dredged at 183 m.

As the present revision has shown, it was a mistake by Stebbing (1897) to synonymize A. abyssorum with A. corpulentus , a mistake that later lead to further erroneous identi®cations of A. corpulentus , e.g. Barnard and Karaman, 1991 and Watling and Holman, 1981.