Stegosoladidus ingens ( Chevreux, 1906 )

Berge, JØrgen, 2001, Revision of Stegosoladidus Barnard and Karaman, 1987 (Crustacea: Amphipoda: Stegocephalidae), redescription of two species and description of three new species, Journal of Natural History 35 (4), pp. 539-571 : 569-570

Stegosoladidus ingens ( Chevreux, 1906)

Andaniotes ingens: Chevreux, 1906: 22 .

Andaniotes ingens: Thurston, 1974:70 .

Andaniotes ingens: Barnard and Karaman, 1991: 678 .

Material examined. PARATYPES (Paris), two specimens, M XIV (Maine), one female , 67ss24¾S, 179ss54¾W, 223±232 m; Berlin ZMB 27337, one immature male, 72ss53.10¾S, 19ss29.33¾W, 421±429 m; Berlin ZMB 27337, one female , 62ss38¾S, 55ss45¾W, 277 m; J45341 (Victoria), one immature male, 67ss20¾S, 70ss21¾E, 165 m; J38735 (Victoria), one immature male, 66ss48¾S, 70ss24¾E, 795 m; J38737 (Victoria), one female , 68ss54.88¾S, 76ss37.03¾E, 667 m; J38736 (Victoria), two females , 68ss56.69¾S, 73ss36.78¾E, 786 m.

Distribution. Antarctic, apparently circumpolar.

Description. Rostrum very small.

Antennae short. Antenna 1 shorter than antenna 2, ¯agellum four-articulate, accessory ¯agellum uni-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; epistomal plate (medial keel) produced into a small elongate medial ridge covering the entire epistome.

Mandible incisor transverse, smooth, left lacinia mobilis present, reduced, laterally straight, not conical.

Maxilla 1 palp uni-articulate, rectangular, apex not reaching above the apex of outer plate; outer plate distally rounded, ST in a pseudocrown, ST ®rst row with more than six setae (ST1±5 expanded, ST7), allometric (number of ST 1±5 increasing), ST 1 ordinary (similar to ST 2±4), gap between ST 5 and ST 7, ST A, located distally, part of ®rst row, ST B absent, ST C present; 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, appressed to row B, row A setae pappose, three or four ®rst setae diOEerentiated from the other setae (weakly pappopectinate); row B setae proximally simple, distally without cusps; row C present; row D absent.

Maxilliped palp four-articulate, article 2 distally unproduced, articles 1±3 inner margins with plumose setae, dactylus distally simple (pointed); inner plate not exceeding base of palp article 2; without nodular setae; medial setae row present, not reduced, transverse, setae simple; distal setae row present, setae simple; 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, well developed, setae long robust, slender, appressed to outer setae row; distal setae-group present, setae attached normally, long robust.

Labrum very short; lobes symmetrical, both lobes reduced.

Labium distally broad, oval.

Coxal plates and basis on the pereopods smooth. Coxae 1±3 overlapping, broad.

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

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

Pereopod 4 coxa posteroventral lobe very large, reaching beyond 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 rudimentary, without a row of long plumose setae.

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

Oostegites on pereopod 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 as long as inner. Uropod 3 peduncle longer than half the length of rami, outer ramus two-articulate, outer ramus as long as inner.

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

Males: pereopod 2 propodus equally sized in males and females, urosome ordinary (similar to females), uropods 1±3 with ordinary outer ramus.

Remarks. Chevreux (1906) described this species in a very thorough way, thus it is not ®gured herein. However, it should be noted that the outer ramus of uropod 3 is two-articulated, in contrast to the original description.

In 1969, Barnard transferred the present species to Euandania , and at the same time stated that it`probably should form the type of a new genus because of its reduced ®rst maxillary palp and narrow article 2 of pereopod 4 in combination but in other special characters it ®ts Euandania more than Andaniotes and so is transferre d to the former’ ( Barnard, 1969: 439). However, S. ingens has never since been referred to as belonging to Euandania , even in Barnard and Karaman (1991) S. ingens is treated as an Andaniotes without any further comments on its generic status. It thus appears that the 1969 transfer of S. ingens from Andaniotes to Euandania has passed on unnoticed in the literature, and eventually was also forgotten by Barnard himself.