Epimeria robusta Barnard, 1930

Loerz, Anne, Maas, Elizabeth, Linse, Katrin & Coleman, Charles Oliver, 2009, Do circum-Antarctic species exist in peracarid Amphipoda? A case study in the genus Epimeria Costa, 1851 (Crustacea, Peracarida, Epimeriidae), ZooKeys 18, pp. 91-128 : 106-112

Epimeria robusta Barnard, 1930

Figs 6–9

Epimeria robusta Barnard, 1930: 375 , 449, figs 40a, 41.

Figured individual: NIWA 20257, TAN0402/22, 71.8010°S, 170.9413°E, 151–180m, 09 02 2004 female, 37 mm.

Additional material examined. The following Epimeria robusta specimen were collected during “The International Polar Year” expedition TAN0802: NIWA 36856, NIWA 36618, st 100, 76°12.13´S, 176°14.86´E, 447 m ; NIWA 37110, NIWA 37148, st 117, 72 35.41 S, 175 20.53 E, 475 m ; NIWA 37209, st 115, 72 35.10 S, 175 18.49 E, 447 m ; NIWA 37613, st 157, 72 01.41 S, 173 10.81 E, 814 m. Following Epimeria robusta specimen were collected during the BioRoss expedition TAN0402: NIWA 20258, NIWA 20259, NIWA 20263, st 25, 71 47.92 S, 170 55.96 E, 140 m ; NIWA 202760, NIWA 20261, st 39, 71 45.30 S, 171 08.55 E, 251 m ; NIWA 20262, st 48, 72 19.00 S, 170 21.73 E, 132 m ; NIWA 20264, NIWA 20265, NIWA 20267, st 105, 71 15.45 S, 170 38.08 E 470 m ; NIWA 202668, st 124, 71 18.58 S, 170 28.63 E, 212 m ; NIWA 20269, st 126, 71 18.55 S, 170 27.01 E, 161 m ; NIWA 20270, st 130, 71 19.80 S, 170 27.55 E, 120 m ; NIWA 20271, st 140, 72 00.81 S, 170 46.47 E, 231 m ; NIWA 20272, st 149, 71 58.87 S, 171 57.99 E, 456 m ; NIWA 20273, st 150, 71 58.77 S, 171 58.09 E, 480 m ; NIWA 20274, st 153, 72 00.51 S, 172 13.36 E, 540 m ; NIWA 20275, NIWA 20276, st 154, 72 00.07 S, 172 13.33 E, 586 m ; NIWA 20277, st 157, 71 59.11 S, 172 10.71 E, 737 m ; NIWA 20278, st 190, 71 34.75 S, 170 52.36 E, 230 m .

Description. Anterior cephalic margin sinuous, lateral cephalic lobe slightly produced; rostrum same length as head, reaching proximal part of antenna 1 peduncle article 1; eyes present, oval, 0.4 × head height. Pereonite 1 subequal in length to head (excluding rostrum), pereonite 2 approx. 0.75 × length of 1, pereonites 1 to 6 lacking mid-dorsal or dorsolateral processes; pereonite 7 posterior margin with dorsolateral carina weakly developed; pleonite 1 shallow keel, post margin not drawn out straight, pleonite 2 with shallow keel, pleonite 3 with carinae. Urosomite 2 shortest, lacking mid-dorsal process, urosomite 3 with pointed posterior process.

Epimeron 1 antero- and posteroventral angle rounded; epimeron 2 and 3 posteroventral angle produced.

Antenna 1 peduncle article 1 with 2 small processes; article 2 with no process, shorter than article 1; article 3 shortest; accessory flagellum scale-like; primary flagellum of 45 articles. Antenna 2 articles 1–5 lacking distal processes, flagellum with 53 articles.

Mandible Incisor and lacinia mobilis strongly dentate; molar produced and triturative; palp article 3 densely setose medially, with long stout SS distally. Maxilla 1 medial plate subtriangular, obliquely convex inner margin with 11 stout, plumose SS; lateral plate distal margin oblique, with medially lobate RS; palp strongly exceeding outer plate; palp article 1 short, article 2 slightly curved medially with stout SS distomedially, stout RS distally. Maxilla 2 with long, distally crenulate setae distally on lateral and medial plates. Maxilliped lateral plate broadly rounded distally, medial plate with nodular RS and a row of long plumose SS on medial, anterior face; palp medial margin strongly setose; merus distally slightly expanded; dactyl with serrate medial margin.

Pereopods. Gnathopod 1: coxa 1 long and slender, basis linear, slender, posterior margin with numerous fine SS; merus slightly longer than ischium, anterior margin very short, distal margin oblique, posterodistal angle acute, setose; carpus linear, distal half of posterior margin with long SS; propodus slightly expanded distally, anterior margin naked except for distal fringe of short SS, palm finely crenulate, slightly oblique, with cluster of RS defining rounded distal margin, posterior margin with numerous long SS; dactylus slender, slightly curved, posterior margin strongly serrate. Gnathopod 2: coxa 2 wider than coxa 1, basis linear, ischium anterior margin very short, distal margin obliquely articulating with carpus, carpus linear, anterior margin naked except for transverse row of SS distally, posterior margin with numerous stout SS distally; propodus linear, palm almost transverse, rounded, finely crenulated, lined with numerous submarginal RS; dactylus large, not exceeding palm, posterior margin serrate. Pereopod 3: coxa anteroventrally obliquely truncate, basis linear, anterior and posterior margin finely setulose; merus slightly expanded distally; carpus shorter than merus, anterior margin naked, posterior margin with 6 pairs of RS; propodus naked anteriorly, posterior margin with 9 pairs of RS; dactylus stout, curved. Pereopod 4: coxa much larger than 3, wide posteroventral angle projecting somewhat ventrally; basis to dactylus as for pereopod 3. Pereopod 5: coxa posteroventrally subacute, pointed; basis bearing posteromarginal tooth; merus drawn out posterodistally; carpus slightly widened distally, posterior margin with 7 pairs of RS; propodus linear, posterior margin with 10 pairs of RS; dactylus curved, stout, approx. 0.3 × propodus length. Pereopod 6: coxa posteroventrally subacute, pointed, anterior half hidden by coxa 5, anterior margin weakly concave, posterior margin slightly drawn out; basis posteromarginal tooth larger than in pereopod 5; merus drawn out posterodistally, ischium to dactylus as in pereopod 5. Pereopod 7: coxa subrectangular; basis widened distally, but without tooth, posterodistally and posteroventrally pointed; ischium to dactylus as in pereopods 5 and 6.

Urosome and telson. Uropod 1: peduncle subequal in length to inner ramus, medial margin with 1 RS distally, distal margin with close row of short RS; inner ramus lateral margin with spaced row of short RS, medial margin with sparse RS; outer ramus marginally shorter than inner. Uropod 2: peduncle with row of short setae; inner ramus nearly twice the length outer ramus, both margins sparse lined with RS; outer ramus, both margins with few short RS. Uropod 3: peduncle short, approx. 0.3 × length of inner ramus, medial and inner margins of both rami with sparse row of short RS. Telson slightly longer than wide, u-shaped emargination 0.2 × lengths, lobes triangular, broadly rounded apically.

Figures

Figure 6. Epimeria robusta, NIWA 20257, female, 37 mm. A Lateral habitus B metasome and urosome C maxilla 2 D antenna 1 E mandibular palp F mandibular body.

Figure 7. Epimeria robusta, NIWA 20257, female, 37 mm. A Maxilliped B maxillipedal palp C frontal face of inner maxillipedal endite D frontal face of outer maxillipedal endite E labrum F maxilla 1.

Figure 8. Epimeria robusta, NIWA 20257, female, 37 mm. A Gnathopod 1 B pereopod 7 C gnathopod 2 D antenna 2 E pereopod 4 F pereopod 3.

Figure 9. Epimeria robusta, NIWA 20257, female, 37 mm. A Uropod 1 B uropod 2 C uropod 3 D telson E pereopod 6 F pereopod 7.