Epimeria larsi, Lörz, Anne-Nina, 2009

Lörz, Anne-Nina, 2009, Synopsis of Amphipoda from two recent Ross Sea voyages with description of a new species of Epimeria (Epimeriidae, Amphipoda, Crustacea), Zootaxa 2167, pp. 59-68 : 61-66

publication ID	https://doi.org/ 10.5281/zenodo.189125
DOI	https://doi.org/10.5281/zenodo.6213407
persistent identifier	https://treatment.plazi.org/id/03A987C6-8977-1F5E-FF3A-D055FD14FC2B
treatment provided by	Plazi
scientific name	Epimeria larsi
status	sp. nov.

Treatment

Epimeria larsi View in CoL sp. nov.

( Figs 2–6 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Material examined. Holotype: NIWA 48484, male, 39 mm, TAN0802/167, 71° 51' 21"S, 71° 53' 24"E, 1990– 1954 m, 25/02/2008. Paratype: NIWA 37752, female, 58 mm, collected together with holotype.

Etymology. The species is dedicated to Lars Bock.

Description. Anterior cephalic margin sinuous, lateral cephalic lobe slightly produced; rostrum longer than head, reaching proximal part of antenna 1 peduncle article 2; eye present, oval, 0.5 × head height. Pereonite 1 shorter in length than head, pereonite 2 about 0.75 × length of 1; pereonites 1–4 lacking middorsal or dorsolateral processes; pereonite 5–7 dorsolateral carina developed; pleonites 1–3 with acute middorsal teeth curved posteriorly

Epimeron 1 antero- and posteroventral angle rounded; epimeron 2 and 3 posteroventral angle produced. Urosomite 1 with a keel-like middorsal bump. Urosomite 2 shortest middorsally flat. Urosomite 3 bearing mid-dorsal processes.

Antenna 1 accessory flagellum scale-like; primary flagellum of 30 articles. Antenna 2 peduncle article 1 with 3 long processes; article 2 with 2 slight processes, slightly shorter than article 1; article 3 longest, articles 3–5 lacking distal processes, flagellum with 49 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 13 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 outer plate, reaching mid length of merus; row of RS; medial plate reaching half the length of outer plate; palp medial margin strongly setose; merus, carpus, propodus margins parallel; dactyl with serrate medial margin.

Gnathopod 1 coxa long and slender, basis linear, slender, anterior margin with numerous fine SS; merus slightly longer than ischium, anterior margin very short, distal margin oblique, posterodistal angle acute, setose; carpus posterior curved margin with long SS; propodus 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, scurved, posterior margin strongly serrate.

Gnathopod 2 coxa slightly wider than coxa 1, basis to propodus very similar to gnathopod 1.

Pereopod 3 coxa larger than coxa 2, basis linear, anterior and posterior margin finely setulose; merus slightly expanded distally, carpus slightly shorter than merus, anterior margin naked, posterior margin with 5 pairs of RS; propodus naked anteriorly, posterior margin with 6 pairs of RS; dactylus stout, curved.

Pereopod 4 coxa longer than 3, very wide, anterior and posterior margins straight, posterodistal corner rounded; basis to dactylus as for pereopod 3.

Pereopod 5 coxa subrectangular, posterodistal corner produced; posterior margin straight; basis expanded midposteriorly; merus constricted proximally; carpus slightly widened distally; propodus linear, posterior margin with 6 pairs of RS; dactylus curved, stout, about 0.3 × propodus length.

Pereopod 6 coxa anterior half hidden by coxa 5, anterior margin weakly concave, posterior margin straight; basis expanded and posteriorly notched, ischium to dactylus as in pereopod 5.

Pereopod 7 coxa subrectangular; basis expanded midposteriorly; ischium to dactylus as in pereopods 5 and 6.

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 naked, produced into two processes; inner ramus length 1.3 × outer ramus, both margins sparse RS; outer ramus, both margins with few short RS.

Uropod 3 peduncle short, about 0.3 × length of inner ramus; medial and inner margins of both rami with sparse row of short RS.

Telson 1.2 × longer than wide; V-shaped emargination 0.25 × length, lobes triangular, pointed apically.

Colour in life. Eyes orange (fig. 6); body rose-red. All appendages, including antennae, mouthparts, pereopods, pleopods, uropods, telson and urosomite 3 dark red, coxae lighter red; head, pereonites, pleonites and urosomites very light red.

Remarks. Epimeria larsi sp. nov., superficially resembles E. robusta K.H. Barnard, 1930 [type locality: McMurdo Sound, Ross Sea]. Epimeria larsi , however, differs from E. robusta has the posteroventral corner of coxa 5 produced rather than unproduced (best seen from dorsal view). Further, the posteroventral corners of the epimera of E. larsi are rounded on plate l plate 1 and pointed on, plates 2 and 3, rather than pointed on all three plates ( E. robusta ). The coxae of pereopods 1–3 in E. larsi are apically rounded with parallel anterior margins of distal half, whereas coxa 1–3 of E. robusta are taper distally to a pointed apex.

Distribution. Western Ross Sea, 1954–1990 m.