Megamoera

Labay, Vjacheslav S., 2013, Review of amphipods of the Melita group (Amphipoda: Melitidae) from the costal waters of Sakhalin Island (Far East of Russia). I. Genera Megamoera Bate, 1862 and Armatomelita gen. nov., Zootaxa 3700 (1), pp. 65-112 : 100

Key to species of genus Megamoera

1. Eyes absent.......................................................................................... 2

– Eyes present.......................................................................................... 3

2. Dorsal carination of pleon segments 1–3 without produced central tooth, lateral teeth more than submedial teeth................................................................................. Megamoera pallida (G. O. Sars, 1879)

– Dorsal carination of pleon segments 2–3 with produced central tooth each; pleon segment 1 without dorsal carination........................................................................... Megamoera lignophila (Barnard, 1961)

3. Head, lower margin of anterior lobe without accessory processes ( Fig. 23 a)........................................ 4

– Head, lower margin of anterior lobe with accessory processes ( Fig. 1 c)........................................... 7

4. Dorsal carination of pleon segments 1–3 without strong central tooth................... Megamoera aequidentatum sp. n.

– Pleon segments 1–3 with another combination of dorsal teeth................................................... 5

5. Pleon segment 1 with strong medial tooth dorsally; pleon segments 2 & 3 without strong medial tooth dorsally (medial tooth equal to lateral teeth in size); pleon plate 3 without strong processed tooth at the posterior-distal corner................................................................................... Megamoera borealis Jarret & Bousfield, 1996

– Pleon segments 1–3 with strong medial tooth dorsally; pleon plate 3 with strong processed tooth at the posterior-distal corner..................................................................................................... 6

6. Pleon segments 1 & 2 with 1–3 lateral denticles each side dorsally, pleon segment 3 with 3 lateral denticles each side dorsally........................................................................ Megamoera dentata (Krøyer, 1842)

– Pleon segments 1 & 2 without lateral denticles dorsally, pleon segment 3 with only one lateral denticle each side dorsally.................................................................... Megamoera unimaki Jarret & Bousfield, 1996

7. Urosomite 1 with 5+ dorsal teeth......................................................................... 8

– Urosomite 1 with 3 dorsal teeth.......................................................................... 9

8. Pleon segments 1 & 2 with 4+ lateral denticles each side dorsally, pleon segment 3 with 3 lateral denticles each side dorsally...................................................................... Megamoera subtener (Stimpson, 1864)

– Pleon segments 1 & 2 with 3 lateral denticles each side dorsally, pleon segment 3 with 4+ lateral denticles each side dorsally......................................................................... Megamoera falsomikulitschae sp. n.

9. Pleon plate 3 without strong processed tooth at the posterior distal corner........................................ 10

– Pleon plate 3 with strong processed tooth at the posterior distal corner........................................... 11

10. Pleon segments 1 & 2 with central tooth and 3–4 minute lateral denticles each side; pleon segment 3 with central tooth and 2– 3 lateral denticles................................................... Megamoera kodiakensis (J.L. Barnard, 1964)

– Pleon segments 1 & 3 with central tooth and 2 minute lateral denticles each side..................................................................................................... Megamoera glacialis Jarret & Bousfield, 1996

11. Pleon segments 1 & 2 with central tooth and 3 minute lateral denticles each side; pleon segment 3 with central tooth and 5 lat- eral denticles each side.............................................. Megamoera mikulitschae (Gurjanova, 1985)

– Pleon segments 1–3 with another configuration of dorsal armament............................................. 12

12. Pleon segment 3 without central tooth, with 3 lateral teeth each side........ Megamoera bowmani Jarret & Bousfield, 1996

– Pleon segment 3 with central tooth, with 2–3 lateral teeth each side............................................. 13

13. Pleon segment 3 without strong medial tooth dorsally (medial tooth equal to lateral teeth in size).......................................................................................... Megamoera rafiae Jarret & Bousfield, 1996

– Pleon segment 3 with strong medial tooth dorsally.......................................................... 14

14. Pereopods 5–7, bases regular, narrowed distally; sculpture of surface without points........ Megamoera similidentata sp. n.

– Pereopods 5–7, bases expanded, rounded posteriorly; sculpture of surface pointed............... Megamoera striata sp. n.

Figures

FIGURE 1. Megamoera similidentata sp. n., holotype, male: a—lateral view without uropod 3, b—carination of abdominal segments, c—cephalon, d—antenna 1, e—antenna 2, f—upper lip; scale: a, b— 10 mm; c – f— 1 mm.

FIGURE 23. Megamoera aequidentata sp. nov., holotype, female: a—lateral view, b—carination of abdominal segments, cantenna 1, d—antenna 2, e—upper lip; scale: a, b— 5 mm; c, d— 1 mm; e— 0.1 mm.