Megamphopus

Bakir, Kerem, Sezgin, Murat & Myers, Alan A., 2011, A new species of amphipod, Megamphopus katagani sp. nov. (Crustacea: Peracarida: Photidae) from the Sea of Marmara (Turkey), with a key to the species of Megamphopus in the North Atlantic, Mediterranean and associated Seas, Zootaxa 2791, pp. 63-67 : 67

Key to the species of Megamphopus from the North-East Atlantic, Mediterranean and associated seas

1. Gnathopod 2 grossly enlarged, at least twice size of gnathopod 1 (males).......................................... 2

- Gnathopod 2 not larger or only a little larger than gnathopod 1 (females).......................................... 6

2. Male coxa 2 much deeper than broad...................................................................... 3

- Male coxa 2 subsquare................................................................................. 4

3. Male gnathopod 2 dactylus more than two thirds length of propodus..................... M. longicornis Chevreux, 1911

- Male gnathopod 2 dactylus very short, less than half length of propodus................... M. brevidactylus Myers, 1976

4. Male gnathopod 1 dactylus longer than propodus............................................ M. katagani sp. nov.

- Male gnathopod 1 dactylus shorter than propodus............................................................ 5

5. Male gnathopod 2 dactylus subequal in length with propodus......................... M. longidactylus Chevreux, 1925

- Male gnathopod 2 dactylus scarcely half length of propodus............................... M. cornutus Norman, 1869

6. Female uropod 2 peduncle with inter-ramal spine............................................................. 7

- Female uropod 2 peduncle lacking inter-ramal spine.......................................... M. katagani sp. nov.

7. Female ocular lobes acute..................................................... M. longidactylus Chevreux, 1925

- Female ocular lobes sub-acute...........................................................................8

8 Ocular lobes terminating in blunt tip; antenna 2 flagellum with about 10 articles............... M. cornutus Norman, 1869

- Ocular lobes terminating in sharp point; antenna 2 flagellum with more than 15 articles............................. 9

9. Female gnathopod 2 propodus longer than carpus..................................... M. brevidactylus Myers, 1976

- Female gnathopod 2 propodus subequal with carpus.................................. M. longicornis Chevreux, 1911