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 Author Bakir, Kerem Author Sezgin, Murat Author Myers, Alan A. text Zootaxa 2011 2791 63 67 journal article 10.5281/zenodo.207651 ba18d441-374d-42fb-b726-f5129403d20a 1175-5326 207651 Megamphopus Norman, 1869 Diagnosis. Head with lateral lobes strongly produced, subocular margin strongly recessed. Mandible palp article 3 spatulate, shorter than article 2. Antenna 1 peduncle article 3 longer than article 1; accessory flagellum very small but distinct. Coxa 2 the largest, especially in male; coxae 3–7 relatively shallow. Gnathopods subchelate; male gnathopod 2 greatly enlarged. Uropod 3 rami longer than peduncle. Telson broad with a strong robust seta on each lateral crest. Remarks. Megamphopus can be distinguished from all other genera within the Gammaropsis –group of genera, by its differentially enlarged male gnathopod 2 coxa.