Morphological and genetic identification of an invasive species of the genus Melita (Amphipoda: Melitidae) from the Azov–Black Sea basin

The species of the genus Melita that was found in the Kerch Strait is morphologically similar to M. setiflagella and M. nitida.A comparative analysis of the morphological parameters of 14 body parts with those in the known melitid amphipods M. setiflagella and M. nitida, and also those in a species identified as M. cf.setiflagella recorded from the Kerch Strait waters in March 2019, has shown that such character as setation of antennae 2 pair cannot be diagnostic at the species level and is probably a response of individuals to variations in their habitat conditions.According to the results of a genetic analysis, the species M. cf.setiflagella is actually M. nitida.