Taxonomic status of the Mediterranean-endemic goby <i>Pomatoschistus adriaticus</i> Miller, 1973 inferred with both morphological and genetic data

Minor morphological differences between the Atlantic and Mediterranean populations of Pomatoschistus pictus (Malm, 1865) resulted in the description of two subspecies of this species by Miller (1973): Pomatoschistus pictus pictus and P. p. adriaticus. However, the similarity of morphometric and meristic characteristics led to an ambiguity about their status. Despite high morphological similarities between the Atlantic and Mediterranean populations, we found that the population in the Sea of Marmara (Erdek) differs from the Atlantic population in terms of the frequency of papillae in the occipital rows g and h, the position of the suborbital row b and the colouration of the second dorsal fin. Examination of the DNA sequence of the COI gene showed that the K2P genetic distance between the population in the Atlantic and the Sea of Marmara (Erdek) was 7.9%, while the minimum interspecific distance between any other Pomatoschistus species was determined as 4.3%. We concluded based on the combined genetic and morphological results that the population in the Sea of Marmara represents a species that is distinct from the Atlantic species P. pictus. It is likely that it belongs to Pomatoschistus pictus adriaticus described in the Adriatic Sea and should be given a species rank.