Proterorhinus marmoratus
Proterorhinus marmoratus is a species of gobiid fish, a tubenose goby native to the brackish water parts of the Black Sea and the Sea of Azov, near the coasts of Bulgaria, Georgia, Romania, Ukraine and Russia. Also it is found in the Marmora Sea (Turkey). It can reach a length of TL. Systematics. "Proterorhinus marmoratus", known as the tubenose goby, was formerly considered as the only representative of the genus "Proterorhinus" with a native range extending to the Caspian Sea basin, and a recent invasive range in the freshwaters of Europe and North America. In the 2000s it  was split into several cryptic species based on the molecular and further morphological analyses. In the current concept, "P. marmoratus" is applicable only to marine and brackish water populations of the Black Sea basin. Freshwater populations of this basin are now referable to the western tubenose goby "(P. semilunaris)", except for a local Crimean "Proterorhinus tataricus".