The lamprey collections of the National Museum of Natural History – Sofia and the Regional History Museum – Ruse were examined in order to determine the species composition of the family Petromyzontidae in Bulgaria. In contrast to the four species of lampreys reported in the scientific literature as being present in Bulgaria, i.e. Lampetra fluviatilis, L. planeri, Eudontomyzon danfordi, and E. mariae, only the latter species was determined in the Bulgarian material. The distribution of this species in Bulgaria is restricted to the Danube River basin. The occurrence of E. hellenicus in the Bulgarian segment of the Struma River basin is anticipated in all probability. The species composition of lampreys inhabiting the streams emptying directly into the Black Sea remains to be investigated.
New records of the Ukrainian brook lamprey Eudontomyzon mariae (Berg, 1931) from the upper tributaries of the both Volga (Caspian Sea watershed) and Don (Black Sea watershed) river basins are documented. This significantly extends the range of the Ukrainian brook lamprey eastwards. The Ukrainian brook lamprey and the genus Eudontomyzon are the most distributed species and genus of the lampreys in Europe, respectively.
Nonparasitic lamprey found in the Beli Drim River basin (Drin River drainage, Adriatic Sea watershed) represents a valid species Eudontomyzon stankokaramani Karaman, 1974. From other species of the genus Eudontomyzon it differs in its dentition, and the number and form of velar tentacles. This is the first Eudontomyzon species found in the Adriatic Sea watershed.