*6. Potamophilus acuminatus (Fabricius, 1792)

Local references: Not reported earlier.

Material: Cherniakhovsk district, 2 km S Timofeevka, 54.63°N, 21.90°E, 01.07.2021, 1 ex., riverbank of Angrapa (Fig. 4) .

Comments: First report of the species for Kaliningrad region and Baltic countries fauna. It is known in northern Belarus (Alexandrovitch et al. 1996; Moroz 2018) and Poland (Buczyński et al. 2011). Known aspects of bionomy, distribution and proposal for including of Potamophilus acuminatus to the Red List of IUCN in VU category (vulnerable species) is discussed in Buczyński et al. (2011).