Northward range extension of Atrichops crassipes (Meigen, 1820) (Diptera, Athericidae) in the Baltic ecoregion, with the first record from Latvia

The first record of Atrichops crassipes (Meigen, 1920) (Diptera, Athericidae) in Latvia is reported, together with additional findings from Lithuanian waters in 2015. The data are based on larval records collected during freshwater macroinvertebrate research and water‑quality monitoring. Atrichops crassipes represents a new Diptera species record for Latvia and marks the northernmost limit of the species known range. Our data suggest that A. crassipes is expanding its range northward, possibly driven by climate warming.