Genus Chydorus Leach, 1816

As Frey (1980) stated, the American representative of the Chydorus sphaericus (O.F. Müller) complex, named C. brevilabris Frey, is widely distributed (from Canada to northern Mexico). A comparison with C. sphaericus from Germany revealed more than 17.61% divergence, confirming the true species status of both.