Comments: Formerly included in the genus Lutra. Van Zyll de Jong (1987) used the generic name Lontra for New World otters; this is appropriate if New World otters are more closely related to Aonyx otters of Africa than to Lutra otters of Eurasia and Africa. Jones et al. (1997) and Wozencraft (in Wilson and Reeder 1993, 2005) followed van Zyll de Jong in using Lontra as the generic name. Rice (1998) retained this species in the genus Lutra. Bininda-Emonds et al. 1999) supported the separation of New World otters (except Pteronura) into Lontra.
Patterns of genetic variation do not concur with current subspecific designations (Serfass et al. (1998), and numerous translocations have crossed subspecies' range boundaries; hence the use of subspecific names is not meaningful in many cases.