A New Species of Myotis from the Islas Tres Marias, Nayarit, Mexico, with Comments on Variation in Myotis nigricans

A new Myotis is described from the Islas Tres Marias, Nayarit, Mexico. The new species is distinct from related taxa on the adjacent Mexican mainland (M. californicus, M. leibii, and M. carteri), although most closely related to M. carteri as shown by univariate and canonical variates analyses. An analysis of six groups of M. nigricans from Middle and South America supports the elevation of M. nigricans carteri to specific status, confirms the distinctness of M. nigricans extremus, but fails to substantiate subspecific status for bats from Colombia and Ecuador, recently recognized as M. n. punensis.