However, the boundaries of L. didymus and L. mystaceus are not precise given that these species are separated only on the basis of advertisement call patterns (Heyer et al. 1996); they occur in the western Amazon Basin in far western Brazil, southeastern Peru, and extreme northern Bolivia, in the Department Pando (Heyer et al. 1996; Köhler & Lötters 1999; Frost 2007).