Did Azara discover Myotis simus or Myotis midastacus (Mammalia: Chiroptera: Vespertilionidae) at least a century before their formal description?

ABSTRACT The true identity of the “Chauve-Souris Onzieme ou Chauve-Souris Cannelle” of Azara (1801) and the “LXXXII Murcielago Acanelado” of Azara (1802) has never been clarified. Though it has historically been associated with the Red Myotis, Myotis ruber (É. Geoffroy St.-Hilaire, 1806), there are clear inconsistencies with that species. Unusual features of the description such as the position of the attachment of the wing membrane to the limbs confirm that the species described by Azara belongs to the Myotis simus Thomas, 1901 group. Two members of that group occur in Paraguay, from where Azara described his specimen: Myotis cf. simus and the recently described Myotis midastacus Moratelli & Wilson, 2014. Measurements and collection locality slightly favour its identity as the former, but it is not possible to conclusively state which of these species Azara had in his possession.