Until now, Molossus melini was known only from its type locality, in the south of Santa Fe province, Argentina. Specimens of this species were collected in 2021 from a roost in a Fraxinus tree of the urban woodland of Paraná city, Entre Ríos province, Argentina. Bat identification was made by comparing external and cranial characters and measurements with those reported in the bibliography and corroborated by a phylogenetic analysis based on the cytochrome b gene. Also, multivariate morphometric analyses showed that cranial measurements, but not external ones, are informative enough to discriminate M. melini from the other Molossus species in Argentina ( M. currentium , M. fluminensis , and M. molossus ). This new record extends the distribution of M. melini from the south of Santa Fe province by 230 km to the northeast and represents the first record of the species in the Espinal ecoregion. Supplementary information The online version contains supplementary material available at 10.1007/s13364-023-00679-1.

Incorporamos dos nuevas especies de murciélagos a los citados para la provincia de Santa Fe, Argentina. Un ejemplar de Cynomops planirostris capturado en un bosque en galería del departamento San Javier constituye el primer registro de la especie para la ecorregión Delta e Islas del Paraná y el tercero para el noreste del país. El otro registro corresponde a un ejemplar de Myotis albescens capturado en un ambiente urbano del departamento La Capital. Estos registros aumentan la riqueza de murciélagos de la provincia a 29 especies. Además, brindamos información sobre la historia natural de ambas especies.