ID please: Brazil bats at hummingbird feeders

Hi! I’m new to this Forum. I am a birdwatcher from Mexico with an interest in mammals. I need help with identification, please. I first thought they were some species of Anoura but after looking at diagrams the interfemoral membrane to my untrained eye looked more like Artibeus! (which I doubt these are)

I took these photographs of bats visiting the hummingbird feeders at Guapi Assu Bird Lodge (REGUA) in Rio de Janeiro state, Brazil. The photos may represent different individuals or, indeed, different species (there were several individuals present). All were taken in the evening of October 6 or 7, 2014. The photos can be zoomed into to view details more clearly (I think).

Saludos,

Héctor Gómez de Silva