We report the discovery of a new species of doglike bat (Peropteryx) from the lowland Amazonian forests of Ecuador and Peru. It has transparent wing membranes that are faintly tinged brown with pale-brown arms and digits; ears that are separated on the forehead; and a skull with small, shallow pterygoid pits that are anterolateral to an undivided basisphenoid pit and that are separated by a mesopterygoid extension. These characters distinguish the new species from morphologically similar species with which it was previously confused (P. leucoptera and P. macrotis). A molecular phylogenetic analysis of unlinked loci from each of the four genetic transmission systems of mammals (mitochondrial, nuclear-autosomal, X, and Y chromosomes) independently corroborated the placement of the new species as the sister taxon to a clade that includes P. kappleri, P. macrotis, and P. trinitatis; the basal lineage for the genus is P. leucoptera. This phylogeny suggests that transparent wings (sometimes described as ''white'' but actually lacking pigment), the traditional character used to diagnose Peronymus, is not a unique synapomorphy. Furthermore, based on a molecular dating analysis, the depth of divergence of Peropteryx is equivalent to that of another New World emballonurid genus (Balantiopteryx). Therefore, Peronymus does not warrant higher-level recognition as a subgenus or genus.

Tonatia bidens has a broad distribution in Central and South America; the only extant form is monotypic. Our analysis reveals two species are involved: T. bidens (von Spix) from eastern Brazil, Paraguay, and Argentina; T. saurophila Koopman and Williams from Central America, northern and western South America, and Jamaica. These taxa are sympatric in northeastern Brazil. Both qualitative and quantitative assessments of morphological characters distinguish the species. Dental differences, previously noted between fossil material from Jamaica and mainland specimens representing T. saurophila as well as size differences between Central and South American T. saurophila warrant recognition of two subspecies representing extant mainland populations.

Between 9 and 22 January 1999, radio-tracking revealed that nine Sturnira lzlium (seven females, one lactating, and two males) used hollow trees (N = 5), vine tangles ( N = 2), or the bases of palm fronds (N = 1) as day roosts near Lamanai in Belize over 43 roost days. The bats roosted in hollows of four tree species, and the roost entrances ranged from 2.0 to 7.9 m above the ground. Radio-tagged individuals returned to the same roosts day after day, with the exception of a subadult female that used at least three day roosts over the course of the study. In their day roosts, S. lilium were inconspicuous, difficult to flush, and easily overlooked. Radio-tagged bats usually roosted alone and emerged significantly later than bats without radio tags.

Between 9 and 22 January 1999, radio-tracking revealed that nine Sturnira lzlium (seven females, one lactating, and two males) used hollow trees (N = 5), vine tangles ( N = 2), or the bases of palm fronds (N = 1) as day roosts near Lamanai in Belize over 43 roost days. The bats roosted in hollows of four tree species, and the roost entrances ranged from 2.0 to 7.9 m above the ground. Radio-tagged individuals returned to the same roosts day after day, with the exception of a subadult female that used at least three day roosts over the course of the study. In their day roosts, S.lilium were inconspicuous, difficult to flush, and easily overlooked. Radio-tagged bats usually roosted alone and emerged significantly later than bats without radio tags.

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