Morphometric and morphological variation in South American populations of Myotis albescens (Chiroptera: Vespertilionidae)

Abstract

Myotis albescens (É. Geoffroy, 1806) occurs from Mexico to Uruguay and Argentina. Despite a large number of specimens in collections, its variability in South America has been underestimated, potentially leading to errors in identification. In order to clarify the taxonomic limits of M. albescens and to evaluate previous hypotheses of geographic variation in size we analyzed the type material and studied the variability in South American samples using multivariate exploratory and confirmatory procedures, as well as frequency analyses of discrete morphological data. The presence of a fringe of hairs along the trailing edge of the uropatagium, the long and silky pelage with frosted appearance on the dorsum, ear 9 to 14 mm long, broad interorbital and postorbital constrictions, and a globular braincase were identified as the most useful traits to distinguish M. albescens from its South American congeners. In agreement with Bergman's rule, larger specimens were found in the South. Beyond the geographic component, Individual variation is an important factor affecting the variability in the size and shape of the skull and pelage color

Review ofMyotis(Chiroptera, Vespertilionidae) from Northern South America, Including Description of a New Species

“…South American populations show a trend toward increasing size southward, with smaller specimens found in the north. Venezuelan and Brazilian Amazon basin specimens are similar in size (Moratelli and Oliveira, 2011).…”

“…Myotis albescens (É. Geoffroy, 1806) Currently this species is treated as monotypic and occurs from southern Veracruz, Mexico, southward through Central America into Uruguay and Argentina (Simmons, 2005;Wilson, 2008;Braun et al, 2009;Moratelli and Oliveira, 2011). South American populations show a trend toward increasing size southward, with smaller specimens found in the north.…”

Small Mammals of the Mayo River Basin in Northern Peru, with the Description of a New Species of Sturnira (Chiroptera: Phyllostomidae)

“…The taxonomy and systematics of the genus, especially in the NO. 429 New World, is confused and controversial (e.g., LaVal, 1973;Moratelli and de Oliveira, 2011;Moratelli et al, 201 la,b, 2013;Moratelli and Wil¬ son, 2011;Larsen et al, 2012;Mantilla-Meluk and Munoz-Garay, 2014). Recently, several studies have attempted to clarify the taxonomy of the Myotis nigricans species complex Moratelli et al, 2013;Moratelli and Wilson, 2014).…”

Expansion of the southern limit of Vampyrodes caraccioli Thomas, 1889 (Chiroptera, Phyllostomidae) and first record for Santa Catarina state, southern Brazil

“…Even though the area-volume relation is used to explain the increase in body size of several taxa of mammals in areas of high latitude, factors such as availability and size of food resources can also influence in this relation (see McNab 1971). In Chiroptera, variation in body size between populations of different latitudes has been observed for several species (e.g Tavares and Velazco 2010, Garbino 2011, Moratelli and Oliveira 2011. For almost all measurements, females were larger than males, which could be an indicative of sexual dimorphism for the specimens collected in this study, although Velazco and Simmons (2011) did not observe this dimorphism when a larger number of specimens was analyzed.…”