Abstract
Six mouse opossum species are currently recognized for the genus Thylamys in South America, of which we hypothesized the evolutionary relationships for those located in the Andean Altiplano and canyons of the Region I of Chile, as well as for those located south of the Atacama Desert down to 37˚ S. To that goal we sequenced the cytochrome b mitochondrial gene and data were analyzed using different phylogenetic criteria such as parsimony, distance and likelihood available in the program PAUP 4.0. The different phylogenetic approaches agreed in recovering two well defined clades: one constituted by Thylamys pallidior that included specimens from the coast and the “pre-cordillera” of the Region I of Chile, and the other clade constituted by Thylamys elegans that included populations located south to the Atacama Desert. Therefore, we demonstrate that populations located in the canyons and andean areas of northern Chile belong to T. pallidior, while those located south to the Atacama desert are recognized as T. elegans, results that confirm the occurrence of two thylamyine species in Chile.
Highlights
Los marsupiales tipo ratón o “mouse opossums” del género Thylamys (Didelphidae) se diferencian del resto de las comadrejas enanas sudamericanas por habitar biomas abiertos y secos, y por presentar una serie de adaptaciones a este tipo de ambientes, tales como la capacidad de almacenar grasa en la cola, el pequeño tamaño de los pies y las garras en relación al cuerpo, los orificios nasales estrechos que no se prolongan hacia la sutura maxilo-frontal, un hueso timpánico más prominente, y una región interorbital más estrecha en comparación a otros miembros de la familia (Tate 1933, Creighton 1984)
Six mouse opossum species are currently recognized for the genus Thylamys in South America, of which we hypothesized the evolutionary relationships for those located in the Andean Altiplano and canyons of the Region I of Chile, as well as for those located south of the Atacama Desert down to 37 ̊ S
The different phylogenetic approaches agreed in recovering two well defined clades: one constituted by Thylamys pallidior that included specimens from the coast and the “pre-cordillera” of the Region I of Chile, and the other clade constituted by Thylamys elegans that included populations located south to the Atacama Desert
Summary
Filogeografía de las llacas chilenas del género Thylamys (Marsupialia, Didelphidae) en base a secuencias del gen mitocondrial citocromo b. Seis especies de llacas o “mouse opossums” del género Thylamys se han descrito para Sudamérica, de las cuales investigamos las relaciones evolutivas de aquellas localizadas en el Altiplano y las quebradas de la Primera Región de Chile, y en localidades ubicadas al sur del Desierto de Atacama hasta los 37o S. Demostramos de este modo, que las poblaciones de las quebradas de la Primera Región de Chile corresponden a T. pallidior, lo cual estaría facilitado por la continuidad biogeográfica entre estas quebradas y la Prepuna andina, mientras que las llacas localizadas al sur del Desierto de Atacama, se reconocen como T. elegans.
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