A New Collared Lizard (<i>Tropidurus</i>: Tropiduridae) Endemic to the Western Bolivian Andes and Its Implications for Seasonally Dry Tropical Forests

Abstract

In this study we describe Tropidurus azurduyae, a new species of lizard endemic to the Andes. This species is restricted to inter-Andean dry valleys of central and southern Bolivia, within the ecoregion known as Bolivian Montane Dry Forests. It is currently known from the departments of Chuquisaca, Cochabamba, Potosí, and Santa Cruz, where it ranges in elevation from about 1000 to 2800 m. In addition, our analyses of closely related populations of Tropidurus from Argentina, Bolivia, Brazil, and Paraguay revealed undescribed species in central and northeastern Brazil and eastern Bolivia that render T. etheridgei Cei, 1982, paraphyletic. These results underscore the need for a comprehensive revision of peripheral and disjunct populations currently assigned to widely distributed species of Tropidurus. The phylogenetic relationships and distribution patterns of these new taxa concur with recent findings supporting seasonally dry tropical forests and open formations of dry vegetation from South America as distinct biotic units. Furthermore, they offer no support for seasonally dry tropical forests as closely related areas. In line with these discoveries, we refute biogeographic scenarios based exclusively on vicariance to explain the biogeographic history of Tropidurus.