Integrative taxonomy and biogeography of the genus Oxytrechus (Coleoptera: Carabidae: Trechini) in the tropical alpine ecosystem of Ecuadorian Andes, with the description of six new species

Abstract

Summary This study presents a taxonomic revision of the species of the ground beetle genus Oxytrechus Jeannel, 1927 that inhabit the superpáramo of the Andes of Ecuador, which constitutes the uppermost zone of the tropical alpine ecosystem, above 4200 m. Sixteen species, displayed in three clades, were recorded in this environment, six of which are described as new: Oxytrechus antisanae n. sp. (Mt Antisana), O. giachinoi n. sp. (Mt Illiniza), O. hamatus n. sp. (Mt Atacazo and Pichincha), O. prunai n. sp. (Mt Guamaní), O. reflexus n. sp. (Mt Illiniza and Mt Corazón), and O. robbiolai n. sp. (Mt Pichincha). New distributional data are presented for O. chioriae Quéinnec & Ollivier, 2019, O. lallemandi Jeannel, 1927, O. moreti Mateu, 1988 and O. zoiai Casale & Sciaky, 1985. The first molecular phylogeny of the group, based on fragments of four mitochondrial and two nuclear genes, is given. Dichotomous identification keys are provided to the species groups and the included species. Based on systematic sampling, Oxytrechus exhibits the highest degree of microendemism among páramo ground beetles. No species has been found in more than two sky islands, and half of the species recorded in the superpáramo are single-mountain endemics. As regards their conservation status, eight species (two thirds) can be classified as vulnerable or endangered, due to a mix of low abundance, narrow distribution range, microendemism, limited ecological tolerance, habitat destruction and effects of climate change.