Molecular systematics of chinchilla rats and taxonomic assessment of the Abrocoma cinerea species complex.

This article focuses on the molecular phylogenetics and species delimitation within the rodent family Abrocomidae, commonly known as chinchilla rats, which inhabit the central Andes of South America. Using partial DNA sequences from one mitochondrial gene (Cytochrome b) and two nuclear genes (GHR and RAG1), the study infers phylogenetic relationships among six species, revealing three main clades—Abrocoma bennettii, Cuscomys ashaninka, and the Abrocoma cinerea species complex (ACC)—each potentially representing distinct genera based on genetic divergence and divergence time estimates. Species delimitation analyses within the ACC support recognizing only two species, leading to the proposed synonymy of A. famatina with A. cinerea and A. uspallata with A. schistacea. Divergence time estimates suggest that extant abrocomids originated in the late Miocene (~5.6 million years ago), with diversification likely driven by the topographic uplift and associated climatic changes of the central Andes.