Unveiling the genetic diversity of bicolored-spined porcupines (Rodentia: Erethizontidae): a novel karyotype, population structuring, and evolutionary insights

Abstract

New World porcupines are rodents belonging to the Erethizontidae family which is divided into two subfamilies: Chaetomyinae, represented by the genus Chaetomys, and Erethizontinae, which includes the genera Erethizon and Coendou. Within this family, the taxonomy of Coendou has proven to be particularly complex and challenging. It remains one of the most neglected among New World mammals, and the taxonomic status and phylogenetic relationships of some taxa are still controversial. In this study, we assessed the diversity of Coendou bicolor using the mitochondrial cytochrome b marker and described the chromosome complement of this species for the first time, increasing the knowledge about this taxon. Notably, the karyotype we described for C. bicolor differs from the six karyotypes reported for other species within this genus. Our findings align with previous research, confirming the separation of the three Coendou subgenera into distinct monophyletic clades. The median joining analysis supports these phylogenetic relationships and suggested a population structure in C. bicolor populations, apparently related to the rivers. Samples from northern Peru are separated from the remaining population by the Ucayali River (a tributary of the Amazonas River), while samples from southern Peru and Brazil are separated from Bolivian samples by the Madre de Dios/Beni rivers. These data highlight the potential role of these rivers as geographic barriers, contributing to the genetic differentiation of C. bicolor populations. Our study provides valuable insights into karyotype and genetic diversity of C. bicolor populations, enriching our understanding of this species.