Phylogenetic relationships among cryptic species of the Phyllotis xanthopygus complex (Rodentia, Cricetidae)

Abstract

The leaf‐eared mouse, Phyllotis xanthopygus (Waterhouse 1837) is a widely distributed sigmodontine rodent in South America, with populations ranging from central Peru to southern Argentina and Chile. Previous morphological and molecular contributions have suggested that P. xanthopygus represents a species complex. In order to characterize and disclose this cryptic species complex, we perform a molecular genetic/phylogenetic analysis of representative samples across its geographical distribution. Phylogenetic analyses were based on sequences of cytochrome‐b gene (801 base pairs; n = 114 specimens) and analysed by maximum likelihood and Bayesian approaches. We also employed a Bayesian implementation of the Poisson tree processes (bPTP) as a unilocus species delimitation method. Results from our phylogenetic analyses retrieve eight well‐supported clades. Five of these clades belong to populations known as P. xanthopygus s.l., which were paraphyletic to the closely related species P. bonariensis, P. caprinus, and P. limatus, displaying strong genetic divergences (>8%). The (bPTP) analyses recovered ten species within P. xanthopygus s.l. plus related forms (i.e. P. bonariensis, P. caprinus, and P. limatus). Our results, coupled with chromosomal and morphological evidences, support the recognition of these clades at the species level and provide a new framework to characterize the leaf‐eared mice complex. Our study highlights the importance of integrative approaches in disentangling the biodiversity of Neotropical rodents.

The Phyllotis xanthopygus complex (Rodentia, Cricetidae) in central Andes, systematics and description of a new species

“…Several systematic studies, based both on morphological and molecular data, have contributed to clarifying most of the phylogenetic relationships, species boundaries and taxonomy among the species of this genus (e.g. Ferro et al., 2010; Jayat et al, 2007; Jayat et al., 2016; Steppan, 1995, 1998; Steppan et al., 2007; Pacheco et al., 2014; Rengifo & Pacheco, 2015, 2017; Ojeda et al., 2021). All these studies have substantially expanded our understanding of the species‐level taxonomy of the genus, but several uncertainties still remain, especially for populations representing the nominal forms described for central and southern Andean areas (Ojeda et al., 2021).…”

“…Across this 6,000 km range, populations assigned to P. xanthopygus are often the most common rodent species among small mammal assemblages (Steppan & Ramírez, 2015). Although this rodent shows an apparently continuous geographic distribution across the arid and semiarid Andean ecosystems, some geographically isolated populations occur in central Argentina, within temperate grassland environments (Ojeda et al., 2021; Steppan & Ramírez, 2015; Teta et al., 2018).…”

“…The complex taxonomic history of the nominal forms related to P. xanthopygus has been extensively documented in several publications (e.g. Hershkovitz, 1962; Ojeda et al., 2021; Pearson, 1958; Steppan & Ramírez, 2015; Teta et al., 2018); here, we will provide a brief resume, but readers interested in going further into this topic should consult basic literature. Pearson (1958) and Hershkovitz (1962), in his revision of the genus, considered P. darwini as a widely distributed and polytypic species, including the nominal forms xanthopygus , chilensis Mann 1945, posticalis Thomas, 1912, ricardulus Thomas, 1919, rupestris P. Gervais 1841, limatus Thomas, 1912 and vaccarum Thomas, 1912 as subspecies (later, Crespo [1964] added the nominal form bonariensis ).…”

“…Reig, 1978; Steppan, 1998; Steppan & Ramírez, 2015). Finally, an important milestone should be mentioned; recent molecular studies have challenged the traditional classification of xanthopygus into six subspecies, showing that, as it is currently understood, this taxon is a complex of two or more cryptic species (Albright, 2004; Jayat et al., 2016; Ojeda et al., 2021; Riverón, 2011). The taxonomy of most of the nominal forms related to the P. xanthopygus complex was initially addressed using morphology (e.g.…”

“…The aim of our study was to test the taxonomic status of the main clades obtained in the most recent molecular phylogenetic hypothesis for the P. xanthopygus complex (Ojeda et al., 2021) primarily using morphological evidence but supplemented with new DNA sequence data. The molecular analyses of Ojeda et al.…”