Molecular phylogeny and taxonomy of the Sicista concolor group (Mammalia, Rodentia, Sicistidae) with the description of a new species

Sicista is the sole extant genus in the family Sicistidae and one of the most ancient rodent genera known to date. This genus is of particular importance in mammalian evolutionary studies due to its ancient lineage and specialized ecological niches. In China, species of the genus Sicista are notoriously rare and elusive, making specimen collection exceptionally difficult. Sicista concolor is a poorly studied species within the genus, and its phylogenetic relationships and evolutionary history remain largely unexplored. In this study, we collected 36 specimens of S. concolor , sequenced one mitochondrial gene and two nuclear genes, and conducted morphological analyses, with particular emphasis on penile morphology, to infer its phylogenetic relationships. Our findings reveal that S. concolor represents a species complex comprising four distinct species. We describe a new species, Sicista meiguites sp. nov. , and elevate the subspecies S. c. weigoldi to full species status. Our molecular analyses also revealed a cryptic species.