Untangling the long-tailed planigale (Dasyuridae: Planigale ingrami ) species complex: four species revealed using integrative taxonomy

Abstract Planigales are the smallest marsupials in the world. Seven species are currently recognized, six that occur in Australia (Planigale ingrami, P. gilesi, P. kendricki, P. maculata, P. tealei and P. tenuirostris) and one that occurs only in New Guinea (P. novaeguineae). Genetic studies using mitochondrial and nuclear DNA fragments have suggested cryptic diversity within both the P. ingrami and P. maculata species complexes that warrant formal taxonomic revision. Here, we addressed the unrecognized diversity in the P. ingrami complex using comprehensive genetic sampling and morphological assessments of specimens from museum collections. We built on previous studies by obtaining DNA sequences from the mitochondrial 12S ribosomal RNA locus and thousands of nuclear single nucleotide polymorphism loci for >220 individuals, comprehensively sampling across species distributions. Phylogenetic analyses and species delimitation approaches were used to define species boundaries and assess divergence between existing and novel species. This was coupled with a thorough morphological examination of museum specimens, including cranial and external morphometrics. We found three diagnosable forms within the P. ingrami species complex. We reinstate Planigale subtilissima, occurring in the Kimberley, from synonymy, synonymize P. ingrami brunnea, and describe a new and highly distinctive species, Planigale petrophila sp. nov., from Arnhem Land in northern Australia.