Intraspecific phylogeny of the New Zealand short-tailed bat Mystacina tuberculata inferred from multiple mitochondrial gene sequences.

An intraspecific phylogeny was established for the New Zealand short-tailed bat Mystacina tuberculata using a 2,878-bp sequence alignment from multiple mitochondrial genes (control region, ND2, 12S ribosomal RNA [rRNA], 16S rRNA, and tRNA). The inferred phylogeny comprises six lineages, with estimated divergences extending back between 0.93 and 0.68 million years to the middle Pleistocene. The lineages do not correspond to the existing subspecific taxonomy. Although multiple lineages occur sympatrically in many populations, the lineages are geographically structured. This structure has persisted despite repeated cycles of range expansion and contraction in response to climatic oscillations and catastrophic volcanic eruptions. The distribution of lineages among populations in central North Island indicates that a hybrid zone was formed by simultaneous colonization from single-lineage source populations inhabiting remote forest refugia. The observed pattern is not typical of microbats, which because of their high mobility generally exhibit low levels of genetic differentiation and geographic structure over continental ranges. Although lineages of M. tuberculata occur sympatrically in many populations, genetic distances between them are sufficiently large to suggest that they may be considered evolutionary significant units or taxonomic subspecies.

The demographic history of the New Zealand short-tailed bat Mystacina tuberculata inferred from modified control region sequences.

Short-tailed bats Mystacina tuberculata were widespread throughout the forest that dominated prehuman New Zealand, but extensive deforestation has restricted them to scattered populations in forest fragments. In a previous study, the species' intraspecific phylogeny was investigated using multiple mitochondrial gene sequences. Six phylogroups were identified with estimated divergences of 0.93-0.68 Ma. In the current study, the phylogeographical structure and demographic history of the phylogroups were investigated using control region sequences modified by removing homoplasic sites. Phylogeographical structure in the North Island was generally consistent with an isolation-by-distance dispersal model. Coalescent-based analyses (i.e. mismatch distributions, skyline plots, lineage dispersal analysis and nested clade analysis) indicated that the three phylogroups found in central and southern North Island expanded before the last glacial maximum, presumably during interstadials when Nothofagus forest was most extensive. Genetic structure within a central North Island hybrid zone was consistent with range expansion from separate refugia following reforestation after catastrophic volcanic eruptions. Phylogeographical structure in the South Island was consistent with southern populations originating during rapid southward range expansion from refugia in northern South Island following postglacial reforestation of the South Island 10-9 kya.