New Miocene mystacinid bat fossils from New Zealand, including a small new species of the endemic genus Mystacina (Chiroptera: Noctilionoidea: Mystacinidae)

New mystacinid bat fossils recovered from Miocene lacustrine sediments near St Bathans in Central Otago, South Island, New Zealand represent several taxa, including a new species. This new mystacinid species is the smallest yet recorded from St Bathans, and the smallest mystacinid known from New Zealand. It is similar in size to the Australian Miocene mystacinid Icarops paradox. The dental morphology of the new St Bathans mystacinid aligns with that of Mystacina species. A phylogenetic analysis using both maximum parsimony and undated Bayesian analysis of 292 unordered dental characters with a molecular scaffold enforced supports monophyly of an endemic New Zealand mystacinid clade comprising all known Mystacina species. Also assigned here to the genus Mystacina is a previously reported but still unnamed mystacinid from St Bathans. A decline in mystacinid diversity in New Zealand since the Early Miocene is evident.