Molecular and morphological analyses support recognition of Prostanthera volucris (Lamiaceae), a new species from the Central Tablelands of New South Wales

Abstract

Research into the systematics of Prostanthera has recently revealed a close evolutionary relationship among P. phylicifolia s. str., the critically endangered P. gilesii, and a population of uncertain identity from the Central Tablelands of New South Wales, Australia. Previous analyses were unable to establish whether genetic boundaries separated these taxa. This study aimed to assess the species boundaries among these three taxa using a combination of single-nucleotide polymorphisms (SNP) sampled at the population-scale and multivariate analysis of morphological characters. Non-parametric and parametric statistics, neighbour-network analysis, phylogenetic analysis, and ancestry coefficient estimates all provided support for discrete genetic differences between the three taxa. Morphological phenetic analysis identified a suite of characters that distinguished each of these taxa. This corroboration of evidence supports the presence of three independently evolving lineages. Prostanthera gilesii and P. phylicifolia s. str. are distinct species independent from the third taxon which is described here as P. volucris R.P.ODonnell. A detailed description, diagnostic line drawings and photographs are provided. We evaluate P. volucris as satisfying criteria to be considered Critically Endangered.