Taxonomic and biogeographic insights into Australasian fingerworts in the Lepidozia ulothrix clade

Abstract

The floras of Australia and New Zealand are characterised by very high endemism of bryophytes. The highly diverse genus Lepidozia (fingerworts; family Lepidoziaceae) is represented by more than 20 mostly endemic species in these countries. The genus has been monographed in New Zealand, but issues surrounding species circumscription remain. This study focused on the Lepidozia ulothrix clade, with members shared between Australia and New Zealand. We performed phylogenetic analyses of a multilocus data set and applied several methods for molecular species delimitation. Our results support the conspecificity of L. serrulata and L. ulothrix, which is compatible with patterns of morphological variation observed in Tasmanian and New Zealand populations. The distribution of L. septemfida extends to the Wet Tropics Bioregion of north-east Queensland, where the species is represented by a distinct subspecies rather than a completely different species. The morphological differences between the Queensland and south-east Australian populations, as well as the inconsistency among the species-delimitation results, support the division of the species into two subspecies. Tasmanian and Victorian specimens previously attributed to the New Zealand endemic L. hirta belong to a distinct and unnamed lineage. Our study shows that integrative taxonomic approaches can uncover overlooked diversity and refine existing species circumscriptions, even in relatively well-studied Australasian lineages such as Lepidozia.