The phylogenomics of diversification on an island: applying Anchored Hybrid Enrichment to New Zealand Leptospermum scoparium (Myrtaceae)

Leptospermum scoparium (Myrtaceae) is a morphologically highly variable species found in mainland Australia, Tasmania and New Zealand. In New Zealand up to six morphologically distinct varieties of this species have been described, although only two – var. scoparium and var. incanum – are widely recognised. In the present study we used Anchored Hybrid Enrichment to acquire sequence data from a ca. 485 orthologous low-copy nuclear loci for 27 New Zealand and three Australian accessions of L. scoparium as well as representatives of several other Leptospermum species. The final concatenated data matrix contained in excess of 32 × 106 nucleotide positions of which more than 53000 were parsimony informative. Phylogenetic trees constructed using different approaches differ in the level of resolution provided but together with a network analysis suggest broadly similar patterns of relationship. In particular, all our analyses are consistent with three geographically delimited groups within New Zealand L. scoparium. We discuss the implications of our results in terms of the evolution and intraspecific taxonomy of L. scoparium in New Zealand.