Do we have enough data yet? Phylogenomics of a rapid island species radiation: an example from New Zealand Myosotis (Boraginaceae)
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Proposed Symposium Title: Do we have enough data yet? Phylogenomics of a rapid island species radiation: an example from New Zealand Myosotis (Boraginaceae)
Heidi M. Meudt1, Sofie Pearson2,3, Weixuan Ning2,4, Jessica M. Prebble5, Jennifer A. Tate2
Affiliations: 1 Museum of New Zealand Te Papa Tongarewa, PO Box 467, Cable St, Wellington, 6140, New Zealand 2 School of Natural Sciences, Massey University, Private Bag 11222, Palmerston North, 4442, New Zealand 3 Present address: The University of Queensland, Warwick, QLD, Australia 4 Present address: Iowa State University, Ames, IA, USA 5 Manaaki Whenua – Landcare Research, PO Box 69040, Lincoln 7640, New Zealand
Island systems represent natural laboratories for studies of species radiations, but they often present several challenges for species delimitation. New Zealand forget-me-nots (Myosotis, Boraginaceae) are a typical example where the c. 50 species are morphologically divergent but often lack sufficient genetic diversity to distinguish among the identifiable lineages. Many of these Myosotis species are geographically restricted in alpine areas, uncommon, threatened, and have high taxonomic and conservation priority. Several previous studies have attempted to identify species boundaries and groups using numerous data sources, including single-gene sequences (ITS, ETS, and plastid markers), AFLPs, and microsatellites. Here we present phylogenomic results based on Angiosperms353 baits, whole plastomes, and nrDNA to address long-standing questions in the southern hemisphere lineage of Myosotis. We sampled 300 individuals distributed across New Zealand representing all species and subspecies, and included representatives from the two native Australian species. Specifically, we address whether these genomic-level datasets identify taxonomically useful groups (subgeneric, species, subspecies) that are recognized by morphological attributes, including vegetative and reproductive characteristics and pollen. Additional questions we aim to address using these datasets include: Do species form monophyletic groups? Do geographic patterns exist? Can the data be used to delimit species as well as place individuals whose identity was uncertain based on their morphological characteristics? Overall, the phylogenomic data reflect earlier studies that show a recent, rapid species radiation of Myosotis in New Zealand. Although the backbone of the phylogenies generally have short branches with low support, collectively the phylogenomic data presented here are more useful than previous studies in identifying species groups. Finally, although this phylogenomic study does not fully overcome all of the challenges regarding species delimitation of rapid island species radiations, it nevertheless makes an important contribution to an integrative taxonomic revision of the southern hemisphere species of Myosotis.