A phylogenomics approach to resolving one of the world’s most diverse, tropical angiosperm radiations: Melastomataceae

Fabian A. Michelangeli and collaborators

The Melastomataceae are the eighth-largest family of flowering plants on the planet with more than 5700 species. The family is pantropical with the bulk of its diversity in the Neotropics, where it is especially diverse in Andean South America, eastern Brazil and the Greater Antilles. Fossil floras suggest that the family may have once been abundant in Laurasia, with the oldest fossils reported from 77-million-year-old deposits from western North America, but the geographic origin of the family is contentious. Although Melastomataceae are found in many habitat types, they are especially diverse in montane forest systems, and thus, their diversification is likely tied closely to the geologic history of the areas where they occur. The family exhibits fascinating floral morphology, with modifications of parts of the flowers in some groups to attract and provide stability for pollinators. There are a host of other morphological modifications (e.g., ant and mite domatia) that also likely have played a role in the diversification of the family. While the majority of species are shrubs and small trees, they also consist of annuals to woody or herbaceous epiphytes, vines and emergent trees. Considering the number of species in the family and the massive subclades within parts of the family, such as the genus Miconia s.l. (ca. 1900 spp.), it appears clear that subclades often represent significant rapid radiations with high diversification rates. We will build the largest existing phylogenomic dataset (including ca. 2500 + species) across any major evolutionary group of tropical angiosperms, allowing us to test the geographic origin and subsequent movement of the family, the evolution of morphological characters and associated diversification rate shifts throughout the worldwide distribution of Melastomataceae. Nuclear, single-copy locus and plastome datasets will be easily incorporable into existing large datasets across angiosperms, further filling phylogenetic gaps in our current knowledge of flowering plant relationships in a large group of ca. 90,000 species (the Rosids) with currently only 34% sampling. Results from this highly collaborative project would provide a foundational example that other researchers could follow for tackling diverse and extensively widespread tropical angiosperm radiations.

A collaborative team of researchers from the University of Florida and the New York Botanical Garden will train two post-doctoral associates and one graduate student, giving them the necessary tools to further their development as plant systematists and publicly engaged scientists. They will learn bioinformatics techniques for handling capture-seq and genome skimming data for downstream phylogenetic and associated analyses. Both post-doctoral associates will have the opportunity to learn valuable skills in project management, mentoring, course development and herbarium curatorial work. The graduate student involved in this work will have the opportunity to participate in outreach nationally and internationally through museum programs, and a plant systematics workshop to be given in southern Haiti. One short course on plant systematics will be given to students in Peru in association with the post-doctoral associate at New York Botanical Garden. Undergraduate students from Brazil and the US will be trained simultaneously in plant systematics at New York Botanical Garden and will learn scanning electron microscopy techniques along with morphological analytical methods. We will highlight all of our work with exhibits in the Florida Museum of Natural History and New York Botanical Garden, which have a combined annual visitation rate of over 500,000 people.

Miconia dodecandra: Photo taken in the field.