Phylogeny of Myrcia s.l. (Myrtaceae)
Myrtaceae is the fourth largest family in the Neotropics (c. 2500 species); within the family, Myrcia s.l. is the second largest genus, with c. 700 species. Myrcia s.l. is extremely widespread in South America and is the second most species-rich tree genus in the threatened Brazilian cerrado and Atlantic forest biomes. In this latter biome, it is of particular ecological importance as it is an indicator of total angiosperm diversity and has been used to set conservation priorities. Nevertheless, evolutionary relationships within Myrcia s.l. remain unclear and identification to species is a frustrating and routine problem. Species are regularly missed or mis-named in ecological inventories/surveys of Neotropical forests, a serious problem for biodiversity management as well as preventing the use of Myrcia s.l. species as environmental tools.
A molecular phylogeny provides framework for systematic, clade by clade monographic treatment of the genus and will also provide the basis for a new subgeneric classification. Recent molecular phylogenies indicate Myrcia s.l. to comprise three other traditional genera, Calyptranthes (c. 270 spp), Gomidesia (c. 50 spp) and Marlierea (c.100 spp), united by their unique inflorescences and ovary arrangements. Sampling to date indicates that clades corresponding to Calyptranthes and Gomidesia are monophyletic. Resulting molecular hypotheses are interpreted and supported by results from parallel morphological studies in the group.
The main objectives of the Myrcia s.l. phylogeny project is to clarify generic relationships within the subtribe. To this end, ongoing collaborative work on a detailed phylogenetic overview of the group including morphological interpretation has been presented on several occasions and was published in 2011. This work identified nine main clades within Myrcia s.l.. As a result of activity to date, expertise and material available at Kew, current research is now focused on subclades of the initial sample with collaborating researchers often choosing Kew as a logical place to carry out more detailed study of the sub-clades within Myrcia s.l. An improved sample of calyptrate species traditionally considered Calyptranthes is underway and it is anticipated that collaborative studies on two further sub-clades will take place in the Jodrell during 2012.
Ongoing field work continues to enrich the Kew DNA bank, with trips to the Dominican Republic in 2009 and Brazil (Roraima and Amazonas in 2010, Mato Grosso in 2011) yielding additional important Myrcia s.l. species for inclusion in the molecular and morphological parts of this project.
- Lucas, E.J., Matsumoto, K., Harris, S.J., Nic Lughadha, E.M., Bernardini, B., & Chase, M.W. (2011) Phylogenetics, Morphology, and evolution of the large genus Myrcia s.l. (Myrtaceae). Int. J. Plant Sci. 172(7): 915.
- Lucas, E.J. & Sobral, M., (2011) Proposal to conserve Myrcia DC. ex Guillaumin over Calyptranthes Swartz. Taxon 60(2) 605.
- Govaerts, R., Sobral, M., Ashton, P., Barrie, F., Holst, B.K., Landrum, L.L., Matsumoto, K., Mazine, F.F., Nic Lughadha, E., Proença, C., Soares-Silva, L.H., Wilson, P.G. & Lucas, E. (2008) World Checklist of Myrtaceae. (Kew Publishing: Royal Botanic Gardens, Kew).
Project partners and collaborators
- University of São Paulo
- University of Campinas, State of São Paulo
- Federal University of Goiás, State of Goiás
- Department of Plant Sciences, Oxford University
- Royal Botanic Garden Edinburgh
Part funded in 2009 by the Systematics Research Fund