Evolution of Tribe Poranthereae (Phyllanthaceae) - COMPLETED 2010

Leptopus decaisnei (Phyllanthaceae) drawn by Maria Vorontsova.

Tribe Poranthereae is an unexpected discovery of the recent Euphorbiaceae sensu lato (Malpighiales) molecular phylogenetic studies. Actephila, Andrachne, Leptopus, Meineckia, Oreoporanthera, Poranthera, Zimmermannia and Zimmermanniopsis were previously classified in three different tribes and three different subtribes. They exhibit distinct morphologies, occupy contrasting ecological niches and have different global distributions: a great deal of change seems to have taken place within a relatively short period of evolutionary time. This case study was an example of dry environment adaptation and rapid changes in global distribution. The aim of this PhD project was to reconstruct as far as possible the evolutionary history of tribe Poranthereae in both space and time. The relatively low number of species,  111, allowed a variety of methods to be used: traditional morphological study, molecular phylogenetics and biogeographical analysis.

The project has resulted in clarification of the circumscription of tribe Porantherae and in an assessment of the relationships between members of the tribe using molecular phylogenetic methods.

A complete taxonomic revision has been made of two genera - Leptopus and Phyllanthopsis, and 3 new genera and one new subgenus have been described (Pseudophyllanthus, Phyllanthopsis, Notoleptopus & Meineckia subgenus Petaliferae) Also, six new combinations and one nomen novum have been made at the species level. One species was found to belong outside the tribe.

The work has resulted in 6 peer- reviewed publications, including 2 in  'high impact' journals. Project presentations have been made at the Systematics Association Biennial Meeting at BM, at Kew and at Leiden. There has been collaboration with Herbaria at St Petersburg (Russia), Guangzhou and Nanning (China), Hanoi and Ho Chi Minh (Vietnam) and at Edinburgh, Vienna, Leiden and Paris. Fieldwork in Vietnam has resulted in enhanced collections at Kew.

   Maria Vorontsova was awarded her doctorate in 2008.