Laboratory of Plant Systematics and Biodiversity
Conservatory & Botanical Garden of the City of Geneva

Direction: Dr Laurent Gautier (cc) and Dr. Yamama Naciri (cc)

Duration: 1.5 years

Sideroxylon is a pantropical tree genus represented in Madagascar by six described endemic species, and three additional varieties. Biogeographic relationships of the genus worldwide indicate that the Malagasy and Mascarene species form a clade that diverged from the larger African/Arabian clade some 20 to 35 mya and colonized Madagascar by over-sees dispersal, with the three analysed Mascarene species forming a monophyletic clade with a crown age of 2-6 my (Stride et al. 2014). On Madagascar, the genus comprises one variable widespread dry forest species: S. saxorum, which extends south to the dry spiny thicket, and five moist dense moist forest species, including the widespread S. gerrardianum. Varieties have been described within S. saxorum and S. beguei, but their status is doubtful, and the genus as a whole deserves further attention, with 2-4 possible new species.

The topic of this Master thesis will be to revise the systematics, regional biogeography and conservation status of the Western Indian Ocean species of the genus Sideroxylon, based on molecular phylogenetics using gene capture and next generation sequencing. The aim is to publish the revision of the genus, including a threat assessment of the species based on the IUCN categories, to be forwarded to local NGO’s for effective conservation action.

Skills and interests. This subject allies morphological and genetic approaches, a practice in a worldwide herbarium and in a lab using the latest sequencing methodologies, bioinformatic analyses and interests in species evolutionary history, biogeography and diversity with new species description. The research team working on the whole family Sapotaceae in Madagascar, comprises two senior researchers (L. Gautier & Y. Naciri), a post-doctoral fellow (C.G. Boluda) and a PhD student (A. Randriarisoa).