Format: ORAL

Lantotiana RANDRIAMANANA1, Bernard RIERA2, Timothe LE PECHON3,4, Sylvain RAZAFIMANDIMBISON4, Florian JABBOUR1.

1 Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, 57 rue Cuvier CP39, Paris 75005, France 2 Muséum National d’Histoire Naturelle, mécanismes adaptifs et Evolution UMR 7179 MECADEV-CNRS, 57 rue Cuvier CP 50, 75231 Paris, France 3 Meise Botanic Garden, Nieuwelaan 38, 1860 Meise, Belgium 4 Fédération Wallonie-Bruxelles, Service Général de l’Enseignement Supérieur et de la Recherche Scientifique, Rue A. Lavalée, 1, 1080 Brussels, Belgium 5 Department of Botany, Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden

Madagascar is known for its exceptional wealth of biodiversity, particularly flora. The Rubiaceae family is one of the largest flowering plant families in Madagascar, encompassing approximately 650 described species distributed across 95 genera. Notably, 98% of these species and 30% of the genera are endemic to Madagascar, highlighting the islands significance as a hotspot for Rubiaceae endemism. Despite the numerous ongoing research projects on this family, the Malagasy Rubiaceae remain understudied and its Flora treatment for Madagascar has not been completed. A case in point is Saldinia(tribe Lasiantheae, subfamily Rubioideae), which is a poorly known genus mostly endemic to Madagascar, with 22 shrub species. The main objective of this study is to reconstruct the first phylogeny of the genus as a precursor to its taxonomic revision. A comprehensive morphological dataset was compiled based on more than a thousand specimens from P, TAN, and BR herbaria, including all Saldinia types and 125 newly collected specimens from Madagascar during spring 2023. Total DNA was extracted from silica-dried leaves and herbarium material. Four markers (nrITS and nrETS, and matk, trnT-F) from nuclear and plastid genome were sequenced. We will perform the maximum likelihood and Bayesian inference analyses using outgroup taxa from the subfamily Rubioideae. The results of our analyses will be presented and discussed. This study significantly contributes to Madagascars biodiversity knowledge and advances research on Saldinia and Rubiaceae. Challenges in sample collection highlight the need for further exploration in unexplored regions, especially the Comoro Islands and specific Madagascar areas.