Évolution de la biodiversité végétale malgache durant le Tertiaire:

Systématique et biogéographie de Légumineuses menacées d’extinction M. Babineau & A. Bruneau Leguminosae diversity in Madagascar

Legume Hot Spot • 667 species • 69% native • 80% endemic • 22 endemic genera

D.J DuPuy et al. 2001

Impressive biodiversity pool

Schatz, 2001 Genus Delonix Distribution of Malagasy species for genus Delonix, Colvillea and Eleven species : Lemuropisum . From DuPuy 1995 • Nine are endemic to Madagascar

D. boiviniana D. pumila

D. decaryi D. floribunda D. regia

• Two are distributed in East Africa • Closely related endemic and monotypic genera

D. elata

Colvillea racemosa Lemuropisum edule Pictures from A. Bruneau,Gwil Lewis Conservation issues

• All of the above species are endangered despite being important ecological resource of local and worldwide economic interest.

• The three diversity centers of Delonix are being rapidly deforested

How many species of Delonix are there? How are they related to one another? How old are they? Where are they from?

IUCN Red List 2011, DuPuy 1995 Harper et al , 2007 Classification

• Colvillea and Lemuropisum supported as distinct genera based on:

• Large terminal panicles • Brachyblast • Resupinate flowers • Uniquely shaped • Fused calyx pods

• Different groups within Delonix species based on: • Pollinator: moth VS sunbird • Pollen structure: three distinct categories • Habitat: dry deciduous forest VS xerophytic woodland • Morphology: trunk shape, leaflets number

MOLECULAR? Delonix appears to be paraphyletic Lack of resolution within Delonix-Colvillea-Lemuropisum clade Objectives

• Determine the phylogenetic status of Delonix with respect to Colvillea racemosa and Lemuropisum edule

• Establish robust phylogenetic relationships between the eleven Delonix species

• Estimate divergence times and historical dispersal patterns for these species

Lemuropisum Delonix Colvillea Analyses

Phylogenetic analyses Chloroplast Nuclear Parsimony analysis of 42 taxa concatenated matrix rps16 ITS matK/trnK + tRALs 6910 bp trnL-trnF Bayesian partitioned matrix trnD-trnT Chloroplast = HKY +G Nuclear = GTR +G

* Used in previous studies on six or fewer species of Delonix Age Estimate Analyses • Penalized Likelihood with Truncated Newton algorithm Sanderson 2002 • Calibration at Dinizia stem node: Eomimosoidea fossil = 45 Ma Herendeen&Dilcher 1990 • Other methods tested (Langley-Fitch) give similar estimates Biogeographic Analyses • Dispersion Extinction Cladogenesis Model Ree & Smith 2008 • Dispersion and extinction rates estimated by the model • Areas: Africa, Antsiranana ( North ), Ankara plateau ( West ), Toliara ( South ) • Tested NULL hypothesis and dispersal constraint hypothesis Results Ancestral dispersal pattern

• DIFFICULT to determine if the ancestral species is from Madagascar or Africa

-Preliminary analysis suggest southern Madagascar

… more parsimonious to consider ONE dispersal to Africa from a Malagasy ancestor, than TWO dispersals to Madagascar from Africa Afro-Malagasy dispersal during the Miocene

• Long distance dispersal across the Mozambique canal • Melastomeae dispersal between 12-17 Ma via migratory birds Renner 2004, Moreau 1966

• Presence of a land bridge from late Eocene (45 Ma) to early Miocene (26 Ma) • Linking southern Madagascar ( Toliara ) with Eastern coast of Africa McCall 1997

McCall 1997 Taxonomic implications

• Delonix is strongly supported as polyphyletic

Two options : • Split Delonix in at least three parts… • Lump the two clades in genus Delonix, consider Colvillea and Lemuropisum as Delonix species (as proposed by Haston et al , 2005) and divide into 2 sections or subgenera

« Widespread clade » = Delonix sensu stricto type specimen Delonix regia

« Spiny thicket clade » = Aprevalia containing D. velutina and D. floribunda Back to conservation

The «Spiny thicket clade » contains species with • Most geographically restricted • Most urgent conservation status • Highest morphological diversity since half the species in this clade were/are currently assigned to distinct genera

Only four of the 22 nationals parks covers this habitat in Madagascar

NEED better coverage to generates and maintain an assemblage of diversified Legumes species

Ministère de l’Environnement, Eaux et des Forêts de Madagascar, 2003 Acknowledgement

Bruneau/Brouillet Lab

Collectors and Partners : Rolland Ranaivojaona Tefyharison Andriamihajarivo Felix Forest Gwilym Lewis

D. floribunda