The following paper was presented at the International Symposium on the Biogeography of Madagascar
held in Paris 26-28 September 1995. The printed version of the paper was published in the Symposium volume (Schatz, G.E. 1996. Malagasy/Indo-Australo-Malesian phytogeographic connections. In: W.R. Lourenço (ed.),
Biogeography of Madagascar. Editions ORSTOM, Paris).
ABSTRACT
Despite the continuous close proximity of Madagascar to
Africa since its separation from the continent ca. 165 MYA, the
Malagasy flora exhibits a remarkably high affinity with the Indo-
autralo-malesian floras far to the east. Such phytogeographic
connections are especially prevalent among eastern humid forest
taxa, and represent both ancient vicariance that has resulted in
relictual (Cretaceous) Gondwanan disjunctions, as well as
continuous dispersal events across the Indian Ocean. Three major
patterns of dispersal/vicariance modality can be identified: 1)
Cretaceous dispersal to Madagascar with ensuing distributions
from India (and/or South Africa) across Antarctica to South
America and Australo-E. Malesia during the time of the initial
radiation of the angiosperms; 2) Eocene-Oligocene (and continuing
to the present) dispersal to Madagascar (and Africa) from
Laurasia and W. Malesia via India (pre- and post-collision with
Asia) along "Lemurian Stepping-stones" in the western Indian
Ocean; and 3) continuous (and recent) long distance dispersal
(LDD) to Madagascar as a function of the prevailing easterly
winds and Indian Ocean currents.
