Fig. 1.

ACR vertebrate time-tree based on a 50% majority rule consensus tree from a Bayesian analysis of 1,747-bp DNA sequences of the RAG1 and BDNF genes. Black dots at nodes indicate Bayesian support >0.98, gray dots 0.95–0.98, and white dotted nodes were topology-constrained before the analysis. Colors indicate geographic distribution of taxa and numbers denote clades as listed in Table 1. Only representative taxa of the clades occurring in Madagascar and their sister groups are named (see SI Appendix for tree with names of all terminals); Inset pictures show one representative species for most of the numbered Malagasy clades. Major clade abbreviations: Act, Actinopterygii; Anu, Anura; Arch, Archosauria; Li, Lissamphibia; Ma, Mammalia; Per, Percomorpha; Sq, Squamata; Tes, Testudines. Vertical gray dotted lines separate four main time intervals, at bottom: (a) <15 Mya, corresponding to the period where surface currents did not favor dispersal from Africa; (b) 66–16 Mya, when sea currents favored overseas rafting from Africa; (c) 120–66 Mya, when overland dispersal or short-distance rafting from Asia was possible; (d) >121 Mya, when overland dispersal from Africa and Antarctica might have been possible (15).