The northwest corner of South America harbours a region of spectacular and mysterious landscapes called Pantepui. Due to its ancient age and fragmented topography Pantepui has been assumed to be an ideal nursery of speciation, and tepuis (table mountains) have been seen as potential inland counterparts to oceanic islands. Tepuis are often called __islands in the sky__ and their summits seem indeed ideal candidates to harbour relict species, isolated from the rest of the world for millions of years. However our knowledge about the origin and diversification of the Pantepui biota is at least as fragmentary as the tepui physiography itself. This led some authors to consider the origin of local biodiversity and endemism a still-unresolved evolutionary enigma. This work aims to (1) better understand the species diversity, the evolutionary history, the dynamics of biotic interchanges between tepui summits, and the patterns of endemism of the fauna in the Pantepui region, using morphological analyses and molecular phylogenies of six amphibian and reptile taxa; (2) provide new insights in the timing of the geomorphological evolution of the tepuis in the light of amphibian and reptile species diversification inferred from molecular phylogeny reconstructions and estimates of divergence time.UBL - phd migration 201