Cladistic biogeography of the N eotropical region: identifying the main events in the diversification of the terrestrial biota

A cladistic biogeographical analysis was undertaken to identify the main events in the biotic diversification of the terrestrial N eotropical biota. For the 36 animal and plant taxa analysed, a component × area matrix was constructed, associating geographical data only with informative nodes, and it was analysed under implied weights using the software TNT . The general area cladogram obtained shows that the Neotropical region constitutes a monophyletic unit, with a first split separating the Antilles and a second one dividing the continental areas into a north‐western and a south‐eastern component. Within the north‐western component the areas split following the sequence northern A mazonia, south‐western A mazonia, north‐western S outh A merica, and M esoamerica. Within the south‐eastern component the areas split following the sequence south‐eastern A mazonia, C haco, and P arana. The three main components are treated as subregions: A ntillean, A mazonian (northern A mazonian, south‐western A mazonian, M esoamerican, and north‐western S outh A merican dominions), and C hacoan (south‐eastern A mazonian, C hacoan, and Parana dominions). Dispersal and vicariant events postulated to explain these pattens might have occurred during the Cretaceous, when the Caribbean plate collided with the A mericas, a combination of eustatic sea‐level changes and tectonic deformations of the continental platform exposed large parts of S outh A merica to episodes of marine transgressions, and the Andean uplift reconfigured the A mazonian area. Tertiary and Q uaternary events are assumed to have later induced the diversification within these large biogeographical units.