Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data indicated that the members of Gryposuchinae and the genus Gryposuchus may in fact be paraphyletic and rather an evolutionary grade towards Gavialis and the gharial, as shown in the cladogram below: Paleoecology The Miocene epoch represents the only history of gavialoids (solely of the subfamily Gryposuchinae) in South America, from a Caribbean launchpad (Aktiogavialis from the Middle Oligocene of Puerto Rico, and Dadagavialis from the Early Miocene of Panama). Although there were six other confirmed genera of gryposuchine, Gryposuchus was almost certainly the most successful, with an existence potentially encompassing almost all of the Miocene, and a range from Venezuela to Argentina in the Middle to Late Miocene. This dominance was likely due to the fact that Gryposuchus was one of only two freshwater adapted gryposuchines (other than Hesperogavialis), whereas the others (such as Siquisiquesuchus and Piscogavialis) were either primarily estuarine, coastal or marine based predators. This would certainly have been useful in taking advantage of the extensive continental waterways and swamps of what would become the Amazon basin. Gryposuchus can be observed far and wide, from coastally adjacent and inclusive formations, such as the Urumaco Formation of Venezuela, to even beyond the northern drainage basins, into Argentina. This is in contrast with almost all the other species within the subfamily, which are limited to certain time periods near or on coast, with only Hesperogavialis penetrating into Brazil in the Late Miocene. Although Gryposuchus had already reached Argentina by the Middle Miocene, known species diversity reached its peak by the Late Miocene, with four of the five species present, three of which were also overlapping in the Urumaco Formation. Gryposuchinae diversity also reached its peak, at five genera across South America. However, at the Miocene/Pliocene boundary, all Gavialoidea and Crocodyloidea (another superfamily colonising in the Miocene) were likely extirpated from South America, with the endemic Caimaninae undergoing a severe reduction in size and diversity as well. This was likely due to the continuing elevation of the northern sections of the Andes chain creating the future Amazon basin, re-rerouting drainage flowing towards the Caribbean to the much cooler Atlantic, and transforming the mega-wetlands responsible for the hyper-diversity of crocodilians into a fully developed riverine drainage system. The co-current aridification of the continental interior, and filling of peripheral wetland basins, further restricted the space and food resources of