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during major rearrangment of flow patterns associated with Andean orogeny, 

 contributing to allopatric speciation. Following the formation of the Andes, 

 reorganization of the river drainages would have allowed for dispersal and the 

 present sympatric distributions. Some of the endemism observed today (e.g., the 

 Guianas, lower and upper Amazon) may be the result of hydrographic stability 

 following geological vicariant events, thereby reducing potential for dispersal 

 between drainage basins. ' ' 



At present, little else can be said about the biogeography of ageneiosids, due 

 to their incompletely resolved phylogenetic relationships and the lack of detailed 

 ecological and distributional information. 



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