are derived from the Amazon population and are not genetically distinct. Comparative morphological research also indicates that I. g. humboldtiana is not distinguishable from I. g. geoffrensis. However, Cañizales (2020) found that I. g. humboldtiana skulls were morphologically distinct and recommended that it be elevated to species status.

In 2012, it was proposed that I. g. boliviensis was a different species based on skull morphology. In 2002, following the analysis of mitochondrial DNA specimens from the Orinoco basin, the Putumayo River