The phylogenetic relationships of the highly morphologically, vocally, and behaviorally apomorphic Helmeted Hornbill Buceros vigil remain unclear (Viseshakul et al. 2011, Gonzalez et al. 2013), but it is clearly a strongly diverged lineage, and thus Rhinoplax vigil is now used for this species, as with Gill and Wright (2006, IOC v.1.0).