Rhyticeros

Rhyticeros is a genus of medium to large hornbills (Bucerotidae family) found in forests from south-east Asia to the Solomons. They are sometimes included in the genus Aceros. On the contrary, most species generally placed in Aceros are sometimes moved to Rhyticeros, leaving Aceros as a monotypic genus only containing the Rufous-necked Hornbill.

All species generally placed in Rhyticeros have relatively low, conspicuously wreathed casques, and a mainly dull whitish-horn bill. Both sexes have a mainly black plumage, but the head and neck of the males are white or rufous. The tail is white, except in the black-tailed Sumba Hornbill. They have conspicuous inflatable skin on the throat that is blue in all except the males of the Plain-pouched and Wreathed Hornbills, where it is yellow.

Species
As generally recognized, the following species belong in the genus Rhyticeros:


 * Papuan (or Blyth's) Hornbill (Rhyticeros plicatus)
 * Narcondam Hornbill (Rhyticeros narcondami)
 * Plain-pouched Hornbill (Rhyticeros subruficollis)
 * Wreathed Hornbill (Rhyticeros undulatus)
 * Sumba Hornbill (Rhyticeros everetti)
 * Knobbed Hornbill (Rhyticeros cassidix)

An undescribed extinct hornbill species from Lifou in the Loyalty Islands, living until at least some 30.000 years ago, was initially placed in Aceros. But its biogeography places it with the species now in Rhyticeros (Steadman, 2006).