As of 2004, the following species were considered valid:

As generally recognized, the following species belong in Aceros:

Santa Cruz County is home to the following endangered species:

Although the taxonomy of the genus has not been reviewed since 1955, the following species are recognised:

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

Monterey County has habitat to support the following endangered species:

It contains at least the following species :

The genus contains at least the following species:

Up to 2004 the following species had occurred:

The taxonomy of the group is unclear, it contains at least the following species: