In the context of this paper, regional extirpation is defined as the
absence of a species from the known modern beetle fauna of the
region from which it was previously found in a fossil assemblage. In
most instances, this means that a species identified from a fossil
assemblage in the Rocky Mountain region is no longer found in the
Rockies. In some cases, the species is known from a different part of
the Rockies, but is absent from the fossil locality region. For
instance, a species might inhabit the Northern Rockies today (the
ranges from Alberta and British Columbia to northern Wyoming),
but is absent from the Southern Rockies (the ranges from southern
Wyoming to New Mexico), where it was found as a Pleistocene
fossil. These are noted in the ‘Modern Range’ descriptions for species
listed in Table 2.