This is a continuation of a study on geographical variation of the Elaphrus americanus Dejean species complex. This paper is devoted to E. finitimus Casey, which includes at least seven populations: White Mountains of California, Colorado Plateau, western Great Basin, western Arizona, central California, southern California, and southern Sierra Nevada. Three main groups of populations were recognized by means of numerical taxonomic analyses: White Mountains of California (one population), Intermontane (Colorado Plateau and western Great Basin), and southwestern (remaining four populations). The above groups were discerned from clustering by UPGMA (unweighted pair group using arithmetic averages) of Mahalanobis distances, and are characterized in a discriminant analysis. Other geographically distinct populations were recognized by univariate analysis of nominal characters. All seven populations are allopatric and are isolated presently from one another by vast expanses of dry regions (prairies and piñon–juniper woodlands), or by different life zones with altitude. We postulated that during the glacial phases of the Pleistocene similar barriers existed, though the gaps were narrower than at present. The reconstructed glacial ranges of these populations offer a hypothesis as to the origin of some populations, and direction of limited gene flow between some populations.
Phylogenetic revision of the psammophilic Trogloderus LeConte (Coleoptera: Tenebrionidae), with biogeographic implications for the Intermountain Region