A phylogenetic revision of the North American Asidini based on molecular and morphological data is presented. Evolutionary relationships within and between the North American Asidini (Coleoptera: Tenebrionidae) genera were reconstructed using a combined dataset containing partial sequences of mitochondrial COI (660bp) and nuclear 28s (492bp), and 100 morphological characters for 50 North American asidine species, representing 20 of the 27 previously described genera and one new genus. Species from two additional tenebrionid tribes (Branchini and Coniontini) and the South American asidine genus Cardiogenius were chosen as outgroups. Analyses were performed using maximum parsimony and Bayesian inference methods. Clade support was inferred based on the posterior probability distribution of tree topologies, nonparametric bootstrap analysis, and partitioned Bremer support indices. The generic classification of the North American Asidini was revised based on the results.

Twenty previously described genera are placed in synonymy and ten genera are recognized. Seven current genera: Craniotus LeConte, Heterasida Casey, Litasida Casey, Microschatia Solier, Pelecyphorus Solier, Philolithus Lacordaire, Stenomorpha Solier, are redescribed and three new genera: Micrasida, Ardamimicus, and Ferveoventer are described, including three new species: Micrasida obrienorum, Ardamimicus cognatoi, and Ferveoventer browni.

A taxonomic revision of the North American genus Pelecyphorus Solier is presented. Eight subgenera are erected and described, seven based on previously described Asidini genera: Pelecyphorus Solier sensu stricto, Astrotus LeConte, Stenosides Solier, Ucalegon Champion, Zaleucus Champion, Plesiasida Smith (=Parasida Casey), and Sicharbas Champion and one new subgenus: Variodorsus.

Forty species of Pelecyphorus are recognized as valid, including seven new species described herein: P. cavatus, P. cifuentesi, P. crypticus, P. deaztlani, P. doyeni, P. oaxacensis, and P. triplehorni. All valid species are described or redescribed, along with diagnoses, distributions, and images of each. An illustrated key to the subgenera and species is also provided.

The Asidini, like all members of the subfamily Pimeliinae, lack defensive glands. Instead, several morphological and behavioral traits are found within the tribe which may help limit predation. These include the contrasting defensive strategies of crypsis, either through background matching or pattern disruption, and Batesian mimicry of the chemically defended tenebrionid genus Eleodes. A phylogenetic analysis of the North American asidines is presented and the evolution of defensive strategies exhibited within the group is examined.