Onthophagus hoepfneri Harold 1869

Onthophagus hoepfneri species group*. This group is diagnosed by no male head horns present (Fig. 5.14); male protibial apex with some sparse short setae subequal to apical spur (Figs. 1.59 –66); pronotum with a small pointed or rounded anterior-pronotal projection (Fig. 5.14); with coarse punctures in metafemur (Figs. 2.59 –66). We propose, based on the barcode and morphological analyses, that this species group includes, at present, besides O. hoepfneri Harold, four more species, O. coscineus, Bates, O. oklahomensis Brown, O. pennsylvanicus Harold, and O. tuberculifrons Harold. Using a phylogenetic analysis, Emlen et al. (2005: fig. 2, bootstrap support of 79) had already obtained a branch formed by O. coscineus and O. pennsylvanicus. At the same time, because of the low support values indicated by the maximum-likelihood tree (Fig. 8), more species groups might emerge from the O. hoepfneri branch once more species are included. These maximum-likelihood analyses suggest the existence of at least two clades within this species group, one formed by O. coscineus and O. tuberculifrons, another by O. hoepfneri, O. oklahomensis, and O. pennsylvanicus. More specimens are needed to clarify this situation. Boucomont (1932) placed O. hoepfneri in his “8 e Groupe”, which corresponds to the O. landolti species group, and O. oklahomensis, O. pennsylvanicus, and O. tuberculifrons in his “12 e Groupe”; O. coscineus was unassigned. The relationship of the O. hoepfneri species group with the O. crinitus species group suggested in this study (Figs. 1–2) was expected. In another maximum-likelihood genetic analysis, Emlen et al. (2005: fig. 4, Bayesian posterior probability of 99) obtained a branch formed by O. crinitus and O. pennsylvanicus. The Emlen et al. (2005) analysis and the present barcode (Figs 1–2) and partition (Fig. 9) analyses suggest a close relationship between these two groups. Schwery & O'Meara (2021) also recovered a mixed O. hoepfneri – O. crinitus clade with a bootstrap support of 9. The O. hoepfneri species group is distributed from the United States of America to Ecuador.