Onthophagus hippopotamus, Harold, 1869

Halffter, Gonzalo, Zunino, Mario, Moctezuma, Victor & Sánchez-Huerta, José L., 2019, The integration processes of the distributional patterns in the Mexican Transition Zone: Phyletic, paleogeographic and ecological factors of a case study, Zootaxa 4586 (1), pp. 1-34 : 20

The Onthophagus hippopotamus species line and species complex

Within the O. chevrolati species group, the O. hippopotamus species line is one of the two main phyletic sets of species. It can be distinguished by the characters of its external morphology, the male and female genitalia, the time and way in which its geographical distribution occurred, and as previously mentioned, by its ecological requirements. Our hypothesis is that in composition, the distribution and evolution of this line is perfectly differentiated and is associated with the orogenesis of the TMVB. The O. hippopotamus species line comprises (see “Taxonomy of Onthophagus chevrolati species group, updated from Zunino & Halffter (1988a) ”) 12 species compared to the 29 species of the other central species line of the O. chevrolati species group, and most modern O. chevrolati species line. All the species of this species line live in Geomyidae burrows, Neotoma nests, and three of them in caves (one of them in both caves and Neotoma nests).

Within the O. hippopotamus species line, the O. brevifrons species complex comprises five closely related species found in the southwestern United States of America, and in the north and northwest of Mexico. The other species complex ( O. hippopotamus ) comprises seven species associated with pocket gopher nests. One of these species is distributed in the mountains and plains of Nebraska, Arizona, New Mexico and Colorado ( Slay et al. 2012), another in the Sierra Madre Occidental (SMO) in the state of Durango ( O. coproides Horn ). The rest of the species are found along the TMVB and in the Sierra Madre del Sur mountains. Given the major interspecific differences and its fragmented distribution, this species complex is considered by Zunino & Halffter (1988a) to has elderly diversified than other species lines of the O. chevrolati species group that have a continuous distribution in the mountains of the MTZ (e.g., the O. chevrolati species line).