Onthophagus chevrolati Harold 1869
Creators: name: Halffter, Gonzalo
name: Zunino, Mario
name: Moctezuma, Victor
name: Sánchez-Huerta, José L.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Onthophagus
Onthophagus chevrolati

description: The Onthophagus chevrolati species group   
 Venturing into a new kind of biogeographical-phyletic discussion, in which the processes of speciation are properly compared with the geological history of the mountains, requires an adequate knowledge of the taxonomy of the group to be studied. Zunino & Halffter (1988a), based on the morphology of copulation apparatuses and external morphological characters, established the O. chevrolati species group, which they consider to be one of the best taxonomically studied of the American fauna of Onthophagus. These authors included in the group 39 species and subspecies, and later discoveries increased its number of species.   
 Based on the monograph by Zunino and Halffter (1988a), whose approaches continue to be valid, we have updated some details of this group’s taxonomy using the results of recent studies (Delgado & Capistan 1996; Delgado 1999; Sánchez-Huerta et al. 2015, 2018; Arriaga et al. 2016; Moctezuma et al. 2016; Gasca-Álvarez et al. 2018; Joaqui et al. in press). We have also studied the morphology of the genitalia in depth, carrying out a detailed, comparative analysis of the characters of all the species of the O. hippopotamus species complex, except for O. padrinoi of which we have not yet been able to examine the anatomy.   
 With respect to Zunino & Halffter (1988a) we consider the following changes. All formerly recognized subspecies are elevated to species status. Onthophagus mesoamericanus Zunino & Halffter, 1988 (Fig. 9) is provisionally considered a synonym of O. cyanellus (Fig. 8). We consider O. cyanellus to be a species line, with the same rank as the O. chevrolati species line in which it was previously included. Within Onthophagus, the O. chevrolati species group is the model example of the Paleoamerican Mountain distributional sub-pattern, with the exception of O. cyanellus and related species that conform very well to the Paleoamerican Mesoamerican subpattern. The graphic representation of our taxonomic ideas (manually drawn in an intuitive manner, based on morphological similarity and supposed evolution) combined with the distribution of the lines is shown in Fig. 11.   
To distinguish and delimit species, in this work we are following the phylogenetic species concept as defined by Wheeler & Platnick (2000): “The smallest aggregation of (sexual) populations or (asexual) lines diagnosable by a unique set of character states”. Consequently, all of the taxa considered as subspecies in the revision by Zunino & Halffter (1988a) are raised to the rank of species, since each has a set of diagnostic characters that allow it to be distinguished from the others, potentially representing different evolutionary histories.
description: Published as part of 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, pp. 1-34 in Zootaxa 4586 (1) on pages 13-14, DOI: 10.11646/zootaxa.4586.1.1, http://zenodo.org/record/2642570