Phanaeus difformis is a species of true dung beetle in the family Scarabaeidae that is native to south-central United States and adjacent far northern Mexico. It may hybridize with the generally more common P. vindex.
References
Further reading
Arnett, R. H. Jr., M. C. Thomas, P. E. Skelley and J. H. Frank. (eds.). (21 June 2002). American Beetles, Volume II: Polyphaga: Scarabaeoidea through Curculionoidea. CRC Press LLC, Boca Raton, Florida . Arnett, Ross H. (2000). American Insects: A Handbook of the Insects of America North of Mexico. CRC Press. Richard E. White. (1983). Peterson Field Guides: Beetles. Houghton Mifflin Company.