SREL Reprint #3629

Mitochondrial genomes of the United States distribution of gray fox (Urocyon cinereoargenteus) reveal a major phylogeographic break at the Great Plains Suture Zone

Dawn M. Reding1, Susette Castañeda-Rico2,3,4, Sabrina Shirazi2, Courtney A. Hofman2, Imogene A. Cancellare5, Stacey L. Lance6, Jeff Beringer7, William R. Clark8, and Jesus E. Maldonado2,3

1Department of Biology, Luther College, Decorah, IA, United States
2Center for Conservation Genomics, Smithsonian Conservation Biology Institute,
National Zoological Park, Washington, DC, United States
3Department of Biology, George Mason University, Fairfax, VA, United States
4Smithsonian-Mason School of Conservation, Front Royal, VA, United States
5Department of Entomology and Wildlife Ecology, University of Delaware, Newark, DE, United States
6Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, United States
7Missouri Department of Conservation, Columbia, MO, United States
8Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States

Abstract: We examined phylogeographic structure in gray fox (Urocyon cinereoargenteus) across the United States to identify the location of secondary contact zone(s) between eastern and western lineages and investigate the possibility of additional cryptic intraspecific divergences. We generated and analyzed complete mitochondrial genome sequence data from 75 samples and partial control region mitochondrial DNA sequences from 378 samples to investigate levels of genetic diversity and structure through populationand individual-based analyses including estimates of divergence (FST and SAMOVA), median joining networks, and phylogenies. We used complete mitochondrial genomes to infer phylogenetic relationships and date divergence times of major lineages of Urocyon in the United States. Despite broad-scale sampling, we did not recover additional major lineages of Urocyon within the United States, but identified a deep east-west split (~0.8 million years) with secondary contact at the Great Plains Suture Zone and confirmed the Channel Island fox (Urocyon littoralis) is nested within U. cinereoargenteus. Genetic diversity declined at northern latitudes in the eastern United States, a pattern concordant with post-glacial recolonization and range expansion. Beyond the east-west divergence, morphologically-based subspecies did not form monophyletic groups, though unique haplotypes were often geographically limited. Gray foxes in the United States displayed a deep, cryptic divergence suggesting taxonomic revision is needed. Secondary contact at a common phylogeographic break, the Great Plains Suture Zone, where environmental variables show a sharp cline, suggests ongoing evolutionary processes may reinforce this divergence. Follow-up study with nuclear markers should investigate whether hybridization is occurring along the suture zone and characterize contemporary population structure to help identify conservation units. Comparative work on other wide-ranging carnivores in the region should test whether similar evolutionary patterns and processes are occurring.

Keywords: Great Plains Suture Zone, mammal, mitogenome, phylogeography, secondary contact, subspecies

SREL Reprint #3629

Reding, D. M., S. Castañeda-Rico, S. Shirazi, C. A. Hofman, I. A. Cancellare, S. L. Lance, J. Beringer, W. R. Clark, and J. E. Maldonado. 2021. Mitochondrial genomes of the United States distribution of gray fox (Urocyon cinereoargenteus) reveal a major phylogeographic break at the Great Plains Suture Zone. Frontiers in Ecology and Evolution 9: Article 666800.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).