title: Revision of widespread red squirrels (genus: Tamiasciurus) highlights the complexity of speciation within North American forests.
abstract: Integration of molecular methods, ecological modeling, and statistical hypothesis testing are increasing our understanding of differentiation within species and phylogenetic relationships among species by revealing environmental connections to evolutionary processes. Within mammals, novel diversity is being discovered and characterized as more complete geographic sampling is coupled with newer multi-disciplinary approaches. North American red squirrels exemplify a forest obligate genus whose species are monitored as indicators of forest ecosystem condition, yet phylogenetic relationships reflecting evolutionary history within this genus remain tentative. Through testing of competing systematic and niche-based divergence hypotheses, we recognize three species, Tamiasciurus douglasii, T. hudsonicus, and T. fremonti. Our data provide evidence of regional differences in evolutionary dynamics and continental gradients of complexity that are important both for future management and for investigating multiple pathways that can lead to the formation of new species.
authors.affiliation: Division of Biology, Kansas State University, Manhattan, KS 66506, USA. Electronic address: ahope@ksu.edu.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Hope
authors.affiliation: Department of Biology, Austin Peay State University, Clarksville, TN 37044, USA. Electronic address: jmalaney@gmail.com.
authors.forename: Jason L
authors.initials: JL
authors.lastname: Malaney
authors.affiliation: Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131, USA. Electronic address: kayce.bell@gmail.com.
authors.forename: Kayce C
authors.initials: KC
authors.lastname: Bell
authors.affiliation: Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131, USA. Electronic address: f.salazarmiralles@gmail.com.
authors.forename: Fernando
authors.initials: F
authors.lastname: Salazar-Miralles
authors.affiliation: Museum of Vertebrate Zoology and Department of Integrative Biology, University of California-Berkeley, Berkeley, CA 94720, USA. Electronic address: aschavez@berkeley.edu.
authors.forename: Andreas S
authors.initials: AS
authors.lastname: Chavez
authors.affiliation: Biodiversity Institute, University of Wyoming, Laramie, WY 82071, USA. Electronic address: bbarber4@uwyo.edu.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Barber
authors.affiliation: Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131, USA. Electronic address: cookjose@unm.edu.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Cook
mesh_terms: D000818:Animals; D005075:Biological Evolution; D045303:Cytochromes b / Q000235:genetics; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D017753:Ecosystem; D065928:Forests; D014644:Genetic Variation; D009656:North America; D010802:Phylogeny; D012589:Sciuridae / Q000145:classification* / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004247:DNA; D045303:Cytochromes b
keywords: Boreal biome; Quaternary; Sky island; Southeast Alaska; Speciation with gene flow; Species tree estimation