title: The desert tortoise trichotomy: Mexico hosts a third, new sister-species of tortoise in the Gopherus morafkai-G. agassizii group.
abstract: Desert tortoises (Testudines; Testudinidae; Gopherus agassizii group) have an extensive distribution throughout the Mojave, Colorado, and Sonoran desert regions. Not surprisingly, they exhibit a tremendous amount of ecological, behavioral, morphological and genetic variation. Gopherus agassizii was considered a single species for almost 150 years but recently the species was split into the nominate form and Morafka's desert tortoise, Gopherus morafkai, the latter occurring south and east of the Colorado River. Whereas a large body of literature focuses on tortoises in the United States, a dearth of investigations exists for Mexican animals. Notwithstanding, Mexican populations of desert tortoises in the southern part of the range of Gopherus morafkai are distinct, particularly where the tortoises occur in tropical thornscrub and tropical deciduous forest. Recent studies have shed light on the ecology, morphology and genetics of these southern 'desert' tortoises. All evidence warrants recognition of this clade as a distinctive taxon and herein we describe it as Gopherus evgoodei sp. n. The description of the new species significantly reduces and limits the distribution of Gopherus morafkai to desertscrub habitat only. By contrast, Gopherus evgoodei sp. n. occurs in thornscrub and tropical deciduous forests only and this leaves it with the smallest range of the three sister species. We present conservation implications for the newly described Gopherus evgoodei, which already faces impending threats.
authors.affiliation: School of Natural Resources and the Environment. The University of Arizona, Tucson, AZ 85721 USA; University of Arizona Genetics Core, University of Arizona, Tucson, AZ 85721 USA.
authors.forename: Taylor
authors.initials: T
authors.lastname: Edwards
authors.affiliation: P.O. Box 74006, Davis, CA 95617 USA.
authors.forename: Alice E
authors.initials: AE
authors.lastname: Karl
authors.affiliation: Paso Robles, CA 93446 USA.
authors.forename: Mercy
authors.initials: M
authors.lastname: Vaughn
authors.affiliation: School of Natural Resources and the Environment. The University of Arizona, Tucson, AZ 85721 USA.
authors.forename: Philip C
authors.initials: PC
authors.lastname: Rosen
authors.affiliation: Comisión de Ecología y Desarrollo Sustentable del Estado de Sonora, Sonora, México.
authors.forename: Cristina Meléndez
authors.initials: CM
authors.lastname: Torres
authors.affiliation: Royal Ontario Museum, Toronto M5S 2C6, Canada.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Murphy
keywords: Gopherus agassizii; Gopherus morafkai; Sinaloa; Sonora; Testudinidae; Xerobates