Abstract
The Baja California rock squirrel (Otospermophilus atricapillus Bryant) is endemic to the Baja California Peninsula, Mexico and known from only five localities. O. atricapillus is considered as the sister species of O. beecheyi (Richardson) and both have been considered different species mainly by its colorations. In an attempt to better understand the relationship within O. atricapillus and with its sister species O. beecheyi, we used genetic information gathered from O. atricapillus, aiming to investigate the phylogenetic and phylogeography of O. atricapillus O. beecheyi. We analyzed two sets of mitochondrial cytochrome b gene (Cyt b) data: One 800 (bp) fragments of 118 individuals and a second one of 1140 (bp) for the 32 haplotypes found. Our own hypothesis is that specific characteristics used to distinguish O. artricapillus from O. beecheyi are at the same level than the differences among the recognized subspecies of O beecheyi. Under that condition, a genetic analysis will show that O. atricapillus are within the genetic variation of O. beecheyi, and the current diagnostic characters of O. atricapillus could be considered only at subspecific level. The analysis of molecular variance revealed that O. atricapillus is not significantly different from O. beecheyi, and that, apart from highland populations in the Sierra Nevada, the sampled populations of O. beecheyi and O. atricapillus are not significantly different among all of them.References
Álvarez-Castañeda, S.T., Arnaud, G. & Yensen E. (1996) Spermophilus atricapillus. Mammalian Species, 521, 1–3.
Baker, R.J., & Bradley. R.D. (2006) Speciation in mammals and the genetic species concept. Journal of Mammalogy, 87, 643–662.
Bryant, W.E. (1889) Provisional description of supposed new mammals from California and Lower California. Proceedings of the California Academy of Science, 2 series 2, 25–27.
Clement, M., Posada, D & Crandall, K.A. (2000) TCS: a computer program to estimate gene genealogies. Molecular Ecology, 9, 1657–1660.
Cracraft, J. (1997) Species concepts in systematic and conservation biology – an ornithological viewpoint. In: Claridge, M.F., Dawah, H.A. & Wilson M.R. (Eds.). Species: the units of biodiversity. Chapman and Hall, London, UK, pp. 325–340.
Excoffier, L. Smouse, P.E. & Quattro, J.M. (1992) Analysis of molecular variance inferred from metric distances among DNA haplotypes: Application to human mitochondrial DNA restriction data. Genetics, 131, 479–491.
Fu, Y-X. (1997) Statistical test of neutrality of mutations against population growth, hitchhiking and background selection. Genetics, 147, 915–925.
Hall, E.R. (1981) The Mammals of North America. John Wiley and Sons, New York. 1181 pp.
Harrison, R.G., Bogdanowicz, S.M., Hoffmann, R.S., Yensen, E. & Sherman, P.W. (2003) Phylogeny and Evolutionary History of the Ground Squirrels (Rodentia: Marmotinae). Journal of Mammalian Evolution, 10, 249–276.
Hasegawa, M., Kishino, K. & Yano, T. (1985) Dating the human-ape splitting by a molecular clock of mitochondrial DNA. Journal of Molecular Evolution, 22, 160–174.
Helgen, K.M., Cole, F.R. Helgen, L.E. & Wilson D.E. (2009) Generic revision in the holartic ground squirrel Genus Spermophilus. Journal of Mammalogy, 90, 270–305.
Howell, A.H. (1938) Revision of the North American ground squirrels, with a classification of the North American Sciuridae. North America Fauna, 56, 1–256.
Hubbart, J.A. (2001) The Ecology of the California Ground Squirrel (Spermophilus beecheyi). Available from “The California Ground Squirrel website” http://home.earthlink.net/~jahubbart/. (accessed March 2007).
Nylander, J.A.A. (2004) MrModeltest version 2.2. Program distributed by the author. Evolutionary Biology Center. Uppsala University, Sweden.
Oaks, E.C., Young, P.L., Kirkland, G.L.Jr., & Schmidl, D.F. (1987) Spermophilus variegatus. Mammalian Species, 272, 1–8.
Peinado, M., Alcaraz, F. Delgadillo, J. & Aguado, I. (1994) Fitogeografía de la península de Baja California, México. Anales del Jardín Botánico Madrid, 51, 255–277.
Posada, D. (2004). Collapse version 1.1 Available from http://darwin.uvigo.es/software/collapse.html. (accessed April 2004).
Roger, A.R., & Harpending, H. (1992) Population growth makes waves in the distribution of pairwise genetic differences. Molecular, Biology and Evolution, 9, 552–569.
Ronquist, F., & Huelsenbeck, J.P. (2003) MrBayes3: Bayesian phylogenetic inference under mixed models. Bioinformatics, 19, 1572–1574.
Schneider, S., Kueffer, J.M., Roessli, D., & Excoffier, L. (2000) Arlequin ver. 2.000. A software for population genetic data analysis. Genetics and Biometry Laboratory, University of Geneva, Switzerland, 111 pp.
Schoenherr, A.A. (1992) A natural history of California. University of California Press, Berkeley, 742 pp.
Sikes, R.S., Gannon, W.L., & the Animal Care and Use Committee of the American Society of Mammalogy.2011. Guidelines of the American Society of Mammalogists for the use of wild mammals in research. Journal of Mammalogy 92, 235–253.
Swofford, D.L. (2002) PAUP*: phylogenetic analysis using parsimony (* and other methods). Version 4.0b10. Sinauer Associates, Inc., Publishers, Sunderland, Massachusetts.
Templeton, A.R. (2001) Using phylogeographic analyses of gene trees to test species status and processes. Molecular Ecology, 10, 779–791.
Thorington, R.W., & Hoffmann, R.S. (2005) Family Sciuridae. In: Wilson D.E., & Reeder, D.M. (Eds.), Mammal Species of the World. Third Edition. John Hopkins University Press, Baltimore, Maryland, pp. 754–818.
Weir, B. S., & Cockerham, C.C. (1984) Estimating F-statistics for the analysis of population structure. Evolution, 38, 1358–1370.
Well, P.V. (1986) Systematic and distribution of pinyons in late Quaternaty. In: Everett, R.L. (compiler). Proceeedings: Pinyon-Juniper Conference, pp. 104–108.
Well, P.V. (2000) Pleistocene macrofossil records of four-needled pinyon of Juniper encinal in the Northern Vizcaino Desert, Baja California del Norte. Madroño, 47, 189–194.
Yensen, E., & Valdez-Alarcon, M. (1999) Family Sciuridae. In: Álvarez-Castañeda, S.T., & Patton, J.L. (Eds.). Mamíferos del Noroeste de México. Centro de Investigaciones Biológicas del Noroeste. La Paz, Baja California Sur, México. pp. 239–320.