Abstract
Akodon oenos Braun, Mares, and Ojeda, 2000 was described on a large sample of individuals collected from two localities near Mendoza city, Argentina. This sample was obtained in the 1980’s by Julio R. Contreras and María I. Rossi and labeled, but never published, as “Akodon minoprioi new species.” The description provided by Braun and collaborators was limited to craniodental and color pelage traits compared with those of five individuals of the sympatric form A. molinae Contreras, 1968. Akodon oenos was proposed as new and presumptively allied to the A. varius species group of Akodon. In February 2009 we collected an individual of Akodon in Llancanelo Natural Reserve, southern Mendoza, that morphologically fits the original description of A. oenos. Further study of some individuals of the type series of A. oenos reinforces this taxonomic hypothesis for the Llancanelo specimen. However, comparisons with other Akodon species overlooked by Braun and collaborators, reveals striking similarities with the widespread and phenotypically variable species A. spegazzinii Thomas, 1897. The evidence at hand, including morphological, karyological, and genetical traits, allows us to propose a new taxonomic scenario. A. oenos is considered here a junior synonym of A. spegazzinii and therefore belongs to the A. boliviensis species group of Akodon, extending the known geographic distribution for this species at least to southern Mendoza piedmont in the ecotone between the Monte and Patagonia eco-regions. More generally, this situation highlights the necessity when working with complex genera (as many sigmodontines are) to perform extensive comparisons and to use several sets of evidence in order to reduce the probability of generating biologically redundant names and more taxonomic confusion.References
Apfelbaum, L.I. & Reig, O.A. (1989) Allozyme genetic distances and evolutionary relationships in species of akodontine rodents (Cricetidae: Sigmodontinae). Biological Journal of the Linnean Society, 38, 257–280.
Barquez, R.M., Mares, M.A. & Ojeda, R.A. (1991) Mamíferos de Tucumán - Mammals of Tucumán. Oklahoma Museum of Natural History, University of Oklahoma, Norman, 282 pp.
Barquez, R.M., Williams, D.F., Mares, M.A. & Genoways, H.H. (1980) Karyology and morphometrics of three species of Akodon (Mammalia: Muridae) from northwestern Argentina. Annals of Carnegie Museum, Carnegie Museum of Natural History, 49 (22), 379–403.
Bianchi, N.O. & Merani, S. (1984) Cytogenetics of South American Akodont rodents (Cricetidae). X. Karyological distances at generic and intergeneric levels. Journal of Mammalogy, 65, 206–219.
Bianchi, N.O., Reig, O.A., Molina, O.J. & Dulout, F.N. (1971) Cytogenetics of the South American Akodont rodents (Cricetidae). I. A progress report of Argentinian and Venezuelan forms. Evolution, 25, 724–736.
Blaustein, S., Liascovich, R., Apfelbaum, L., Daleffe, L., Barquez, R. & Reig, O. (1992) Correlates of systematic differentiation between two closely related allopatric populations of the Akodon boliviensis group from NW Argentina (Rodentia: Cricetidae). Zeitschrift für Säugetierkunde, 57, 1–13.
Braun, J.K., Coyner, B.S., Mares, M.A. & Van Den Bussche, R.A. (2008) Phylogenetic relationships of South American grass mice of the Akodon varius group (Rodentia, Cricetidae, Sigmodontinae) in South America. Journal of Mammalogy, 89, 768–777.
Braun, J.K., Mares, M.A. & Ojeda, R.A. (2000) A new species of grass mouse, genus Akodon (Muridae: Sigmodontinae), from Mendoza Province, Argentina. Zeitschrift für Säugetierkunde, 65, 216–225.
Contreras, J.R. & Rosi, M.I. (1980a) Comportamiento territorial y fidelidad al habitat en una población de roedores del centro de la provincia de Mendoza. Ecología Argentina (Mendoza), 5, 17–29.
Contreras, J.R. & Rosi, M.I. (1980b) Acerca de la presencia en la provincia de Mendoza del ratón de campo Akodon molinae Contreras, 1968. Historia Natural, 1(26), 181–184.
D’Elía, G. (2003) Phylogenetics of Sigmodontinae (Rodentia, Muroidea, Cricetidae), with special reference to the akodont group, and with additional comments on historical biogeography. Cladistics, 19, 307–323.
D’Elía, G. & Pardiñas, U.F.J. (2004) Systematics of Argentinean, Paraguayan, and Uruguayan swamp rats of the genus Scapteromys (Rodentia, Cricetidae, Sigmodontinae). Journal of Mammalogy, 85, 897–910.
Farris, J.S. (1982) The logical basis of phylogenetic analyis. In: Platnick N. & Funk V. (Eds.), Advances in Cladistics: Proceedings of the Second Meeting of the Willi Hennig Society. New York: Columbia University Press, pp. 7–36.
Farris, J.S., Albert, V.A., Källersjö, M., Lipscomb, D. & Kluge, A.G. (1996) Parsimony jackknifing outperforms neighbor-joining. Cladistics, 12, 99–124.
Felsenstein, J. (1981) Evolutionary trees from DNA sequences: a maximum likelihood approach. Journal of Molecular Evolution, 17, 368–376.
Galliari, C.A., Pardiñas, U.F.J. & Goin, F.J. (1996) Lista comentada de los mamíferos argentinos. Mastozoología Neotropical, 3, 39–61.
Jayat, J.P. (2009) Roedores sigmodontinos de los pastizales de neblina de las Yungas de Argentina. Unpublished doctoral thesis, Universidad Nacional de Tucumán, Tucumán, Argentina.
Jayat, J.P., Ortiz, P.E. & Miotti, M.D. (2008) Distribución de sigmodontinos (Rodentia: Cricetidae) en pastizales de neblina del noroeste argentino. Acta Zoológica Mexicana, 24, 137–177.
Jayat, J.P., Ortiz, P.E., Salazar-Bravo, J., Pardiñas, U.F.J. & D’Elía, G. (2010) The Akodon boliviensis species group (Rodentia: Cricetidae: Sigmodontinae) in Argentina: species limits and distribution, with the description of a new entity. Zootaxa, 2409, 1–61.
Mares, M.A, Ojeda, R.A. & Kosco, M.P. (1981) Observation on the distribution and ecology of the mammals of Salta Province, Argentina. Annals of Carnegie Museum, 50, 151–206.
Mares, M.A, Ojeda, R.A., Braun, J.K. & Barquez, R.M. (1997) Systematics, distribution, and ecology of the mammals of Catamarca Province, Argentina. In: Yates, T.L., Gannon, W.L. & Wilson, D.E. (Eds.), Life among the muses: Papers in honor of James S. Findley. Albuquerque: Museum of Southwestern Biology, University of New Mexico, pp. 89–141.
Musser, G.G. & Carleton, M.D. (2005) Superfamily Muroidea. Pp 894–1531 In: Wilson, D.E. & Reeder, D.M. Mammal species of the world. A taxonomic and geographic reference. Vol. II. Third Edition. The John Hopkins University Press, Baltimore.
Myers, P. (1989) A preliminary revision of the varius group of Akodon (A. dayi, dolores, molinae, neocenus, simulator, toba and varius). In: Redford, K.H. & Eisenberg, J.F. (Eds.), Advances in Neotropical Mammalogy. Gainesville, Florida: Sandhill Crane Press, Inc., pp. 5–54.
Myers, P., Patton, J.L. & Smith, M.F. (1990) A review of the boliviensis group of Akodon (Muridae: Sigmodontinae), with emphasis on Peru and Bolivia. Miscellaneous Publications of the Museum of Zoology, University of Michigan, 177: iv + 104 pp.
Ojeda, R.A. & Mares, M.A. (1989) A biogeographic analysis of the mammals of Salta Province, Argentina. Patterns of species assemblage in the Neotropics. Special Publications, The Museum, Texas Tech University, 27, 1–66.
Pardiñas, U.F.J. (2009) El género Akodon (Rodentia: Cricetidae) en Patagonia: estado actual de su conocimiento. Mastozoología Neotropical, 16, 135–151.
Pardiñas, U.F.J., Teta, P. & Udrizar Sauthier, D.E. (2008). Mammalia, Didelphimorphia and Rodentia, Southwest of the province of Mendoza, Argentina. Check List, 4(3), 218–225.
Pinna-Senn, E., de Barale, D.D., Polop, J.J., Ortiz, M.Y., Provensal, M.C. & Lisanti, J.A. (1992) Estudio cariotípico y morfométrico en una población de Akodon sp. (Rodentia, Cricetidae) de Pampa de Achala. Mendeliana, 10, 59–70.
Polop, J. (1989) Distribution and ecological observations of wild rodents in Pampa de Achala, Córdoba, Argentina. Studies on Neotropical Fauna and Environment, 24, 53–59.
Rannala, B. & Yang, Z. (1996) Probability distribution of molecular evolutionary trees: a new method of phylogenetic inference. Journal of Molecular Evolution, 43, 304–311.
Reig, O.A. (1977) A proposed unified nomenclature for the enamelled components of the molar teeth of the Cricetidae (Rodentia). Journal of Zoology, London, 181, 227–241.
Ronquist, F. & Huelsenbeck, J.P. (2003) MRBAYES 3: Bayesian phylogenetic inference under mixed models. Bioinformatics, 19, 1572–1574.
Smith, M.F. & Patton, J.L. (2007) Molecular phylogenetics and diversification of South American grass mice, genus Akodon. In: Kelt, D., Lessa, E. & Salazar-Bravo, J. (Eds.), Studies in Contemporary Mammalian Biology. Papers Honoring the Remarkable Career of Oliver P. Pearson, 1915–2003. California: University of California Publications in Zoology, pp. 827–858.
StatSoft, Inc. (2001) Statistica for Windows: computer program manual. StatSoft, Inc. Tulsa, Oklahoma.
Swofford, D. (2000) PAUP*: Phylogenetic Analysis Using Parsimony (*and other methods), version 4.0. Sunderland, Massachusetts: Sinauer Associates Inc.
Tamura, K., Dudley, J., Nei., M. & Kumar, S. (2007) MEGA 4: Molecular Evolutionary Genetics Analysis (MEGA) software version 4.0. Molecular Biology and Evolution, 24, 1596–1599.
Tiranti, S.I. (1989) Tres roedores cricétidos nuevos para la fauna de la provincia de La Pampa. 1 Jornada Nacional de Fauna Silvestre, Actas, 489–494.
Thomas, O. (1919) On small mammals from “Otro Cerro,” North-eastern Rioja, collected by Sr. L. Budin. Annals and Magazine of Natural History (London) Series, 9 (3), 489–500.
Thomas, O. (1920) On small mammals from the Famatina Chain, North-western Rioja. Annals and Magazine of Natural History (London) Series, 9 (6), 417–422.
Thompson, J.D., Gibson, T.J., Plewniak, F., Jeanmougin, F. & Higgins, D.G. (1997) The Clustal X windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. Nucleic Acids Research, 24, 4876–4882.
Voss, R.S. (1988) Systematics and ecology of Ichthyomyine rodents (Muroidea): patterns of morphological evolution in a small adaptative radiation. Bulletin of the American Museum of Natural History, 2, 259–493.