Redescripción y posición filogenética del ratón selvático Akodon sylvanus (Rodentia: Cricetidae: Sigmodontinae)

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Recientes trabajos de campo en los alrededores de la localidad tipo de Akodon sylvanus nos han permitido colectar ejemplares de esta forma pobremente conocida. En este trabajo se genera por primera vez una hipótesis filogenética explícita que incluye a este taxón. El análisis filogenético junto con las comparaciones morfológicas efectuadas demuestran que A. sylvanus constituye una especie válida diferente de A. azarae y A. pervalens, dos taxones que en su momento fueron considerados como parte de la misma entidad. Además, nuestro análisis filogenético sugiere que A. sylvanus pertenece al grupo de especies de A. boliviensis. Es así que se brinda una diagnosis enmendada para A. sylvanus, que incluye caracteres morfológicos (cuanti y cualitativos) y datos moleculares (citocromo b). Finalmente, este estudio extiende la distribución geográfica conocida para A. sylvanus mediante la adición de varias localidades nuevas en las provincias de Jujuy y Salta, básicamente restringidas a un ambiente de Yungas entre los 700 y 2300 m de altitud.


Redescription and phylogenetic position of the Silvan Mouse Akodon sylvanus (Rodentia: Cricetidae: Sigmodontinae). Recent field work conducted near the type locality of Akodon sylvanus provided new specimens of this poorly known form. In this paper we provide a phylogenetic hypothesis that for the first time includes A. sylvanus. Phylogenetic and morphologic analyses show that A. sylvanus represents a valid biological species, different from A. azarae and A. pervalens, two taxa at times considered as part of the same biological species as A. sylvanus. Furthermore, our analysis suggest that A. sylvanus belongs to the A. boliviensis species group. We present an emended diagnosis of A. sylvanus, which includes morphological (quanti- and qualitative analyses) and molecular (cyt b sequences) data. Finally, we summarize its known distribution, adding several new recording localities in the Argentinean provinces of Jujuy and Salta, and provide data on its natural history.

Fossil record of the Andean rat, Andinomys edax (Rodentia: Cricetidae), in Argentina

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Andinomys edax (Rodentia, Cricetidae) has a broad distribution in the Central Andean region. The fossil record is restricted to only three localities from Lower-Middle Pleistocene in Bolivia to Upper Holocene in Argentina. Recent field work in northwestern Argentina produced five new paleontological localities: Las Juntas, Catamarca (13.4–12.95 kyr BP); Inca Cueva 4, Jujuy (11–9 kyr BP); Tafí del Valle, Tucumán (10.25–9.75 kyr BP); Los Viscos, Catamarca (1.88 kyr BP); and La Cueva, Jujuy (0.95 kyr BP). The paleontological data indicate that A. edax has been a ubiquitous sigmodontine in northwestern Argentina since the Upper Pleistocene.


Registro fósil de la rata andina, Andinomys edax (Rodentia: Cricetidae), en Argentina. Andinomys edax presenta una amplia distribución en la región andina central. Su registro fósil está restringido a solo tres localidades, desde el Pleistoceno Inferior Medio en Bolivia hasta el Holoceno Superior en Argentina. Recientes trabajos de campo en el noroeste argentino resultaron en cinco nuevas localidades paleontológicas: Las Juntas, Catamarca (13.4–12.95 ka AP); Inca Cueva 4, Jujuy (11–9 ka AP); Tafí del Valle, Tucumán (10.25–9.75 ka AP); Los Viscos, Catamarca (1.88 ka AP); y La Cueva, Jujuy (0.95 ka AP). La información paleontológica indica que A. edax ha sido un sigmodontino ubícuito en el noroeste argentino desde el Pleistoceno Superior.

Distribución de Necromys lactens y Phyllotis osilae (Rodentia: Cricetidae: Sigmodontinae) en el Noroeste argentino: modelos predictivos basados en el concepto de nicho ecológico

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Distribution of Necromys lactens and Phyllotis osilae (Rodentia: Cricetidae: Sigmodontinae) in northwestern Argentina: predictive models based on the concept of ecological niche. We used presence data from field records, museum specimens and literature sources to model the potential distribution of two species of sigmodontine rodents, Necromys lactens and Phyllotis osilae in northwestern Argentina, based on environmental variables. We used the DOMAIN program, which based on presence data defines the environmental space that imposes conditions to the species distribution. We worked with two data sets, one constituted only by reliable data and the other one constituted by these reliable data plus other information considered more doubtful because of its controvertible identification and location. The models obtained from the reliable data set were more efficient in the prediction of distribution than doubtful data, with Kappa index of 0.69 and 0.63 for Necromys lactens and Phyllotis osilae, respectively. These results indicate that both species are restricted to the upper portions of the most important mountains in the region and that their distribution consists of islands or patches immerse in a complex matrix of forest and semi-desert environment. Both species were associated to high altitude grasslands and ecotone environments between 1200 and 3200 m elevation, being P. osilae‘s distribution a little more extended than N. lactens.

Nuevas localidades argentinas para algunos roedores sigmodontinos (Rodentia: Cricetidae)

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New localities for sigmodontine rodents (Rodentia-Cricetidae) in Argentina. New localities for 24 species of sigmodontine rodents in Argentina are reported based on records obtained by direct trapping and/or the analyses of owl pellets. This report includes the first Argentinean record for Akodon boliviensis and Necromys amoenus. Additionally, we extend the known distribution for Akodon budini, A. sylvanus, A. toba, Necromys cf. N. lasiurus, Calomys musculinus, Loxodontomys micropus, Phyllotis osilae, P. xanthopygus, and Phyllotis wolffsohni. Finally, additional localities for Abrothrix illuteus, A. longipilis, Chelemys macronyx, Notiomys edwardsii, Necromys lactens, Bibimys chacoensis, Holochilus chacarius, Oecomys sp., Oryzomys angouya, O. legatus, Reithrodon auritus, Rhipidomys austrinus, and Euneomys mordax are reported. The results suggest that much work remains yet to be done in order to have an adequate picture of the diversity and distribution of Argentinean sigmodontine rodents.

Aportes al conocimiento de la distribución de los carnívoros del noroeste de Argentina

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En este trabajo se agregan 151 nuevas localidades de distribución para 20 especies de carnívoros del noroeste argentino: cinco cánidos, nueve félidos, cuatro mustélidos y dos prociónidos. Se agregan tres especies a la fauna conocida de la provincia de Santiago del Estero y dos a la de Jujuy.


Contribution to the knowledge of the distribution of the carnivores of northwestern Argentina. Northwestern Argentina includes the provinces of Jujuy, Salta, Tucumán, Catamarca, and Santiago del Estero and is a unique area where biotic and abiotic factors have a significant influence on faunal patterns. Most species of carnivores that occur in Argentina are found in this region, with the exception of Speothos venaticus, Oncifelis guigna, Lontra provocax, L. felina, and Conepatus humboldtii. Distributional records were obtained from specimens deposited in systematic collections in Argentina and the United States, as well as from field surveys and personal communication from field workers at collecting localities. One hundred and fifty one new localities for carnivores in northwestern Argentina are presented, and include information on five canids, nine felids, four mustelids and two procyonids. Three species are added to the mammal fauna of the province of Santiago del Estero and two species are added to the mammal fauna of Jujuy province.