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Copyright of American Naturalist is the property of University of Chicago and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Biogeography is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biologists have long pondered the extreme limits of life on Earth, including the maximum elevation at which species can live and reproduce. Here we review evidence of a self-sustaining population of mice at an elevation that exceeds that of all previously reported for mammals. Five expeditions over 10 years to Volcán Llullaillaco on the Argentina/Chile border observed and collected mice at elevations ranging from 5,070 m at the mountain's base to the summit at 6,739 m (22,110 feet). Previously unreported evidence includes observations and photographs of live animals and mummified remains, environmental DNA, and a soil microbial community reflecting animal activity that are evaluated in combination with previously reported video recordings and capture of live mice. All of the evidence identifies the mouse as the leaf-eared mouse Phyllotis vaccarum, and it robustly places the population within a haplotype group containing individuals from the Chilean Atacama Desert and nearby regions of Argentina. A critical review of the literature affirms that this population is not only an elevational record for mammals but for all terrestrial vertebrates to date, and we further find that many extreme elevations previously reported for mammals are based on scant or dubious evidence. Durante mucho tiempo los biólogos han reflexionado sobre los límites extremos de altura a la que las especies pueden vivir y reproducirse. Aquí presentamos nueva evidencia sobre la existencia de una población de ratones establecida a una elevación que supera todos los reports previos para mamíferos. Durante 10 años fueron realizadas 5 expediciones al Volcán Llullaillaco, ubicado en la frontera entre Argentina y Chile; observando y colectando ratones en elevaciones que van desde los 5,070 m hasta la cima de 6,739 m (22,110 feet). La nueva evidencia incluye fotografías de restos momificados, ADN ambiental y la actividad microbiana del suelo que confirman la presencia del animal, la cual fue analizada junto a videos reportados anteriormente y la captura de ejemplares vivos. Toda esta información indica que dicha población corresponde al ratón orejudo amarillento Phyllotis vaccarum y lo posicionan dentro de un grupo de haplotipos compuesto por individuos del Desierto de Atacama y regiones cercanas en Argentina. La revisión crítica de la literatura demostró que esta población no solo es un récord de elevación para los mamíferos, sino para todos los vertebrados terrestres; igualmente, que los reportes de elevaciones extremas reportados para mamíferos se derivan de evidencias escasas y dudosas. [ABSTRACT FROM AUTHOR]

Aim: Tropical South America, in particular Amazonia, has been identified as the area of the basal diversification of several large mammal clades. Whether this scenario also holds for younger and widely distributed clades remains unclear. Here, we assessed the historical biogeography of a young but diverse and widely distributed mammal clade. Location: The Neotropics. Taxon: Long‐tailed mice of the genus Oligoryzomys. Methods: We estimated a dated species tree by sampling five genes (one mitochondrial and four nuclear) from 30 of the 32 living species of the genus. We inferred the distribution of the most recent common ancestors (MRCAs) of distinct species groups, using a 13 ecoregion scheme and fitting three biogeographical models, to simulate dispersal events under the selected model. Results: The DEC model best explained the diversification of Oligoryzomys. The MRCA of the genus had an age of ~2.64 Mya and its ancestral area was inferred as a large region encompassing Boreal and Southern Amazonia, Chaco and Tropical Andes. Subsequent vicariance events, followed by dispersal events towards the present, account for its diversification and wide distribution. Main conclusion The biogeographical history of Oligoryzomys is complex. It originated in the northern half of South America; and then after a series of vicariant events, a series of dispersion events allowed it to colonize southern South America, the Andes and closer to the present Central and North America. This radiation, which constitutes one of the fastest and largest Pleistocene diversifications of Neotropical mammals, involves events previously suggested for other groups (e.g. Andean diversification), others that are novel for rodents and for the most part for South American mammals (e.g. the identification of the Chaco as a centre of diversification). [ABSTRACT FROM AUTHOR]

The genus Euneomys is mostly distributed in the open environments of the central and southern Andes, adjacent Patagonian steppes of Argentina and Chile, and in several islands of the Tierra del Fuego Archipelago. This genus includes three living species: E. chinchilloides, E. fossor, and E. mordax. Euneomys fossor is a poorly known species, with an uncertain geographic provenance and known from a single specimen, whose distinction from the other species of the genus has not been accurately assessed. Here, using qualitative and quantitative morphological evidence, plus published information about karyotypes and genetic variation, we evaluate the taxonomic status of E. fossor and E. noei, a nominal form usually considered a synonym of E. mordax. Based on multivariate analysis of cranial measurements and morphological discrete traits, we recognize two main morphotypes within Euneomys, one referable to E. chinchilloides (with dabbenei, petersoni, and ultimus as synonyms), and another including E. fossor, E. mordax, and E. noei. The recognition of two major groups within Euneomys is also supported by molecular and chromosomal data. By the principle of the priority, the names of E. chinchilloides and E. fossor applies for each one of these morphotypes. In addition, after discussing the pros and cons of replacing the name mordax by fossor, we emended the type localities of both forms. [ABSTRACT FROM AUTHOR]

Oligoryzomys, as currently understood is formed by 25 living species, is the most diverse genus of the tribe Oryzomyini of the New World subfamily Sigmodontinae of cricetid rodents. Nonetheless, the species richness of Oligoryzomys seems to be an underestimate, given some species complex has been proposed in previous studies, at the time that large geographic areas remain to be sampled, and several taxonomic forms have not been assessed with contemporary approaches. In this study, we present a new assessment of the species diversity of Oligoryzomys based on multiple unilocus species delimitation methods (ABGD, BPP, PTP, GMYC and b GMYC), using 665 cytb gene sequences as evidence (532 gathered from Genbank and 133 obtained in this study). We sampled representatives of almost all currently known species of Oligoryzomys, at the time that extending the geographic coverage to the Central Andes, a large area that was largely unrepresented in previous studies. Phylogenetic relationships, based on a non‐redundant alignment, were inferred via maximum likelihood and Bayesian inference; an ultrametric tree, used in species delimitation analyses, was obtained using multiple secondary calibration points. Results of species delimitation methods are discussed at the light of previous knowledge (e.g., taxonomic history and geographic provenance of samples in relation to type localities) and the morphological assessments of some specimens. Results of the distinct delimitation methods are mostly congruent, being BPP and PTP the most sensible to estimate species delimitation, allowing us to suggest that Oligoryzomys is composed of 30 lineages of species level. Of these, 22 correspond to forms currently considered species; some of these include in their synonymy some forms currently considered valid species (e.g., yatesi would be a synonym of longicaudatus). The remaining eight lineages are candidate species that need to be further evaluated. This study, by advancing taxonomic hypothesis that should be further tested in future studies, constitutes a stepping‐stone for upcoming taxonomic and biogeographic studies centred on Oligoryzomys. [ABSTRACT FROM AUTHOR]

Copyright of Therya is the property of Asociacion Mexicana de Mastozoologia, A. C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Environmental limits of animal life are invariably revised when the animals themselves are investigated in their natural habitats. Here we report results of a scientific mountaineering expedition to survey the high-altitude rodent fauna of Volcán Llullaillaco in the Puna de Atacama of northern Chile, an effort motivated by video documentation of mice (genus Phyllotis) at a record altitude of 6,205 m. Among numerous trapping records at altitudes of >5,000 m, we captured a specimen of the yellow-rumped leaf-eared mouse (Phyllotis xanthopygus rupestris) on the very summit of Llullaillaco at 6,739 m. This summit specimen represents an altitudinal world record for mammals, far surpassing all specimen-based records from the Himalayas and other mountain ranges. This discovery suggests that we may have generally underestimated the altitudinal range limits and physiological tolerances of small mammals simply because the world's high summits remain relatively unexplored by biologists. [ABSTRACT FROM AUTHOR]

The glassfrog Centrolene buckleyi has been recognized as a species complex. Herein, using coalescence-based species delimitation methods, we evaluate the specific diversity within this taxon. Four coalescence approaches (generalized mixed Yule coalescents, Bayesian general mixed Yule-coalescent, Poisson tree processes, and Bayesian Poisson tree processes) were consistent with the delimitation results, identifying four lineages within what is currently recognized as C. buckleyi. We propose three new candidate species that should be tested with nuclear markers, morphological, and behavioral data. In the meantime, for conservation purposes, candidate species should be considered evolutionary significant units, in light of observed population crashes in the C. buckleyi species complex. Finally, our results support the validity of C. venezuelense, formerly considered as a subspecies of C. buckleyi. [ABSTRACT FROM AUTHOR]

Information from diversity inventories was used to study patterns of biodiversity and species distribution, to identify potential priority areas for conservation, and to guide future sampling efforts. In this context, we compiled information on non‐volant small mammal communities from the high Andes (>2000 m). Here, we present an open source dataset containing information on diversity (species composition, number of individuals captured), inventory design (type of traps, sampling efforts), and environment (habitat) for both unpublished and published information. This study covers 630 mammalian communities, geographically distributed throughout the Andes in Venezuela, Colombia, Ecuador, Peru, Bolivia, Argentina, and Chile. We compiled a total of 26,412 individual records belonging to 240 species; the order with greatest number of records was Rodentia (n = 25,319, 96.06%), followed by Didelphimorphia (n = 373, 1.42%), Eulipotyphla (n = 358, 1.36%) and Paucituberculata, (n = 307, 1.16%). Andean non‐volant small mammal communities harbor a range from 1 to 17 species, with 93.06% of sites being composed of one to five species, 27.78% of sites with species richness varying from 6 to 10 species, and 4.17% sites composed of more than 10 species. Multiple sampling methods were used to survey non‐volant small mammals; the most representative methods were snap‐traps and Sherman traps, or a combination of both, in more than 81% of the studies. This data paper represents the first large dataset of faunal species inventories for the Andes. There are no copyright restrictions associated with the use of this dataset. Please cite this data paper when its data are used total or partially in research or teaching. [ABSTRACT FROM AUTHOR]

Abrotrichini is a recently defined and diagnosed tribe of Sigmodontinae with a complex taxonomy. Abrotrichine genera, Abrothrix (including Chroeomys), Chelemys, Geoxus, Notiomys and Pearsonomys, are mostly distributed in the central and southern Andes and adjacent lowlands and show terrestrial and fossorial habits. Recent studies have evidenced some incongruence between current taxonomy and abrotrichine phylogeny, such as the polyphyly of Chelemys and paraphyly of Geoxus respect to Pearsonomys. We used DNA sequence data of six loci (one mitochondrial and five nuclear) to resolve the relationships within the tribe. Independent and combined analyses of these loci were carried out using parsimony, maximum likelihood and Bayesian inference. Estimates of divergence time of the main lineages of abrotrichines were calculated with a molecular clock using as calibration, a fossil recently found. The concatenated data set increased the resolution and defined the relationships within the tribe. Our phylogenetic analyses corroborate that Abrothrix is sister of a clade containing the long-clawed abrotrichines. We recovered two main clades within Abrothrix that match morphologic variation and geographic distribution of its species. In addition, we corroborated the lack of monophyly of Chelemys and the lack of monophyly of Geoxus. We discuss different taxonomic scenarios to abrotrichine classification reflects the phylogenetic relationships obtained in this study. Our molecular clock estimated the Abrotrichini crown age to be around the early Pliocene (4.4 Ma) and suggest that the tribe diversified over a short period of time. [ABSTRACT FROM AUTHOR]

Loxodontomys micropus is a rodent that is widely distributed in Andean and Patagonian Argentina and Chile. This range covers a heterogeneous area that has been influenced by geologic and palaeoclimatic events, such as the glaciations during the Neogene. To investigate the genetic structure, phylogeographic pattern, and biogeographic history of this sigmodontine rodent we analyzed a 801-base-pair fragment of the mitochondrial genome (cytochrome-b gene) of 87 specimens from 24 localities from Argentina and Chile. Results indicate that L. micropus has a shallow genealogy that is geographically structured and is a taxon characterized by an historical population expansion. We discuss the distribution of the genetic variation of L. micropus in relation to population history and the concordance with other codistributed sigmodontine rodents. On the basis of molecular evidence, we suggest that the L. pikumche, corresponding to the second extant species of the genus, could be a junior synonym of L. micropus. [ABSTRACT FROM AUTHOR]

[Display omitted] • Current taxonomy does not reflect the real species richness of the genus Octodon. • Depending on the analysis between 7 and 11 species of degus are delimited. • Some of the previously unrecognized species are morphologically distinct. • Some of the previously unrecognized species are morphologically indistinct. As currently understood, the genus Octodon contains five species degus , lunatus , bridgesii , pacificus , and ricardojeda. Previous phylogenetic studies suggest that genus specific diversity is underestimated. In order to evaluate the taxonomic diversity of Octodon , we implemented unilocus (cytochrome-b) and multilocus (cytochrome-b + 4 nuclear genes) species delimitation methods. Octodon degus was recovered as a sister of the other species of the genus. The unilocus bGMYC and mPTP methods, based on cytochrome-b sequences, delimits 11 and 7 candidate species respectively, and both methods fail to recognize O. pacificus from O. ricardojeda. Results of the multilocus analysis (BPP) vary as a function of the dataset used. When the five genes are used 11 species are delimited, while eight species are delimited when only the nuclear genes are used. Octodon bridgesii is shown as comprising at least two species (one on the Pacific coast and the typical form found on the Andean slopes), while O. ricardojeda may comprise two species (one on the Chilean side of the Andes and the other in Argentina). Likewise, both multilocus matrices recover O. pacificus as a distinct species. This shows that species diversity of Octodon is underestimated. Remarkably, many of the delimited species based on genetic data are morphologically differentiated in cranio-dental characteristics. However, a pair of species has not achieved morphological differentiation, being cryptic species. Finally, the incongruence between mitochondrial and nuclear phylogenies suggests that processes such as incomplete lineage sorting and/or introgression have been present during the radiation of the genus. [ABSTRACT FROM AUTHOR]