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On the flanks of > 6000 m Andean volcanoes that tower over the Atacama Desert, leaf‐eared mice (Phyllotis vaccarum) live at extreme elevations that surpass known vegetation limits. The diet of these mice in these barren, hyperarid environments has been the subject of much speculation. According to the arthropod fallout hypothesis, sustenance is provided by windblown insects that accumulate in snowdrifts ("aolian deposits"). Mice may also feed on saxicolous lichen or forms of cryptic vegetation that have yet to be discovered at such high elevations. We tested hypotheses about the diet of mice living at extreme elevations on Atacama volcanoes by combining metagenomic and DNA metabarcoding analyses of gut contents with stable isotope analyses of mouse tissues. Genomic analyses of contents of the gastrointestinal tract of a live‐captured mouse from the summit of Volcán Llullaillaco (6739 m) revealed an opportunistic but purely herbivorous diet, including lichens. Although we found no evidence of animal DNA in gut contents of the summit mouse, stable isotope data indicate that mice from elevations at or near vegetation limits (~5100 m) include a larger fraction of animal prey in their diet than mice from lower elevations. Some plant species detected in the gut contents of the summit mouse are known to exist at lower elevations at the base of the volcano and in the surrounding Altiplano, suggesting that they may occur at higher elevations beneath the snowpack or in other cryptic microhabitats. [ABSTRACT FROM AUTHOR]

In the world's highest mountain ranges, uncertainty about the upper elevational range limits of alpine animals represents a critical knowledge gap regarding the environmental limits of life and presents a problem for detecting range shifts in response to climate change. Here we report results of mountaineering mammal surveys in the Central Andes, which led to the discovery of multiple species of mice living at extreme elevations that far surpass previously assumed range limits for mammals. We livetrapped small mammals from ecologically diverse sites spanning >6,700 m of vertical relief, from the desert coast of northern Chile to the summits of the highest volcanoes in the Andes. We used molecular sequence data and whole-genome sequence data to confirm the identities of species that represent new elevational records and to test hypotheses regarding species limits. These discoveries contribute to a new appreciation of the environmental limits of vertebrate life. [ABSTRACT FROM AUTHOR]

We report an elevational record for the Andean sigmodontine Puna Mouse Punomys , which is also the first record of the genus in Chile. The record is based on a mummified specimen that we discovered at an elevation of 5,461 m (17,917 feet) in the caldera of Volcán Acamarachi, Región de Antofagasta, Chile. Results of a morphological assessment suggest that the specimen can be provisionally referred to the species P. lemminus. This new record also extends the known geographic distribution of the genus by 700 km to the south and brings the known Chilean mammal richness to a total of 170 living species and 88 genera. This finding highlights the need for increased survey efforts in more remote, high-elevation regions and demonstrates that there is still much to be learned about the mammal fauna of the Andean Altiplano. [ABSTRACT FROM AUTHOR]

The Quaternary glaciations had great impacts on the historical biogeography of small mammal species. Recent studies have showed the effects of these climatic cycles on the diversification of several Neotropical rodents, but these have focused on species whose distributions do not encompass the tropical Andes. Thus, the influences of these climatic dynamics on the evolutionary history of tropical Andean rodent species remain unknown. The effects of these climatic changes were addressed on Aepeomys lugens and A. reigi, two Thomasomyine endemics from the Cordillera de Mérida in the Venezuelan Andes. The past potential geographic distribution of both species was inferred using an ecological niche modeling approach. The estimations obtained indicated that the availability of the suitable climatic conditions for these taxa has varied in size and location during the last 140,000 years. The spatial projection of the niche models onto the climatic scenarios explored indicates that the effects over the historical distributions were smaller in A. lugens than in A. reigi. These results show that the current geographic distribution of both Andean rodents conceals complex biogeographic histories, and characterizations of the demographic history and genetic diversity will be required to understand the evolution of the genus Aepeomys in the Andes. [ABSTRACT FROM AUTHOR]

Even when environmental variation over time and space is commonly considered as an important driver of population divergence, few evaluations of intraspecific genetic variation explicitly assess whether observed structure has been caused by or is correlated with landscape heterogeneity. Several phylogeographic studies have characterized the mitochondrial diversity of Abrothrix olivacea, but none has incorporated landscape genetics analyses and ecological niche modeling, leaving a gap in the understanding of the species evolutionary history. Here, these aspects were addressed based on 186 single nucleotide polymorphisms, extracted from sequences of 801 bp of Cytb gene, gathered from 416 individuals collected at 103 localities in Argentina and Chile. Employing multivariate statistical analyses (gPCA, Mantel and Partial Mantel Tests, Procrustes Analysis, and RDA), associations between genetic differences and geographic and climatic distances were evaluated. Presence data was employed to estimate the potential geographic distribution of this species during historical and contemporary climatic scenarios, and to address differences among the climatic niches of their main mitochondrial lineages. The significant influence of landscape features in structuring mitochondrial variability was evidenced at different spatial scales, as well as the role of past climatic dynamics in driving geographic range shifts, mostly associated to Quaternary glaciations. Overall, these results suggest that throughout geographic range gene flow is unevenly influenced by climatic dissimilarity and the geographic distancing, and that studied lineages do not exhibit distributional signals of climatic niche conservatism. Additionally, genetic differentiation occurred by more complex evolutionary processes than mere disruption of gene flow or drift. [ABSTRACT FROM AUTHOR]

Although the mitochondrial diversity of Abrothrix olivacea has been widely studied, the phylogeographic structure and the historical demography of this species are still not fully comprehended. With the aim of better understanding these aspects, a 801 bp fragment of the Cytb gene sampled in 416 individuals (202 from Argentina and 214 from Chile) collected at 103 localities (46 from Argentina and 57 from Chile) was analyzed. This represents the most geographically and numerically widespread sampling used until now to study the mitochondrial variation of this species. The results obtained indicate that the mitochondrial diversity of A. olivacea is structured in four main phylogroups with barely overlapped geographic ranges that replace each other mostly latitudinally from northern Chile (ca. 18° S) to the Isla Grande of Tierra del Fuego (ca. 56° S). In turn, each mitochondrial phylogroup shows distinct crown ages and signals of asynchronous population expansions. Overall, the results obtained here improve the delimitation of the geographic ranges of the intraspecific mitochondrial lineages of this species and suggest that its subspecific taxonomy require an exhaustive revision. In addition, the pattern of genetic structure described here for the Patagonian-Fuegian populations differs from that evidenced by the characterization of nuclear variation. This mito-nuclear discordance could be associated with neutral demographic dynamics and the vagaries of allele sorting and suggest that the evolutionary history of this species could be more complex than that reconstructed from the isolated study of mitochondrial or nuclear variability. [ABSTRACT FROM AUTHOR]

The colored polygons depict the approximate geographic distributions of the subspecific taxonomic scheme derived from the Cytb data. d. Map of southern South America with the ecoregions according to Olson et al. (2001) depicting the genetic clusters identified by Giorello et al. (2021) based on a nuclear SNP genomic assessment. Bayesian posterior probability (PP) and Bootstrap (BP) values are presented for the main clades discussed here. b. Graphic representation of the genetic clusters identified with the DAPC (see Fig. [Extracted from the article]

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 presence of shrews of the genus Cryptotis in the most northern spur of the eastern branch of the Venezuelan Andes was initially known by two specimens collected in the Macizo de Guaramacal. Both specimens were initially assigned to C. thomasi and subsequently to C. meridensis . Posteriorly, additional specimens were collected in several localities of the Cordillera de Mérida, from the Páramo la Cristalina up to the Sierra de Barbacoas. These samples are not referable to C . thomasi , C . meridensis or another Colombian or Venezuelan species, but on the contrary represent an undescribed species, belonging to the C . thomasi species group. The new species is distinguished by a unique set of morphological characters; among the most remarkable features are the lateral displacement of the foramen of the posterior edge of the tympanic process of the petromastoid, a large fourth unicuspid, visible in lateral view of the skull, and a tricuspulate lower incisor. After the recognition of this species, the number of small-eared shrews of the genus Cryptotis increases to 43, 16 of which occur in South America. [ABSTRACT FROM AUTHOR]

The Sierra de Perijá is the northern extension of the Cordillera Oriental of the Andes and includes part of the border between Colombia and Venezuela. The population of small-eared shrews (Mammalia, Eulipotyphla, Soricidae, Cryptotis) inhabiting the Sierra de Perijá previously was known from only a single skull from an individual collected in Colombia in 1989. This specimen had been referred to alternatively as C. thomasi and C. meridensis, but a more precise definition of the known Colombian and Venezuelan species of Cryptotis has since excluded the Sierra de Perijá population from any named species. The recent collection of a specimen from the Venezuelan slope of Sierra de Perijá prompted us to re-evaluate the taxonomic status of this population and determine its relationship with other Andean shrews. Our examination of the available specimens revealed that they possess a unique suite of morphological and morphometrical characters, and we describe the Sierra de Perijá population as a new species in the predominantly South American C. thomasi species group. Recognition of this new species adds to our knowledge of this genus in South America and to the biodiversity of the Sierra de Perijá. [ABSTRACT FROM AUTHOR]

We report a predation event of a Northern Grass Mouse (Necromys urichi) by a Ferruginous Pygmy-Owl (Glaucidium brasilianum) in the Cordillera de la Costa, northern Venezuela. The event consisted in the observation of an adult Ferruginous Pygmy-Owl holding with both legs an individual of N. urichi, which had already been decapitated and partially eaten. Glaucidium brasilianum eats insects and small vertebrates, and it is also able to capture and consume preys such as birds and mammals that exceed its size. In view of the behaviour of G. brasilianum and the high abundance that N. urichi exhibited in the montane ecosystems of the Cordillera de la Costa, it is likely that this rodent represents an important item in the diet of this owl, which neotropical populations are poorly known. [ABSTRACT FROM AUTHOR]

Our understanding of the limits of animal life is continually revised by scientific exploration of extreme environments. Here we report the discovery of mummified cadavers of leaf-eared mice, Phyllotis vaccarum , from the summits of three different Andean volcanoes at elevations 6,029–6,233 m above sea level in the Puna de Atacama in Chile and Argentina. Such extreme elevations were previously assumed to be completely uninhabitable by mammals. In combination with a live-captured specimen of the same species from the nearby summit of Volcán Llullaillaco (6,739 m) 1 , the summit mummies represent the highest altitude physical records of mammals in the world. We also report a chromosome-level genome assembly for P. vaccarum that, in combination with a whole-genome re-sequencing analysis and radiocarbon dating analysis, provides insights into the provenance and antiquity of the summit mice. Radiocarbon data indicate that the most ancient of the mummies are, at most, a few centuries old. Genomic polymorphism data revealed a high degree of continuity between the summit mice and conspecifics from lower elevations in the surrounding Altiplano. Genomic data also revealed equal numbers of males and females among the summit mice and evidence of close kinship between some individuals from the same summits. These findings bolster evidence for resident populations of Phyllotis at elevations >6,000 m and challenge assumptions about the environmental limits of vertebrate life and the physiological tolerances of small mammals. Storz et al. report the discovery of desiccated cadavers ('mummies') of Andean leaf-eared mice on the summits of several >6000 m Atacama volcanoes, elevations that were assumed to be uninhabitable by mammals. Genomic and radiocarbon data shed light on the origin of the mummies and provide a new understanding of the limits of vertebrate life. [ABSTRACT FROM AUTHOR]

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]

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. [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]