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Copyright of Journal of Mammalogy is the property of Oxford University Press / USA 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 Mammalogy is the property of Oxford University Press / USA 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.)

Ctenomys is one of the most speciose genera among South American rodents, whose systematics have not yet been fully elucidated. One of the difficulties for clarifying the identity of its species is the limited information available on some of them, erected more than a century ago and of which only the original descriptions are known, generally very poorly detailed. Our study provides new information about Ctenomys coludo Thomas 1920, based on the collection of topotype specimens that allowed us to perform more detailed morphological and molecular analyses, and to compare them with the available information referred to the holotype, with specimens deposited in museum collections, and other species of the genus that have been proposed as related to C. coludo. Our results allow us to place C. coludo as a member of the mendocinus group, proposing C. famosus Thomas, 1920 as a junior synonym for C. coludo. We also recognize Ctenomys johannis as a valid and full species, and provide unpublished information on it from the collection of specimens at the type locality. Thus, we add new areas for the distribution of these species and present their phylogenetic relationships. [ABSTRACT FROM AUTHOR]

Atlantic Forest (AF) is amongst the most threatened forests in the world. To decide where conservation efforts should be focused to preserve species, assessment of ecological and biogeographic processes nowadays are crucial. Patterns of the distribution of organisms can provide an important source of information underlying the biogeographical history of a biota. Here, our main objective was to identify Areas of Endemism (AoE) for non-volant small mammals in the AF and to investigate if those AoE are covered by protected areas. We performed quantitative and qualitative approaches to delimit AoE and calculated the area overlaid by Conservation Units (CU) within each AoE. Our results supported the recognition of seven AoE for small mammals in the AF, which largely are congruent with previous studies undertaken on other organisms, thereby highlighting the importance of those regions as hotspots of endemism. Most of the AoE recovered in the present study have less than 12% of their territory covered by forest remnants, and less than 11% of their entire range is under legal protection. These findings bring to light an important discussion on how information pertaining to the representativeness of CU within regions of high endemicity could help to identify areas in need of urgent protection within a threatened biodiversity hotspot. [ABSTRACT FROM AUTHOR]

Small mammal assemblages from South America provide a unique opportunity to measure coexistence and niche partitioning between marsupials and placentals. We tested how these two major clades partition environmental resources by comparing stable isotopic ratios of similar sized Didelphidae and Sigmodontinae in four Brazilian biomes: Pampas grassland, Pantanal wetland, Cerrado woodland savanna, and Atlantic Forest. Generally, didelphid isotopic niche follows a scaling law, because we found an association between δ15N enrichment and body mass. Sigmodontines that primarily partition the environment via forest strata showed a greater intake of C4 or/and crassulacean acid metabolism (CAM) plants than didelphids, as reflected by their wider trophic niche. Values of δ13C were highest in savannas and grasslands (Cerrado and Pampas biomes), and values of δ15N were highest in the Atlantic Forest (in sigmodontines) and Pampas (in didelphids). While assessing patterns between the two major Brazilian biomes (Atlantic Forest and Cerrado), we found evidence of a broader trophic niche for both clades in the Cerrado. In the Atlantic Forest, niche occupation by Didelphidae was completely enclosed within the Sigmodontinae trophic niche. Both clades showed less overlap in the Cerrado, a less productive environment. Our results highlight the importance of a comparative framework and the use of stable isotopes for testing ecological questions related to how small mammalian communities partition their niche. [ABSTRACT FROM AUTHOR]

The big crested mastiff bat, Promops centralis , occurs in Central and South America, but knowledge of its ecology is limited due to its open space hunting strategy, making captures extremely challenging. Notwithstanding, members of the species produce echolocation calls that are easy to identify. After recording calls of P. centralis 1,500 km away from its known range in Brazil, we hypothesized that the distribution range of this species was probably greatly underestimated. To improve the accuracy of P. centralis ' real distribution, we employed acoustic surveys throughout parts of Brazil, conducted after a bibliographic review to gather additional records, and used MaxEnt to model the species' potential distribution. We have found that P. centralis has a much wider distribution in South America than previously thought, adding more than 3.8 million km2 to its former known area. We also describe an unusual vocalization pattern of P. centralis , with individuals emitting at least three very distinct but highly variable calls. This study shows that bioacoustic surveys and species distribution models can complement traditional methodologies in studying species that are difficult to capture, such as P. centralis , potentially contributing to more effective conservation and management plans. [ABSTRACT FROM AUTHOR]

The giant armadillo (Priodontes maximus) is the largest living armadillo. This naturally rare and poorly known species is endemic to South America and classified as "Vulnerable" by the IUCN. Here we explored aspects of the spatial ecology of P. maximus in Midwestern Brazil to gain insights on its ecology and biology to support conservation efforts. In 8 years, we identified 50 individuals of P. maximus and monitored 23 of them using telemetry methods. To characterize site fidelity and home range, we fitted individual continuous-time movement models and estimated Autocorrelated Kernel Density Estimates. We built a Structural Equation Model to evaluate how home-range area and daily displacement are related to each other, to sampling effort, and to individual characteristics. We estimated home-range overlap between pairs of different sexes using a bias-corrected Bhattacharyya coefficient. Finally, we formulated a canonical density estimation formula to characterize minimum population density. We gathered a total of 12,168 locations of P. maximus. The best-fitted movement models indicated site fidelity for all individuals and a median adult home-range area of 2,518 ha. Median adult daily displacement was 1,651 m. Home-range area scales positively with daily displacement and daily displacement scales positively with body mass. Median home-range overlap between pairs was low (4%) and adult females presented exclusive home ranges among themselves. Median minimum density was 7.65 individuals per 100 km2 (CI = 5.68–10.19 ind/100 km2). Our results are congruent with characterizing P. maximus as a generally asocial species, most likely promiscuous/polygynous, that establishes large, long-term home ranges, which grants the population a naturally low density. Spatial patterns and biological characteristics obtained in this study can be used to guide future conservation strategies for P. maximus in the Pantanal wetlands and elsewhere. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mammalogy is the property of Oxford University Press / USA 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 Mammalogy is the property of Oxford University Press / USA 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.)

On the basis of an adult individual collected in 1955 plus 3 mandibles of latest Holocene age, we describe a new living species of the amphibious rat Holochilus (Sigmodontinae, Oryzomyini) from west-central Mendoza Province, Argentina. The new species is characterized by its short tail, broad zygomatic plate with rounded anterior-superior comer, bony palate without excrescences, large mesolophostyle in the upper first molars and complex upper third molar shorter than the second, and lacking the hypoflexus. The morphological traits displayed by this new Holochilus combine features observed in both the H. brasiliensis and H. sciureus groups with others unique among the genus (e.g., absence of hypoflexus). This new species is the southernmost expression of the genus along the western side of its current range, where it appears isolated in the middle part of the Río Atuel. The finding reported here uncovers and highlights unexpected diversity in southern South American arid lands. [ABSTRACT FROM AUTHOR]

Phylogenetic affinities of the late Miocene echimyid †Pampamys emmonsae Verzi, Vucetich, and Montalvo, 1995 (Huayquerian South American Land Mammal Age, central Argentina), were analyzed. In the most-parsimonious tree obtained, subfamilies of Echimyidae were nonmonophyletic (except for Dactylomyinae). Two major clades were recovered. One of them included the living fossorial Eumysopinae and the extinct †Theridomysops. The other clade grouped the terrestrial eumysopines Thrichomys (punaré) and Proechimys-Trinomys (spiny rats), and the arboreal eumysopines Mesomys (spiny tree-rats) + Echimyinae-Dactylomyinae. †Pampamys was the sister genus of Thrichomys, suggesting the Huayquerian South American Land Mammal Age (>6.0 million years ago [mya] by biochronology) as a minimum age for the origin of the living genus. Both major echimyid clades recognized here are represented by simplified-molared species in the Huayquerian South American Land Mammal Age. This would be related to the expansion of open environments during the late Miocene, and the geographical bias of the fossiliferous Huayquerian deposits exposed mostly in southern South America. [ABSTRACT FROM AUTHOR]

Much of South America consists of diverse arid and semiarid regions characterized by high mammal endemism as a result of a complex interplay between place and lineage histories. In this review we summarize and highlight several biogeographical and ecological features of the small mammals of South America drylands, with special focus on the Monte Desert biome. We provide information on population characteristics, community structure, food and habitat use, and responses to disturbances. Major findings at different scales include the distinctiveness and high species turnover across South American drylands and Monte Desert ecoregions; synchronous population fluctuations with high variability between years; herbivory and omnivory as dominant trophic strategies; community structure organized through habitat and food segregation; and the importance of a landscape mosaic of grazed and ungrazed areas for maintenance of small and medium-sized mammal diversity. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mammalogy is the property of Oxford University Press / USA 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.)

The genus Myotis has undergone significant taxonomic revision since the advent of DNA sequencing techniques. Prior morphological examination of Myotis has indicated as many as 4 subgenera correlated with foraging strategies. Recent studies using mitochondrial DNA (mtDNA) sequence data have questioned the validity of these subgenera and have indicated that several taxa may require reevaluation as to their position within Vespertilionidae. Nevertheless, no study has used large-scale nuclear DNA sequencing to examine relationships within Myotis. We generated 4,656 base pairs (bp) of nuclear intron (PRKC1, STAT5A, and THY) and exon (APOB, DMP1, and RAG2) sequence data in addition to 2,866 bp of mtDNA sequence data to test previously hypothesized subgeneric groupings of Myotis. We included 21 species of Myotis from all morphological subgenera previously suggested, representatives of all subfamilies and tribes currently recognized in Vespertilionidae, and multiple representatives of all other families currently included in the superfamily Vespertilionoidea. We also included a representative of the rare African genus Cistugo, because significant doubt exists about its familial position. Our phylogenetic analyses did not support the morphologically defined Myotis subgenera and confirm that morphological similarities among Myotis are the result of convergent evolution. Divergence estimates derived from the total data set were concordant with previous studies, suggesting a middle Miocene trans-Beringian dispersal from Asia colonized North America, with subsequent South American colonization and diversification prior to the formation of the Isthmus of Panama 3-4 million years ago. Myotis latirostris fell outside of Myotis, and the high genetic distance separating it from other Myotis suggested that M. latirostris represented a distinct genus. The genus Cistugo, previously a subgenus within Myotis, fell basal to all vespertilionids, with a high genetic distance separating it from Vespertilionidae. We conclude that Cistugo should constitute a distinct family within Vespertilionoidea. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mammalogy is the property of Oxford University Press / USA 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.)

Crab-eating foxes (Cerdocyon thous) and pampas foxes (Lycalopex gymnocercus) are very similar in body size and food habits, with distributional ranges that overlap extensively in South America. We used camera-trap records of both species obtained at the Iberá Nature Reserve (INR), northeastern Argentina, to test the hypothesis that, when living in sympatry, they reduce competition by using different habitats and by being active at different times. Camera-trap records obtained at 2 additional sites inhabited by only 1 of these species, the Atlantic Forest of Misiones (AF) and Lihué Calel National Park (LCNP), were used to determine the activity patterns of these foxes when living alone. At INR, we set 41 camera-trap stations in 2 habitats (shrubland forest and flooded grassland), and in 2 treatments per habitat (with or without cattle). Three stations also were set in gallery forests. We obtained 540 photographs of crab-eating foxes (289 records) and 175 photographs of pampas foxes (115 records) in 1,521 camera-trap days. At LCNP, 27 camera-trap stations (1,002 camera-trap days) provided 109 records of pampas foxes. At AF, 195 camera-trap stations (11,689 camera-trap days) provided 103 records of crab-eating foxes. At INR, crab-eating foxes were more frequently recorded in forest habitats, whereas pampas foxes preferred opened grasslands. However, both species were found in all habitats and their recording rates were not negatively correlated. At INR, crab-eating foxes were nocturnal, with peaks of activity after dusk and before dawn, a pattern similar to that observed at AF and elsewhere. At INR, pampas foxes showed a peak of activity between 0000 and 0400 h and another between 1000 and 1300 h, a pattern that differed from that observed at LCNP and other places, where the species is mostly nocturnal. At INR, pampas foxes reduced their activity at times when activity of presumably dominant crab-eating foxes was high, which may facilitate their coexistence. [ABSTRACT FROM AUTHOR]

Phylogenetic relationships among individuals of 9 taxa of the Akodon varius group of sigmodontine (tribe Akodontini) rodents from Argentina, Bolivia, and Paraguay were examined using nucleotide sequence data from the entire 1,140 base pairs of the mitochondrial cytochrome-b gene to clarify the evolutionary relationships among lineages. Two individuals of A. iniscatus were included to test proposed relationships with the A. varius group. Maximum-parsimony, minimum-evolution, maximum-likelihood (TVM+I+G), and Bayesian analyses revealed 2 major clades, 1 composed of Yungas Forest taxa and 1 of non-Yungas (lowlands) taxa, and 8 wellsupported terminal clades. The Yungas Forest clade includes A. glaucinus, A. simulator, A. tartareus, and A. varius, which are recognized as distinct species. A. iniscatus was the most basal taxon in the lowlands clade containing A. dayi, A. toba, and A. dolores. Results support the proposed conspecificity of A. dolores and A. molinae, and the relationship within the A. varius group, which had not been clearly defined, is clarified. A. dayi and A. toba were found to be more closely related to A. dolores than to the Yungas Forest clade with which they historically have been associated. A low level of percent sequence divergence between A. toba and A. dolores suggests the need for a closer examination of this relationship, as does the high level of within-clade percent sequence divergence for A. dayi. [ABSTRACT FROM AUTHOR]

The taxonomy of gray four-eyed opossums, genus Philander, from northern South America is reviewed by means of comparative morphological and morphometric analyses. Two hundred eighteen specimens belonging to the following geographic samples were used: P. opossum opossum from French Guiana, Guyana, and Suriname; P. o. fuscogriseus from Central America and Colombia; P. andersoni from Colombia, Ecuador, Peru, and Venezuela; P. opossum from the Orinoco River delta (Venezuela); P. opossum from western Venezuela and eastern Colombia; and P. opossum from central Venezuela. Results obtained allow us to describe 2 new Philander species, one of which occurs in the floodplains of the Orinoco River delta and Paria Gulf (Venezuela), and the other of which is distributed in lowlands and uplands at the northern border of the Guiana Shield in Venezuela, as far as the Orinoco River, and foothills of Cordillera Oriental (Colombia) and Cordillera of Mérida (Venezuela). These new taxa were formerly considered to represent forms of P. opossum. In particular, it was suggested that specimens from the Orinoco delta constituted a subspecies of P. opossum, but this taxonomic pattern was not supported with detailed comparative analyses. Furthermore, the subspecific status of animals from western Venezuela and eastern Colombia was controversial and specimens from central Venezuela were considered as P. opossum but no empirical data supported this taxonomic identity. With respect to the other Philander species here considered, the 1st new species clearly differs in features concerning general skull shape and morphology, by its smaller skull size, relatively shorter tail, presence of a wide gray area in the underparts of the coat, and smaller and poorly defined supraorbital spots. The 2nd new species can be distinguished from the other Philander taxa by the general skull shape (relatively wide and short), specific skull traits, pale gray dorsum, and the characteristic coloration of ears (white with a wide black margin). [ABSTRACT FROM AUTHOR]