The physiology of the long-furred woolly mouse opossum (Micoureus paraguayanus) conformed to that of other marsupials. Body temperature at thermoneutrality (all values reported as mean ± SE) was 33.3°C ± 0.3°C and basal metabolic rate was 0.760 ± 0.074 ml O₂ g⁻¹ h⁻¹. Opossums were thermolabile at low ambient temperature (T_a) but still maintained a considerable differential between body temperature and T_a, with an increase in metabolic heat production as T_a decreased. This was accommodated by an increase in minute volume, mediated by an increase in both respiratory frequency and tidal volume at low T_a. Basal respiratory frequency was 34.2 ± 3.8 breaths/min and tidal volume was 1.62 ± 0.28 ml; minute volume was 53 ± 7 ml/min. Oxygen extraction remained constant at 13.6% ± 1.1%. Wet thermal conductance was high (0.338 ± 0.091 ml O₂ g⁻¹ h⁻¹ °C⁻¹; 185% of predicted) but conformed statistically to that of other marsupials. A positive relationship existed between ambient temperature and evaporative water loss; standard evaporative water loss was 2.03 ± 0.21 mg H₂O g⁻¹ h⁻¹. The point of relative water economy was 11°C, the lowest yet measured for a marsupial. We found no evidence that this South American marsupial had an elevated metabolic physiology, as might be expected from its neotropical distribution and sympatry with placental mammals. Clearly, marsupials can survive alongside placental mammals without any specific physiological adaptation, although this ability may be restricted to species with generalized low-energy ecological niches. DOI: 10.1644/09-MAMM-A-138R.1.

Body size is correlated with virtually every morphological, physiological, and life-history trait in mammal species. As a consequence, estimates of body size of fossil species are often used for paleoecological reconstructions. Characters used as proxies for body mass in extinct species include teeth, skull, and skeletal measurements. We show that the body-mass estimates of extinct species from living taxa can be misleading and depend largely on the morphological variable selected as a proxy for body mass. We also discuss statistical tools that are available to assess the accuracy of body-mass estimates in extinct species. Here, we focus on the revision of the mass estimate of the giant Miocene fossil rodent Phoberomys pattersoni (Venezuela), the 2nd largest rodent ever reported, with an estimated body mass between 436 and 741 kg. This is far beyond the range of average body masses in living rodents, which vary from several grams to 40 kg. We conclude that body mass of Phoberomys was most likely overestimated. The species P. pattersoni likely weighed between 220 kg and 280 kg, the mass of a horse or a large antelope.

New well-preserved fossils from Peru reveal details of the dentition and morphology of the mandible and rostrum in 2 late middle to early late Miocene beaked whales (Cetacea, Odontoceti, Ziphiidae). Apical mandibular tusks are present in both Nazcacetus urbinai and Messapicetus sp. In the former the tusks are associated with a strong reduction of the postapical dentition, whereas in Messapicetus sp. a complete series of functional upper and lower teeth is retained. The larger sample of Messapicetus sp. from a single locality and age reveals intraspecific variation in size and shape of the tusks and surrounding structures. In addition, the rostrum of Messapicetus displays thickened premaxillae, dorsally closing the mesorostral groove. By comparison with modern beaked whales, most of them highly sexually dimorphic at the level of the tusks and rostrum, we propose that the tusks of Messapicetus were used in intraspecific fights between adult males. Strengthening of the rostrum through the dorsal closure of its transverse section would have reduced the risk of fractures when facing impacts.

Fluctuating asymmetry, random departure from perfect symmetry in bilateral traits, has been proposed as an indirect indicator of individual quality. Sexually selected traits, such as deer antlers, are hypothesized to demonstrate decreasing level of fluctuating asymmetry with increasing trait size and decreasing level of fluctuating asymmetry with increasing age. These hypotheses have been previously tested for antlers using linear measurements to quantify fluctuating asymmetry. However, antlers are complex, 3-dimensional traits making it difficult to quantify all forms of visual asymmetry using traditional, linear measurements. It is this visual asymmetry that would be assessed by potential mates and rivals. Therefore, we created 3-dimensional computer models of white-tailed deer (Odocoileus virginianus) antlers to measure visual fluctuating asymmetry. Asymmetry measures of various antler traits were computed using the models by measuring distances from the trait to a vertical and horizontal plane created using coordinate points generated within the model. We found no association between degree of fluctuating asymmetry and trait size, nor was any association found between degree of fluctuating asymmetry and age using either the 3-dimensional measures of asymmetry or traditional, linear measures of asymmetry. Examination of these data suggests that fluctuating asymmetry of white-tailed deer antlers is not a reliable indicator of quality.

In many mammals large size is more important for male than female fitness, which may select for bimaturation with males maturing later and attaining a larger size. In bats, however, sexual dimorphism in size tends to be reversed, with females being larger. Exceptions to this can be found, notably in the genus Pteropus. I examined growth, maturation, and sexual size dimorphism in free-ranging gray-headed flying foxes (Pteropus poliocephalus) to better understand the links between life history, behavior, and ecology of this large, polygynous Australian fruit bat. Juveniles left the colony independently at dusk when their forearm length and body mass exceeded 130 mm and 301 g, or 79% and 39% of mean adult dimensions, respectively. Mean forearm length and mass of these volant juveniles increased by 0.72 mm and 4.9 g per week, independent of sex. However, significant dimorphism and bimaturation were observed: adult males averaged 1.8–4.5% larger for skeletal measurements and 25% heavier than adult females, but 40% heavier at the start of the breeding season. Males also were sexually mature at a larger skeletal size and at a higher mass (604 g) than females (514 g). Sexual size dimorphism in P. poliocephalus likely results from prolonged male growth and delayed maturation. Intrasexual selection among males for fighting ability is implicated as the cause for dimorphism, together with a release of female size from the constraints posed by carrying heavy young. Bimaturation likely results from the high costs of maintaining mating territories that confer few reproductive benefits for small males.

Temperate bat species are well-known predators of nocturnal insects; however, their role in forest nutrient cycling is unclear. We tested the “nutrient hot spot” hypothesis, which suggests that colonial bats should create nutrient peaks in and around their roosts via guano deposits. We measured the mass and nitrogen content of guano deposited outside of roosts occupied by maternal colonies of 2 tree-roosting species, Myotis septentrionalis and M. sodalis. We assessed whether these measures were related to date, species, and bat abundance using least-squares regression. We then compared the expected amount of nitrogen deposited over a maternity season to the expected annual amount of nitrogen mineralized by a forest. Mass of guano deposited increased with bat abundance and corresponded to periods of parturition and lactation. Nitrogen mineralization near a large roost of bats can be 380% of that due to decay of leaf litter. Such nutrient peaks could influence patterns of forest vegetation by impacting growth of herbaceous plants and development of tree seedlings, and the magnitude of these effects should increase in nutrient-poor areas.

The use of habitat selection models to predict the likely occurrence of wild populations is an important tool in conservation planning and wildlife management. The goal of our study was to build habitat selection models for the dusky dolphin (Lagenorhynchus obscurus) in Golfo Nuevo, Argentina. Random transects were surveyed by boat in 2002–2007. A grid of 1.5 × 1.5-km squares (cells) was constructed for the study area. We characterized each cell by depth, slope, distance from shore, sea-surface temperature, concentration of chlorophyll a, presence–absence of dolphins, and a coefficient of use by dusky dolphins. Models were developed for warm and cold seasons and for all data combined. Data collected during 2002–2005 were pooled to develop the model, and data collected during 2006–2007 were used for cross-validation. Logistic regression with a binomial error structure and a logit-link function were used to relate the presence of dolphins to habitat variables. Models with gamma structure and log-link function were used to relate area use to habitat variables. Models were selected with deviance analysis and Akaike's information criterion. All predictor variables significantly influenced distribution of dolphins, which preferred steep areas at depths of 50–60 m, distance from shore of 3–5 km, and higher values of chlorophyll. In the warm season dolphins preferred colder waters and avoided deeper and warmer areas. Dusky dolphins in Golfo Nuevo are exploited as a tourism resource, and selected models should be considered when deciding the impact of dolphin-watching activities on management.

Analyses of feces, stomach contents, and regurgitated pellets are common techniques for assessing diets of vertebrates and typically contain more than 1 food item per sampling unit. When analyzed, these individual food items have traditionally been treated as independent, which represents pseudoreplication. When food types are recorded as present or absent, these samples can be treated as multinomial vectors of food items, with each vector representing 1 realization of a possible diet. We suggest such data have a similar structure to capture histories for closed-capture, capture–mark–recapture data. To assess the effects of landscapes and presence of a potential competitor, we used closed-capture models implemented in program MARK into analyze diet data generated from feces of swift foxes (Vulpes velox) and coyotes (Canis latrans) in northwestern Texas. The best models of diet contained season and location for both swift foxes and coyotes, but year accounted for less variation, suggesting that landscape type is an important predictor of diets of both species. Models containing the effect of coyote reduction were not competitive (ΔQAIC_c  =  53.6685), consistent with the hypothesis that presence of coyotes did not influence diet of swift foxes. Our findings suggest that landscape type may have important influences on diets of both species. We believe that multinomial models represent an effective approach to assess hypotheses when diet studies have a data structure similar to ours.

Where dispersal is energetically expensive, feeding and food availability can influence dispersal success. The endemic Prince of Wales northern flying squirrel (Glaucomys sabrinus griseifrons) inhabits a landscape mosaic of old-growth, 2nd-growth, and clear-cut stands, with the latter 2 representing energetically expensive habitats. We estimated the diet of flying squirrels using stable isotope and fecal analyses, determined whether food availability varies among forest stands, and assessed the likelihood of foraging across a managed landscape given the distribution of foods on Prince of Wales Island (POW), Alaska. Both stable isotope and fecal analyses revealed that conifer seeds, lichens, and fungi were the main dietary items consumed and assimilated by flying squirrels. Similarly, soil macroinvertebrates were consumed by squirrels, whereas berries were not. Nonetheless, although examination of stable isotope data suggested that squirrels assimilated few nutrients from truffles, this food source was among the most frequent diet items in feces, probably because flying squirrels assimilate elements other than nitrogen from fungi. Our surveys showed that conifer seeds, truffles, and lichens were more prevalent in old-growth than 2nd-growth and clear-cut habitats. Thus, our results indicate that diet and availability of food items on POW may influence foraging success and dispersal movements of G. sabrinus across fragmented landscapes because of limited availability of food resources in the managed habitats.

The golden takin (Budorcas taxicolor bedfordi) is a large, forest-dwelling ungulate endemic to the Qinling Mountains, China. A recent study showed that golden takin move to different elevations depending on the season, remaining at high elevations in summer, intermediate elevations in winter, and at low elevations for short periods in spring and autumn. We proposed the following hypotheses: seasonal movement of golden takin is a response to a shift in vegetation phenology, which affects forage quality; and uphill movement of golden takin in winter is an adaptation to select areas with higher thermal energy. To test the 1st hypothesis we used relative phenological development derived from the normalized difference vegetation index time series to link seasonal shifts in vegetation phenology to movement patterns of golden takin. Golden takin descended to a low elevation with the greening of vegetation in early spring, ascended to a high elevation in late spring, and descended again in autumn as vegetation senesced. To test the 2nd hypothesis we compared thermal energy in the winter habitat with that in other areas of the home range, using the amount of solar radiation calculated by a solar radiation model. In winter, preference of the golden takin for exposed southern slopes at intermediate elevations correlated closely with areas of higher solar radiation. Our results indicate that solar radiation and vegetation phenology are critical factors in driving seasonal movement of golden takin.

Patterns of space use can provide valuable insights into patterns of activity and social structure of poorly known mammal species. From April 2005 to November 2006 we radiotracked a low-density population of ferret badgers (Melogale moschata) in central China. Fourteen males and 8 females were caught. Nine of these individuals (6 males and 3 females) were followed; mean (± SD) 100% minimum convex polygon (MCP100) home range was 128.3 ± 131.9 ha, with no difference between sexes. For MCP100, neither nightly movement distances nor daily activity patterns revealed significant variation due to sex or season. Core areas (50% minimum convex polygon [MCP50]) were typically located centrally within overall home ranges. Two distinct groups of animals were evident in the radiotracked subpopulation, one consisting of 7 adults and the other composed of at least the 2 remaining collared badgers with field signs of additional badgers from the periphery of our study area. Within each group, home ranges of radiocollared individuals overlapped extensively (62.1% ± 26.5% for MCP100; 59.6% ± 23.0% for MCP95; 37.1% ± 24.5% for MCP50), and up to 4 adults per group shared the same burrow (sett). We consider the implications of our data for understanding of mustelid sociospatial behavior.

Knowledge of the local and migratory movements of humpback whales (Megaptera novaeangliae) from New Caledonia is very limited. To investigate this topic, we attached satellite-monitored tags to 12 whales off southern New Caledonia. Tag longevity ranged from 1 to 52 days (X¯  =  22.5 days). Tagged whales generally moved to the south or southeast, with several spending time in a previously unknown seamount habitat named Antigonia before resuming movement, generally toward Norfolk Island or New Zealand. However, 1 female with a calf traveled the entire length of the western coast of New Caledonia (∼450 km) and then west in the direction of the Chesterfield Reefs, a 19th century American (“Yankee”) whaling ground. None of the New Caledonia whales traveled to or toward eastern Australia, which is broadly consistent with the low rate of interchange observed from photo-identification comparisons between these 2 areas. The connections between New Caledonia and New Zealand, together with the relatively low numbers of whales seen in these places generally, support the idea that whales from these 2 areas constitute a single population that remains small and unrecovered.

I examined dispersal, home-range establishment, and home-range fidelity in American black bears (Ursus americanus) using radiotelemetry data for individuals whose natal ranges were known (n  =  43), individuals whose natal ranges were identified using microsatellite DNA (n  =  13), and individuals whose natal ranges were unknown (n  =  86). Dispersal was highly male-biased. Nearly all males emigrated 22–62 km from their natal ranges between the ages of 1 and 3 years. Some males continued to float, moving their ranges 15–68 km between successive years. Most males settled into a permanent home range by age 4 years, and all males settled by age 7 years. One 8-year-old male apparently did not disperse and resided only 7 km from his natal range. Females were more philopatric and settled 0–7 km from their natal ranges. Only 1 female moved her range >20 km at the age of 5 years. The adaptive significance of male-biased natal dispersal is discussed.

During 1994–2007 a total of 156,416 raccoons was live-captured in Ontario, Canada, as part of mark–recapture studies to estimate raccoon density during rabies-control operations. Mean density in southern Ontario ranged between 3.4 and 13.6 raccoons/km² when density in northern Ontario was <1.5 raccoons/km². Raccoon density also was significantly higher in mixed cropland and deciduous habitats than in large tracts of deciduous forest in southern Ontario. Raccoons generally travelled <5 km between years during 1994–1997 mark–recapture movement studies in Niagara; however, movements as great as 45 km and among-year differences in movements were observed. Raccoons in rural habitats also moved more extensively than those in urban areas in 1994. Mean home range (minimum convex polygon) for raccoons in eastern Ontario during 2003–2007 was 3.9 km² for very-high-frequency–collared raccoons and 3.4 km² for global positioning system–collared raccoons. Mean movement from the release site by collared raccoons over the study period was 1.5 km with the longest movement being 10.3 km. No single habitat was used more or less by collared raccoons than expected. Survival of radiocollared raccoons over the course of the study was 0.62 with survival of raccoons initially captured and released as juveniles and adults being an average of 964 and 786 days. Knowledge of the ecology of raccoons should be used during planning for disease management, and was critical to evaluating the success of rabies-control programs in Ontario, Canada.

We investigated the ectoparasitic mite loads (Macronyssus: Macronyssidae: Acarina) on 2 species of flat-headed bats, Tylonycteris pachypus and T. robustula (Mammalia: Chiroptera: Vespertilionidae) in 2 counties of Guangxi Province, southern China, from 2002 to 2005. In Longzhou County both species of bat occur sympatrically, but only T. pachypus occurs in Ningming County. Individuals of the smaller species (T. pachypus) harbored significantly more mites than did those of T. robustula. In both species males harbored more mites than nonreproductive females, pregnant females had more mites than lactating and nonreproductive females, and juveniles harbored more mites than adults. Mite load on both species of bats showed significant seasonal variation, declining from spring to winter. No correlation was found between mite load and size of the host colony. We discuss our findings in relation to the ecology and biology of both hosts and parasites.

Given worldwide rapid human population growth resulting in degradation or loss of habitats, it is important to understand how anthropogenic factors affect species presence and activity, and consequently, how well species tolerate or adapt to anthropogenically altered environments. This study, conducted in Panama, focuses on aerial insectivorous bats, a highly mobile and ecologically important, but largely understudied group. Acoustic monitoring was used to investigate habitat use in a tropical forest–town interface and microhabitat use around streetlights differing in wavelength (type of light) and accessibility (distance to vegetation). Plasticity in microhabitat use also was examined in relation to season and moonlight. We recorded a total of 25 aerial insectivorous bat species in the study area and found a subset of 20 species in town of which 18 frequently foraged around streetlights. Bat activity (passes/min) was lowest at the forest site, highest at streetlights, and intermediate in the dark areas of town. General bat activity at streetlights was concentrated at bluish-white lights compared to yellow-white and orange lights. However, bats revealed species-specific microhabitats with regard to light type, distance to vegetation, and relative light intensity. Season and moon phase affected microhabitat use around streetlights leading to microhabitat plasticity of individual species. Thus, in the forest–town interface most, but not all, aerial insectivorous bats were present in town and regularly foraged around streetlights, suggesting a species-specific tolerance for habitat alteration. Bats foraging at streetlights used microhabitats, and some species even changed microhabitats, according to season or moon phase. This indicates species-specific requirements for microhabitats and the importance of preserving habitat heterogeneity.

We evaluated long-term patterns of human-caused mortality among free-living spotted hyenas (Crocuta crocuta) in a Kenyan game reserve and also assessed nonlethal anthropogenic effects on hyena behavior. We monitored naturally occurring vigilance in 2 clans of hyenas, 1 disturbed and the other undisturbed. The disturbed clan, living on the edge of the reserve, experienced much human disturbance from both tour vehicles and livestock grazing, whereas the undisturbed clan, living in the center of the reserve, also experienced tour vehicles but no livestock grazing. The proportion of all deaths with known causes that could be attributed to humans increased between 1988 and 2006 in the disturbed population; humans caused no mortality in the undisturbed population. Disturbed hyenas were more than twice as vigilant when resting, and they nursed their young closer to bushes, than undisturbed hyenas. Disturbed hyenas also were most vigilant on days when livestock were present in their territory, but we observed no effects of tourism on hyena vigilance. We next conducted playback experiments in which we used cowbells as treatment sounds and church bells as control sounds to determine whether hyenas from the 2 clans responded differently. After hearing cowbells, disturbed hyenas increased their vigilance more than did undisturbed hyenas. However, disturbed hyenas also increased their vigilance after hearing church bells, suggesting that disturbed hyenas may exhibit heightened responsiveness to a wide array of anthropogenic sound stimuli. Our findings suggest that human activities related to pastoralism are having measurable effects on hyena mortality, and that hyenas appear to be responding to this threat by modifying their behavior.

A sample of 834 female New Zealand sea lions (Phocarctos hookeri), which were aged and measured, was obtained between 1998 and 2001. In addition, the reproductive histories of 505 marked females from the Auckland Islands were recorded from 1998 to 2005. These data sets were used to investigate growth and reproductive rates. Length and weight ranged from 134 to 197 cm and 49 to 156 kg, respectively. A Gompertz growth model best described growth and predicted that females attained 90% of asymptotic length (161.7 cm) and weight (112.0) at ages 4 and 11 years, respectively. No significant differences were found in growth rates among years, nor between the 2 major breeding colonies in the Auckland Islands. Females reproduced between the ages of 3 and 26 years, with evidence of reproductive senescence starting at age 23 years. Although females up to age 28 years were observed, no females over 26 years were recorded as reproductive. Age-specific reproductive rate p(x) increased rapidly between ages 3 and 7 years, reached a plateau between ages 7 and 23 years, and then declined rapidly after age 23 years. Mean observed reproductive rate was p(x)_3–28  =  0.67 (SE  =  0.01). This is the 1st robust estimate of reproductive rate for this species, is consistent with rates reported for other sea lions, and is considerably lower than assumed rates used in recent population modeling for this species. This calls into question the current method for estimating levels of sustainable bycatch. Low growth and reproductive rates are consistent with a population that is occupying a marginal foraging environment. These factors, along with a recent significant decline in pup production, suggest that current management is insufficient to ensure population stasis, let alone meet the statutory goal of recovery.

Establishing accurate demographic information for free-ranging populations of animals is difficult without knowledge of individual chronological age. We estimated the birth dates of 743 koala (Phascolarctos cinereus) joeys at 3 sites in Queensland, Australia, using body mass obtained from a reference population with known birth dates. From these age estimates we compared the annual distribution of births across calendar months. At all 3 locations about 60% of births occurred between December and March. The annual pattern of births was identical for males and females within locations, but overall annual patterns of births differed between the southern and northern sites. We conclude that koalas can bear offspring in every month of the year, but breed seasonally across Australia, and that a sex bias in the timing of births is absent from most regions.

The colony of Brazilian free-tailed bats (Tadarida brasiliensis) at Carlsbad Cavern, New Mexico, is a well-known example of this highly gregarious and conspicuous species in North America. For nearly a century researchers have tried to estimate the size of this colony, but different census methods and lack of repeatability have resulted in questionable estimates that have given rise to poorly understood but highly popularized, long-term population trends for this migratory species. In this study we present accurate seasonal estimates of colony size based on a recently developed census method—thermal infrared imaging and computer vision analysis. The size of the colony was estimated several times monthly from March through October 2005. Our estimates range from 67,602 to 793,838 bats, values that are orders of magnitude lower than the largest historic estimates. Consecutive estimates of nightly emergences show fluctuations of as many as 291,000 individuals, indicating that colony composition is considerably more dynamic than previously thought. Our results, combined with a quantitative analysis of emergence behavior, question the validity of early historic estimates that millions of bats once roosted in this cave and suggest that the long-term pattern of decline reported for this species might not be as severe as currently thought.

Little is known about abundance–climate relationships for animals because few long-term field studies address the issue. We present results from a 20-year study of abundance of Peromyscus leucopus (white-footed mouse) and Microtus pennsylvanicus (meadow vole). P. leucopus exhibited a biennial cycle with an overall population increase. M. pennsylvanicus did not exhibit a population cycle, and population size declined. We attribute long-term changes in abundance of both species to succession from grass-dominated to tree-dominated vegetation. The only significant association we found between abundance of either species over 20 years and 4 climate variables was a positive relationship between M. pennsylvanicus and summer precipitation. However, all but 1 of the potential abundance–climate relationships were significant when temporal subsets of the original data were analyzed. Weak associations may exist between climate and abundance that are contingent upon other unidentified factors, which further suggests that abundance–climate correlations are sensitive to the particular time frame of a study.

Population fluctuations can have a pronounced effect on genetic diversity, behavioral adaptations, and population viability in small mammals. Little is known as to how genetic diversity is associated with population dynamics, and whether genetic bottlenecks or genetic resilience occur in fluctuating populations of small rodents. Using DNA microsatellites and 6 years of data, we investigated changes in genetic diversity of the greater long-tailed hamster (Tscherskia triton) at 2 sites in the North China Plain. Genetic diversity was measured as mean number of alleles per locus (N_a), allelic richness (A), expected heterozygosity (H_E), and observed heterozygosity (H_O). Genetic diversity changed rapidly with changes in population density, and the relationship was positive. A bottleneck effect was detected only in some low-density years. Our results demonstrate an obvious genetic resilience and capacity for recovery in this species. We discuss this pattern in the context of dispersal and other behaviors of greater long-tailed hamsters, and how agriculture-related disturbance affects their genetic diversity.

Dispersal and gene flow are significant components of metapopulation structure and dynamics. We examined gene flow in the pygmy rabbit (Brachylagus idahoensis), a sagebrush specialist that occurs in small, isolated populations in the Great Basin region and is believed to have limited dispersal abilities. We examined genetic diversity, gene flow, and population genetic structure, and investigated the effects of putative barriers to gene flow in 8 sample locations within 2 study areas in Idaho during 2002–2006. Potential barriers included secondary roads, highways, creeks, and agricultural pastures. Distance between sample locations ranged from 0.5 to 32 km. We expected that gene flow would be limited and that moderate levels of genetic structure would be apparent among sample locations separated by barriers and distances over several kilometers. However, analyses based on 15 microsatellite loci from 239 rabbits revealed low to moderate levels of genetic differentiation among sample locations. Bayesian cluster analyses suggested that sample locations separated by <14 km comprised 1 genetic cluster with high levels of gene flow among sample locations within clusters. We documented no significant evidence of a sex bias in dispersal based on sex-specific F_ST among sample locations, and relatedness (r), mean assignment index (mAI), and variance of assignment index (vAI) within sample locations; however, spatial autocorrelation suggested that juvenile females might disperse farther than males. These results indicate that dispersal capabilities of pygmy rabbits greatly exceed previous estimates, and that creeks and roads were not effective barriers to gene flow in our study areas.

Pteronotus davyi, Davy's naked-backed bat, is a tropical bat whose current distribution in Mexico covers the watersheds of the Pacific and the Gulf coasts of Mexico, converges at the Isthmus of Tehuantepec, and continues into the Yucatan peninsula. We evaluated phylogeographic relationships among 18 populations in Mexico using data from the nucleotide sequence of the hypervariable II domain of the mitochondrial DNA control region from 105 specimens. Extant populations were distributed over 3 geographic regions (Pacific Coast, Gulf Coast, and Southeastern) that were delineated a priori according to floristic characteristics and biogeography. Coalescent simulations supported a phylogeographic model of 2 refugia situated in the south of Mexico (Arc and Soconusco refuges) during the late Pleistocene, followed by expansion into Pacific Coast, Gulf Coast, and Southeastern groups. The populations of the Southeast were genetically divergent from the Pacific and Gulf Coast populations, supporting the existence of 2 distinct lineages of P. davyi in Mexico, likely due to the Isthmus of Tehuantepec acting as a geographical barrier. Examination of our data revealed genetic differentiation of the Pacific and Gulf coastal groups but at a lower level relative to the Southeast. This pattern suggests that the Sierra Madre Occidental, Sierra Madre Oriental, and Sierra Madre del Sur act as physical barriers to dispersal for P. davyi.

This study describes in detail the phylogeographic pattern of the edible dormouse (Glis glis) a European rodent with pronounced hibernating behavior. We used sequences of 831 base pairs of the mitochondrial DNA cytochrome-b gene from 130 edible dormice collected at 43 localities throughout its distribution. Our results reveal presence of 3 main haplogroups: Sicilian, South Italian (restricted to the Calabrian region), and European (a widespread lineage corresponding to all remaining western, central, and eastern European populations). Examination of paleontological data confirms refugial regions for G. glis in the 3 Mediterranean peninsulas, although overall low genetic diversity is found. The low diversity of the European lineage is probably the result of a recent expansion (dated around 2,000 years ago) from a single refugium. Other factors, such as the ecological constraints on the species, may have caused genetic bottlenecks that reinforced the low genetic variability of G. glis. This work could have important implications for strategies to conserve the edible dormouse by defining important areas for their conservation.

As presently recognized, the genus Galea is composed of 3 species, G. musteloides, G. flavidens, and G. spixii. The most widely distributed species is G. musteloides (the common yellow-toothed cavy), ranging from southern Peru to southern Argentina and from sea level to over 4,000 m elevation. Our current taxonomic and systematic understanding of Galea is based primarily on morphological studies that have been limited in both taxonomic and geographic sampling. In this study phylogenetic analyses of sequences from the cytochrome-b gene were used to test hypotheses related to the content, limits, and systematic relationships within G. musteloides. Our data support restricting G. musteloides to the highlands of northwestern Bolivia, southeastern Peru, and extreme northeastern Chile. We elevate G. leucoblephara Burmeister, 1861, for populations occupying the lowlands of Bolivia and Paraguay to central Argentina, and we elevate G. comes Thomas, 1919, for populations from the Andes of southern Bolivia and northern Argentina. Our results also suggest the presence of a previously unrecognized form at midelevations in the southern Bolivian Andes. We find support for treating G. spixii campicola as a junior synonym of G. l. demissa and G. monasteriensis as a junior synonym of G. musteloides boliviensis. Most of the evolution of the taxa within the G. musteloides complex appears to have occurred in the Prepuna biogeographic province, with 2 independent vicariant events culminating in the separation of the G. musteloides, G. comes, and G. leucoblephara clades. Dating estimates suggest a late Miocene divergence between G. spixii and the G. musteloides group, followed by species-level divergence within the G. musteloides group during the Pliocene.

Spiny rats of the genus Clyomys Thomas, 1916, include 2 recognized species both described on the basis of a small number of specimens, C. laticeps (Thomas, 1909) comprised of the nominotypical form and subspecies C. laticeps whartoni Moojen, 1952, and C. bishopi Avila-Pires and Wutke, 1981. Univariate and multivariate analyses of craniodental measurements obtained from 78 adult specimens from 8 pooled geographic samples representative of the distributional range of Clyomys structured the samples morphometrically into 2 geographic groups, which do not correspond to the taxonomic units postulated in previous studies. These morphometric groups were checked against data on qualitative skull morphology and pelage coloration from 128 specimens in a search for patterns supporting the taxonomic recognition of the morphometric groups revealed. The morphometric and qualitative analyses do not corroborate the current taxonomic framework of the genus Clyomys, and indicate that C. bishopi is a junior synonym of C. laticeps.