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A female usually obtains sufficient sperm to fertilize all her eggs from a single insemination, and mating can be costly. Yet, paradoxically, polyandry (i.e., copulation with 2 or more males) is common among organisms of all types, from amoebae through humans. Research that spanned 35 years shows that females of 3 species of prairie dogs benefited from polyandry by rearing more yearlings (a component of fitness that is my best estimate of female reproductive success); females of a 4th species (the black-tailed prairie dog [Cynomys ludovicianus]) evidently did not benefit from polyandry. Reasons for the higher production of yearlings by polyandrous females differed among species. For Gunnison's prairie dogs (C. gunnisoni), 3 other components of fitness contributed to the higher production of yearlings: a higher probability of conception and parturition, larger litter size at weaning, and a higher survivorship of offspring during the first 9 months after weaning. The 2nd and 3rd components applied to Utah prairie dogs (C. parvidens), but only the 1st component applied to white-tailed prairie dogs (C. leucurus). Female Gunnison's and white-tailed prairie dogs paid a cost from copulating with more than 1 male, because they were less likely to survive until the next mating season.
Shrews (Soricomorpha: Soricidae) are particularly vulnerable to mortality associated with small-mammal livetrapping. We compiled data on mortality rates and protocols from 16 different small-mammal studies and analyzed 16 years of livetrapping data from a single study in Algonquin Provincial Park, Ontario to assess factors affecting shrew mortality. In the comparison across studies, accidental mortality ranged from 10% to 93%. Mortality was lower in studies conducted in locations and at times of year with warmer average temperatures. We found no differences in mortality among bait and trap types across these 16 studies. In our intrastudy analysis from Algonquin Park, Sorex spp. experienced high mortality (81%) regardless of environmental conditions. In contrast, northern short-tailed shrews had low overall mortality (13%), but mortality increased on rainy nights and on colder nights when overnight temperatures dropped below 10°C. Comparisons between 2 trapping protocols within Algonquin Park suggested that both Blarina brevicauda and Sorex sp. experienced higher mortality in Sherman compared with Longworth traps, but these effects were confounded by other differences in methodology between studies. Although we found evidence consistent with some shrew mortality being caused by caloric constraints, experimental studies on bait supplements are necessary to test whether providing high-calorie baits is an efficient method to reduce the widespread shrew mortality that occurs in small-mammal livetrapping studies.
Accidental mortality is pervasive in small mammal livetrapping studies and presents a welfare concern for the particularly vulnerable shrews (Soricomorpha: Soricidae). Although small mammal researchers are aware of this problem and generally suspect that high mortality rates are caused by nutritional constraints and potentially high moisture requirements, these hypotheses have not been widely tested and the problem persists for lack of a practical solution. We conducted a field experiment to assess the effects of providing either high-energy palatable food or water supplements on mortality rates of Blarina brevicauda and Sorex spp. using standard small mammal livetrapping techniques. Water supplements had no effect on shrew mortality, but mortality rates declined by 49% for B. brevicauda and by 64% for Sorex spp. when sunflower seed bait was supplemented with 4 g of mealworms (Tenebrio molitor) compared to controls. Furthermore, the addition of mealworms as a bait supplement eliminated the adverse effect on mortality of the length of time that Sorex were in traps prior to release. The supplementation of live-trap baits with mealworms, therefore, represents a practical method for small mammal researchers to reduce accidental shrew mortality during small mammal livetrapping.
In short-term hoarding rodents, reproduction and hoarding often overlap and reproductive status can alter hoarding behavior. In long-term hoarders these activities are often separated seasonally. Therefore, annual and sex-specific variation in the timing of reproduction relative to the hoarding season may influence variation in the hoarding behavior of long-term hoarders. North American red squirrels (Tamiasciurus hudsonicus) clip and hoard white spruce (Picea glauca) cones each autumn, but have variation in reproductive timing such that in some years the hoarding season overlaps with reproductive activity. Over 4 years with naturally varying cone availability we quantified reproductive timing and hoarding behavior. Males completed mating 22–90 days before the onset of hoarding, whereas large numbers (45–86%) of females during large cone crop years weaned litters after hoarding commenced. Despite these differences in reproductive timing, across all years females clipped more cones than did males, whereas males hoarded more cones and had a higher propensity to larder-hoard than did females. Interestingly, in the years with large cone crops, females that weaned their litters later (during the hoarding season) did not have reduced hoarding or reproductive performance (offspring growth and recruitment) than females that weaned their litters earlier. In the year with the most extensive overlap between female reproduction and hoarding, lactating females did not differ from males in the amount of time they allocated to hoarding. In this year, the daily energy expenditure of lactating females during the hoarding season did not differ from that of males engaged in hoarding or from that of lactating females prior to the hoarding season. Hence, under high-resource conditions the competing demands of lactation and hoarding can both be sustained, allowing red squirrels flexibility in the separation between reproduction and hoarding.
The abundances and habitat preferences of peccaries in Neotropical forests are important to understand because these keystone species influence many aspects of the ecosystem. In the Caribbean lowlands of Costa Rica, we conducted walking surveys for ∼2 years to study the behavior and population trends of collared peccaries (Pecari tajacu), and found that peccaries are abundant at La Selva Biological Station and overall, detection rates were relatively constant through time. A stable estimate of detection rates was achieved only after 7–9 months of surveying. We found no habitat preferences between primary and secondary forest, yet there were some differences in group dynamics—group radius was larger and sighting distance was greater in primary forest, whereas the number of singletons was higher in secondary forest. More peccaries were seen closer to the laboratory clearing than at greater distances, for a variety of probable reasons: habituation to humans, lower predation and hunting pressure, and various environmental and habitat factors. Peccary groups had spatially clumped distributions across the landscape and were more active diurnally than nocturnally. Collared peccary densities are relatively high at La Selva compared to other Neotropical sites, with the exception of Barro Colorado Island. We combined our data with a review of the historical literature to assess changes in the populations of peccaries in the Caribbean lowlands. We found that collared peccaries have likely increased in abundance at La Selva, seemingly a few years after the extirpation of white-lipped peccaries (Tayassu pecari), which were abundant in the area 40–50 years ago. An understanding of the group dynamics, behavior, and habitat preference of collared peccaries is essential for management decisions and conservation efforts. Additionally, assessment of population changes should be carefully considered in a historical context, with a particular focus on how the populations of the 2 peccary species have changed, and how these species might differentially affect their environment.
Entender la abundancia y la preferencia de hábitat de las 2 especies de sainos en bosques neotropicales es importante porque estas especies clave afectan muchos aspectos del ecosistema. En las tierras bajas del Caribe costarricense, llevamos a cabo muestreos a pie durante ∼2 años para estudiar el comportamiento y tendencias poblacionales del saino (Pecari tajacu), y encontramos que son abundantes en la Estación Biológica La Selva y las tasas de detección fueron relativamente constantes a través del tiempo. Se obtuvo una tasa estable de detección después de 7–9 meses de muestreos. Las tasas de detección fueron similares en bosque primario y secundario, sin embargo, se encontraron algunas diferencias en la dinámica de grupo (el radio de distribución del grupo era más grande y la distancia de observación fue mayor en bosques primarios, mientras que el número de individuos solitarios fue mayor en bosques secundarios). Más sainos fueron vistos alrededor de las zonas abiertas rodeando el laboratorio, debido a varias posibles razones: habituación a la presencia de seres humanos, menos presión por depredación o cacería y otros factores ambientales o de hábitat. Los sainos están distribuidos de forma aglomerados y son más activos de día que de noche. Las densidades de sainos son relativamente altas en comparación con otros sitios neotropicales, con excepción de la Isla de Barro Colorado. El saino probablemente ha aumentado en abundancia en La Selva, aparentemente unos años después de la extirpación del cariblanco (Tayassu pecari), que eran abundantes en el área hace unos 40–50 años. El conocimiento de la dinámica de grupos, comportamiento y preferencias de hábitat del saino
Three of the 4 species of giant sengis or elephant shrews (genus Rhynchocyon) have restricted geographic distributions in eastern Africa and are threatened by anthropogenic habitat loss. However, little is known about their ecology and habitat relationships. We used remotely triggered cameras to detect the gray-faced sengi (Rhynchocyon udzungwensis), which is endemic in the Udzungwa Mountains of Tanzania, with the aim of defining distributional limits, estimating occupancy patterns, and determining habitat requirements. We deployed 183 camera stations over 6 years and accumulated 4,600 camera trapping days. We refined the area of known occurrence to be 390 km2, thus confirming the species' restricted range and vulnerability. We estimated the average occupancy at 56% of sites occupied on sites sampled, and found that occupancy was best predicted by the forest habitat type, with interior, closed-canopy forest supporting highest estimated sengi occupancy. Terrain slope and distance to the nearest park boundary were less important covariates, but nevertheless included among the best models. Camera-trapping rate (photographic events by day) was significantly correlated with subcanopy tree coverage. Combined, these habitat features may provide optimal conditions for antipredation vigilance (vegetation cover), and for nest-building and/or foraging on invertebrates in the thicker leaf litter on gentle slopes. Our results offer new insights into the ecology of giant sengis and confirm the potential utility of camera trapping for occupancy analysis of small, forest-dwelling mammals.
Improving our understanding of resources required by threatened small mammals is directly relevant to the success of habitat restoration and species reintroduction programs. In a case study based on southern brown bandicoots (Isoodon obesulus obesulus; Mammalia: Peramelidae) occupying a remnant of open forest with a sclerophyllous shrub understory, we investigated microhabitat composition using multivariate analysis, and disproportional use of these habitats using a variety of techniques, including principal canonical correlation vectors, chi-square test, compositional analysis (CA), and nonparametric multiplicative regression. Spool-and-line tracking of bandicoots enabled floristic and structural parameters to be recorded from sites of activity and compared with sites randomly located within 5-ha grids centered over each trapping transect. Each of the 4 methods applied contributed useful interrogation of the potential resources required by I. o. obesulus, with most disproportional use of microhabitats across activities detected using CA. Analyses supported fine-scale preference for Xanthorrhoea semiplana–dominated microhabitat across all activities, nesting in Banksia ornata–dominated microhabitat, moving and foraging in Allocasuarina muelleriana subsp. muelleriana microhabitat, impartial use of and increased reliance on burrows for shelter in Eucalyptus cosmophylla open forest with Melaleuca decussata understory microhabitats, and avoidance of Cyperaceae-dominated microhabitat and mixed heath. These results show that within broadly suitable vegetation communities, I. o. obesulus differentially utilizes a mosaic of microhabitats for a range of activities associated with shelter and foraging. Hence, the success of reintroduction and habitat restoration programs may be improved by considering the availability of preferred microhabitats (or alternative structures in suboptimal habitats, e.g., burrows), and protecting or revegetating indicator and associated species of known preferred microhabitats, respectively.
In the Arctic tundra, snow is believed to protect lemmings from mammalian predators during winter. We hypothesized that snow quality (depth and hardness) should affect mammalian predation rates on lemmings, but that this effect would depend on the predator hunting strategy; and that predation by ermines (Mustela erminea), which can hunt lemmings under the snow, should be higher in preferred lemming habitats. We measured snow depth and hardness at tunnels made by arctic fox (Vulpes lagopus) predation attempts, at winter nests nonpredated and predated by ermines, and at random locations. We also determined winter nest density in 3 habitats (wet, mesic, and gully). Deep and hard snow restricted fox predation attempts made by jumping through the snow, but not those made by digging. Ermine predation was unaffected by snow depth and weakly by nest density but was higher in gully and intermediate in mesic habitats, which are conducive to high snow accumulation, compared to the wet habitat. These results indicate that habitat-related topographical features are more important than snow depth or nest density per se in affecting the winter foraging strategy of ermines. Overall, even though we found a relatively weak effect of the snow cover on predation by foxes and ermines, it is difficult to predict how upcoming changes to the snow cover will affect lemming vulnerability to mammalian predators because a wide range of snow conditions may result from climate warming.
Apex predators such as Pacific white-sided dolphins (Lagenorhynchus obliquidens) have the potential to impact prey populations and to be affected by changes in prey abundance. As abundant predators that range widely across the North Pacific Ocean, their interactions with prey populations may have conservation implications. The energy required by individual Pacific white-sided dolphins was estimated using a bioenergetic model that accounted for different age classes and reproductive stages (calf, juvenile, adult, pregnant, and lactating). Monte Carlo simulations incorporating variability in model parameters (i.e., body mass, growth rate, costs of gestation and lactation, metabolic rate, cost of activity, and assimilation efficiencies) were used to predict ranges in energetic requirements of this species. Mean (± SD) total energy requirements in MJ/day were 40.3 ± 6.2 for calves, 70.8 ± 8.2 for juveniles, 69.0 ± 3.6 for adults, 70.3 ± 3.6 for pregnant females, and 98.4 ± 20.0 for lactating females. Estimates of energy requirements were most sensitive to uncertainty in values used for resting metabolic rates and energetic costs of activity. Estimated mass-specific energy requirements in MJ kg−1 day−1 were elevated in calves (1.55 ± 0.23), juveniles (0.97 ± 0.11), and lactating females (1.01 ± 0.21) when compared with nonreproductive adults and pregnant females (∼0.71 ± 0.04). Based on a high-energy diet, an average-sized dolphin (78 kg) would consume approximately 12.5–15.8 kg of fish or 16–20% of its body mass per day. These high energetic requirements may indicate a reliance of dolphins on energy-rich prey, which has implications for fisheries management and conservation of marine mammals.
Grizzly bears (Ursus arctos) have been reported as either nocturnal or diurnal in various studies, but have not been known to switch between the 2 times unless disturbed by humans. Black bears (Ursus americanus) are almost solely diurnal in studies unless human influences occur. Because human disturbance is often difficult to control, the relative temporal niche of both species remains ill-defined. Thus, the present study examined bears in Yellowstone National Park (Wyoming) where hunting does not occur, human activities are relatively benign, and bear species are sympatric to determine if niche occupancy was a stable feature of the species. Onset of activity was anticipatory of both sunrise or morning civil twilight (illumination sufficient for human vision) for individuals of either species. The peak hour of activity in black bears was consistently midday, but fluctuated in grizzly bears from midday during early spring, late summer, and fall to evening during late spring and early summer. Black bears did not temporally avoid the times when the more dominant grizzly bears were active. Mean activity levels were higher for male black bears than for both male and female grizzly bears. Together, results suggest that the foraging needs of black bears necessitate ingestion of less-digestible, lower-quality foods requiring longer foraging time during daytime hours, whereas grizzly bears adapt their diet to seasonally available food sources, necessitating greater temporal flexibility.
The International Union for Conservation of Nature has classified all subspecies of tigers (Panthera tigris) as endangered and prey depletion is recognized as a primary driver of declines. Prey depletion may be particularly important for Amur tigers (P. t. altaica) in the Russian Far East, living at the northern limits of their range and with the lowest prey densities of any tiger population. Unfortunately, rigorous investigations of annual prey requirements for any tiger population are lacking. We deployed global positioning system (GPS) collars on Amur tigers during 2009–2012 to study annual kill rates in the Russian Far East. We investigated 380 GPS location clusters and detected 111 kill sites. We then used logistic regression to model both the probability of a kill site at location clusters and the size of prey species at kill sites according to several spatial and temporal cluster covariates. Our top model for predicting kill sites included the duration of the cluster in hours and cluster fidelity components as covariates (overall classification success 86.3%; receiver operating characteristic score of 0.894). Application of the model to all tiger GPS data revealed that Amur tigers in this study made a kill once every 6.5 days (95% confidence interval [95% CI] 5.9–7.2 days) and consumed an estimated average of 8.9 kg of prey biomass per day (95% CI 8.8–9.0 kg/day). The success of efforts to reverse tiger declines will be at least partially determined by wildlife managers' ability to conserve large ungulates at adequate densities for recovering tiger populations.
Most dental microwear texture studies to date have focused on enamel surfaces. However, for xenarthran microwear we must, in effect, “reinvent the wheel,” because adult xenarthrans lack enamel. Dentin is softer than enamel and may record microwear differently. Thus, we aim to determine if dental microwear texture analysis (DMTA, which quantifies microwear in 3 dimensions) of dentin can yield biologically meaningful results by asking: do dentin and enamel in other eutherians record microwear texture the same way; and can DMTA differentiate between extant xenarthrans with different diets? We analyzed the carnassials of Florida panthers (Puma concolor coryi, n = 14), which have functional dentin and enamel, and found differences in texture fill volume and heterogeneity, suggesting that enamel and dentin DMTA cannot be directly compared. Next, we analyzed the teeth of sloths (Bradypus variegatus, n = 12; Choloepus hoffmanni, n = 9) and the 9-banded armadillo (Dasypus novemcinctus, n = 12), which differ in 2 attributes (surface complexity and fill volume) associated with food or abrasive properties. Other DMTA attributes show no differences between trophic groups, suggesting that dentin and enamel may differ in types of texture attributes that separate taxa by diet.
La mayoría de los estudios de la textura del micro-desgaste dental a la fecha se han enfocado en superficies del esmalte. Sin embargo, para el micro-desgaste en xenarthrans debemos, en efecto, “reinventar la rueda,” porque los dientes de xenarthrans adultos no tienen esmalte. La dentina es más dúctil que el esmalte, y puede registrar la textura del micro-desgaste en los dientes de manera diferente. Por lo tanto, nuestro objetivo es determinar si el análisis de la textura del micro-desgaste (DMTA, el cual cuantifica microdesgaste en 3 dimensiones) de la dentina puede mostrar resultados biológicos significativos, preguntando: ¿Pueden la dentina y el esmalte en otros Euterios registrar texturas de micro-desgaste de la misma manera? y ¿Se puede diferenciar entre xenarthrans extantes con dietas diferentes usando DMTA? Analizamos panteras de Florida (Puma concolor coryi, n = 14) cuyos carnasiales contienen dentina y esmalte funcionales y encontramos que hay existen diferencias en el volumen de llenado de textura y en la heterogeneidad, lo cual sugiere que la textura del micro-desgaste tanto en el esmalte como en la dentina no puede ser comparada directamente. Después, analizamos los dientes de perezosos (Bradypus variegatus, n = 12; Choloepus hoffmanni, n = 9) y del armadillo de nueve bandas (Dasypus novemcinctus, n = 12), los cuales difieren en dos atributos (complejidad de superficie y volumen de llenado) asociados con propiedades de alimento y abrasivas. Otros atributos de DMTA no muestran diferencias entre los grupos tróficos, lo que sugiere que la dentina y el esmalte posiblemente difieren en los tipos de atributos de textura que separan taxones por la dieta.
Previous understanding of the relationships among the species of bats in the genus Eumops has been primarily based on phenetic and cladistic analyses of morphological genetic similarity data. The objective of this study was to construct a phylogeny using DNA sequence data from 2 mitochondrial loci (cytochrome-b [Cytb] and nicotinamide adenine dinucleotide dehydrogenase subunit 1 [ND1]) and 1 nuclear locus (β-fibrinogen intron 7 [βFib]) for members of Eumops and outgroups from the family Molossidae. Data for each locus were analyzed separately using maximum-likelihood and Bayesian methods and combined for complete data analyses using Bayesian inference and Bayesian concordance analysis on a total of 2,715 base pairs. The monophyly of Eumops was significantly supported in all analyses and molecular dating estimated a most recent common ancestor of the genus at approximately 15.7 million years ago. Placement of E. hansae was problematic, with ND1 analyses supporting a sister relationship with E. patagonicus and E. nanus, whereas Cytb and βFib analyses placed this species as a basal lineage in the genus. Analysis of all genes recovered E. hansae as a poorly supported basal lineage with E. patagonicus and E. nanus as sister to the remaining species. These 3 major lineages of Eumops diverged during the mid-Miocene.
Although significant work has been done to define species relationships within the Neotropical genus Micronycteris, the group has yet to be fully resolved. In Bolivia Micronycteris is represented by 4 species: M. hirsuta, M. megalotis, M. minuta, and M. sanborni. Through examination of morphological characters and analyses of cranial measurements and genetic data, we determine that M. sanborni is not found in Bolivia and describe a new species closely related to it. The new species is morphometrically distinct from its congeners, forming a cluster separate from M. schmidtorum, M. minuta, and M. brosseti along principal component (PC) 1 (explaining 57.3% of the variation and correlated with maxillary toothrow length) and also separate from M. sanborni along PC 2 (explaining 35.4% of the variation and correlated with condylobasal length). The new species forms a statistically supported clade in all phylogenetic analyses; however, a sister relationship to M. sanborni is not supported. Genetic distance values that separate Micronycteris sp. nov. from its closest relatives range from 5.3% (versus M. sanborni) to 10.4% (versus M. minuta from Guyana). We diagnose and describe the new species in detail and name it in honor of the late Terry Lamon Yates for his contributions to Bolivian mammalogy. Micronycteris sp. nov. is Bolivia's 1st endemic bat species and because of its importance, the conservation implications are discussed.
A pesar de que se ha realizado un trabajo significativo para definir las relaciones interespecíficas en el género Micronycteris, estas todavía no han sido plenamente resueltas. En Bolivia, el género Micronycteris está representado por 4 especies: M. hirsuta, M. megalotis, M. minuta y M. sanborni. Mediante el examen de caracteres morfológicos y análisis de medidas craneanas y datos genéticos, determinamos que M. sanborni no se encuentra en Bolivia y describimos una nueva especie cercanamente relacionada a esta. La nueva especie es morfométricamente distinta de sus congéneres, formando un grupo separado de M. schmidtorum, M. minuta y M. brosseti en el componente principal 1 (el cual explica 57.3% de la variación y está correlacionado con el largo dentario del maxilar) y separado de M. sanborni en el componente principal 2 (el cual explica 35.4% de la variación y está correlacionado con la longitud condilobasal). La nueva especie forma un clado con soporte estadístico en todos los análisis filogenéticos, sin embargo su relación de especie hermana con M. sanborni carece de soporte. Los valores de distancias genéticas que separan Micronycteris sp. nov. de sus parientes más cercanos varía de 5.3% (versus M. sanborni) a 10.4% (versus M. minuta de Guyana). Diagnosticamos y describimos la nueva especie en detalle y la nombramos en ho
Three island populations of the marsh rice rat (Oryzomys palustris) found in Florida have been described as taxonomically unique; the Pine Island rice rat (O. p. planirostris) and Sanibel Island rice rat (O. p. sanibeli), originally described as subspecies, and the endangered silver rice rat (O. argentatus), originally described as a separate species. We aimed to resolve the phylogenetic relationships among these island populations and investigate their genetic distinctness with DNA sequence data from the mitochondrial control region and cytochrome-b gene. Using parsimony, maximum-likelihood, and Bayesian analyses, we estimated the phylogenetic relationships and genetic distances among the 3 island populations and 4 other described subspecies. Our mitochondrial DNA analyses indicate that the silver rice rat and Sanibel Island rice rat are genetically divergent from mainland populations, but the Pine Island rice rat is not. The silver rice rat and Sanibel Island rice rat may be genetically isolated due to geographic separation resulting in reduced gene flow. They have the potential to become distinct phylogenetic groups and eventually species.
Tres poblaciones insulares de Oryzomys palustris de la Florida han sido descritas como únicas taxonómicamente; O. p. planirostris y O. p. sanibeli, descritas originalmente como subespecies, y la O. argentatus, actualmente amenazada y originalmente identificada como especie. Este trabajo tenía como objetivo resolver las relaciones filogenéticas entre estas poblaciones insulares y dilucidar su similaridad genética a partir de datos de secuencias de ADN mitocondrial de la región control y del gen Citocromo-b. Las relaciones filogenéticas y las distancias genéticas entre las 3 poblaciones insulares y otras 4 subespecies descritas fueron evaluadas utilizando parsimonia, máxima verosimilitud y análisis bayesianos. Nuestros análisis de ADN mitocondrial indican que las poblaciones de O. argentatus y O. p. sanibeli son divergentes genéticamente de las poblaciones continentales, más sin embargo, O. p. planirostris no lo es. Es posible que las poblaciones O. argentatus y O. p. sanibeli estén aisladas genéticamente debido a la separación geográfica y que esto haya resultado en una reducción del flujo génico. Estas poblaciones tienen el potencial de convertirse en grupos filogenéticamente distintivos y eventualmente en distintas especies.
According to the Carnaval–Moritz (CM) model of Pleistocene refugia, during the Last Glacial Maximum, forested areas of the Atlantic Forest (AF) were restricted to isolated refugia and later expanded to their current distribution. Phylogeographic patterns of several vertebrate species corroborated the existence of the so-called Pernambuco, Bahia, and São Paulo refugia in the central and northern AF. Here we shift focus to the neglected southern and interior AF by addressing the phylogeography of the mouse Akodon montensis as inferred through analysis of cytochrome-b gene sequences of 86 specimens collected at 36 localities in Argentina, Brazil, and Paraguay. Three main clades were recovered with average genetic divergence of 2.5%: a northern clade, differentiated in the Bahia refuge, a southern clade—for which we propose the Rio Grande do Sul refugium—and a central clade (widely extending from coastal Brazil to Argentina and Paraguay). Within the latter, genetic diversity and historical demographic estimations support differentiation in the São Paulo refugium and their later population expansion toward interior AF. Additionally, no riverine barrier effect was found associated with the main river in the interior AF, the Paraná River. Taken as a whole, the phylogeographic pattern of A. montensis and its recent population history are mainly concordant with the CM model.
Según el modelo Carnaval–Moritz de refugios Pleistocénicos, durante el Último Máximo Glacial, el Bosque Atlántico (BA) se fragmentó a refugios aislados desde los cuales posteriormente se expandieron hasta ocupar su distribución actual. Los patrones filogeográficos de varios vertebrados corroboran la existencia de los refugios de Pernambuco, Bahía y São Paulo en las zonas central y norte del BA. En este estudio nos enfocamos en el BA sur e interior mediante el estudio filogeográfico del ratón Akodon montensis en base a secuencias del gen citocromo–b de 86 especímenes colectados en 36 localidades en Argentina, Brasil y Paraguay. Se observaron 3 clados principales que divergen en promedio en 2.5%; un clado norte, diferenciado en el refugio de Bahía; un clado sur que se diferencia en el aquí propuesto refugio de Río Grande do Sul; y un clado central ampliamente distribuido desde la costa de los estados de Río de Janeiro y São Pablo en Brasil hasta el Paraguay oriental. Dentro de éste último, las estimaciones de diversidad genética y demografía histórica sustentan un escenario de diferenciación en el refugio de São Pablo y posterior expansión poblacional hacia el BA interior. Adicionalmente, se muestra que el Río Paraná no afecta la estructura filogeográfica de A. montensis en el BA interior. En su conjunto, el patrón filogeográfico de A. montensis y su historia poblacional reciente son concordantes con el modelo Carnaval–Moritz.
Based on examination of 705 museum specimens, including the holotype and individuals identified using molecular attributes, we characterized Schmidly's deer mouse (Peromyscus schmidlyi) using a set of morphometric and morphological characteristics. Discriminant function analysis was performed on 14 cranial attributes to find those most useful to separate species. Factorial analysis of variance and multivariate analysis of variance were used to test for significant differences due to species, sex, age, and geographic location. We compared and contrasted P. schmidlyi with P. boylii rowleyi and P. spicilegus, morphologically similar and partially sympatric species, and reevaluated the distribution of the 3 species in the Sierra Madre Occidental (SMO) of Mexico. P. schmidlyi is a medium-sized Peromyscus distinguishable by a set of characters including overall size intermediate between P. spicilegus and P. boylii rowleyi, relatively wider braincase and zygoma, hourglass-shaped interorbital constriction, large auditory bullae, and strongly bicolored, tufted tail. Morphometric characterization is possible only when age and geographic location are taken into consideration. Several specimens previously identified as P. boylii rowleyi were reidentified as P. schmidlyi. Records available showed that P. schmidlyi is distributed in forested highlands of the SMO, from northern Chihuahua to northern Jalisco, between 1,550 (on the western versant) and 3,000 m of elevation. The species is sympatric with P. boylii rowleyi between 2,100 and 2,400 m along the eastern versant of the SMO and with P. spicilegus along a narrower band (1,550–2,000 m) on the steeper western slope. Distribution of these species closely reflects the most recent ecological regionalization of the SMO.
Se examinaron 705 ejemplares de museo incluyendo el holotipo e individuos identificados usando citocromo-b mitocondrial, para caracterizar Peromyscus schmidlyi desde el punto de vista morfológico y morfométrico. Se midieron 14 variables craneales y se realizó un análisis de funciones discriminantes para encontrar aquellas más útiles para separar especies. Se utilizaron análisis de varianza univariados (ANOVA) y multivariados (MANOVA) factoriales para evaluar diferencias entre especies, sexos y distribución geográfica. P. schmidlyi se comparó con P. boylii rowleyi y P. spicilegus, especies morfológicamente similares y parcialmente simpátricas con P. schmidlyi. Finalmente, se reevaluó la distribución de las 3 especies en la Sierra Madre Occidental (SMO). P. schmidlyi es de tamaño mediano, distinguible por un conjunto de caracteres incluyendo: tamaño general intermedio entre P. spicilegus y P. boylii rowleyi, caja craneana y arco cigomático relativamente anchos, región interorbital en forma de reloj de arena, bulas auditivas grandes, y cola marcadamente bicolor con un pincel en la punta. La caracterización morfológica de P. schmidlyi requiere tomar en cuenta la edad relativa y localidad de los ejemplares. Individuos previamente identificados como P. boylii rowleyi fueron reidentificados como P. schmidlyi. Como resultado, se puede concluir que P. schmidlyi se distribuye en los bosques de coníferas y pino–encino de la SMO, del norte de Chihuahua al norte de Jalisco, entre 1,550 (en la vertiente occidental) y 3,000 m sobre el nivel del mar. Es si
The common treeshrew, Tupaia glis, represents a species complex with a complicated taxonomic history. It is distributed mostly south of the Isthmus of Kra on the Malay Peninsula and surrounding islands. In our recent revision of a portion of this species complex, we did not fully assess the population from Java (T. “glis” hypochrysa) because of our limited sample. Herein, we revisit this taxon using multivariate analyses in comparisons with T. glis, T. chrysogaster of the Mentawai Islands, and T. ferruginea from Sumatra. Analyses of both the manus and skull of Javan T. “glis” hypochrysa show it to be most similar to T. chrysogaster and distinct from both T. glis and T. ferruginea. Yet, the Javan population and T. chrysogaster have different mammae counts, supporting recognition of T. hypochrysa as a distinct species. The change in taxonomic status of T. hypochrysa has conservation implications for both T. glis and this Javan endemic.
We investigate the potential flaws of estimating animal home range using indexes based on distance between captures as proposed by Püttker et al. (2012, Journal of Mammalogy 93:115–123). Through simulated capture distributions we demonstrated that distance indexes are inherently correlated with home-range estimates derived from the same data set. We also arrived at a similar conclusion using a real capture data set from the spiny rat (Thrichomys pachyurus). However, distance indexes were not correlated to home range based on radiotelemetry for the same individuals of T. pachyurus. Our results strongly support that the conclusions presented by Püttker et al. (2012) were due to statistical dependence between correlated measures and that these indexes might not represent the biological phenomenon of interest—the home range.
Nós investigamos as potenciais falhas em estimar a área de vida de animais utilizando índices baseados na distância entre capturas propostos por Puttker et al. (2012, Journal of Mammalogy 93:115–123). Através de distribuições espaciais de capturas simuladas, demonstramos que índices de distância estão inerentemente correlacionados com as estimativas de área de vida produzidas pelo mesmo conjunto de capturas simuladas. Nós também obtivemos resultados similares usando um conjunto real de dados de captura-marcação-recaptura de punarés (Thrichomys pachyurus). No entanto, os índices de distância entre capturas não foram correlacionados com as áreas de vidas estimadas usando informações providas por radiotelemetria para os mesmos indivíduos de T. pachyurus. Nossos resultados sugerem fortemente que as conclusões apresentadas por Puttker et al. (2012) foram devido a dependência estatística entre duas estimativas inerentemente correlacionadas, e que índices de distância entre capturas podem não representar o fenômeno biológico de interesse—a área de vida.
We respond to the comment by Oliveira-Santos et al. (2013) on the article on the suitability of distance metrics as indexes of home-range size by Püttker et al. (2012). We argue that geometrical relationships between distances and area are not an artifact, but 1st principles that warrant the use of movement distances as indexes for home-range area. Indeed, the simulations provided by Oliveira-Santos et al. corroborate this view. Although we agree that the use of minimum convex polygons (MCPs) based on trapping data as estimates of home-range size requires confirmation, this was beyond the scope of our study, which centered on the relationship of distance and area for a given method (MCP) and field protocol (trapping). Moreover, the analyses of Oliveira-Santos et al. testing the relationship between distance metrics (obtained by trapping) and area (estimated by radiotelemetry) are of limited utility due to confounding factors related to differences in field methods and time interval considered to obtain the 2 estimates (distance and area), and the inadequate size of their trapping grids for estimating movement distances.
Thorington, R. W., Jr., J. L. Koprowski, M. A. Steele, and J. F. Whatton. 2012. Squirrels of the World. Johns Hopkins University Press, Baltimore, Maryland, 459 pp. ISBN-13 978-1-4214-0469-1, price (hardbound), $75.00.
Patterson, B. D., and L. P. Costa (eds.). 2012. Bones, Clones and Biomes. The History and Geography of Recent Neotropical Mammals. University of Chicago Press, Chicago, Illinois, 432 pp. ISBN-13: 978-0-226-64919-1, price (hardbound), $65.
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