BAZILIO, S.; BASTIANI, E.; GOLEC, C. 2015. New records and description of the microstructural patterns of guard hair in Conepatus chinga (Molina, 1782) (Carnivora, Skunk) for the states of Paraná and Santa Catarina, southern Brazil. Biotemas 28(1):79-84. doi: http://dx.doi.org/10.5007/2175-7925.2015v28n1p79
Abstract. This article aims to show new records of Conepatus chinga for the states of Paraná and Santa Catarina, in southern Brazil, contributing to increase knowledge on its distribution, besides describing the microstructural patterns of its guard hair. Three run-over specimens were found in highway BR-280, two of them in the town of Palmas, in Paraná, and one in the town of Abelardo Luz, in Santa Catarina. For describing the cuticular and medullary pattern of guard hairs, sixty slides were made. Conepatus chinga has a cross-sectional and undulated cuticular pattern and an anisocytic medullary pattern. The description of microstructural patterns of C. chinga makes it easier to conduct studies related to its ecology, increasing the chances to identify hairs found in fecal samples from carnivores in mastofauna studies.
Mostrando postagens com marcador morphology. Mostrar todas as postagens
Mostrando postagens com marcador morphology. Mostrar todas as postagens
sábado, 28 de fevereiro de 2015
sábado, 14 de fevereiro de 2015
Origin of the lumbosacral plexus in Galea spixii (Wagler, 1831) (Rodentia, Caviidae)
OLIVEIRA, G.B.; RODRIGUES, M.N.; SOUSA, R.S.; MOURA, C.E.B.; MIGLINO, M.A.; OLIVEIRA, M.F. 2014. Origin of the lumbosacral plexus in Galea spixii (Wagler, 1831) (Rodentia, Caviidae). Biotemas 27(4):107-115. http://dx.doi.org/10.5007/2175-7925.2014v27n4p107
Abstract. The yellow-toothed cavy is a rodent belonging to the Caviidae family that inhabits the semiarid region of northeastern Brazil. We used 20 cavies that had died of natural causes, obtained from the Reproduction Center of Wild Animals (CEMAS) of the Federal Rural University of the Semi-Arid (UFERSA). The animals were ixed in aqueous solution of 10% formaldehyde and, after 48 hours, they were dissected to visualize plexus. The topographic relations of the lumbosacral plexus were grouped into tables and then they underwent statistical analysis (chi-square test with Yates’ correction). The lumbosacral plexus stemmed from the ventral roots of the last 3 lumbar nerves and the irst 3 sacral nerves, corresponding to 65% of the animals under study (L5L6L7S1S2S3). These nerves stemmed from plexus: femoral, obturator, ischiatic, cranial gluteal, caudal gluteal, and pudendal.
Key words: Anatomy; Nerves; Nervous system; Rodent; Yellow-toothed cavy.
Abstract. The yellow-toothed cavy is a rodent belonging to the Caviidae family that inhabits the semiarid region of northeastern Brazil. We used 20 cavies that had died of natural causes, obtained from the Reproduction Center of Wild Animals (CEMAS) of the Federal Rural University of the Semi-Arid (UFERSA). The animals were ixed in aqueous solution of 10% formaldehyde and, after 48 hours, they were dissected to visualize plexus. The topographic relations of the lumbosacral plexus were grouped into tables and then they underwent statistical analysis (chi-square test with Yates’ correction). The lumbosacral plexus stemmed from the ventral roots of the last 3 lumbar nerves and the irst 3 sacral nerves, corresponding to 65% of the animals under study (L5L6L7S1S2S3). These nerves stemmed from plexus: femoral, obturator, ischiatic, cranial gluteal, caudal gluteal, and pudendal.
Key words: Anatomy; Nerves; Nervous system; Rodent; Yellow-toothed cavy.
sábado, 6 de dezembro de 2014
First record of leucism in Artibeus phaeotis (Miller, 1902) (Chiroptera: Phyllostomidae) from Guatemala
TRUJILLO, L.A.; BARAHONA, R. 2014. First record of leucism in Artibeus phaeotis (Miller, 1902) (Chiroptera: Phyllostomidae) from Guatemala. Chiroptera Neotropical 20(1):1252-1254.
Abstract. The aim of this communication is to report the first documented case of leucism in Artibeus phaeotis from Guatemala. The bat was captured in Laguna del Tigre National Park, Petén, in northern Guatemala, while we were conducting a bat sampling in the area. Leucism is a condition rarely observed in nature, which is characterized by the partial or total depigmentation of fur; in this case the specimen is distinguished by a depigmentation in the ventral side of the body.
Abstract. The aim of this communication is to report the first documented case of leucism in Artibeus phaeotis from Guatemala. The bat was captured in Laguna del Tigre National Park, Petén, in northern Guatemala, while we were conducting a bat sampling in the area. Leucism is a condition rarely observed in nature, which is characterized by the partial or total depigmentation of fur; in this case the specimen is distinguished by a depigmentation in the ventral side of the body.
sábado, 8 de novembro de 2014
The application of Bergmann's Rule to Carollia perspicillata Linnaeus 1758 (Mammali, Chiroptera)
BARROS, L.A.V.; FORTES, R.R.; LORINI, M.L. 2014. The application of Bergmann's Rule to Carollia perspicillata Linnaeus 1758 (Mammali, Chiroptera). Chiroptera Neotropical 20(1):1243-1251.
Abstract. Bergmann’s Rule describes the association between body size of species and latitude. The proposed mechanism to explain the pattern would be the lowest surface/volume ratio found in large animals, which should result in an energy advantage in cold environments. The present study tested to what extent this pattern can be applied in bat populations of Carollia perspicillata (Linnaeus, 1758). We used secondary data, taken from the collection of Universidade Federal Rural do Rio de Janeiro (UFRRJ) and raw data provided by researchers, covering a latitude gradient ranging from 23º03' S to 0º10' N, at altitudes ranging from 10 to 1093m above sea level. Climatological data were obtained from the website of Instituto Nacional de Meteorologia (INMET). Body size analyses were based on mean and maximum length of forearm and body mass, and carried out through latitude, altitude and temperature gradients. A total of 488 adult specimens were analyzed, summarizing data for 23 localities. Body size variables showed a decrease toward higher latitudes and higher altitudes, and an increase in relation to increasing temperature. The results partially follow an inverse trend of the original proposal, called Bergmann’s Rule "converse". Bats’s wings are highly vascularized naked membranes, making their surface/volume ratio higher than that of other animals of similar size; thus a large body size would in fact result in bigger ratios and greater heat loss. The low values of all explicability indexes (R²) and linear coefficients (β) suggest that geographical variation in a species’ morphology cannot be only explained on the basis of latitudinal clines.
Abstract. Bergmann’s Rule describes the association between body size of species and latitude. The proposed mechanism to explain the pattern would be the lowest surface/volume ratio found in large animals, which should result in an energy advantage in cold environments. The present study tested to what extent this pattern can be applied in bat populations of Carollia perspicillata (Linnaeus, 1758). We used secondary data, taken from the collection of Universidade Federal Rural do Rio de Janeiro (UFRRJ) and raw data provided by researchers, covering a latitude gradient ranging from 23º03' S to 0º10' N, at altitudes ranging from 10 to 1093m above sea level. Climatological data were obtained from the website of Instituto Nacional de Meteorologia (INMET). Body size analyses were based on mean and maximum length of forearm and body mass, and carried out through latitude, altitude and temperature gradients. A total of 488 adult specimens were analyzed, summarizing data for 23 localities. Body size variables showed a decrease toward higher latitudes and higher altitudes, and an increase in relation to increasing temperature. The results partially follow an inverse trend of the original proposal, called Bergmann’s Rule "converse". Bats’s wings are highly vascularized naked membranes, making their surface/volume ratio higher than that of other animals of similar size; thus a large body size would in fact result in bigger ratios and greater heat loss. The low values of all explicability indexes (R²) and linear coefficients (β) suggest that geographical variation in a species’ morphology cannot be only explained on the basis of latitudinal clines.
sábado, 26 de julho de 2014
Tafonomía de restos de micromamíferos recuperados del sitio arqueológico Agua de La Mula (Mendoza, Argentina) y su implicancia en la subsistencia humana
FERNÁNDEZ, F.J.; DE SANTIS, L.J.M. 2013. Tafonomía de restos de micromamíferos recuperados del sitio arqueológico Agua de La Mula (Mendoza, Argentina) y su implicancia en la subsistencia humana. Cuadernos del Instituto Nacional de Antropología y Pensamiento Latinoamericano - Series Especiales 1(1):181-195.
Abstract. Micromammal remains from the archaeological sequence of Agua de La Mula (35º22'24,9''S, 68º15'04,2''W, south-central Mendoza, Argentina) are taphonomically studied. The remains (NISP=1026, MNE=1,026, MNI=491) were recovered from the Late Holocene layers (1,600-1,000 years C14 BP). The micromammal assemblages are composed by 10 taxa of rodents, one chiropteran and two marsupials, associated to transitional mosaic of Patagonian steppe and Monte desert environments. The absence of cut marks and the presence of few burned remains recovered from the site would indicate no human consumption. Moreover, the presence of pellets preserved in stratigraphy and light digestive corrosion on some teeth, indicate that the main accumulator agents were probably avian strigiforms. The absence of weathering, rodent marks, hydraulic transport, root action, and diagenesis, suggest a good preservation and a rapid incorporation of the material in the stratigraphic context. However, trampling, sedimentary corrosion and manganese oxide evidences were seen on the micromammal remains, indicating some episodes of humidity inside the cave. Finally, this information provided here would help us to explain the scope of the resource intensification process, proposed for the region in previous researches. In this sense, possibly this process could not have been so pronounced for that hunter-gatherers exploit the micromammals.
Abstract. Micromammal remains from the archaeological sequence of Agua de La Mula (35º22'24,9''S, 68º15'04,2''W, south-central Mendoza, Argentina) are taphonomically studied. The remains (NISP=1026, MNE=1,026, MNI=491) were recovered from the Late Holocene layers (1,600-1,000 years C14 BP). The micromammal assemblages are composed by 10 taxa of rodents, one chiropteran and two marsupials, associated to transitional mosaic of Patagonian steppe and Monte desert environments. The absence of cut marks and the presence of few burned remains recovered from the site would indicate no human consumption. Moreover, the presence of pellets preserved in stratigraphy and light digestive corrosion on some teeth, indicate that the main accumulator agents were probably avian strigiforms. The absence of weathering, rodent marks, hydraulic transport, root action, and diagenesis, suggest a good preservation and a rapid incorporation of the material in the stratigraphic context. However, trampling, sedimentary corrosion and manganese oxide evidences were seen on the micromammal remains, indicating some episodes of humidity inside the cave. Finally, this information provided here would help us to explain the scope of the resource intensification process, proposed for the region in previous researches. In this sense, possibly this process could not have been so pronounced for that hunter-gatherers exploit the micromammals.
Key Words:
Argentina,
arid environments,
Chiroptera,
Didelphimorphia,
evolution,
morphology,
neotropical mammals,
Rodentia,
small mammals,
zoology
sábado, 21 de junho de 2014
Revision of the systematic status of Patagonian and Pampean gray foxes (Canidae: Lycalopex griseus and L. gymnocercus) using 3D geometric morphometrics
PREVOSTI, F.J.; SEGURA, V.; CASSINI, G.; MARTIN, G.M. 2013. Revision of the systematic status of Patagonian and Pampean gray foxes (Canidae: Lycalopex griseus and L. gymnocercus) using 3D geometric morphometrics. Mastozoología Neotropical 20(2):289-300.
Abstract. Argentinean “zorros de campo” are currently included in two species: Lycalopex griseus and L. gymnocercus. Lycalopex gymnocercus lives in northern Patagonia and in most of central and northern Argentina. Lycalopex griseus is smaller and lives in Patagonia and throughout western Argentina. A previous traditional morphometric study using cranio-dental measurements considered both forms to be the same species, showing clinal reduction in size from northeastern to southwestern Argentina. Here we tested the synonymy of these foxes and the existence of clinal variation using a large sample and geometric morphometric methods. Our results rejected the separation of these foxes in two different species and confirmed, based on cranium and mandible size and shape that they belong to the same species. Also, we show there is a clinal variation in size that has an allometric component in cranial and mandibular shape, which accounts for the differences between these foxes.
Abstract. Argentinean “zorros de campo” are currently included in two species: Lycalopex griseus and L. gymnocercus. Lycalopex gymnocercus lives in northern Patagonia and in most of central and northern Argentina. Lycalopex griseus is smaller and lives in Patagonia and throughout western Argentina. A previous traditional morphometric study using cranio-dental measurements considered both forms to be the same species, showing clinal reduction in size from northeastern to southwestern Argentina. Here we tested the synonymy of these foxes and the existence of clinal variation using a large sample and geometric morphometric methods. Our results rejected the separation of these foxes in two different species and confirmed, based on cranium and mandible size and shape that they belong to the same species. Also, we show there is a clinal variation in size that has an allometric component in cranial and mandibular shape, which accounts for the differences between these foxes.
sábado, 24 de maio de 2014
External features of the dusk dolphin Lagenorhynchus obscurus (Gray, 1828) from Peruvian waters
WAEREBEEK, K.V. 1993. External features of the dusk dolphin Lagenorhynchus obscurus (Gray, 1828) from Peruvian waters. Estudos Oceanológicos 12:37-53.
Abstract. Individual, sexual and developmental variation is quantified in the external morphology and colouration of the dusky dolphin Lagenorhynchus obscurus from Peruvian coastal waters. No significant difference in body length between sexes is found (p = 0.09) and, generally, little sexual dimorphism is present. However, males have a more anteriorly positioned genital slit and anus and their dorsal fin is more curved, has a broader base and a greater surface area than females Although the dorsal fin apparently serves as a secondary sexual character, the use of it for sexing free-ranging dusky dolphins is discouraged because of high overlap in values. Relative growth in 25 body measurements is characterized for both sexes by multiplicative regression equations. The colouration pattern of the dorsal fin, flank patch, thoracic field, flipper stripe and possibly (X², p = 0.08) the eye patch, are independent of maturity status. Flipper blaze and lower lip patch are less pigmented in juveniles than in adults No sexual dimorphism is found in the colour pattern The existence of a discrete "Fitzroy" colour form can not be confirmed from available data. Various cases of anomalous, piebald pigmentation are described, probably equivalent to so-called partial albinism. Adult dusky dolphins from both SW Africa and New Zealand are 8-10 cm shorter than Peruvian specimens, supporting conclusions of separate populations from a recent skull variability study.
Abstract. Individual, sexual and developmental variation is quantified in the external morphology and colouration of the dusky dolphin Lagenorhynchus obscurus from Peruvian coastal waters. No significant difference in body length between sexes is found (p = 0.09) and, generally, little sexual dimorphism is present. However, males have a more anteriorly positioned genital slit and anus and their dorsal fin is more curved, has a broader base and a greater surface area than females Although the dorsal fin apparently serves as a secondary sexual character, the use of it for sexing free-ranging dusky dolphins is discouraged because of high overlap in values. Relative growth in 25 body measurements is characterized for both sexes by multiplicative regression equations. The colouration pattern of the dorsal fin, flank patch, thoracic field, flipper stripe and possibly (X², p = 0.08) the eye patch, are independent of maturity status. Flipper blaze and lower lip patch are less pigmented in juveniles than in adults No sexual dimorphism is found in the colour pattern The existence of a discrete "Fitzroy" colour form can not be confirmed from available data. Various cases of anomalous, piebald pigmentation are described, probably equivalent to so-called partial albinism. Adult dusky dolphins from both SW Africa and New Zealand are 8-10 cm shorter than Peruvian specimens, supporting conclusions of separate populations from a recent skull variability study.
sábado, 17 de maio de 2014
Ecomorphology of orbit orientation and the adaptative significance of binocular vision in primates and other mammals
HEESY, C.P. 2008. Ecomorphology of orbit orientation and the adaptative significance of binocular vision in primates and other mammals. Brain, Behaviou and Evolution 71:54-67. doi: 10.1159/000108621
Abstract. Primates are characterized by forward-facing, or convergent, orbits and associated binocular field overlap. Hypotheses explaining the adaptive significance of these traits often relate to ecological factors, such as arboreality, nocturnal visual predation, or saltatory locomotion in a complex nocturnal, arboreal environment. This study re-examines the ecological factors that are associated with high orbit convergence in mammals. Orbit orientation data were collected for 321 extant taxa from sixteen ordens of metatherian (marsupial) and eutherian mammals. These taxa were coded for activity pattern, degree of faunivory, and substrate preference. Results demonstrate that nocturnal and cathemeral mammals have significantly more convergent orbits than diurnal taxa, both within and across ordens. Faunivorous eutherians (noth nocturnal and diurnal) have higher mean orbit convergence that opportunistically foraging or non-faunivorous taxa. However, substrate preference is not associated with higher orbit convergence and, by extension, greater binocular visual field overlap. These results are consistent with the hypothesis that mammalian predators evolved higher orbit convergence, binocular vision, and stereopsis to counter camouflage in prey inhabiting a nocturnal environment. Strepsirhine primates have a range of orbit convergence values similar to nocturnal or cathemeral prodatory non-primates mammals. These data are entirely consistent with the nocturnal visual predation hypothesis of primate origins.
Abstract. Primates are characterized by forward-facing, or convergent, orbits and associated binocular field overlap. Hypotheses explaining the adaptive significance of these traits often relate to ecological factors, such as arboreality, nocturnal visual predation, or saltatory locomotion in a complex nocturnal, arboreal environment. This study re-examines the ecological factors that are associated with high orbit convergence in mammals. Orbit orientation data were collected for 321 extant taxa from sixteen ordens of metatherian (marsupial) and eutherian mammals. These taxa were coded for activity pattern, degree of faunivory, and substrate preference. Results demonstrate that nocturnal and cathemeral mammals have significantly more convergent orbits than diurnal taxa, both within and across ordens. Faunivorous eutherians (noth nocturnal and diurnal) have higher mean orbit convergence that opportunistically foraging or non-faunivorous taxa. However, substrate preference is not associated with higher orbit convergence and, by extension, greater binocular visual field overlap. These results are consistent with the hypothesis that mammalian predators evolved higher orbit convergence, binocular vision, and stereopsis to counter camouflage in prey inhabiting a nocturnal environment. Strepsirhine primates have a range of orbit convergence values similar to nocturnal or cathemeral prodatory non-primates mammals. These data are entirely consistent with the nocturnal visual predation hypothesis of primate origins.
sábado, 30 de novembro de 2013
geomorph: an R package for the collection and analysis of geometric morphometric shape data
ADAMS, D.C.; OTÁROLA-CASTILLO, E. 2013. geomorph: an R package for the collection and analysis of geometric morphometric shape data. Methods in Ecology and Evolution 4:393-399. doi: 10.1111/2041-210X.12035.
Abstract. Many ecological and evolutionary studies seek to explain patterns of shape variation and its covariation with other variables. Geometric morphometrics is often used for this purpose, where a set of shape variables are obtained from landmark coordenates following a Procruster superimaposition.
We introduce geomorph: a software package for performing geometric morphometric shape analysis in the R statistical computing environment.
Geomorph provides routines for all stages of landmark-based geometric morphometric analysis in two and three-dimensios. It is an open source package to read, manipulate, and digitize landmark data, generate shape variables via Procruster analysis for points, curves and surfaces, perform statistical analyses of shape variation and covariation, and to provide graphical depictions of shape and patterns of shape variation. An important contribution of geomorph is the ability to perform Procrustes superimposition on landmark points, as well as semilandmark from curves and surfaces.
A wide range of statistical methods germane to testing ecological and evolutionary hypotheses of shape variation are provided. These include standard multivariate methods such as principal components analysis, and approaches for multivariate regression and group comparison. Methods for more specialized analyses, such as for assessing shape allometry, comparing shape trajectories, examining morphological integration, and for assessing phylogenetic signal, are also included.
Several functions are provided to graphically visualize results, including routines for examining variation in shape space, visualizing allometric trajectories, comparing specific shapes to one another and for plotting phylogenetic changes in morphospace.
Finally, geomorph participates to make available advanced geometric morphometric analysis through the R statistical computing platform.
Abstract. Many ecological and evolutionary studies seek to explain patterns of shape variation and its covariation with other variables. Geometric morphometrics is often used for this purpose, where a set of shape variables are obtained from landmark coordenates following a Procruster superimaposition.
We introduce geomorph: a software package for performing geometric morphometric shape analysis in the R statistical computing environment.
Geomorph provides routines for all stages of landmark-based geometric morphometric analysis in two and three-dimensios. It is an open source package to read, manipulate, and digitize landmark data, generate shape variables via Procruster analysis for points, curves and surfaces, perform statistical analyses of shape variation and covariation, and to provide graphical depictions of shape and patterns of shape variation. An important contribution of geomorph is the ability to perform Procrustes superimposition on landmark points, as well as semilandmark from curves and surfaces.
A wide range of statistical methods germane to testing ecological and evolutionary hypotheses of shape variation are provided. These include standard multivariate methods such as principal components analysis, and approaches for multivariate regression and group comparison. Methods for more specialized analyses, such as for assessing shape allometry, comparing shape trajectories, examining morphological integration, and for assessing phylogenetic signal, are also included.
Several functions are provided to graphically visualize results, including routines for examining variation in shape space, visualizing allometric trajectories, comparing specific shapes to one another and for plotting phylogenetic changes in morphospace.
Finally, geomorph participates to make available advanced geometric morphometric analysis through the R statistical computing platform.
sábado, 3 de agosto de 2013
Primer registro de un ejemplar juvenil de Glyptodon sp. (Cingulata, Glyptodontidae) del Cuaternario de la provincia de Córdoba, Argentina
LUNA, C.A.; KRAPOVICKAS, J.M. 2011. Primer registro de un ejemplar juvenil de Glyptodon sp. (Cingulata, Glyptodontidae) del Cuaternario de la provincia de Córdoba, Argentina. Mastozoología Neotropical 18(1):135-141.
Abstract. First record of a juvenile specimen of Glyptodon sp. (Cingulata, Glyptodontidae) from the Quaternary of Córdoba province, Argentina. The first record of a juvenile specimen of Glyptodon sp. (Cingulata, Glyptodontidae) from the Quaternary of Córdoba province, Argentina, is reported. The material consists of 90 osteoderms of the dorsal carapace, 19 osteoderms of the caudal armor and some post-cranial bones. This specimen principally presents hexagon shape osteoderms, with high thickness/maximum diameter ratio, circular or subcircular central figure, elevated in relation with the peripheric surface, with central depression, large piliferous perforations, poorly defined or completely absent peripheric figures and with a concave internal surface.
Abstract. First record of a juvenile specimen of Glyptodon sp. (Cingulata, Glyptodontidae) from the Quaternary of Córdoba province, Argentina. The first record of a juvenile specimen of Glyptodon sp. (Cingulata, Glyptodontidae) from the Quaternary of Córdoba province, Argentina, is reported. The material consists of 90 osteoderms of the dorsal carapace, 19 osteoderms of the caudal armor and some post-cranial bones. This specimen principally presents hexagon shape osteoderms, with high thickness/maximum diameter ratio, circular or subcircular central figure, elevated in relation with the peripheric surface, with central depression, large piliferous perforations, poorly defined or completely absent peripheric figures and with a concave internal surface.
sábado, 4 de maio de 2013
Anomalous color in Neotropical mammals: a review with new records for Didelphis sp. (Didelphidae, Didelphimorphia) and Arctocephalus australis (Otariidae, Carnivora)
ABREU, M.S.L.; MACHADO, R.; BARBIERI, F.; FREITAS, N.S.; OLIVEIRA, L.R. 2013. Anomalous color in Neotropical mammals: a review with new records for Didelphis sp. (Didelphidae, Didelphimorphia) and Arctocephalus australis (Otariidae, Carnivora). Brazilian Journal of Biology 73(1):185-194.
Abstract. Anomalous colourations occur in many tropical vertebrates. However, they are considered rare in wild populations, with very few records for the majority of animal taxa. We report two new cases of anomalous colouration in mammals. Additionally, we compiled all published cases about anomalous pigmentation registered in Neotropical mammals, throughout a comprehensive review of peer reviewed articles between 1950 and 2010. Every record was classified as albinism, leucism, piebaldism or eventually as undetermined pigmentation. As results, we report the new record of a leucistic specimen of opossum (Didelphis sp.) in southern Brazil, as well as a specimen of South American fur seal (Arctocephalus australis) with piebaldism in Uruguay. We also found 31 scientific articles resulting in 23 records of albinism, 12 of leucism, 71 of piebaldism and 92 records classified as undetermined pigmentation. Anomalous colouration is apparently rare in small terrestrial mammals, but it is much more common in cetaceans and michrochiropterans. Out of these 198 records, 149 occurred in cetaceans and 30 in bats. The results related to cetaceans suggest that males and females with anomolous pigmentation are reproductively successful and as a consequence their frequencies are becoming higher in natural populations. In bats, this result can be related to the fact these animals orient themselves primarily through echolocation, and their refuges provide protection against light and predation. It is possible that anomalous colouration occurs more frequently in other Neotropical mammal orders, which were not formally reported. Therefore, we encourage researchers to publish these events in order to better understand this phenomenon that has a significant influence on animal survival.
Abstract. Anomalous colourations occur in many tropical vertebrates. However, they are considered rare in wild populations, with very few records for the majority of animal taxa. We report two new cases of anomalous colouration in mammals. Additionally, we compiled all published cases about anomalous pigmentation registered in Neotropical mammals, throughout a comprehensive review of peer reviewed articles between 1950 and 2010. Every record was classified as albinism, leucism, piebaldism or eventually as undetermined pigmentation. As results, we report the new record of a leucistic specimen of opossum (Didelphis sp.) in southern Brazil, as well as a specimen of South American fur seal (Arctocephalus australis) with piebaldism in Uruguay. We also found 31 scientific articles resulting in 23 records of albinism, 12 of leucism, 71 of piebaldism and 92 records classified as undetermined pigmentation. Anomalous colouration is apparently rare in small terrestrial mammals, but it is much more common in cetaceans and michrochiropterans. Out of these 198 records, 149 occurred in cetaceans and 30 in bats. The results related to cetaceans suggest that males and females with anomolous pigmentation are reproductively successful and as a consequence their frequencies are becoming higher in natural populations. In bats, this result can be related to the fact these animals orient themselves primarily through echolocation, and their refuges provide protection against light and predation. It is possible that anomalous colouration occurs more frequently in other Neotropical mammal orders, which were not formally reported. Therefore, we encourage researchers to publish these events in order to better understand this phenomenon that has a significant influence on animal survival.
Key Words:
aquatic mammals,
Carnivora,
Cetartiodactyla,
Chiroptera,
Cingulata,
Didelphimorphia,
morphology,
Neotropical region,
Pilosa,
Rodentia,
small mammals
sábado, 8 de dezembro de 2012
Rarity in Neotropical bats: correlations with phylogeny, diet, and body mass
ARITA, H.T. 1993. Rarity in Neotropical bats: correlations with phylogeny, diet, and body mass. Ecological Applications 3(3):506-517.
Abstract. Bats are an important component of tropical faunas, both in terms of number of species and total biomass. Very little information, however, is available on the status and conservation of this diverse group. To contribute to the solution of this problem, rarity among Neotropical bats was analyzed using a set of 150 species. Rarity was quantified by local abundance and area of distributional range and by a combined index of rarity created by compounding these two variables. Nested analyses of variance showed local abundance to be more variable among genera than at any other taxonomic level, and area of distribution to be more variable among species. No significant correlation with body mass was found for local abundance or for area of distribution. Similarly, no correlation was found between distribution and abundance. Local abundance, but not area of distribution, varied significantly among taxonomic and trophic categories. At the local level, bats of the family Molossidae tend to be less abundant than other species. Bats that feed on plant parts or products (fruit, nectar, and pollen) are more abundant than insectivores and carnivores. The distribution of species among Rabinowitz' categories of rarity varied among taxonomic and trophic groups. The classification of rarity and the combined index of rarity introduced here can be used as guidelines for the identification of vulnerable species.
Abstract. Bats are an important component of tropical faunas, both in terms of number of species and total biomass. Very little information, however, is available on the status and conservation of this diverse group. To contribute to the solution of this problem, rarity among Neotropical bats was analyzed using a set of 150 species. Rarity was quantified by local abundance and area of distributional range and by a combined index of rarity created by compounding these two variables. Nested analyses of variance showed local abundance to be more variable among genera than at any other taxonomic level, and area of distribution to be more variable among species. No significant correlation with body mass was found for local abundance or for area of distribution. Similarly, no correlation was found between distribution and abundance. Local abundance, but not area of distribution, varied significantly among taxonomic and trophic categories. At the local level, bats of the family Molossidae tend to be less abundant than other species. Bats that feed on plant parts or products (fruit, nectar, and pollen) are more abundant than insectivores and carnivores. The distribution of species among Rabinowitz' categories of rarity varied among taxonomic and trophic groups. The classification of rarity and the combined index of rarity introduced here can be used as guidelines for the identification of vulnerable species.
sábado, 17 de novembro de 2012
Jumping ability in the arboreal locomotion of didelphid marsupials
DELCIELLOS, A.C.; VIEIRA, M.V. 2009. Jumping ability in the arboreal locomotion of didelphid marsupials. Mastozoología Neotropical 16(2):299-307.
Abstract. Didelphid marsupials are considered to cross discontinuities between arboreal supports using a cautious locomotion, using the prehensile tail as fifth limb. However, this ability was only described for Caluromys philander. We describe and compare the locomotory performance and postural behavior of seven species of didelphid marsupials crossing discontinuities between artificial supports representing arboreal gaps. Individuals were captured in areas of Atlantic Forest in Rio de Janeiro State, Brazil. Animals were stimulated to jump from a fixed horizontal support one meter above the ground to an inclined support of same diameter. We measured the maximum distance of jump (40, 60, 80 or 100 cm) and reach or distance actually reached by the jump. Arboreal species (Marmosops incanus, Gracilinanus microtarsus, Micoureus paraguayanus, and C. philander) jumped longer distances and had longer relative reach in jumps than semi-terrestrial species (Didelphis aurita, and Philander frenatus). Only the specialized terrestrial Metachirus nudicaudatus did not jump in the tests. The relation between absolute reach and body size was weak and non significant. This study did not corroborate the view that didelphid marsupials cross discontinuities between arboreal supports only through a cautious locomotion, without jumping. On the contrary, we identified patterns of jumping performance and behavior of didelphid marsupials related to their use of the vertical strata.
sábado, 29 de setembro de 2012
Toward an ecological synthesis: a case for habitat selection
MORRIS, D.W. 2003. Toward an ecological synthesis: a case for habitat selection. Oecologia 136:1-13.
Abstract. Habitat selection, and its associated density and frequency-dependent evolution, has a profound influence on such vital phenomena as population regulation, species interactions, the assembly of ecological communities, and the origin and maintenance of biodiversity. Different strategies of habitat selection, and their importance in ecology and evolution, can often be revealed simply by plots of density in adjacent habitats. For individual species, the strategies are closely intertwined with mechanisms of population regulation, and with the persistence of populations through time. For interacting species, strategies of habitat selection are not only responsible for species coexistence, but provide one of the most convenient mechanisms for measuring competition, and the various community structures caused by competitive interactions. Other kinds of interactions, such as those between predators and prey, demonstrate that an understanding of the coevolution of habitat-selection strategies among strongly interacting species is essential to properly interpret their spatial and temporal dynamics. At the evolutionary scale, the frequency dependence associated with habitat selection may often allow populations to diverge and diversify into separate species. Habitat selection thereby demonstrates how we can map microevolutionary strategies in behavior onto their population and community consequences, and from there, onto macroevolutionary patterns of speciation and adaptive radiation. We can anticipate that future studies of habitat selection will not only help us complete those maps, but that they will also continue to enrich the panoply of ideas that shape evolutionary ecology.
Abstract. Habitat selection, and its associated density and frequency-dependent evolution, has a profound influence on such vital phenomena as population regulation, species interactions, the assembly of ecological communities, and the origin and maintenance of biodiversity. Different strategies of habitat selection, and their importance in ecology and evolution, can often be revealed simply by plots of density in adjacent habitats. For individual species, the strategies are closely intertwined with mechanisms of population regulation, and with the persistence of populations through time. For interacting species, strategies of habitat selection are not only responsible for species coexistence, but provide one of the most convenient mechanisms for measuring competition, and the various community structures caused by competitive interactions. Other kinds of interactions, such as those between predators and prey, demonstrate that an understanding of the coevolution of habitat-selection strategies among strongly interacting species is essential to properly interpret their spatial and temporal dynamics. At the evolutionary scale, the frequency dependence associated with habitat selection may often allow populations to diverge and diversify into separate species. Habitat selection thereby demonstrates how we can map microevolutionary strategies in behavior onto their population and community consequences, and from there, onto macroevolutionary patterns of speciation and adaptive radiation. We can anticipate that future studies of habitat selection will not only help us complete those maps, but that they will also continue to enrich the panoply of ideas that shape evolutionary ecology.
sábado, 8 de setembro de 2012
Building large trees by combining phylogenetic information: a complete phylogeny of the extant Carnivora (Mammalia)
BININDA-EMONDS, O.R.P.; GITTLEMAN, J.L.; PURVIS, A. 1999. Building large trees by combining phylogenetic information: a complete phylogeny of the extant Carnivora (Mammalia). Biol. Rev. 74:143-175.
Abstract. One way to build large, more comprehensive phylogenies is to combine the vast amount of phylogenetic information already available. We review the two main strategies for accomplishing this (combining raw data versus combining trees), but employ a relatively new variant of the latter: supertree construction. The utility of one supertree technique, matrix representation using parsimony analysis (MRP), is demonstrated by deriving a complete phylogeny for all 271 extant species of the Carnivora from 177 literature sources. Beyond providing a 'consensus' estimate of carnivore phylogeny, the tree also indicates taxa for which the relationships remain controversial (e.g. herpestids, viverrids, and intrageneric relationships in the procyonids). Times of divergence throughout the tree were also estimated from 74 literature sources based on both fossil and molecular data. We use the phylogeny to show that some lineages within the Mustelinae and Canidae contain significantly more species than expected for their age, illustrating the tree's utility for studies of macroevolution. It will also provide a useful foundation for comparative and conservational studies involving the carnivores.
Abstract. One way to build large, more comprehensive phylogenies is to combine the vast amount of phylogenetic information already available. We review the two main strategies for accomplishing this (combining raw data versus combining trees), but employ a relatively new variant of the latter: supertree construction. The utility of one supertree technique, matrix representation using parsimony analysis (MRP), is demonstrated by deriving a complete phylogeny for all 271 extant species of the Carnivora from 177 literature sources. Beyond providing a 'consensus' estimate of carnivore phylogeny, the tree also indicates taxa for which the relationships remain controversial (e.g. herpestids, viverrids, and intrageneric relationships in the procyonids). Times of divergence throughout the tree were also estimated from 74 literature sources based on both fossil and molecular data. We use the phylogeny to show that some lineages within the Mustelinae and Canidae contain significantly more species than expected for their age, illustrating the tree's utility for studies of macroevolution. It will also provide a useful foundation for comparative and conservational studies involving the carnivores.
sábado, 24 de dezembro de 2011
Arboreal walking performance in seven didelphid marsupials as an aspect of their fundamental niche
DELCIELLOS, A.C.; VIEIRA, M.V. 2006. Arboreal walking performance in seven didelphid marsupials as an aspect of their fundamental niche. Austral Ecology 31:449-457.
Abstract. Species of didelphid marsupials (Didelphimorphia, Didelphidae) differ in their use of the forest strata, but it is not clear whether these differences are in fundamental or realized niches. The fundamental niche of seven species of didelphids (Caluromys philander, Didelphis aurita, Gracilinanus microtarsus, Marmosops incanus, Metachirus nudicaudatus, Micoureus demerarae, and Philander frenatus) was compared using their performance in arboreal walking. The association between performance and vertical use of the forest also was tested accounting for phylogenetic and allometric effects. Tests consisted of making the animal cross five 3 m long horizontal supports of different diameters, 1 m from the ground. The cycle of maximum speed was chosen to measure stride length, frequency and velocity. Arboreal species performed better than the terrestrial ones, but a major part of the variation in stride length (70.95%) and stride frequency (88.10%) was associated with body size. Part of the variation in stride length independent of body size (14.05%) was associated with the degree of vertical use of the forest, after phylogenetic effects were accounted for. Fundamental niches of six of the seven species were discriminated with the performance tests used. Discrepancies between the realized and fundamental niches can be inferred for two of these species, D. aurita and P. frenatus.
Abstract. Species of didelphid marsupials (Didelphimorphia, Didelphidae) differ in their use of the forest strata, but it is not clear whether these differences are in fundamental or realized niches. The fundamental niche of seven species of didelphids (Caluromys philander, Didelphis aurita, Gracilinanus microtarsus, Marmosops incanus, Metachirus nudicaudatus, Micoureus demerarae, and Philander frenatus) was compared using their performance in arboreal walking. The association between performance and vertical use of the forest also was tested accounting for phylogenetic and allometric effects. Tests consisted of making the animal cross five 3 m long horizontal supports of different diameters, 1 m from the ground. The cycle of maximum speed was chosen to measure stride length, frequency and velocity. Arboreal species performed better than the terrestrial ones, but a major part of the variation in stride length (70.95%) and stride frequency (88.10%) was associated with body size. Part of the variation in stride length independent of body size (14.05%) was associated with the degree of vertical use of the forest, after phylogenetic effects were accounted for. Fundamental niches of six of the seven species were discriminated with the performance tests used. Discrepancies between the realized and fundamental niches can be inferred for two of these species, D. aurita and P. frenatus.
sábado, 26 de novembro de 2011
Differences in population density and energy use between birds and mammals: a macroecological perspective
SILVA, M.; BROWN, J.H.; DOWNING, J.A. 1997. Differences in population density and energy use between birds and mammals: a macroecological perspective. Journal of Animal Ecology 66(3):327-340.
Abstract.
1. Data from 364 mammal and 564 bird species were used to compare these two taxa in the patterns of variation in population density and energy use as a function of body mass.
2. This study demonstrates previously unappreciated quantitative differences between mammals and birds. Over a wide range of sizes, population densities and rates of energy use are at least one order of magnitude higher in mammals than in birds of similar size. The highest population densities are found in species that weigh about 100 g in mammals and 30 g in birds.
3. Comparisons between mammals and birds from the same dietary category indicate that mammals maintain higher densities and use more energy than birds. Insectivorous mammals and birds maintain the lowest densities.
4. Flying mammals and birds reach lower densities and use more energy than nonflying forms.
Abstract.
1. Data from 364 mammal and 564 bird species were used to compare these two taxa in the patterns of variation in population density and energy use as a function of body mass.
2. This study demonstrates previously unappreciated quantitative differences between mammals and birds. Over a wide range of sizes, population densities and rates of energy use are at least one order of magnitude higher in mammals than in birds of similar size. The highest population densities are found in species that weigh about 100 g in mammals and 30 g in birds.
3. Comparisons between mammals and birds from the same dietary category indicate that mammals maintain higher densities and use more energy than birds. Insectivorous mammals and birds maintain the lowest densities.
4. Flying mammals and birds reach lower densities and use more energy than nonflying forms.
5. These findings reveal relationships between the morphology, physiology and behaviour of individual organisms and the ecological performance of these endothermic vertebrates in populations, communities and ecosystems: relationships that have not previously been appreciated.
Assinar:
Postagens (Atom)