CULVER, M.; JOHNSON, W.E.; PECON-SLATTERY, J.; O'BRIEN, S.J. 2000. Genomic ancestry of the American puma (Puma concolor). The Journal of Heredity 91(3):186-197.
Abstract. Puma concolor, a large American cat species, occupies the most extensive range of any New World terrestrial mammal, spanning 110 degrees of latitude from the Canadian Yukon to the Straits of Magellan. Until the recent Holocene, pumas co-existed with a diverse array of carnivores including the American lion (Panthera atrox), the North American cheetah (Myracynonyx trumani), and the saber toothed tiger (Smilodon fatalis). Genomic DNA specimens from 135 pumas of specified geographic origin (261 contemporany and 54 museum specimens) were collected for molecular genetic and phylogenetic analyses of three mitochrondrial gene sequences (16S rRNA, ATPase-8, and NADH-5) plus composite microsatellite genotypes (10 feline loci). Six phylogeographic groupings or subspecies were resolved, and the entire North American population (186 individuals from 15 previously named subspecies) was genetically homogeneous in overall variation relative to central and South American populations. The marked uniformity of mtDNA and a reduction in microsatellite allele size expansion indicates that North American pumas derive from a recent (late Pleistocene circa 10,000 years ago) replacement and recolonization by a small number of founders who themselves originated from a centrum of puma genetic diversity in eastern South America 200,000-300,000 years ago. The recolonization of North American pumas was coincident with a massive late Pleistocene extinction event that eliminated 80% of large vertebrates in North America and may have extirpated pumas from that continent as well.
Mostrando postagens com marcador evolution. Mostrar todas as postagens
Mostrando postagens com marcador evolution. Mostrar todas as postagens
sábado, 3 de janeiro de 2015
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, 12 de julho de 2014
Impacts of the Cretaceous terrestrial revolution and KPg extinction on mammal diversification
MEREDITH, R.W.; JANEčKA, J.E.; GATESY, J.; RYDER, O.A.; FISCHER, C.A.; TEELING, E.C.; GOODBLA, A.; EIZIRIK, E.; SIMÃO, T.L.L.; STADLER, T.; RABOSKY, D.L.; HONEYCUTT, R.L.; John J. FLYNN, J.J.; INGRAM, C.M.; STEINER, C.; WILLIAMS, T.L.; ROBINSON, T.J.; BURK-HERRICK, A.; WESTERMAN, M.; AYOUB, N.A.; SPRINGER, M.S.; William J. MURPHY, W.J. 2011. Impacts of the Cretaceous terrestrial revolution and KPg extinction on mammal diversification. Science 28(334):521-524.
Abstract. Previous analyses of relations, divergence times, and diversification patterns among extant mammalian families have relied on supertree methods and local molecular clocks. We constructed a molecular supermatrix for mammalian families and analyzed these data with likelihood-based methods and relaxed molecular clocks. Phylogenetic analyses resulted in a robust phylogeny with better resolution than phylogenies from supertree methods. Relaxed clock analyses support the long-fuse model of diversification and highlight the importance of including multiple fossil calibrations that are spread across the tree. Molecular time trees and diversification analyses suggest important roles for the Cretaceous Terrestrial Revolution and Cretaceous-Paleogene (KPg) mass extinction in opening up ecospace that promoted interordinal and intraordinal diversification, respectively. By contrast, diversification analyses provide no support for the hypothesis concerning the delayed rise of present-day mammals during the Eocene Period.
Abstract. Previous analyses of relations, divergence times, and diversification patterns among extant mammalian families have relied on supertree methods and local molecular clocks. We constructed a molecular supermatrix for mammalian families and analyzed these data with likelihood-based methods and relaxed molecular clocks. Phylogenetic analyses resulted in a robust phylogeny with better resolution than phylogenies from supertree methods. Relaxed clock analyses support the long-fuse model of diversification and highlight the importance of including multiple fossil calibrations that are spread across the tree. Molecular time trees and diversification analyses suggest important roles for the Cretaceous Terrestrial Revolution and Cretaceous-Paleogene (KPg) mass extinction in opening up ecospace that promoted interordinal and intraordinal diversification, respectively. By contrast, diversification analyses provide no support for the hypothesis concerning the delayed rise of present-day mammals during the Eocene Period.
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, 10 de maio de 2014
Late Pleistocene (Rancholabrean) Glyptodont and Pampathere (Xenarthra, Cingulata) from Sonora, Mexico
MEAD, J.I.; SWIFT, S.L.; WHITE, R.S. MCDONALD, H.G.; BAEZ, A. 2007. Late Pleistocene (Rancholabrean) Glyptodont and Pampathere (Xenarthra, Cingulata) from Sonora, Mexico. Revista Mexicana de Ciências Geológicas 24(3):439-449.
Abstract. The fossil-rich deposits of Térapa (east-central Sonora) contain more than 60 zoological taxa, many with tropical affinities such as Crocodylus (crocodylian), Hydrochaeris (capybara), and many birds. The deposits also contain the dermal ossicles (osteoderms) of two extinct xenarthrans, a glyptodont (Glyptotherium cylindricum) and a pampathere (giant armadillo; Pampatherium cf. mexicanum). Glyptodont remains are also known from other less-well studied localities in Sonora. The faunas from these localities also contain the genus Bison, which indicates that the deposits are of the Rancholabrean Land Mammal Age, late Pleistocene. The presence of Pampatherium at Térapa and the presence of Glyptotherium at Térapa and the Río Mayo/Río Yaqui sites represent the first published accounts of these species from Sonora, and greatly extends their known geographical distribution during the Rancholabrean by about 1,100 km into northwestern Mexico.
Abstract. The fossil-rich deposits of Térapa (east-central Sonora) contain more than 60 zoological taxa, many with tropical affinities such as Crocodylus (crocodylian), Hydrochaeris (capybara), and many birds. The deposits also contain the dermal ossicles (osteoderms) of two extinct xenarthrans, a glyptodont (Glyptotherium cylindricum) and a pampathere (giant armadillo; Pampatherium cf. mexicanum). Glyptodont remains are also known from other less-well studied localities in Sonora. The faunas from these localities also contain the genus Bison, which indicates that the deposits are of the Rancholabrean Land Mammal Age, late Pleistocene. The presence of Pampatherium at Térapa and the presence of Glyptotherium at Térapa and the Río Mayo/Río Yaqui sites represent the first published accounts of these species from Sonora, and greatly extends their known geographical distribution during the Rancholabrean by about 1,100 km into northwestern Mexico.
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.
segunda-feira, 12 de agosto de 2013
I Simpósio de Evolução de Mamíferos
A Sociedade Brasileira de Mastozoologia (SBMz) em conjunto com o Programa de Pós Graduação em Genética da UFRJ e com o apoio da UERJ, IOC-FIOCRUZ e UNIRIO estão organizando o I Simpósio de Evolução de Mamíferos que será realizado no Rio de Janeiro, de 23 a 25 de Outubro de 2013, no auditório 53 da UERJ, campus Maracanã.
A SBMz irá ainda oferecer auxílio para três alunos de graduação (sócios pagantes de 2013) das regiões Norte, Nordeste e Centro-oeste, pagando a inscrição e passagem de ida e volta para o Rio de Janeiro. Para concorrer os interessados devem enviar uma carta de intenção e o link do Currículo Lattes para a SBMz.
A SBMz irá ainda oferecer auxílio para três alunos de graduação (sócios pagantes de 2013) das regiões Norte, Nordeste e Centro-oeste, pagando a inscrição e passagem de ida e volta para o Rio de Janeiro. Para concorrer os interessados devem enviar uma carta de intenção e o link do Currículo Lattes para a SBMz.
sábado, 10 de agosto de 2013
The pampas cat group (genus Lynchailurus Severtzov, 1858) (Carnivora: Felidae), a systematic and biogeographic review
GARCIA-PEREA, R. 1994. The pampas cat group (genus Lynchailurus Severtzov, 1858) (Carnivora: Felidae), a systematic and biogeographic review. American Museum Novitates 3096:1-36.
Abstract. A systematic study of 86 specimens of South American cats formerly known as Felis colocolo reveals three species, in addition to a new subspecies described herein. The three species are grouped in the genus Lynchailurus on the basis of shared character states. Lynchailurus pajeros occurs on high-elevation steppes from Ecuador to Bolivia and Argentina (eastern slope of the Andes), and farther south in Argentina into lowland steppe, shrubland, and dry forest habitats. Its southern limit is Patagonia (Argentinean and Chilean). Lynchailurus braccatus is found in Brazil, Paraguay, and Uruguay, where it occupies humid and warmer grassland and forested areas, at moderate elevations. Lynchailurus colocolo occurs in subtropical forests at middle elevations in central Chile, and in high-elevation steppes in northern Chile on the western slope of the Andes. The latter species may be endangered, because its distribution is limited. Assigned subspecies are as follows: L. pajeros budini and L. p. crespoi, in northwestern Argentina; L. p. crucinus, in southern Argentina and Chile; L. p. garleppi, in Peru; L. p. pajeros, in central Argentina; L. p. steinbachi, in Bolivia; L. p. thomasi, from Ecuador; L. braccatus braccatus, in southwestern Brazil and Paraguay; L. b. munoai, in Uruguay and southern Brazil; L. colocolo colocolo, in central Chile; and L. c. wolffsohni (new subspecies), in northern Chile.
Abstract. A systematic study of 86 specimens of South American cats formerly known as Felis colocolo reveals three species, in addition to a new subspecies described herein. The three species are grouped in the genus Lynchailurus on the basis of shared character states. Lynchailurus pajeros occurs on high-elevation steppes from Ecuador to Bolivia and Argentina (eastern slope of the Andes), and farther south in Argentina into lowland steppe, shrubland, and dry forest habitats. Its southern limit is Patagonia (Argentinean and Chilean). Lynchailurus braccatus is found in Brazil, Paraguay, and Uruguay, where it occupies humid and warmer grassland and forested areas, at moderate elevations. Lynchailurus colocolo occurs in subtropical forests at middle elevations in central Chile, and in high-elevation steppes in northern Chile on the western slope of the Andes. The latter species may be endangered, because its distribution is limited. Assigned subspecies are as follows: L. pajeros budini and L. p. crespoi, in northwestern Argentina; L. p. crucinus, in southern Argentina and Chile; L. p. garleppi, in Peru; L. p. pajeros, in central Argentina; L. p. steinbachi, in Bolivia; L. p. thomasi, from Ecuador; L. braccatus braccatus, in southwestern Brazil and Paraguay; L. b. munoai, in Uruguay and southern Brazil; L. colocolo colocolo, in central Chile; and L. c. wolffsohni (new subspecies), in northern Chile.
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, 9 de março de 2013
The historical ecology of human and wild primate malarias in the New World
CORMIER, L.A. 2010. The historical ecology of human and wild primate malarias in the New World. Diversity 2(2):256-280. doi: 10.3390/d2020256.
Abstract. The origin and subsequent proliferation of malarias capable of infecting humans in South America remain unclear, particularly with respect to the role of Neotropical monkeys in the infectious chain. The evidence to date will be reviewed for Pre-Columbian human malaria, introduction with colonization, zoonotic transfer from cebid monkeys, and anthroponotic transfer to monkeys. Cultural behaviors (primate hunting and pet-keeping) and ecological changes favorable to proliferation of mosquito vectors are also addressed.
Abstract. The origin and subsequent proliferation of malarias capable of infecting humans in South America remain unclear, particularly with respect to the role of Neotropical monkeys in the infectious chain. The evidence to date will be reviewed for Pre-Columbian human malaria, introduction with colonization, zoonotic transfer from cebid monkeys, and anthroponotic transfer to monkeys. Cultural behaviors (primate hunting and pet-keeping) and ecological changes favorable to proliferation of mosquito vectors are also addressed.
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, 1 de outubro de 2011
Evolution of nakedness in Homo sapiens
RANTALA, M.J. 2007. Evolution of nakedness in Homo sapiens. Journal of Zoology 273:1-7.
Abstract. Homo sapiens L. is the only existing primate species lacking in functionally effective thermally insulating fur. As all other primates have considerable hair covering, it has always been accepted that our ancestors must once have had a respectable amount of body hair. Unfortunately, fossils cannot help us when it comes to differences in skin and hair. Recent DNA analysis, however, has given us some idea of when and where the great denudation took place. A number of hypotheses have been proposed to account for this feature, but none of these has gained general acceptance. In this paper, I present these hypotheses in the light of current empirical evidence and discussion.
Abstract. Homo sapiens L. is the only existing primate species lacking in functionally effective thermally insulating fur. As all other primates have considerable hair covering, it has always been accepted that our ancestors must once have had a respectable amount of body hair. Unfortunately, fossils cannot help us when it comes to differences in skin and hair. Recent DNA analysis, however, has given us some idea of when and where the great denudation took place. A number of hypotheses have been proposed to account for this feature, but none of these has gained general acceptance. In this paper, I present these hypotheses in the light of current empirical evidence and discussion.
sábado, 24 de setembro de 2011
Holocene vegetation chance and the mammal faunas of South America and Africa
VIVO, M.; CARMIGNOTTO, A.P. 2004. Holocene vegetation chance and the mammal faunas of South America and Africa. Journal of Biogeography 31:943-957.
Abstract
Aim. Although sharing many similarities in their vegetation types, South America and Africa harbour very dissimilar recent mammal faunas, not only taxonomically but also in terms of several faunistic patterns. However late Pleistocene and mid-Holocene faunas, albeit taxonomically distinct, presented many convergent attributes. Here we propose that the effects of the Holocene climatic change on vegetation physiognomy has played a crucial role in shaping the extant mammalian faunistic patterns.
Location. South America and Africa from the late Pleistocene to the present.
Methods. Data presented here have been compiled from many distinct sources, including palaeontological and neontological mammalian studies, palaeoclimatology, palynology, and publications on vegetation ecology. Data on Pleistocene, Holocene and extant mammal faunas of South America and Africa allowed us to establish a number of similar and dissimilar faunistic patterns between the two continents across time. We then considered what changes in vegetation physiognomy would have occurred under the late Pleistocene last
Abstract
Aim. Although sharing many similarities in their vegetation types, South America and Africa harbour very dissimilar recent mammal faunas, not only taxonomically but also in terms of several faunistic patterns. However late Pleistocene and mid-Holocene faunas, albeit taxonomically distinct, presented many convergent attributes. Here we propose that the effects of the Holocene climatic change on vegetation physiognomy has played a crucial role in shaping the extant mammalian faunistic patterns.
Location. South America and Africa from the late Pleistocene to the present.
Methods. Data presented here have been compiled from many distinct sources, including palaeontological and neontological mammalian studies, palaeoclimatology, palynology, and publications on vegetation ecology. Data on Pleistocene, Holocene and extant mammal faunas of South America and Africa allowed us to establish a number of similar and dissimilar faunistic patterns between the two continents across time. We then considered what changes in vegetation physiognomy would have occurred under the late Pleistocene last
glacial maximum (LGM) and the Holocene climatic optimum (HCO) climatic regimes. We have ordained these proposed vegetation changes along rough physiognomic seral stages according to assumptions based on current botanical research. Finally, we have associated our hypothesized vegetation changes in South America and Africa with mammalian faunistic patterns, establishing a putative causal relationship between them.
Results. The extant mammal faunas of South America and Africa differ widely in taxonomical composition; the number of medium and large species they possess; behavioural and ecological characteristics related to herbivore herding, migration and predation; and biogeographical patterns. All such distinctions are mostly
related to the open formation faunas, and have been completely established around the mid-Holocene. Considering that the mid-Holocene was a time of greater humidity than the late Pleistocene, vegetation cover in South America and Africa would have been dominated by forest or closed vegetation landscapes, at
least for most of their lower altitude tropical regions. We attribute the loss of larger-sized mammal lineages in South America to the decrease of open vegetation area, and their survival in Africa to the existence of vast savannas in formerly steppic or desertic areas in subtropical Africa, north and south of the equator. Alternative explanations, mostly dealing with the disappearance of South American megamammals, are then reviewed and criticized.
Main conclusions. The reduction of open formation areas during the HCO in South America and Africa explains most of the present distinct faunistic patterns between the two continents. While South America would have lost most of its open formations within the 30 latitudinal belt, Africa would have kept large areas suitable to the open formation mammalian fauna in areas presently occupied by desert and semi-arid vegetation. Thus, the same general climatic events that affected South America in the late Pleistocene and Holocene also affected Africa, leading to our present day faunistic dissimilarities by maintaining the African mammalian communities almost unchanged while dramatically altering those of South America.
sábado, 30 de julho de 2011
Marsupial relationships and a timeline for marsupial radiation in South Gondwana
NILSSON, M.A.; ARNASON, U.; SPENCER, P.B.S.; JANKE, A. 2004. Marsupial relationships and a timeline for marsupial radiation in South Gondwana. Gene 340:189-196.
Abstract. Recent marsupials include about 280 species divided into 18 families and seven orders. Approximately 200 species live in Australia/New Guinea. The remaining species inhabit South American with some of these secondarily ranging into North America. In this study, we examine marsupial relationships and estimate their divergences times using complete mitochondrial (mt) genomes. The sampling, which includes nine new mtDNAs and a total number of 19 marsupial genomes, encompasses all extant orders and 14 families. The analysis identified a basal split between Didelphimorphia and remaining orders about 69 million years before present (MYBP), while other ordinal divergences were placed in Tertiary times. The monotypic South American order Microbiotheria (Dromiciops gliroides, Monito del Monte) was solidly nested among its Australian counterparts. The results suggest that marsupials colonized Australia twice from Antarctica/South America and that the divergence between Microbiotheria and its Australian relatives coincided with the geological separation of Antarctica and Australia. Within Australia itself, several of the deepest divergences were estimated to have taken place close to the Eocene/Oligocene transition.
Abstract. Recent marsupials include about 280 species divided into 18 families and seven orders. Approximately 200 species live in Australia/New Guinea. The remaining species inhabit South American with some of these secondarily ranging into North America. In this study, we examine marsupial relationships and estimate their divergences times using complete mitochondrial (mt) genomes. The sampling, which includes nine new mtDNAs and a total number of 19 marsupial genomes, encompasses all extant orders and 14 families. The analysis identified a basal split between Didelphimorphia and remaining orders about 69 million years before present (MYBP), while other ordinal divergences were placed in Tertiary times. The monotypic South American order Microbiotheria (Dromiciops gliroides, Monito del Monte) was solidly nested among its Australian counterparts. The results suggest that marsupials colonized Australia twice from Antarctica/South America and that the divergence between Microbiotheria and its Australian relatives coincided with the geological separation of Antarctica and Australia. Within Australia itself, several of the deepest divergences were estimated to have taken place close to the Eocene/Oligocene transition.
segunda-feira, 6 de junho de 2011
3rd Biological Evolution Workshop
Entre os dias 7 e 9 de novembro de 2011 ocorrerá em Porto Alegre o 3º Workshop sobre Biologia Evolutiva, no Auditório do Departamento de Genética da UFRGS. O evento trata de questões evolutivas em geral, não apenas sobre mamíferos. Uma das palestras, entretanto, fala sobre pigmentação adaptativa em vertebrados, e contará com a participação dos professores Thales R.O. de Freitas (da UFRGS) e Eduardo Eizirik (da PUCRS), dois mastozoólogos conhecidos por seus trabalhos no campo da genética.
Maiores informações no Departamento de Genética da UFRGS (prédio 43312, Campus do Vale) e no endereço http://www.biologicalevolution.com.br/.
Clique aqui para fazer download do pdf com a programação.
Maiores informações no Departamento de Genética da UFRGS (prédio 43312, Campus do Vale) e no endereço http://www.biologicalevolution.com.br/.
Clique aqui para fazer download do pdf com a programação.
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