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The phylogeny of South American spiny rats (Rodentia; Echimyidae) was studied using the exon 28 of the von Willebrand Factor nuclear gene (vWF). Sequences were analysed separately and in combination with a mitochondrial dataset (cyt b,... more
The phylogeny of South American spiny rats (Rodentia; Echimyidae) was studied using the exon 28 of the von Willebrand Factor nuclear gene (vWF). Sequences were analysed separately and in combination with a mitochondrial dataset (cyt b, 12S and 16S rRNAs) used in previous publications. The basal polytomy of echimyids was partially resolved and unexpected intergeneric clades were recovered. Thus, the intimate nested position of Myocastor within echimyids is evidenced. A well-supported clade is identified, including all the arboreal genera, and a group formed by Myocastor, Thrichomys, and Proechimys+Hoplomys. The clustering of Euryzygomatomys+Clyomys with Trinomys is also suggested. On the opposite, the phylogenetic position of Capromys as well as the relationships among arboreal genera remain unclear. Molecular divergence times were estimated using a Bayesian relaxed molecular clock and suggest a Middle Miocene origin for most of modern genera. The ecomorphological diversification of echimyids is discussed in the light of these new results and past environmental modifications in South America.
Research Interests: Evolutionary Biology, Genetics, Phylogenetics, Biology, Natural History, and 15 moreMedicine, Rodentia, Phylogeny, Molecular clock, Animals, Molecular Phylogenetics and Evolution, South America, Biological evolution, Molecular phylogenetics, Phylogenetic Tree, Bayes Theorem, Divergence Time, Middle Miocene, Likelihood Functions, and Arboreal Locomotion
Research Interests: Evolutionary Biology, Genetics, Geography, Biology, Peru, and 15 moreBiometry, Medicine, Discriminant Analysis, Animals, Ancient DNA, French Guiana, Cluster Analysis, Molecular Phylogenetics and Evolution, Molecular phylogenetics, Amazon rainforest, Cytochrome B Gene, Holotype, Base Sequence, Likelihood Functions, and Molecular Sequence Data
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We analyzed the phylogenetic relationships of echimyid genera based on sequences of the cytochrome b, 12S, and 16S mitochondrial genes. Our results corroborate the monophyly of Octodontoidea and the rapid diversification of echimyid... more
We analyzed the phylogenetic relationships of echimyid genera based on sequences of the cytochrome b, 12S, and 16S mitochondrial genes. Our results corroborate the monophyly of Octodontoidea and the rapid diversification of echimyid rodents as previously proposed. The analyses indicate that the family Echimyidae, including Myocastor to the exclusion of Capromys, is paraphyletic, since Capromys and Myocastor are well-supported sister-taxa. We therefore suggest the inclusion of both Capromys and Myocastor in the family Echimyidae. Five other suprageneric clades are well supported: Dactylomys+Kannabateomys, Euryzygomatomys+Clyomys, Proechimys+Hoplomys, Mesomys+Lonchothrix, and Makalata+(Echimys+Phyllomys). Trinomys and Thrichomys have no clear close relatives, and Isothrix emerged as sister to Mesomys+Lonchothrix, but with no support. We suggest that most of the cladogenesis leading to the extant echimyid genera probably occurred during the Late Miocene, about eight million years ago.
Research Interests: Evolutionary Biology, Genetics, Zoology, Biology, Medicine, and 15 moreRodentia, Phylogeny, Late Miocene, Animals, Paraphyly, Molecular Phylogenetics and Evolution, South America, Biological evolution, ribosomal RNA, Cytochrome B, Rats, Time Factors, Monophyly, Cladogenesis, and Likelihood Functions
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Phenotypic (co)variation is a prerequisite for evolutionary change, and understanding how (co)variation evolves is of crucial importance to the biological sciences. Theoretical models predict that under directional selection, phenotypic... more
Phenotypic (co)variation is a prerequisite for evolutionary change, and understanding how (co)variation evolves is of crucial importance to the biological sciences. Theoretical models predict that under directional selection, phenotypic (co)variation should evolve in step with the underlying adaptive landscape, increasing the degree of correlation among co-selected traits as well as the amount of genetic variance in the direction of selection. Whether either of these outcomes occurs in natural populations is an open question and thus an important gap in evolutionary theory. Here, we documented changes in the phenotypic (co)variation structure in two separate natural populations in each of two chipmunk species ( Tamias alpinus and T. speciosus ) undergoing directional selection. In populations where selection was strongest (those of T. alpinus ), we observed changes, at least for one population, in phenotypic (co)variation that matched theoretical expectations, namely an increase of ...
Research Interests: Evolutionary Biology, Genetics, Biology, Quantitative Genetics, Medicine, and 15 moreNatural Selection, Biological Sciences, Population, Models, Animals, Selection, Sciuridae, Biological evolution, Phenotype, Genetic variation, Ecology Coservation, Adaptive Landscape, Genetic, directional selection, and Medical and Health Sciences
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Nesse documento atualiza-se a lista dos mam feros que ocorrem no Brasil, incluido formas terrestres, aqu ticas e marinhas. De acordo com os dados existentes, o pa s possui 483 mam feros continentais e 41 marinhos, totalizando 524 esp... more
Nesse documento atualiza-se a lista dos mam feros que ocorrem no Brasil, incluido formas terrestres, aqu ticas e marinhas. De acordo com os dados existentes, o pa s possui 483 mam feros continentais e 41 marinhos, totalizando 524 esp cies, distribu das em 11 ordens, 46 ...
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The taxonomic history ofEuryoryzomys legatushas been complex and controversial, being either included in the synonymy of other oryzomyine species or considered as a valid species, as in the most recent review of the genus. Previous... more
The taxonomic history ofEuryoryzomys legatushas been complex and controversial, being either included in the synonymy of other oryzomyine species or considered as a valid species, as in the most recent review of the genus. Previous phylogenetic analyses segregatedE. legatusfromE. russatus, its putative senior synonym, but recovered it nested withinE. nitidus. A general lack of authoritative evaluation of morphological attributes, details of the chromosome complement, or other data types has hampered the ability to choose among alternative taxonomic hypotheses, and thus reach a general consensus for the status of the taxon. Herein we revisit the status ofE. legatususing an integrated approach that includes: (1) a morphological review, especially centered on specimens from northwestern Argentina not examined previously, (2) comparative cytogenetics, and (3) phylogenetic reconstruction, using mitochondrial genes.Euryoryzomys legatusis morphologically and phylogenetically distinct from ...
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Field expeditions in 2011 that inventoried the terrestrial vertebrate fauna of two wildlife protected areas in the tropical Caribbean of Guatemala have produced the first confirmed records of two bats for the country: the white-bellied... more
Field expeditions in 2011 that inventoried the terrestrial vertebrate fauna of two wildlife protected areas in the tropical Caribbean of Guatemala have produced the first confirmed records of two bats for the country: the white-bellied big-eared bat,
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We combine morphological (qualitative and quantitative data) and genetic (one mitochondrial and one nuclear gene) data from a large set of specimens of Octodon from the four currently recognized living species of the genus. The... more
We combine morphological (qualitative and quantitative data) and genetic (one mitochondrial and one nuclear gene) data from a large set of specimens of Octodon from the four currently recognized living species of the genus. The integration of the results (qualitative assessment, multivariate analysis of cranial measurements, and gene trees) allows us to state that 1) the current taxonomic scheme does not reflect the species diversity of Octodon; 2) in particular, as currently understood O. bridgesii likely is a complex of three species; 3) one of these, encompassing the southern populations of the genus, in the Araucanía Region (Chile) and Neuquén Province (Argentina), is named and described here as a new species; and 4) the mitochondrial gene tree departs from the nuclear gene tree with respect to O. pacificus and the new species here described.
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We examined geographic patterns of diversification in the highly impacted San Joaquin kangaroo rat, Dipodomys nitratoides, throughout its range in the San Joaquin Valley and adjacent basins in central California. The currently recognized... more
We examined geographic patterns of diversification in the highly impacted San Joaquin kangaroo rat, Dipodomys nitratoides, throughout its range in the San Joaquin Valley and adjacent basins in central California. The currently recognized subspecies were distinct by the original set of mensural and color variables used in their formal diagnoses, although the Fresno kangaroo rat (D. n. exilis) is the most strongly differentiated with sharp steps in character clines relative to the adjacent Tipton (D. n. nitratoides) and short-nosed (D. n. brevinasus) races. The latter two grade more smoothly into one another but still exhibit independent, and different, character clines within themselves. At the molecular level, as delineated by mtDNA cytochrome b sequences, most population samples retain high levels of diversity despite significant retraction in the species range and severe fragmentation of local populations in recent decades due primarily to landscape conversion for agriculture and ...
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The importance of the environment in shaping phenotypic evolution lies at the core of evolutionary biology. Chipmunks of the genus Tamias (subgenus Neotamias) are part of a very recent radiation, occupying a wide range of environments... more
The importance of the environment in shaping phenotypic evolution lies at the core of evolutionary biology. Chipmunks of the genus Tamias (subgenus Neotamias) are part of a very recent radiation, occupying a wide range of environments with marked niche partitioning among species. One open question is if and how those differences in environments affected phenotypic evolution in this lineage. Herein we examine the relative importance of genetic drift versus natural selection in the origin of cranial diversity exhibited by clade members. We also explore the degree to which variation in potential selective agents (environmental variables) are correlated with the patterns of morphological variation presented. We found that genetic drift cannot explain morphological diversification in the group, thus supporting the potential role of natural selection as the predominant evolutionary force during Neotamias cranial diversification, although the strength of selection varied greatly among spec...
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" Two new species of Oxymycterus were recently discovered in the yungas of Peru and Bolivia. Both are much smaller than any species previously known. A description of the two species and a review of the characters of the oxymycterine... more
" Two new species of Oxymycterus were recently discovered in the yungas of Peru and Bolivia. Both are much smaller than any species previously known. A description of the two species and a review of the characters of the oxymycterine group suggest certain ...
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... Journal of Heredity 100:3, 322-328 Online publication date: 20-Mar-2009. TEREZA JEZKOVA, MANUEL LEAL, JAVIER A. RODRÍGUEZ-ROBLES. ... Marjorie D. Matocq a b , James L. Patton a c , Maria Nazareth F. da Silva d e . (2000) POPULATION... more
... Journal of Heredity 100:3, 322-328 Online publication date: 20-Mar-2009. TEREZA JEZKOVA, MANUEL LEAL, JAVIER A. RODRÍGUEZ-ROBLES. ... Marjorie D. Matocq a b , James L. Patton a c , Maria Nazareth F. da Silva d e . (2000) POPULATION GENETIC ...
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Predicting how individual taxa will respond to climatic change is challenging, in part because the impacts of environmental conditions can vary markedly, even among closely related species. Studies of chipmunks (Tamias spp.) in Yosemite... more
Predicting how individual taxa will respond to climatic change is challenging, in part because the impacts of environmental conditions can vary markedly, even among closely related species. Studies of chipmunks (Tamias spp.) in Yosemite National Park provide an important opportunity to explore the reasons for this variation in response. While the alpine chipmunk (T. alpinus) has undergone a significant elevational range contraction over the past century, the congeneric and partially sympatric lodgepole chipmunk (T. speciosus) has not experienced an elevational range shift during this period. As a first step toward identifying the factors underlying this difference in response, we examined evidence for dietary changes and changes in cranial morphology in these species over the past century. Stable isotope analyses of fur samples from modern and historical museum specimens of these species collected at the same localities indicated that signatures of dietary change were more pronounced in T. alpinus, although diet breadth did not differ consistently between the study species. Morphometric analyses of crania from these specimens revealed significant changes in cranial shape for T. alpinus, with less pronounced changes in shape for T. speciosus; evidence of selection on skull morphology was detected for T. alpinus but not T. speciosus. These results are consistent with growing evidence that T. alpinus is generally more responsive to environmental change than T. speciosus but emphasize the complex and often geographically variable nature of such responses. Accordingly, future studies that make use of the taxonomically and spatially integrative approach employed here may prove particularly informative regarding relationships between environmental conditions, range changes, and patterns of phenotypic variation. This article is protected by copyright. All rights reserved.
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Patterns of variation in life history, ecological distribution, genetic and morphological differentiation, and speciation of pocket gophers, family Geomyidae, have been examined in the context of the genetic demography of local... more
Patterns of variation in life history, ecological distribution, genetic and morphological differentiation, and speciation of pocket gophers, family Geomyidae, have been examined in the context of the genetic demography of local populations. Emphasis has been placed on the structure of local breeding populations, dispersal potential leading to effective gene flow, and the influence of patchy distributions due to the availability of suitable soils. The focus of this paper is on those factors contributing to differentiation among geographic segments of species, or among different species--that is, to those processes responsible for converting phenotypically expressed variation within populations to that differentiating among them.
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Abstract Patton, JL, SY Yang, and P. Myers 1975. Genetic and morphologic divergence among introduced rat populations (Rattus rattus) of the Galápagos Archipelago, Ecuador. Syst. Zool. 24: 296310.The roof rat (Rattus rattus Linnaeus) was... more
Abstract Patton, JL, SY Yang, and P. Myers 1975. Genetic and morphologic divergence among introduced rat populations (Rattus rattus) of the Galápagos Archipelago, Ecuador. Syst. Zool. 24: 296310.The roof rat (Rattus rattus Linnaeus) was initially introduced into ...