Journal ArticleJournal of anatomy · November 2021
Reorientation of the nasal passage away from the anteroposterior axis has evolved rarely in mammals. Unlike other mammals, cetaceans (e.g., whales, dolphins, and porpoises) have evolved a "blowhole": posteriorly repositioned nares that open dorsad. Accompa ...
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ConferenceThe FASEB Journal · April 2020
Although the external bony nares have become posteriorly repositioned in the evolution of numerous groups of mammals (e.g. elephants, tapirs), reorientation of the nasal passage away from the anteroposterior axis has evolved rarely. In cetacean (wh ...
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Journal ArticleAnatomical record (Hoboken, N.J. : 2007) · July 2019
Many modifications to the mammalian bauplan associated with the obligate aquatic lives of cetaceans-fusiform bodies, flukes, flippers, and blowholes-are evident at a glance. But among the most strikingly unusual and divergent features of modern cetacean an ...
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Journal ArticleTrends in ecology & evolution · March 2017
Topographically complex regions on land and in the oceans feature hotspots of biodiversity that reflect geological influences on ecological and evolutionary processes. Over geologic time, topographic diversity gradients wax and wane over millions of years, ...
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Journal ArticleMethods in Ecology and Evolution · March 1, 2016
To what extent can natural selection act on groupings above the species level? Despite extensive theoretical discussion and growing practical concerns over increased rates of global ecological turnover, the question has largely evaded empirical resolution. ...
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Journal ArticleProceedings of the National Academy of Sciences of the United States of America · 2016
Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater dive ...
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Journal ArticleProceedings of the Royal Society of London B: Biological Sciences · June 17, 2015
The tendency for island populations of mammalian taxa to diverge in body size from their mainland counterparts consistently in particular directions is both impressive for its regularity and, especially among rodents, troublesome for its exceptions. Howeve ...
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Journal ArticleJournal of Vertebrate Paleontology · July 1, 2012
How is the bone tissue in skeletal supports of a neonatal elephant organized, and how does this histological structure differ among the neonates of modern species, mammoths, and insular dwarfs? We used synchrotron X-ray microtomography (SR-CT) to obtain hi ...
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Journal ArticleProceedings of the National Academy of Sciences of the United States of America · May 2012
Mammals are characterized by the complex adaptations of their dentition, which are an indication that diet has played a critical role in their evolutionary history. Although much attention has focused on diet and the adaptations of specific taxa, the role ...
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Journal ArticleThe American naturalist · April 2012
Many hypotheses have been proposed to explain size changes in insular mammals, but no single variable suffices to explain the diversity of responses, particularly within Rodentia. Here in a data set on insular rodents, we observe strong consistency in the ...
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Journal ArticleJournal of the Royal Society, Interface · August 2010
In most mammals, footpads are what first strike ground with each stride. Their mechanical properties therefore inevitably affect functioning of the legs; yet interspecific studies of the scaling of locomotor mechanics have all but neglected the feet and th ...
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Journal ArticleMammalian genome : official journal of the International Mammalian Genome Society · November 2009
The RNase A ribonucleases are a complex group of functionally diverse secretory proteins with conserved enzymatic activity. We have identified novel RNase 1 genes from four species of squirrel (order Rodentia, family Sciuridae). Squirrel RNase 1 genes enco ...
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Journal ArticleCurrent Science · October 10, 2008
Current diversity is the result of macroevolutionary processes of origination and extinction of lineages through time. Here we make use of a fossil-calibrated molecular-clock phylogeny of modern squirrel genera to estimate both rates of 'birth' and 'death' ...
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Journal ArticleBiological Journal of the Linnean Society · 2008
In mammals, ‘female-biased’ sexual size dimorphism (SSD), in which females are larger than males, is uncommon.
In the present study, we examined Sylvilagus, a purported case of female-biased SSD, for evolutionary correlations
among species between SSD, bod ...
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Chapter · 2005
Studies of macroevolutionary change are uniquely focused on events and processes that require time, including events that occur infrequently (or just once), or processes that are long in duration. With respect to phenotypic variation, macroevolution is typ ...
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Journal ArticleScience (New York, N.Y.) · March 2003
By modifying habitats and creating bridges and barriers between landmasses, climate change and tectonic events are believed to have important consequences for diversification of terrestrial organisms. Such consequences should be most evident in phylogeneti ...
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Journal ArticleAmerican Zoologist · January 1, 2000
SYNOPSIS. Morphometric approaches facilitate the analysis of quantitative variation in form, typically becoming most useful for the study of organisms that have completed morphogenesis and arc at differing stages of growth. Recent conceptual and technical ...
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Journal ArticleJournal of morphology · May 1997
We compared the shape of the mandible among New World tree squirrels and selected outgroup taxa using linear measurements and areas defined by the median axis and conventional anatomical landmarks. We modified the median axis technique to define novel meas ...
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Journal ArticleThe Journal of heredity · September 1996
California blonde is a coat color mutation in the deer mouse (Peromyscus maniculatus) discovered among descendants of wild-type animals collected on Santa Cruz Island, California. The phenotype is produced by the presence of brown, rather than black, eumel ...
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Journal ArticleAmerican Zoologist · January 1, 1996
SYNOPSIS. High correlations among measurements of the cranium in the fox squirrel suggested to Olson and Miller (1958) that the skull in this species is highly integrated: that is, it tends to vary as a unit, and without clear subdivision into discrete ind ...
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Journal ArticleJournal of morphology · June 1995
The jaw, suprahyoid, and extrinsic tongue muscles are described for eight species of New World squirrels, spanning more than an order of magnitude in body mass. Anatomical differences are discussed in the light of body size, natural history, and phylogeny. ...
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Journal ArticlePaleobiology · January 1, 1992
Dental measurements are commonly used in the diagnosis of fossil elephant species, yet elephant teeth develop slowly, within a highly dynamic context that enhances opportunities for physical deformation (or its subtler manifestation, quantitative phenotypi ...
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Journal ArticleOxford surveys in evolutionary biology. Vol. 8 · January 1, 1992
Introduces the "island rule' for mammalian body size: the tendency of small mammals to enlarge and carnivores and ungulates to dwarf. For large mammals, resource limitation favours smaller body size; the genetic background to this is reviewed. Occurrence o ...
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Journal ArticleJournal of Evolutionary Biology · January 1, 1991
Homology as a topic in phylogenetic analysis has to do with what is conserved in evolution. The problem of homology in systematics — to find homologues, and in so doing, to identify taxa — is distinct from the problem of identifying what kinds of features ...
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Journal ArticlePaleobiology · January 1, 1989
A marked retardation of dental ontogeny characterizes the family Elephantidae. As a consequence of this retardation, elephant teeth are subject to the forces of mastication, eruption, and progression while still in a developing and pliant stage. As specime ...
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Journal ArticleQuaternary Research · January 1, 1984
Mammoth remains on Santa Cruz Island, one of the four Northern Channel Islands of California, are very sparse, in marked contrast to those reported from Santa Rosa and San Miguel Islands of the same island group. A probable major reason for this scarcity i ...
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Journal ArticleBiological Journal of the Linnean Society · January 1, 1984
The currently most widely used definitions of homology, which concentrate exclusively on what I call phylogenetic homology, involve comparisons between taxa. Although they share important conceptual relationships with phylogenetic homology and their role i ...
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