1,721,069 research outputs found
Morphological disparity in Plio−Pleistocene large carnivore guilds from Italian peninsula
No full textMeloro, C. 2011. Morphological disparity in Plio−Pleistocene large carnivore guilds from Italian peninsula. Act
Cats and Dogs Down the Tree: The Tempo and Mode of Evolution in the Lower Carnassial of Fossil and Living Carnivora. Integrating ecology into macroevolutionary research
No full textanalisis filoenetica della diversificazione in canidi e felid
Locomotory Adaptations in 3D Humerus Geometry of Xenarthra: Testing for Convergence
Full text linkThree-dimensional (3D) models of fossil bones are increasingly available, thus opening a novel frontier in the study of organismal size and shape evolution. We provide an example of how photogrammetry can be combined with Geometric Morphometrics (GMM) techniques to study patterns of morphological convergence in the mammalian group of Xenarthra. Xenarthrans are currently represented by armadillos, sloths, and anteaters. However, this clade shows an incredibly diverse array of species and ecomorphotypes in the fossil record, including gigantic ground sloths and glyptodonts. Since the humerus is a weight-bearing bone in quadrupedal mammals and its morphology correlates with locomotor behavior, it provides an ideal bone to gain insight into adaptations of fossil species. A 3D sample of humerii belonging to extant and fossil Xenarthra allowed us to identify a significant phylogenetic signal and a strong allometric component in the humerus shape. Although no rate shift in the evolution of the humerus shape was recorded for any clade, fossorial and arboreal species humerii did evolve at significantly slower and faster paces, respectively, than the rest of the Xenarthran species. Significant evidence for morphological convergence found among the fossorial species and between the two tree sloth genera explains these patterns. These results suggest that the highly specialized morphologies of digging taxa and tree sloths represent major deviations from the plesiomorphic Xenarthran body plan, evolved several times during the history of the group
Species occupancy and its course in the past: macroecological patterns in extinct communities.
No full textNew Avenues for old travellers. Phenotypic evolutionary trends meet morphodynamics, and both enter the global change biology era
Full text linkEvolutionary trends (ETs) are traditionally defined as substantial changes in the state of traits through time produced by a persistent condition of directional evolution. ETs might also include directional responses to ecological, climatic or biological gradients and represent the primary evolutionary pattern at high taxonomic levels and over long-time scales. The absence of a well-supported operative definition of ETs blurred the definition of conceptual differences between ETs and other key concepts in evolution such as convergence, parallel evolution, and divergence. Also, it prevented the formulation of modern guidelines for studying ETs and evolutionary dynamics related to them. In phenotypic evolution, the theory of morphodynamics states that the interplay between evolutionary factors such as phylogeny, evo-devo constraints, environment, and biological function determines morphological evolution. After introducing a new operative definition, here we provide a morphodynamics-based framework for studying phenotypic ETs, discussing how understanding the impact of these factors on ETs improves the explanation of links between biological patterns and processes underpinning directional evolution. We envisage that adopting a quantitative, pattern-based, and multifactorial approach will pave the way to new potential applications for this field of evolutionary biology. In this framework, by exploiting the catalysing effect of climate change on evolution, research on ETs induced by global change might represent an ideal arena for validating hypotheses about the predictability of evolution
Effect of predation on prey abundance and survival in Plio-Pleistocene mammalian communities.
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Similarities between lions and sympatric carnivores in diel activity, size and morphology
Full text linkTemporal separation in diel activity between species can be caused either by different realized niches or by competition avoidance. Morphologically similar species tend to have similar ecological niches. Therefore, morphological similarities among sympatric species may be related to both overlap in diel activity and possibilities for competition. In carnivores, competition is often strong and asymmetric. Africa contains one of the most species rich carnivore assemblages in the world, where the African lion (Panthera leo) is dominant wherever it is present. Using camera trap data on South African carnivores, we evaluated how overlap with lions in diel activity related to similarities to lions in body mass, skull and long bone morphology. We found a positive association between overlap in diel activity with lions and similarities in log body mass, but we only observed this association using dry season activity data. We found no associations between overlap in diel activity with lions and similarities in either long bone or skull morphology, nor did we find associations between differences in overlap in diel activity within species between one reserve with and one without lions and morphological similarity with lions. Our results suggest that niche utilization rather than avoidance of lions dictated carnivore diel activity, although we acknowledge that lion avoidance could have been manifested in spatial rather than temporal separation. Our study supports recent suggestions of context dependencies in the effects of apex predator presences
Inconstancy in predator/prey ratios in Quaternary large mammal communities of Italy, with an appraisal of mechanisms. Quaternary Research
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