61 research outputs found

    ON THE VALIDITY OF TEREBRATULA SINUOSA (BROCCHI)

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    Here we aim to fix some nomenclatural problems relating to the definition of Terebratula sinuosa. In 1616 Fabio Colonna first described two different brachiopod specimens from Italy which were later attributed to the genus Terebratula. In 1758 Linnaeus erected Anomia terebratula in reference to the drawings of Colonna. He described the heavily sulciplicate specimen figured on the upper left (specimen number 4) but addressed the specimen as if it was the number 1 in the figure (upper right). Several authors later inadvertently followed the error of Linnaeus. The neotype for T. terebratula, indicated in 1998 by Lee & Brunton, refers to the specimen number 1 in Colonna’s figure (the one to the upper right). The two specimens in Colonna were originally considered synonyms. However, the sulciplicate specimen number 4, originally figured by Colonna, refers to a distinctive Miocene Terebratula species, which has been often referred to as Terebratula sinuosa. We review evidence in favour of such a designation and provide stratigraphic and morphological evidence that T. sinuosa deserves the full rank of species. The name T. sinuosa should be maintained given the long tradition of the name in the literature, and the definition of T. terebratula should therefore be amended

    Testing for changes in rate of evolution and position of the climatic niche of clades

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    1. There is solid recognition that phylogenetic effects must be acknowledged to appreciate climatic niche variability among species clades properly. Yet, most currently available methods either work at the intra- specific level (hence they ignore phylogeny) or rely on the Brownian motion model of evolution to estimate phylogenetic effects on climatic niche variation. The Brownian mo-tion model may be inappropriate to describe niche evolution in several cases, and even a significant phylogenetic signal in climatic variables does not in-dicate that the effect of shared ancestry was relevant to niche evolution.2. We introduce a new phylogenetic comparative method which describes sig-nificant changes in the width and position of the climatic niche at the inter-specific (clade) level, while making no a priori assumption about how niche evolution took place.3. We devised the R function phylo.niche.shift to estimate whether the climatic niches of individual clades in the tree are either wider or narrower than expected, and whether the niche occupies unexpected climates. We tested phylo.niche.shift on realistic virtual species’ distribution patterns applied to a phylogeny of 365 extant primate species.4. We demonstrate via simulations that the new method is fast and accurate under widely different climatic niche evolution scenarios. phylo.niche.shift showed that the capuchin monkeys and langurs occupy much wider, and prosimian much narrower, climatic niche space than expected by their phylogenetic positions.5. phylo.niche.shift may help to improve research on niche evolution by allow-ing researchers to test specific hypotheses on the factors affecting clades’ realised niche width and position, and the potential effects of climate change on species’ distribution

    Target Deformation of the Equus stenonis Holotype Skull : A Virtual Reconstruction

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    Equus stenonis is one of the most prevalent European Pleistocene fossil horses. It is believed to be the possible ancestor of all Old World Early Pleistocene Equus, extant zebras and asses, and as such provides insights into Equus evolution and its biogeography and paleoecology. The Equus stenonis holotype skull (IGF560) was first described by Igino Cocchi in 1867, from the Early Pleistocene locality of Terranuova (Upper Valdarno basin, Italy). IGF560 is a nearly complete, although medio-laterally crushed and badly compressed skull. Here we provide the first application of a new virtual reconstruction protocol, termed Target Deformation, to the Equus stenonis holotype. The protocol extends beyond classic retrodeformation by using target specimens as a guide for the virtual reconstruction. The targets used as a reference are two fragmentary, yet well-preserved E. stenonis skulls, coming from Olivola (Italy; IGF11023) and Dmanisi (Georgia; Dm 5/154.3/4.A4.5), both Early Pleistocene in age. These two specimens do not display any major deformation, but preserve different, only slightly overlapping portions of the skull. The virtual reconstruction protocol we carried out has shown its feasibility, by producing two 3D models whose final morphology is perfectly congruent with the natural variability of a comparative sample of E. stenonis specimens. This study shows the potential of using even broken or otherwise fragmentary specimens to guide retrodeformation in badly distorted and damaged specimens. The application of Target Deformation will allow us to increase the availability of comparative specimens in studies of fossil species morphology and evolution, as well as to the study of taphonomic processes

    A new, fast method to search for morphological convergence with shape data

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    Morphological convergence is an intensely studied macroevolutionary phenomenon. It refers to the morphological resemblance between phylogenetically distant taxa. Currently available methods to explore evolutionary convergence either: rely on the analysis of the phenotypic resemblance between sister clades as compared to their ancestor, fit different evolutionary regimes to different parts of the tree to see whether the same regime explains phenotypic evolution in phylogenetically distant clades, or assess deviations from the congruence between phylogenetic and phenotypic distances. We introduce a new test for morphological convergence working directly with non-ultrametric (i.e. paleontological) as well as ultrametric phylogenies and multivariate data. The method (developed as the function search.conv within the R package RRphylo) tests whether unrelated clades are morphologically more similar to each other than expected by their phylogenetic distance. It additionally permits using known phenotypes as the most recent common ancestors of clades, taking full advantage of fossil information. We assessed the power of search.conv and the incidence of false positives by means of simulations, and then applied it to three well-known and long-discussed cases of (purported) morphological convergence: the evolution of grazing adaptation in the mandible of ungulates with high-crowned molars, the evolution of mandibular shape in sabertooth cats, and the evolution of discrete ecomorphs among anoles of Caribbean islands. The search.conv method was found to be powerful, correctly identifying simulated cases of convergent morphological evolution in 95% of the cases. Type I error rate is as low as 4-6%. We found search.conv is some three orders of magnitude faster than a competing method for testing convergence

    Diversification Rates and the Evolution of Species Range Size Frequency Distribution

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    The geographic range sizes frequency distribution (RFD) within clades is typically right-skewed with untransformed data, and bell-shaped or slightly left-skewed under the log-transformation. This means that most species within clades occupy diminutive ranges, whereas just a few species are truly widespread. A number of ecological and evolutionary explanations have been proposed to account for this pattern. Among the latter, much attention has been given to the issue of how extinction and speciation probabilities influence RFD. Numerous accounts now convincingly demonstrate that extinction rate decreases with range size, both in living and extinct taxa. The relationship between range size and speciation rate, though, is much less obvious, with either small or large ranged species being proposed to originate more daughter taxa. Herein, we used a large fossil database including twenty-one animal clades and more than 80,000 fossil occurrences distributed over more than 400 million years of marine metazoans (exclusive of vertebrates) evolution, to test the relationship between extinction rate, speciation rate, and range size. As expected, we found that extinction rate almost linearly decreases with range size. In contrast, speciation rate peaks at the large (but not the largest) end of the range size spectrum. This is consistent with the peripheral isolation mode of allopatric speciation being the main mechanism of species origination. The huge variation in phylogeny, fossilization potential, time of fossilization, and the overarching effect of mass extinctions suggest caution must be posed at generalizing our results, as individual clades may deviate significantly from the general pattern

    From Smart Apes to Human Brain Boxes. A Uniquely Derived Brain Shape in Late Hominins Clade

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    Modern humans have larger and more globular brains when compared to other primates. Such anatomical features are further reflected in the possession of a moderately asymmetrical brain with the two hemispheres apparently rotated counterclockwise and slid anteroposteriorly on one another, in what is traditionally described as the Yakovlevian torque. Developmental disturbance in human brain asymmetry, or lack thereof, has been linked to several cognitive disorders including schizophrenia and depression. More importantly, the presence of the Yakovlevian torque is often advocated as the exterior manifestation of our unparalleled cognitive abilities. Consequently, studies of brain size and asymmetry in our own lineage indirectly address the question of what, and when, made us humans, trying to trace the emergence of brain asymmetry and expansion of cortical areas back in our Homo antecedents. Here, we tackle this same issue by studying the evolution of human brain size, shape, and asymmetry on a phylogenetic tree including 19 apes and Homo species, inclusive of our fellow ancestors. We found that a significant positive shift in the rate of brain shape evolution pertains to the clade including modern humans, Neanderthals, and Homo heidelbergensis. Although the Yakovlevian torque is well evident in these species and levels of brain asymmetry are correlated to changes in brain shape, further early Homo species possess the torque. Even though a strong allometric component is present in hominoid brain shape variability, this component seems unrelated to asymmetry and to the rate shift we recorded. These results suggest that changes in brain size and asymmetry were not the sole factors behind the fast evolution of brain shape in the most recent Homo species. The emergence of handedness and early manifestations of cultural modernity in the archeological record nicely coincide with the same three species sharing the largest and most rapidly evolving brains among all hominoids

    A major change in rate of climate niche envelope evolution during hominid history

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    Homo sapiens is the only species alive able to take advantage of its cognitive abilities to inhabit almost all environments on Earth. Humans are able to culturally construct, rather than biologically inherit, their occupied climatic niche to a degree unparalleled within the animal kingdom. Precisely when hominins acquired such an ability remains unknown, and scholars disagree on the extent to which our ancestors shared this same ability. Here, we settle this issue using fine-grained palaeoclimatic data, extensive archaeological data and phylogenetic comparative methods. Our results indicate that whereas early hominins were forced to live under physiologically suitable climatic conditions, with the emergence of H. heidelbergensis, the Homo climatic niche expanded beyond its natural limits, despite progressive harshening in global climates. This indicates that technological innovations providing effective exploitation of cold and seasonal habitats predated the emergence of Homo sapiens

    Myopalladin promotes muscle growth through modulation of the serum response factor pathway

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    Myopalladin (MYPN) is a striated muscle-specific, immunoglobulin-containing protein located in the Z-line and I-band of the sarcomere as well as the nucleus. Heterozygous MYPN gene mutations are associated with hypertrophic, dilated, and restrictive cardiomyopathy, and homozygous loss-of-function truncating mutations have recently been identified in patients with cap myopathy, nemaline myopathy, and congenital myopathy with hanging big toe

    Dosaggio della Carbohidrate-Deficient Tranferrin (CDT) in addetti alla guida di veicoli stradali

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    The purpose of this study is to estimate abuse of alcohol in the drivers, they are a risk for chronic alcoholism. It has been detected elevation of the serum Carbohidrate-Deficient Transferrin (CDT), biomarker of high and prolonged consumption of alcohol, analyzed by HLPC (High Pressure Liquid Chromatography), alterations of enzymes of liver damage (ALT, AST, GGT) and erythrocyte mean corpuscular volume (MCV), as indicators traditionally associated with dependencies by alcohol, on 105 drivers observed in the last year, all male and mean age 46 ± 8.82 years. Data analysis revealed conditions of alcohol dependence, measured by increase in CDT (cut-off 2.6%), in three subjects (2.85%). In a event (33.33%) the increase of the CDT it is associated with alterations of ALT, AST and GGT, while there aren't change in the MCV. The evidence emerged confirming the CDT gold standard for the estimation of dependence by alcohol and early indicator than other traditional indicators

    Fast production of large, time-calibrated, informal supertrees with tree.merger

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    Abstract Assembling informal supertrees inclusive of extinct species is a useful but particularly long and complex procedure. We introduce a new, interactive, piece of software that allows the fast production of large, time-calibrated informal supertrees, single-handedly mixing multiple phylogenetic information from different sources. The software, embodied in the tree.merger function available as part of the RRphylo R package, allows the merging of different trees into one or adding individual species to a target phylogeny. Time calibration is implemented automatically within the function according to user-specified, optional age values that can be provided for nodes and/or tips. We applied tree.merger to two different case-studies. The first, hypothetical, case study pertains to the tree of odontocete cetaceans. The second case study regards the expansion of the new, higher-level phylogeny of dinosaurs proposing the sister clade relationship between Ornithoscelida and Sauropodomorpha from c. 50 to a 357 species tree. The two case studies took less than five seconds each to complete, on a regular personal computer
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