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Paleontology

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https://www.readbyqxmd.com/read/28630903/comment-1-on-formation-of-the-isthmus-of-panama-by-o-dea-et-al
#1
Carlos Jaramillo, Camilo Montes, Agustín Cardona, Daniele Silvestro, Alexandre Antonelli, Christine D Bacon
A review and reanalysis of geological, molecular, and paleontological data led O'Dea et al. (1) to propose (i) that reports by Montes et al. (2) and Bacon et al. (3) regarding a middle Miocene closure of the Central American Seaway (CAS) are unsupported, and (ii) a new age of the formation of the Isthmus at 2.8 million years ago (Ma). Here, we reject both of these conclusions.
June 2017: Science Advances
https://www.readbyqxmd.com/read/28630902/comment-2-on-formation-of-the-isthmus-of-panama-by-o-dea-et-al
#2
Peter Molnar
O'Dea et al. challenged the inference that the Isthmus of Panama has been in place for the last 10 million years or more and from "an exhaustive review and reanalysis of geological, paleontological, and molecular records," they argued for a "formation of the Isthmus of Panama sensu stricto around 2.8 Ma." I review environmental changes since ~5 Ma throughout Earth, and I argue that environmental changes in the Central American-Caribbean region have been part of a concurrent, worldwide phenomenon that requires a global, not local, explanation...
June 2017: Science Advances
https://www.readbyqxmd.com/read/28622927/evolution-of-the-hominin-knee-and-ankle
#3
Mélanie A Frelat, Colin N Shaw, Simone Sukhdeo, Jean-Jacques Hublin, Stefano Benazzi, Timothy M Ryan
The dispersal of the genus Homo out of Africa approximately 1.8 million years ago (Ma) has been understood within the context of changes in diet, behavior, and bipedal locomotor efficiency. While various morphological characteristics of the knee and ankle joints are considered part of a suite of traits indicative of, and functionally related to, habitual bipedal walking, the timing and phylogenetic details of these morphological changes remain unclear. To evaluate the timing of knee and ankle joint evolution, we apply geometric morphometric methods to three-dimensional digital models of the proximal and distal tibiae of fossil hominins, Holocene Homo sapiens, and extant great apes...
July 2017: Journal of Human Evolution
https://www.readbyqxmd.com/read/28555244/estimation-of-ancestry-for-an-undocumented-mandibular-sample-using-dental-morphology
#4
Luís Miguel Marado, Ana Maria Silva
Dental morphology is a useful resource in archaeology, anthropology and paleontology, due to its genetic determination. Teeth are a material of high durability and stability. This work aims to study the dental morphology and test the Portuguese and European biological affinities of an undocumented mandibular sample, through comparison with global and Iberian samples. The dental traits in 163 mandibles (kept at the Museum of Natural History of the University of Oporto, Portugal) were scored using a standardized methodology (ASUDAS: Arizona State University Dental Anthropology System) and compared to other world-wide and Iberian samples through Principal Components (PCA) and Mean Measure of Divergence analyses...
May 30, 2017: Anthropologischer Anzeiger; Bericht über die Biologisch-anthropologische Literatur
https://www.readbyqxmd.com/read/28543226/interactions-within-and-between-clades-shaped-the-diversification-of-terrestrial-carnivores
#5
Mathias M Pires, Daniele Silvestro, Tiago B Quental
A longstanding debate in evolutionary biology and paleontology is whether ecological interactions such as competition impose diversity dependence on speciation and extinction rates. Here we analyze the fossil record of terrestrial mammalian carnivores in North America and Eurasia using a Bayesian framework to assess whether their diversity dynamics were affected by diversity dependence within and between families (12 in Eurasia, 10 in North America). We found eight instances of within-clade diversity dependence suppressing speciation rates and detected between-clade effects increasing extinction rates in six instances...
May 22, 2017: Evolution; International Journal of Organic Evolution
https://www.readbyqxmd.com/read/28486705/a-new-model-for-ancient-dna-decay-based-on-paleogenomic-meta-analysis
#6
Logan Kistler, Roselyn Ware, Oliver Smith, Matthew Collins, Robin G Allaby
The persistence of DNA over archaeological and paleontological timescales in diverse environments has led to a revolutionary body of paleogenomic research, yet the dynamics of DNA degradation are still poorly understood. We analyzed 185 paleogenomic datasets and compared DNA survival with environmental variables and sample ages. We find cytosine deamination follows a conventional thermal age model, but we find no correlation between DNA fragmentation and sample age over the timespans analyzed, even when controlling for environmental variables...
May 9, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28484858/functional-morphology-in-paleobiology-origins-of-the-method-of-paradigms
#7
Martin J S Rudwick
From the early nineteenth century, the successful use of fossils in stratigraphy oriented paleontology (and particularly the study of fossil invertebrates) towards geology. The consequent marginalising of biological objectives was countered in the twentieth century by the rise of 'Paläobiologie', first in the German cultural area and only later, as 'paleobiology', in the anglophone world. Several kinds of paleobiological research flourished internationally after the Second World War, among them the novel field of 'paleoecology'...
May 8, 2017: Journal of the History of Biology
https://www.readbyqxmd.com/read/28450996/a-clinical-correlation-between-stature-and-posterior-tooth-length
#8
Smitha Reddy, Bhuvan Shome, Jayaprakash Patil, Pradeep Koppolu
INTRODUCTION: Exploration and determination of the relationship between stature and length of tooth is essential in Paleontology, Forensic Odontology and Endodontology. This study aimed to determine any association between stature and posterior tooth length in a group of patients who required root canal treatment. METHODS: Age, sex and standing height of adults were considered for posterior tooth length measurement. Molars and Premolars of apparently normal males (n=115 for molars, n= 75 for premolars) and females (n=124 for molars, n=80 for premolars), aged 20-50 years with intact cuspal morphology, which required RCT were selected for this study...
2017: Pan African Medical Journal
https://www.readbyqxmd.com/read/28434537/new-cranium-of-the-endemic-caribbean-platyrrhine-antillothrix-bernensis-from-la-altagracia-province-dominican-republic
#9
Lauren B Halenar, Siobhán B Cooke, Alfred L Rosenberger, Renato Rímoli
Recent paleontological collection in submerged caves in the eastern Dominican Republic has yielded new specimens of Antillothrix bernensis. Here we describe a complete cranium of an adult individual (MHD 20) and provide phenetic comparisons to other endemic Caribbean taxa and extant mainland platyrrhines using three-dimensional geometric morphometric methods (3DGM). Qualitative and quantitative comparisons support conclusions based on other recently described fossil material: Antillothrix has a dentition lacking clear dietary specialization, an elongated brain case with strong temporal lines, and a vertically oriented nuchal plane...
May 2017: Journal of Human Evolution
https://www.readbyqxmd.com/read/28416654/reconstructed-ancestral-enzymes-suggest-long-term-cooling-of-earth-s-photic-zone-since-the-archean
#10
Amanda K Garcia, J William Schopf, Shin-Ichi Yokobori, Satoshi Akanuma, Akihiko Yamagishi
Paleotemperatures inferred from the isotopic compositions (δ(18)O and δ(30)Si) of marine cherts suggest that Earth's oceans cooled from 70 ± 15 °C in the Archean to the present ∼15 °C. This interpretation, however, has been subject to question due to uncertainties regarding oceanic isotopic compositions, diagenetic or metamorphic resetting of the isotopic record, and depositional environments. Analyses of the thermostability of reconstructed ancestral enzymes provide an independent method by which to assess the temperature history inferred from the isotopic evidence...
May 2, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28391977/live-phylogeny-with-polytomies-finding-the-most-compact-parsimonious-trees
#11
D Papamichail, A Huang, E Kennedy, J-L Ott, A Miller, G Papamichail
Construction of phylogenetic trees has traditionally focused on binary trees where all species appear on leaves, a problem for which numerous efficient solutions have been developed. Certain application domains though, such as viral evolution and transmission, paleontology, linguistics, and phylogenetic stemmatics, often require phylogeny inference that involves placing input species on ancestral tree nodes (live phylogeny), and polytomies. These requirements, despite their prevalence, lead to computationally harder algorithmic solutions and have been sparsely examined in the literature to date...
March 30, 2017: Computational Biology and Chemistry
https://www.readbyqxmd.com/read/28355329/parkinson-s-disease-200-years-the-outstanding-contribution-of-old-hubert
#12
Hélio A G Teive, Renato P Munhoz, Andrew J Lees
Two hundred years after the publication, of "An Essay on the Shaking Palsy", this indisputable landmark in our understanding of the nature of Parkinson's disease still remains. What is frequently overlooked, however, is the originality of James Parkinson's ideas about how clinical observations could be segregated into diagnostic entities. Parkinson was a surgeon apothecary with wide ranging interests outside medicine including geology and paleontology. He was also a strong campaigner for social change and a political pamphleteer, writing under the nom de plume of "Old Hubert"...
March 2017: Arquivos de Neuro-psiquiatria
https://www.readbyqxmd.com/read/28338720/from-teeth-to-baleen-and-raptorial-to-bulk-filter-feeding-in-mysticete-cetaceans-the-role-of-paleontological-genetic-and-geochemical-data-in-feeding-evolution-and-ecology
#13
Annalisa Berta, Agnese Lanzetti, Eric G Ekdale, Thomas A Deméré
The origin of baleen and filter feeding in mysticete cetaceans occurred sometime between approximately 34 and 24 million years ago and represents a major macroevolutionary shift in cetacean morphology (teeth to baleen) and ecology (raptorial to filter feeding). We explore this dramatic change in feeding strategy by employing a diversity of tools and approaches: morphology, molecules, development, and stable isotopes from the geological record. Adaptations for raptorial feeding in extinct toothed mysticetes provide the phylogenetic context for evaluating morphological apomorphies preserved in the skeletons of stem and crown edentulous mysticetes...
December 16, 2016: Integrative and Comparative Biology
https://www.readbyqxmd.com/read/28296327/fricke-gel-dosimeter-with-improved-sensitivity-for-low-dose-level-measurements
#14
Mauro Vaiente, Wladimir Molina, Lila Carrizales Silva, Rodolfo Figueroa, Francisco Malano, Pedro Pérez, Mauricio Santibañez, José Vedelago
Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue-equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, independence of dose rate and incident direction, as well as linear dose response. This work presents the development and characterization of an improved Fricke gel system, based on modified chemical compositions, making possible its application in clinical radiology due to its improved sensitivity...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28289222/fossil-and-genomic-evidence-constrains-the-timing-of-bison-arrival-in-north-america
#15
Duane Froese, Mathias Stiller, Peter D Heintzman, Alberto V Reyes, Grant D Zazula, André E R Soares, Matthias Meyer, Elizabeth Hall, Britta J L Jensen, Lee J Arnold, Ross D E MacPhee, Beth Shapiro
The arrival of bison in North America marks one of the most successful large-mammal dispersals from Asia within the last million years, yet the timing and nature of this event remain poorly determined. Here, we used a combined paleontological and paleogenomic approach to provide a robust timeline for the entry and subsequent evolution of bison within North America. We characterized two fossil-rich localities in Canada's Yukon and identified the oldest well-constrained bison fossil in North America, a 130,000-y-old steppe bison, Bison cf...
March 28, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28276513/widespread-platinum-anomaly-documented-at-the-younger-dryas-onset-in-north-american-sedimentary-sequences
#16
Christopher R Moore, Allen West, Malcolm A LeCompte, Mark J Brooks, I Randolph Daniel, Albert C Goodyear, Terry A Ferguson, Andrew H Ivester, James K Feathers, James P Kennett, Kenneth B Tankersley, A Victor Adedeji, Ted E Bunch
Previously, a large platinum (Pt) anomaly was reported in the Greenland ice sheet at the Younger Dryas boundary (YDB) (12,800 Cal B.P.). In order to evaluate its geographic extent, fire-assay and inductively coupled plasma mass spectrometry (FA and ICP-MS) elemental analyses were performed on 11 widely separated archaeological bulk sedimentary sequences. We document discovery of a distinct Pt anomaly spread widely across North America and dating to the Younger Dryas (YD) onset. The apparent synchroneity of this widespread YDB Pt anomaly is consistent with Greenland Ice Sheet Project 2 (GISP2) data that indicated atmospheric input of platinum-rich dust...
March 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28276199/new-insights-into-a-hot-environment-for-early-life
#17
REVIEW
Jianghong Dai
Investigating the physical-chemical setting of early life is a challenging task. In this contribution, the author attempted to introduce a provocative concept from cosmology - cosmic microwave background (CMB), which is the residual thermal radiation from a hot early Universe - to the field. For this purpose, the author revisited a recently deduced biomarker, the 1,6-anhydro bond of sugars in bacteria. In vitro, the 1,6-anhydro bond of sugars reflects and captures residual thermal radiation in thermochemical processes and therefore is somewhat analogous to CMB...
March 9, 2017: Environmental Microbiology Reports
https://www.readbyqxmd.com/read/28265519/specimen-level-phylogenetics-in-paleontology-using-the-fossilized-birth-death-model-with-sampled-ancestors
#18
Andrea Cau
Bayesian phylogenetic methods integrating simultaneously morphological and stratigraphic information have been applied increasingly among paleontologists. Most of these studies have used Bayesian methods as an alternative to the widely-used parsimony analysis, to infer macroevolutionary patterns and relationships among species-level or higher taxa. Among recently introduced Bayesian methodologies, the Fossilized Birth-Death (FBD) model allows incorporation of hypotheses on ancestor-descendant relationships in phylogenetic analyses including fossil taxa...
2017: PeerJ
https://www.readbyqxmd.com/read/28196688/biodiversity-and-topographic-complexity-modern-and-geohistorical-perspectives
#19
REVIEW
Catherine Badgley, Tara M Smiley, Rebecca Terry, Edward B Davis, Larisa R G DeSantis, David L Fox, Samantha S B Hopkins, Tereza Jezkova, Marjorie D Matocq, Nick Matzke, Jenny L McGuire, Andreas Mulch, Brett R Riddle, V Louise Roth, Joshua X Samuels, Caroline A E Strömberg, Brian J Yanites
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, tracking tectonic or climatic history. Topographic diversity gradients from the present day and the past can result from the generation of species by vicariance or from the accumulation of species from dispersal into a region with strong environmental gradients...
March 2017: Trends in Ecology & Evolution
https://www.readbyqxmd.com/read/28187191/empirical-and-bayesian-approaches-to-fossil-only-divergence-times-a-study-across-three-reptile-clades
#20
Alan H Turner, Adam C Pritchard, Nicholas J Matzke
Estimating divergence times on phylogenies is critical in paleontological and neontological studies. Chronostratigraphically-constrained fossils are the only direct evidence of absolute timing of species divergence. Strict temporal calibration of fossil-only phylogenies provides minimum divergence estimates, and various methods have been proposed to estimate divergences beyond these minimum values. We explore the utility of simultaneous estimation of tree topology and divergence times using BEAST tip-dating on datasets consisting only of fossils by using relaxed morphological clocks and birth-death tree priors that include serial sampling (BDSS) at a constant rate through time...
2017: PloS One
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