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Paleontology

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https://www.readbyqxmd.com/read/28808022/genomic-evidence-reveals-a-radiation-of-placental-mammals-uninterrupted-by-the-kpg-boundary
#1
Liang Liu, Jin Zhang, Frank E Rheindt, Fumin Lei, Yanhua Qu, Yu Wang, Yu Zhang, Corwin Sullivan, Wenhui Nie, Jinhuan Wang, Fengtang Yang, Jinping Chen, Scott V Edwards, Jin Meng, Shaoyuan Wu
The timing of the diversification of placental mammals relative to the Cretaceous-Paleogene (KPg) boundary mass extinction remains highly controversial. In particular, there have been seemingly irreconcilable differences in the dating of the early placental radiation not only between fossil-based and molecular datasets but also among molecular datasets. To help resolve this discrepancy, we performed genome-scale analyses using 4,388 loci from 90 taxa, including representatives of all extant placental orders and transcriptome data from flying lemurs (Dermoptera) and pangolins (Pholidota)...
August 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28798543/morphological-and-geochemical-variations-of-cyprideis-ostracoda-from-modern-waters-of-the-northern-neotropics
#2
J Meyer, C Wrozyna, M Gross, A Leis, W E Piller
The variability of modern Cyprideis salebrosa and Cyprideis americana (Ostracoda) from the northern Neotropics were investigated in order to understand site specific influences on the isotopic composition of their valves (δ(18)O, δ(13)C) in comparison to their host water and to connect this to morphological features of their valves (valve size, nodosity). C. salebrosa was found in a stream (Shell Creek, Florida) and a slightly brackish lake (Laguna del Rincon, Dominican Republic; salinity <0.7 psu) while C...
2017: Limnology
https://www.readbyqxmd.com/read/28791147/two-types-of-bone-necrosis-in-the-middle-triassic-pistosaurus-longaevus-bones-the-results-of-integrated-studies
#3
Dawid Surmik, Bruce M Rothschild, Mateusz Dulski, Katarzyna Janiszewska
Avascular necrosis, diagnosed on the basis of either a specific pathological modification of the articular surfaces of bone or its radiologic appearance in vertebral centra, has been recognized in many Mesozoic marine reptiles as well as in present-day marine mammals. Its presence in the zoological and paleontologic record is usually associated with decompression syndrome, a disease that affects secondarily aquatic vertebrates that could dive. Bone necrosis can also be caused by infectious processes, but it differs in appearance from decompression syndrome-associated aseptic necrosis...
July 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28746768/de-extinction-and-the-community-of-being
#4
Curt Meine
Extinction deeply colors the way we think about conservation and the role of humans in nature. It is easy to overlook how recently, in fact, it has entered our consciousness. Only in the last two centuries has science sought to critically study life's origins, development, and diversification. Only in the last several generations have we identified and calibrated life's five major extinction events and speculated on their causes and effects. And only in recent decades have we come to appreciate the still-unfolding fate of life's diversity under the increasing influence of humanity...
July 2017: Hastings Center Report
https://www.readbyqxmd.com/read/28734068/evolution-of-antero-posterior-patterning-of-the-limb-insights-from-the-chick
#5
REVIEW
Matthew Towers
The developing limbs of chicken embryos have served as pioneering models for understanding pattern formation for over a century. The ease with which chick wing and leg buds can be experimentally manipulated, while the embryo is still in the egg, has resulted in the discovery of important developmental organisers, and subsequently, the signals that they produce. Sonic hedgehog (Shh) is produced by mesenchyme cells of the polarizing region at the posterior margin of the limb bud and specifies positional values across the antero-posterior axis (the axis running from the thumb to the little finger)...
July 22, 2017: Genesis: the Journal of Genetics and Development
https://www.readbyqxmd.com/read/28720889/acquisition-of-terrestrial-life-by-human-ancestors-influenced-by-forest-microclimate
#6
Hiroyuki Takemoto
Bipedalism, terrestriality and open habitat were thought to be linked to each other in the course of human evolution. However, recent paleontological evidence has revealed that early hominins evolved in a wooded, humid environment. Did the evolutionary process from arboreal to terrestrial life actually require open habitat? Here I report the seasonal change in forest utilization height of West African chimpanzees (Pan troglodytes) and central African bonobos (Pan paniscus), and show that the difference in terrestriality between these two species was mainly caused by ambient temperature differences between the two study sites...
July 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28695206/a-fourth-denisovan-individual
#7
Viviane Slon, Bence Viola, Gabriel Renaud, Marie-Theres Gansauge, Stefano Benazzi, Susanna Sawyer, Jean-Jacques Hublin, Michael V Shunkov, Anatoly P Derevianko, Janet Kelso, Kay Prüfer, Matthias Meyer, Svante Pääbo
The presence of Neandertals in Europe and Western Eurasia before the arrival of anatomically modern humans is well supported by archaeological and paleontological data. In contrast, fossil evidence for Denisovans, a sister group of Neandertals recently identified on the basis of DNA sequences, is limited to three specimens, all of which originate from Denisova Cave in the Altai Mountains (Siberia, Russia). We report the retrieval of DNA from a deciduous lower second molar (Denisova 2), discovered in a deep stratigraphic layer in Denisova Cave, and show that this tooth comes from a female Denisovan individual...
July 2017: Science Advances
https://www.readbyqxmd.com/read/28678817/a-method-for-rapid-3d-scanning-and-replication-of-large-paleontological-specimens
#8
Anshuman J Das, Denise C Murmann, Kenneth Cohrn, Ramesh Raskar
We demonstrate a fast and cost-effective technique to perform three dimensional (3D) scanning and replication of large paleontological specimens, in this case the entire skull of a Tyrannosaurus rex (T.rex) with a volume in the range of 2 m3. The technique involves time-of-flight (TOF) depth sensing using the Kinect scanning module commonly used in gesture recognition in gaming. Raw data from the Kinect sensor was captured using open source software and the reconstruction was done rapidly making this a viable method that can be adopted by museums and researchers in paleontology...
2017: PloS One
https://www.readbyqxmd.com/read/28670785/constraining-the-timing-of-the-great-oxidation-event-within-the-rubisco-phylogenetic-tree
#9
B Kacar, V Hanson-Smith, Z R Adam, N Boekelheide
Ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase (RuBisCO, or Rubisco) catalyzes a key reaction by which inorganic carbon is converted into organic carbon in the metabolism of many aerobic and anaerobic organisms. Across the broader Rubisco protein family, homologs exhibit diverse biochemical characteristics and metabolic functions, but the evolutionary origins of this diversity are unclear. Evidence of the timing of Rubisco family emergence and diversification of its different forms has been obscured by a meager paleontological record of early Earth biota, their subcellular physiology and metabolic components...
July 3, 2017: Geobiology
https://www.readbyqxmd.com/read/28650986/evolutionary-history-and-phylogeographic-relationships-of-shrews-from-sorex-araneus-group
#10
Paweł Mackiewicz, Magdalena Moska, Heliodor Wierzbicki, Przemysław Gagat, Dorota Mackiewicz
Shrews of the Sorex genus are an evolutionarily successful group that includes more than 77 species widely distributed in Eurasia and North America. The genus is one of the rare cases where karyotypic changes reflect well the evolutionary relationships among its species. The taxa showing the greatest variation in karyotype are usually classified into the Sorex araneus group. Its evolution was associated with chromosomal rearrangements, which could have promoted fast diversification of this group into many chromosomal races and species...
2017: PloS One
https://www.readbyqxmd.com/read/28630903/comment-1-on-formation-of-the-isthmus-of-panama-by-o-dea-et-al
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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