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Paleontology

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https://www.readbyqxmd.com/read/28917702/hominin-track-assemblages-from-okote-member-deposits-near-ileret-kenya-and-their-implications-for-understanding-fossil-hominin-paleobiology-at-1-5%C3%A2-ma
#1
Kevin G Hatala, Neil T Roach, Kelly R Ostrofsky, Roshna E Wunderlich, Heather L Dingwall, Brian A Villmoare, David J Green, David R Braun, John W K Harris, Anna K Behrensmeyer, Brian G Richmond
Tracks can provide unique, direct records of behaviors of fossil organisms moving across their landscapes millions of years ago. While track discoveries have been rare in the human fossil record, over the last decade our team has uncovered multiple sediment surfaces within the Okote Member of the Koobi Fora Formation near Ileret, Kenya that contain large assemblages of ∼1.5 Ma fossil hominin tracks. Here, we provide detailed information on the context and nature of each of these discoveries, and we outline the specific data that are preserved on the Ileret hominin track surfaces...
September 13, 2017: Journal of Human Evolution
https://www.readbyqxmd.com/read/28917701/paleoecological-insights-from-fossil-freshwater-mollusks-of-the-kanapoi-formation-omo-turkana-basin-kenya
#2
Bert Van Bocxlaer
The Early Pliocene Kanapoi Formation of the Omo-Turkana Basin consists of two fluvial/deltaic sedimentary sequences with an intermediate lacustrine sequence that was deposited in Paleolake Lonyumun, the earliest large lake in the basin. Overall, the geology and vertebrate paleontology of the Kanapoi Formation are well studied, but its freshwater mollusks, despite being a major component of the benthic ecosystem, have not been subjected to in-depth study. Here I present the first treatment of these mollusks, which have been retrieved mainly from the lacustrine but also from the upper fluvial sediments, with a focus on paleoecological implications...
September 13, 2017: Journal of Human Evolution
https://www.readbyqxmd.com/read/28916155/ancestral-resurrection-of-anthropoid-estrogen-receptor-%C3%AE-demonstrates-functional-consequences-of-positive-selection
#3
Amy Weckle, Michael R McGowen, Jun Xing, Caoyi Chen, Kirstin N Sterner, Zhuo-Cheng Hou, Roberto Romero, Derek E Wildman
Anthropoid primates arose during the Eocene approximately 55 million years ago (mya), and extant anthropoids share a most recent common ancestor ∼40 mya. Paleontology has been very successful at describing the morphological phenotypes of extinct anthropoids. Less well understood is the molecular biology of these extinct species as well as the phenotypic consequences of evolutionary variation in their genomes. Here we resurrect the most recent common ancestral anthropoid estrogen receptor β gene (ESR2) and demonstrate that the function of this ancestral estrogen receptor has been maintained during human descent but was altered during early New World monkey (NWM) evolution by becoming a more potent transcriptional activator...
September 12, 2017: Molecular Phylogenetics and Evolution
https://www.readbyqxmd.com/read/28902506/non-invasive-synchrotron-based-x-ray-raman-scattering-discriminates-carbonaceous-compounds-in-ancient-and-historical-materials
#4
Pierre Gueriau, Jean-Pascal Rueff, Sylvain Bernard, Josiane Albert Kaddissy, Sarah Goler, Christoph J Sahle, Dimosthenis Sokaras, Roy A Wogelius, Philip L Manning, Uwe Bergmann, Loïc Bertrand
Carbon compounds are ubiquitous and occur in a diversity of chemical forms in many systems including ancient and historic materials ranging from cultural heritage to paleontology. Determining their speciation cannot only provide unique information on their origin, but may also elucidate degradation processes. Synchrotron-based X-ray absorption near-edge structure (XANES) spectroscopy at the carbon K-edge (280-350 eV) is a very powerful method to probe carbon speciation. However, the short penetration depth of soft X-rays imposes stringent constraints on sample type, preparation and analytical environment...
September 13, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28888396/middle-and-late-holocene-micromammal-pathologies-from-cueva-tixi-tandilia-range-buenos-aires-province-argentina
#5
Leandro Luna, Claudia Aranda, Carlos Quintana
Paleopathology in bones of very small mammals has rarely been studied. Different types of osseous lesions of mammals weighing under 0.2kg, recovered from the Holocene strata of Cueva Tixi archaeological and paleontological site (Tandilia range, province of Buenos Aires, Argentina), are described and discussed in this report. Several types of trauma, entheseal changes, degenerative joint diseases, and probable osteomyelitis were identified. The lesions were chronic, indicating that the animals were able to survive a period of convalescence, although in many cases the decreased capacity for locomotion likely was significant...
September 2017: International Journal of Paleopathology
https://www.readbyqxmd.com/read/28875070/dinosaur-origin-of-egg-color-oviraptors-laid-blue-green-eggs
#6
Jasmina Wiemann, Tzu-Ruei Yang, Philipp N Sander, Marion Schneider, Marianne Engeser, Stephanie Kath-Schorr, Christa E Müller, P Martin Sander
Protoporphyrin (PP) and biliverdin (BV) give rise to the enormous diversity in avian egg coloration. Egg color serves several ecological purposes, including post-mating signaling and camouflage. Egg camouflage represents a major character of open-nesting birds which accomplish protection of their unhatched offspring against visually oriented predators by cryptic egg coloration. Cryptic coloration evolved to match the predominant shades of color found in the nesting environment. Such a selection pressure for the evolution of colored or cryptic eggs should be present in all open nesting birds and relatives...
2017: PeerJ
https://www.readbyqxmd.com/read/28870618/revisiting-the-theoretical-basis-of-the-endosymbiotic-origin-of-plastids-in-the-original-context-of-lynn-margulis-on-the-origin-of-mitosing-eukaryotic-cells
#7
Naoki Sato
Fifty years ago, Lynn Margulis proposed a comprehensive hypothesis on the origin of eukaryotic cells with an emphasis on the origin of mitosis. This hypothesis postulated that the eukaryotic cell is a composite of different parts as a result of the symbiosis of various different bacteria. In this hypothesis, she integrated previously proposed ideas that mitochondria and chloroplasts were descendants of endosymbionts that originated from aerobic bacteria and blue-green algae (now cyanobacteria), respectively...
September 1, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28838563/a-volumetric-technique-for-fossil-body-mass-estimation-applied-to-australopithecus-afarensis
#8
Charlotte A Brassey, Thomas G O'Mahoney, Andrew T Chamberlain, William I Sellers
Fossil body mass estimation is a well established practice within the field of physical anthropology. Previous studies have relied upon traditional allometric approaches, in which the relationship between one/several skeletal dimensions and body mass in a range of modern taxa is used in a predictive capacity. The lack of relatively complete skeletons has thus far limited the potential application of alternative mass estimation techniques, such as volumetric reconstruction, to fossil hominins. Yet across vertebrate paleontology more broadly, novel volumetric approaches are resulting in predicted values for fossil body mass very different to those estimated by traditional allometry...
August 21, 2017: Journal of Human Evolution
https://www.readbyqxmd.com/read/28836344/insights-on-the-role-of-hox-genes-in-the-emergence-of-the-pentadactyl-ground-state
#9
REVIEW
Yacine Kherdjemil, Marie Kmita
Tetrapods are characterized by the presence of digits at the distal end of their limbs, which have emerged during the transition from fins to limbs. While variations in digit number are observed in extant tetrapods, most have five digits per limb and divergence from this pentadactyl ground state is always a reduction in digit number. Paleontological data revealed that stem-group tetrapods were polydactylous indicating that the evolution from fish fin to modern tetrapod limbs involved two major transitions; the emergence of digits and the shift from polydactyly to pentadactyly...
August 24, 2017: Genesis: the Journal of Genetics and Development
https://www.readbyqxmd.com/read/28808022/genomic-evidence-reveals-a-radiation-of-placental-mammals-uninterrupted-by-the-kpg-boundary
#10
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 29, 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
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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...
September 2017: Geobiology
https://www.readbyqxmd.com/read/28650986/evolutionary-history-and-phylogeographic-relationships-of-shrews-from-sorex-araneus-group
#19
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
#20
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
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