Some recent mainly non-dino papers:
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Free pdf:
Ross Barnett, Michael V. Westbury, Marcela Sandoval-Velasco, Filipe Garrett Vieira, Sungwon Jeon, Grant Zazula, Michael D. Martin, Simon Y.W. Ho, Niklas Mather, Shyam Gopalakrishnan, JazmÃn Ramos-Madrigal, Marc de Manuel, M. Lisandra Zepeda-Mendoza, Agostinho Antunes, Aldo Carmona Baez, Binia De Cahsan, Greger Larson, Stephen J. OâBrien, Eduardo Eizirik, Warren E. Johnson, Klaus-Peter Koepfli, Andreas Wilting, JÃrns Fickel, Love DalÃn, Eline D. Lorenzen, Tomas Marques-Bonet, Anders J. Hansen, Guojie Zhang, Jong Bhak, Nobuyuki Yamaguchi & M. Thomas P. Gilbert (2020)
Genomic Adaptations and Evolutionary History of the Extinct Scimitar-Toothed Cat, Homotherium latidens.
Current Biology (advance online publication)
DOI:
https://doi.org/10.1016/j.cub.2020.09.051https://www.cell.com/current-biology/fulltext/S0960-9822(20)31421-4Free pdf:
https://www.cell.com/action/showPdf?pii=S0960-9822%2820%2931421-4Highlights
Nuclear genome and exome analyses of extinct scimitar-toothed cat, Homotherium latidens
Homotherium was a highly divergent lineage from all living cat species (~22.5 Ma)
Genetic adaptations to cursorial and diurnal hunting behaviors
Relatively high levels of genetic diversity in this individual
Summary
Homotherium was a genus of large-bodied scimitar-toothed cats, morphologically distinct from any extant felid species, that went extinct at the end of the Pleistocene. They possessed large, saber-form serrated canine teeth, powerful forelimbs, a sloping back, and an enlarged optic bulb, all of which were key characteristics for predation on Pleistocene megafauna. Previous mitochondrial DNA phylogenies suggested that it was a highly divergent sister lineage to all extant cat species. However, mitochondrial phylogenies can be misled by hybridization, incomplete lineage sorting (ILS), or sex-biased dispersal patterns, which might be especially relevant for Homotherium since widespread mito-nuclear discrepancies have been uncovered in modern cats. To examine the evolutionary history of Homotherium, we generated a ~7x nuclear genome and a ~38x exome from H. latidens using shotgun and target-capture sequencing approaches. Phylogenetic analyses reveal Homotherium as highly divergent (~22.5 Ma) from living cat species, with no detectable signs of gene flow. Comparative genomic analyses found signatures of positive selection in several genes, including those involved in vision, cognitive function, and energy consumption, putatively consistent with diurnal activity, well-developed social behavior, and cursorial hunting. Finally, we uncover relatively high levels of genetic diversity, suggesting that Homotherium may have been more abundant than the limited fossil record suggests. Our findings complement and extend previous inferences from both the fossil record and initial molecular studies, enhancing our understanding of the evolution and ecology of this remarkable lineage.
News
A deadly long-distance hunter: DNA study reveals insights about the scimitar-toothed cat
Pasquale Raia, Alessandro Mondanaro, Marina Melchionna, Mirko Di Febbraro, Josà A.F. Diniz-Filho, Thiago F. Rangel, Philip B. Holden, Francesco Carotenuto, Neil R. Edwards, Matheus S. Lima-Ribeiro, Antonio Profico, Luigi Maiorano, Silvia Castiglione, Carmela Serio & Lorenzo Rook (2020)
Past Extinctions of Homo Species Coincided with Increased Vulnerability to Climatic Change
One Earth (advance online publication)
DOI:
https://doi.org/10.1016/j.oneear.2020.09.007https://www.cell.com/one-earth/fulltext/S2590-3322(20)30476-0
Free pdf:
Climate change is a major factor in evolution, shaping the history of life on Earth
Humans usually feel excluded by climate change-induced extinction risk
We demonstrate that climate change drove past human species extinct
Science for Society
The message of the extinction rebellion protest movement, that human-induced climate change poses a threat to our species' survival, is reawakening consciences worldwide. Climate change is known to have been a major player in the turnover of species throughout the geological record. Were our ancestors, forged through the continually oscillating Pleistocene glacial cycles, not shielded from this danger? To date, the lack of sufficiently detailed and long-timescale climate information and the scarcity of data on early humans have left this question unanswered. By combining a mammoth data collation and analysis with novel paleoclimate modeling, we discovered that, for vanished human species, extinction had a candid, unquestionable climatic drive, which in the case of Neanderthals adds to the effect of competition with ourselves. Notably, Homo sapiens is the only species whose climatic niche was still expanding toward the end of our analysis, when the Neanderthals went extinct.
Summary
At least six different Homo species populated the World during the latest Pliocene to the Pleistocene. The extinction of all but one of them is currently shrouded in mystery, and no consistent explanation has yet been advanced, despite the enormous importance of the matter. Here, we use a recently implemented past climate emulator and an extensive fossil database spanning 2,754 archaeological records to model climatic niche evolution in Homo. We find statistically robust evidence that the three Homo species representing terminating, independent lineages, H. erectus, H. heidelbergensis, and H. neanderthalensis, lost a significant portion of their climatic niche space just before extinction, with no corresponding reduction in physical range. This reduction coincides with increased vulnerability to climate change. In the case of Neanderthals, the increased extinction risk was probably exacerbated by competition with H. sapiens. This study suggests that climate change was the primary factor in the extinction of Homo species.
News
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Ziheng Li, Zhong-Qiang Chen, Feifei Zhang, James G.Ogg & Laishi Zhao (2020)
Global carbon cycle perturbations triggered by volatile volcanism and ecosystem responses during the Carnian Pluvial Episode (late Triassic).
Earth-Science Reviews 103404 (advance online publication)
doi:
https://doi.org/10.1016/j.earscirev.2020.103404 https://www.sciencedirect.com/science/article/abs/pii/S0012825220304505The Carnian Pluvial Episode (CPE) was a dramatic climatic event during the early Late Triassic. The CPE has been recognized worldwide and is marked by the termination of carbonate platform successions and by pronounced negative Î13C excursions (denoted as the CPE excursion). The onset of the CPE has been proposed to be linked with the volatile eruption of the Wrangellia Large Igneous Province (W-LIP). However, this extreme climatic event remains disputed in terms of its precise global correlation, timing of onset, duration, and global magnitude. We compiled a database of 13 conodont biozone-controlled stable-isotope reference sections throughout the Tethyan region. After a reexamination of previously published conodont taxonomy from each section, the statistics on the conodont assemblages/zones yield a global set of 17 high-resolution conodont Unitary Association Zones (UAZs) spanning the entire Carnian successions. A set of age-tie points placed an age model on this global UAZ scale. We added paired Î13Ccarb and Î13Corg data from two sections in South China to other records in this global database, and then normalized all carbon-isotope datasets. A pronounced negative Î13Ccarb excursion with a magnitude of â2Ââ0.5â (from an average of ~3â to ~1â) is evident in these normalized trends and is recognized around the entire Tethys realm. The CPE excursion coincides with conodont UAZ-4 (~234âMa) through UAZ-8 (within the Mazzaella carnica and Paragondolella praelindae zones, Julian2) and has a duration of ca. 1.5 Myr. We note that an apparent delayed onset of the CPE excursion in South China relative to elsewhere in the Tethys as suggested by previous studies may have been an artifact caused by incomplete conodont-stratigraphic records and/or irregularities in taxonomic identification. A carbon and phosphorus cycle model highlight the strong relationship between the eruption of the W-LIP and CPE excursion; however, the estimated amount of CO2volatiles released by the W-LIP would directly account for only ~25% of the total amount of lightâcarbon required to explain the combined magnitude and duration of the global CPE excursion.
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A footprint is a biosedimentary feature that corresponds to a deformation event involving the sediment.
The origin and preservation of a track is related to distinct substrate and environmental factors.
Dinostatic pressure can result in displacement rim, fluidization, impact structure, concentric cracks and load casts.
Mesozoic tracks from Gondwana, as sedimentary structures, are useful to paleoenvironmental interpretations.
Abstract
The origin and preservation of a track are related to many distinct environmental factors, concerning especially the substrate cohesiveness, plasticity, grain size, texture and water content. Then, the environment, through the sedimentation processes, plays a role that enhances the origin and quality of the tracks and their preservation. Three distinct contexts - tidal flats, aeolian, fluvial-lacustrine paleoenvironments, that encompass the majority of fossil footprints occurrences are analyzed. Footprints as biosedimentary structures, due to their close relationships with physical and chemical processes that control their formation, represent an important clue to paleoenvironmental interpretation. The present study is mainly based on the direct examination of ichnosites that allow us to evaluate the aspects of Mesozoic tracks from different regions of the paleocontinent Gondwana, currently correspondent to Argentina, Australia, Bolivia, Brazil, Congo, Iran, India, Madagascar and Morocco as sedimentary structures and their use in paleoenvironmental interpretations.
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Free pdf:
Danielle Fraser, Laura C. Soul, Anikà B. TÃth, Meghan A. Balk, Jussi T. Eronen, Silvia Pineda-Munoz, Alexandria B. Shupinski, Amelia VillaseÃor, W. Andrew Barr, Anna K. Behrensmeyer, Andrew Du, J. Tyler Faith, Nicholas J. Gotelli, Gary R. Graves, Advait M. Jukar, Cindy V. Looy, Joshua H. Miller, Richard Potts & S. Kathleen Lyons (2020)
Investigating Biotic Interactions in Deep Time.
Trends in Ecology & Evolution (advance online publication)
doi:
https://doi.org/10.1016/j.tree.2020.09.001 https://www.sciencedirect.com/science/article/pii/S0169534720302500Highlights
Challenging the widespread perspective that long-term diversity patterns are shaped primarily by climate is not possible without using fossil record data to understand the role of biotic interactions.
Important recent development and application of models that utilize data of both living and extinct species have enabled analyses to move beyond simply excluding potential abiotic drivers to explicitly modeling biotic drivers for the first time.
Analyses of paleontological data show that biotic interactions shape the temporal diversity trajectories and rates of origination and extinction for numerous taxa.
Extinction of keystone species has disproportionate impacts on biotic interactions among surviving species.
Recovery from extinction events can be sped up or slowed down by biotic interactions among surviving species.
Historically, humans (Homo sapiens) have acted as large, generalist predators, disrupting interaction networks among non-human species.
Abstract
Recent renewed interest in using fossil data to understand how biotic interactions have shaped the evolution of life is challenging the widely held assumption that long-term climate changes are the primary drivers of biodiversity change. New approaches go beyond traditional richness and co-occurrence studies to explicitly model biotic interactions using data on fossil and modern biodiversity. Important developments in three primary areas of research include analysis of (i) macroevolutionary rates, (ii) the impacts of and recovery from extinction events, and (iii) how humans (Homo sapiens) affected interactions among non-human species. We present multiple lines of evidence for an important and measurable role of biotic interactions in shaping the evolution of communities and lineages on long timescales.
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