Some additional recent mainly non-dino papers:
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In a recent paper, a new species of the crocodyliform genus Isisfordia was erected based on, in part, a specimen previously designated as the holotype of 'Crocodylus (Bottosaurus)'selaslophensis. This new species was given the name Isisfordia molnari. However, because the holotype of 'Crocodylus (Bottosaurus)' selaslophensis displays a unique combination of characters and does not overlap with the holotype of I. molnari, both names remain valid according to ICZN regulations.
Results
The present work instates Isisfordia selaslophensis comb. nov., recognising the seniority of the original specific epithet given to the specimen. The specimen is also reaffirmed as the holotype of the species. Isisfordia molnari is rediagnosed based on non-overlapping material but is potentially referable to Isisfordia selaslophensis. All other analyses, descriptions, diagnoses and conclusions stated by the original study remain valid.
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Mesoclemmys vanegasorum sp. nov.
Mesoclemmys is the most diverse extant genus of South American pleurodires or side-necked turtles, with at least 10 species inhabiting fluvial to littoral environments. Despite this high extant diversity and extensive geographic distribution, the evolutionary history and fossil record of this genus are completely unknown. Here, we describe the first fossil record of this genus, which supports a previous molecular-based hypothesis that indicates a minimum split time of 13.5 Ma between this and other genera of South American chelids. Mesoclemmys vanegasorum, sp. nov., is represented by a nearly complete shell (carapace and plastron) and some postcranial bones found in the middle Miocene (13.6âÂâ0.2 Ma), La Victoria Formation, Tatacoa Desert, Colombia, increasing the turtle paleodiversity of La Venta Fauna. It differs from all extant species of Mesoclemmys by vertebral scute 1 reaching the sutural boundary between peripherals 1 and 2; shorter cervical and marginal scutes 1 to 3; pleurals 1 very advanced over the peripherals; pygal bone with a posteromedial shallow notch; vertebral 5 covering half of the pygal bone; small extragulars reaching only half of the epiplastra length; and a fine microvermiculation of the shell. Our phylogenetic results show a close relationship between M. vanegasorum, sp. nov., and the extant M. hogei. The overall morphology and size of Mesoclemmys genus have remained relatively constant for at least the last 13.6 million years. However, its geographic distribution has decreased drastically in northwestern South America, being restricted today to the lower region of the Magdalena River Basin.
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Yuto Kurumada, ÂShogo Aoki, ÂKazumasa Aoki, ÂDaichi Kato, ÂMototaka Saneyoshi, ÂKhishigjav Tsogtbaatar, ÂBrian F. Windley & ÂShinobu Ishigaki (2020)
Calcite U-Pb age of the Cretaceous vertebrateâbearing Bayn Shire Formation in the Eastern Gobi Desert of Mongolia: usefulness of caliche for age determination.
Terra Nova (advance online publication)
doi:
https://doi.org/10.1111/ter.12456https://onlinelibrary.wiley.com/doi/10.1111/ter.12456
To verify the usefulness of calcite U-Pb measurement for vertebrateâbearing strata in the Eastern Gobi, Mongolia, we performed laser ablationâinductively coupled plasmaâmass spectrometry calcite U-Pb and trace element analyses of three caliche (calcrete) of the Bayn Shire Formation. The trace element analysis demonstrates high concentration of U in the calcites. Two meaningful calcite U-Pb ages were obtained; 89.6 Â 4.0 and 95.9 Â 6.0 Ma, which are consistent with published ages from the Bayn Shire Formation. Our results demonstrate that the calcite UâPb method can be powerful tool for age determination of vertebrateâbearing strata in the Gobi that do not contain index fossils or beds, but do contain caliches. This would make it possible for a comparison of biostratigraphy between the Gobi and other areas yielding abundant vertebrate fossils in Asia, North America and Europe, based on chronological data.
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Two types of unusual concretions with similar biotic contents but markedly different shapes and distributions were found in close stratigraphic proximity within the Lower Jurassic Whitmore Point Member of the Moenave Formation in St. George, Utah. Both types of concretions formed in lacustrine sediments and contain abundant ganoid fish scales, numerous ostracode carapaces, and apparent rip-up clasts. Elongate, cylindrical concretions developed in parallel and regularly spaced rows in one horizon, and comparatively flat and irregularly shaped and distributed concretions formed in an overlying layer only a few centimeters above. Microprobe and Raman analyses of concretion samples reveal abundant hematite in both concretions as well as groundmass minerals dominated by silica in the cylindrical concretions and dolomite in the flat concretions. The abundance of fish skeletal debris in concretions from two consecutive horizons may suggest recurring fish mass mortality in ancient Lake Dixie, the large lake that occupied the St. George area during the Early Jurassic. We propose a model for the formation of the concretions based on their shapes, distributions, and chemistry. In this model, accumulations of disarticulated fish debris were colonized and consolidated by microbial mats and shaped by oscillatory flow (in the case of the cylindrical concretions) or lack thereof (in the case of the flat concretions). Then, after burial, groundwater chemistry and possibly the metabolic activities of microorganisms led to the precipitation of minerals around and within the masses of fish material. Finally, diagenetic alteration changed the mineral makeups of the cylindrical and flat concretions into what they are today.
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Marisa S. Storm, Stephen P. Hesselbo, Hugh C. Jenkyns, Micha Ruhl, Clemens V. Ullmann, Weimu Xu, Melanie J. Leng, James B. Riding, and Olga Gorbanenko (2020)
Cyclic variations in Earthâs orbit drive periodic changes in the oceanâatmosphere system at a time scale of tens to hundreds of thousands of years. The Mochras Î13CTOC record illustrates the continued impact of long-eccentricity (405-ky) orbital forcing on the carbon cycle over at least â18 My of Early Jurassic time and emphasizes orbital forcing as a driving mechanism behind medium-amplitude Î13C fluctuations superimposed on larger-scale trends that are driven by other variables such as tectonically determined paleogeography and eruption of large igneous provinces. The dataset provides a framework for distinguishing between internal Earth processes and solar-system dynamics as the driving mechanism for Early Jurassic Î13C fluctuations and provides an astronomical time scale for the Sinemurian Stage.
Abstract
Global perturbations to the Early Jurassic environment (â201 to â174 Ma), notably during the TriassicâJurassic transition and Toarcian Oceanic Anoxic Event, are well studied and largely associated with volcanogenic greenhouse gas emissions released by large igneous provinces. The long-term secular evolution, timing, and pacing of changes in the Early Jurassic carbon cycle that provide context for these events are thus far poorly understood due to a lack of continuous high-resolution Î13C data. Here we present a Î13CTOC record for the uppermost Rhaetian (Triassic) to Pliensbachian (Lower Jurassic), derived from a calcareous mudstone succession of the exceptionally expanded Llanbedr (Mochras Farm) borehole, Cardigan Bay Basin, Wales, United Kingdom. Combined with existing Î13CTOC data from the Toarcian, the compilation covers the entire Lower Jurassic. The dataset reproduces large-amplitude Î13CTOC excursions (>3â) recognized elsewhere, at the SinemurianâPliensbachian transition and in the lower Toarcian serpentinum zone, as well as several previously identified medium-amplitude (â0.5 to 2â) shifts in the Hettangian to Pliensbachian interval. In addition, multiple hitherto undiscovered isotope shifts of comparable amplitude and stratigraphic extent are recorded, demonstrating that those similar features described earlier from stratigraphically more limited sections are nonunique in a long-term context. These shifts are identified as long-eccentricity (â405-ky) orbital cycles. Orbital tuning of the Î13CTOC record provides the basis for an astrochronological duration estimate for the Pliensbachian and Sinemurian, giving implications for the duration of the Hettangian Stage. Overall the chemostratigraphy illustrates particular sensitivity of the marine carbon cycle to long-eccentricity orbital forcing.
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Although Ancient Egyptians mummified millions of animals over the course of one millennium, many details of these mummification protocols remain unknown. Multi-scale propagation phase-contrast X-ray synchrotron microtomography was used to visualise an ancient Egyptian crocodile mummy housed at the MusÃe des Confluences (Lyon, France). This state-of-the-art non-destructive imaging technique revealed the complete interior anatomy of the mummy in three dimensions. Here, we present detailed insight into the complex post-mortem treatment of a decaying crocodile cadaver in preparation for mummification. Except for the head and the extremities of the limbs, everything beneath the skin of the crocodile (i.e. organs, muscles, and even most of the skeleton) was removed to cease further putrefaction. This unexpected finding demonstrates that earlier knowledge obtained from textual and other archaeological sources does not sufficiently reflect the diversity of mummification protocols implemented by Ancient Egyptians.