Ben Creisler
Recent non-dino papers:
Free pdf:
Takuya IMAI, Yuta TSUKIJI and Yoichi AZUMA (2018)
Description of bird tracks from the Kitadani Formation (Aptian), Katsuyama, Fukui, Japan with three-dimensional imaging techniques.
Memoir of the Fukui Prefectural Dinosaur Museum 17: 1-8Â
The Early Cretaceous ichnofossils of birds numerously occur in South Korea and China. Together with rich skeletal record from northeastern China, they facilitate our understanding about distribution and diversity of birds during the time. In contrast, in Japan, the fossil record of the Early Cretaceous birds is poorly known. Here, we report two ichnotaxa of the Early Cretaceous birds from the Aptian Kitadani Formation. We employ three-dimensional imaging techniques to objectively document and describe the specimens. Specimens include FPDM-F-74 and FPDM-F-75 recovered from an alternating sequence of fine sandstone and mudstone of the Kitadani Formation cropping out in the Kitadani Dinosaur Quarry, Katsuyama, Fukui, Japan. FPDM-F-74 is large in size, bears slender digits with pointy ends (claw impressions), and lacks hallux and webbing traces. These characters allow assignment of FPDM-F-74 to cf. Aquatilavipes ichnosp. FPDM-F-74 is particularly large compared to other Aquatilavipes ichnospecies. FPDM-F-75 is smaller than FPDM-F-74, lacks hallux trace, and has webbing traces between digits II and III, and III and IV. It is assignable to cf. Gyeongsangornipes ichnosp. FPDM-F-75 is larger than most avian ichnotaxa with webbing traces. Its webbing traces between digits II and III, and III and IV are characterized by their extension only up to the proximal half of the digits. FPDM-F-75 differs from Gyeongsangornipes lockleyi from the Albian Jindong Formation, Gyeongsang, South Korea in having larger size and smaller divarication between digits II and IV, and the extension of webbing traces. These specimens indicate the presence of possibly two medium-sized avian taxa in the Kitadani Formation and increase our knowledge of the Early Cretaceous avifauna in Japan. Additionally, webbing traces in FPDM-F-75 and other late Early Cretaceous avian tracks from Asia may suggest that such morphological feature was common among the fossil birds during the time.
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Daria Kiseleva, Oleg Shilovsky, Evgeny Shagalov, Anastasia Ryanskaya, Maria Chervyakovskaya, Elizaveta Pankrushina & Nadezhda Cherednichenko (2019)
Composition and structural features of two Permian parareptile (Deltavjatia vjatkensis, Kotelnich Site, Russia) bone fragments and their alteration during fossilisation
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
Highlights
Permian pareiasaur bones are characterised by excellent preservation.
White blood cell (WBC)-like structures are detected and interpreted as leukocytes.
Oxidising and possibly alkaline environment during the early stages of diagenesis
Abstract
The Kotelnich vertebrate fossil site, one of the richest of the Permian period, is characterised by the excellent preservation of fossil remains due to their burial in a silty anaerobic environment similar to modern peat bogs. The aim of the work is to carry out a comprehensive study of the composition and structure of bone fragments of the Permian parareptile Deltavjatia vjatkensis, as well as that of its embedding rocks, to support further paleoecological and fossilisation reconstructions. Fossil bones and their surrounding strata were investigated using optical and scanning electron microscopy, Raman spectroscopy, X-ray diffraction and inductively coupled plasma mass spectrometry (ICP-MS). The carbonate-rich composition of the sediment was found to favour the preservation of the bone apatite. The mineral phase of the bone tissue corresponds to fluorapatite. Organic matrix vibration bands arising on the Raman spectra correspond to CH vibrations of lipids and proteins and possibly cholecterol. The obtained data indicate a high degree of integrity of both bone mineral phase and its organic proteinaceous residue. White blood cell (WBC)-like structures were detected, which possibly could be interpreted as leukocytes. Elemental mapping of fossil bones was used to reveal element distribution features (uniform or with zones of apparent enrichment-depletion) and secondary mineralisation zones. Ca, P, Mg, Mn and S are uniformly distributed through the bone; conversely, elevated quantities of Fe are assigned to cracks and large pores formed as a consequence of the decomposition of organic materials. As compared to bone apatite, the authigenic calcite filling of bone porosities is significantly depleted in terms of microelements. The apatite rare earth element (REE) composition of bone tissue, which is inherited from seawater, can be used for paleoreconstructions of redox conditions and water composition. La/Sm ratios (0.4â0.5), high Y/Ho ratios, high uranium content and high La/Yb ratios (2â3) in the bone apatite indicate the absence of recrystallisation during the late stages of diagenesis. A positive cerium anomaly detected in the bones indicates the presence of an oxidising and possibly alkaline environment during the early stages of diagenesis in shallow coastal basin of the Kotelnich paleolocality. It is shown that 10 to 20% of REE in bone apatite is derived from seawater absorption (hydrogenous source), with the remainder having been derived from host rock (lithogenic) sources.
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Also may be of interest (free pdf in any case):
Matthew R. Borths & Nancy J. Stevens (2019)
Simbakubwa kutokaafrika, gen. et sp. nov. (Hyainailourinae, Hyaenodonta, âCreodonta,â Mammalia), a gigantic carnivore from the earliest Miocene of Kenya.
Journal of Vertebrate Paleontology Article: e1570222Â
Free pdf:
Hyainailourine hyaenodonts are among the largest terrestrial carnivorous mammals known. The clade is widely dispersed, found in Eurasia, North America, and Afro-Arabia in the Paleogene and early Neogene. In this study, we describe dental and postcranial material from Simbakubwa kutokaafrika, gen. et sp. nov., the most complete hyainailourine known from sub-Saharan Africa. The material is from a relatively young adult from the early Miocene locality of Meswa Bridge, Kenya. Simbakubwa differs from Hyainailouros in exhibiting lingually oriented molar protocones, gracile metastyles, and buccolingually compressed, shearing canines. Like other large Miocene hyainailourines, Simbakubwa has deep carnassial notches on the molars and tall paracones fused to shorter metacones forming single piercing cusps. A Bayesian phylogenetic analysis recovers Simbakubwa as the sister taxon of a clade of large-bodied Miocene hyainailourines that includes Hyainailouros and Megistotherium. Bayesian ancestral state reconstruction supports an Afro-Arabian origin for Hyainailourinae with subsequent dispersal to Eurasia during the early Miocene. Regression analysis based on carnassial size is applied to Simbakubwa and closely related hyainailourines, recovering a body mass up to 1,500âkg for the new taxon. The evolution and extinction of Hyainailourinae offers important insights for interpreting ecological transitions from Paleogene to Neogene faunas in Afro-Arabia and Eurasia.