90 research outputs found

    A simulated bird gastric mill and its implications for fossil gastrolith authenticity

    Get PDF

    The rarity of gastroliths in sauropod dinosaurs – a case study in the Late Jurassic Morrison Formation, western USA

    Get PDF
    Occurrences of suspected sauropod geo-gastroliths and "exoliths" (exotic clasts) are compared with authentic finds of stomach stones in the sauropods Diplodocus, Cedarosaurus, and Camarasaurus. Sedimentological and taphonomical evidence from classic sauropod dinosaur localities in the Late Jurassic Morrison Formation (Cleveland-Lloyd Dinosaur Quarry, Dry Mesa Dinosaur Quarry, Carnegie Quarry/Dinosaur National Monument, Howe Quarry, Como Bluff, and Bone Cabin Quarry) reveals very few sauropod finds with unambiguous gastroliths. The scarcity of clasts in the fine-grained sediments of most of the localities suggests that only a small number of sauropods possessed gastroliths. The occurrence of a hypothetical avian-style gastric mill in sauropods is not supported by taphonomical evidence. Exoliths that are abundant in the Early Cretaceous of the western USA are nearly absent in Late Jurassic sediments. Without an association with fossil bone, there is no convincing evidence that such clasts represent former gastroliths. It is more plausible that most exoliths have been transported in hyperclastic flows or that surface-collected stones are weathering relicts of former conglomerate layers

    Precious, Tiny and Shiny: Close range photogrammetry for artists and others

    Full text link
    Close Range Photogrammetry is increasingly being used to create digital assets across a range of disciplines, and can provide 3D ‘scans’ and surface ‘textures’ to very high resolution. The techniques of capture and processing usually present challenges for objects that are very small, monochromatic, reflective or relatively lacking in features. This ongoing visual arts project seeks to capture, re-examine and ultimately transform specific military and religious insignia as part of an investigation into their interrelated iconographies and histories. The materiality (highly reflective) and scale (very detailed embroidery) of these objects has required different approaches to achieving the accurate 3D models required. This paper will present the apparatus, methods and devices that have been developed to help solve these problems. Together they offer affordable, reliable, and scalable solutions to the traditional challenges of ‘3D scanning’ for particular types of objects, and robust methods applicable to a wide range of situations. They also help reduce the investment (of capital cost, time and labour) required to achieve accurate digital models with high resolution textures, opening up creative possibilities further down the virtual or material ‘pipeline’

    Osteosclerosis in the extinct Cayaoa Bruneti (Aves, anseriformes) : insights on behavior and fligftlessness

    Get PDF
    Fil: Mendoza, Ricardo de. División Paleontología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La PlataFil: Tambussi, Claudia Patricia. Centro de Investigaciones en Ciencias de la Tierra (CICTERRA). Universidad Nacional de Córdoba; Argentin

    A plesiosaur containing an ichthyosaur embryo as stomach contents from the Sundance Formation of the Bighorn Basin, Wyoming

    Get PDF
    Herein we report the discovery of an ichthyosaur embryo from the Upper Member of the Sundance Formation (Oxfordian) of the Bighorn Basin, Wyoming. The specimen is the first known ichthyosaur embryo from the Upper Jurassic, and is the first Jurassic ichthyosaur embryo from North America. The embryo was discovered in close association with the abdomen of an articulated partial plesiosaur skeleton, and several lines of evidence support the interpretation of the embryo as plesiosaur stomach contents. The small size and extremely poor ossification of the embryo indicate that the animal was probably not a neonate. Although the taxonomic affinities of the fossil are unknown, the large ichthyosaurian (sensu stricto) Opthalmosaurus natans is the only known ichthyosaur from the Sundance Formation, and the embryo may belong to that taxon

    Creative Reverse Engineering – from remote sensuality to haptic metrology

    Full text link
    Our ongoing experimentation in close-range Photogrammetry has overcome common challenges to generate accurate, high-resolution 3D models using a single DSLR camera and innovative approaches and computer-coded devices. More recent investigations across disciplines sought to bridge the gap between traditional creative skills and modes of visualisation, and what can be made possible through digital means. Working as artists and designers alongside museums and historians, we have developed new photogrammetry equipment and approaches to help overcome the complex fluid geometry, shadowy occlusions and delicate lamina edges of challenging monochromatic garments. The resulting 3D models have allowed the rapid extraction of faithful seams and surfaces direct from the processed ‘mesh’ and into CAD modelling environments for the production of new designs, patterns and production tooling. Current collaborations seek to apply these developments to the capture, visualisation and reverse engineering of iconic garments and museum artefacts, alongside the 'remote sensing' of traditional pattern cutters whose eyes, minds and hands are the equivalent of the digital approaches explored in our paper. The second phase sought to unpick some of the familiar structures of object- and asset creation in and for Virtual and Augmented Reality. Experimenting with equipment, methods and processing techniques allowed us to explore the potential of 3D visualisations and readily available tools within Virtual and Augmented Reality for garment design and other forms of object-based creative ideation, sketching and prototyping. In the next stages of our ongoing research we explored a more haptic form of CAD-enabled modelling and metrology, aiming to bring these approaches within the reach of a wider range of creative users: enabling artists, designers and makers to move more seamlessly between digital tools and virtual environments, and actual things in real time and space

    Osteological and Soft-Tissue Evidence for Pneumatization in the Cervical Column of the Ostrich (Struthio camelus) and Observations on the Vertebral Columns of Non-Volant, Semi-Volant and Semi-Aquatic Birds

    Get PDF
    © 2015 Apostolaki et al. This is an open access article distributed under the terms of the Creative Commons Attribution License [4.0], which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

    A basal lithostrotian titanosaur (Dinosauria: Sauropoda) with a complete skull: Implications for the evolution and paleobiology of titanosauria

    Get PDF
    We describe Sarmientosaurus musacchioi gen. et sp. nov., a titanosaurian sauropod dinosaur from the Upper Cretaceous (Cenomanian - Turonian) Lower Member of the Bajo Barreal Formation of southern Chubut Province in central Patagonia, Argentina. The holotypic and only known specimen consists of an articulated, virtually complete skull and part of the cranial and middle cervical series. Sarmientosaurus exhibits the following distinctive features that we interpret as autapomorphies: (1) maximum diameter of orbit nearly 40% rostrocaudal length of cranium; (2) complex maxilla - lacrimal articulation, in which the lacrimal clasps the ascending ramus of the maxilla; (3) medial edge of caudal sector of maxillary ascending ramus bordering bony nasal aperture with low but distinct ridge; (4) ´tongue-like´ ventral process of quadratojugal that overlaps quadrate caudally; (5) separate foramina for all three branches of the trigeminal nerve; (6) absence of median venous canal connecting infundibular region to ventral part of brainstem; (7) subvertical premaxillary, procumbent maxillary, and recumbent dentary teeth; (8) cervical vertebrae with ´strut-like´ centroprezygapophyseal laminae; (9) extremely elongate and slender ossified tendon positioned ventrolateral to cervical vertebrae and ribs. The cranial endocast of Sarmientosaurus preserves some of the most complete information obtained to date regarding the brain and sensory systems of sauropods. Phylogenetic analysis recovers the new taxon as a basal member of Lithostrotia, as the most plesiomorphic titanosaurian to be preserved with a complete skull. Sarmientosaurus provides a wealth of new cranial evidence that reaffirms the close relationship of titanosaurs to Brachiosauridae. Moreover, the presence of the relatively derived lithostrotian Tapuiasaurus in Aptian deposits indicates that the new Patagonian genus represents a ´ghost lineage´ with a comparatively plesiomorphic craniodental form, the evolutionary history of which is missing for at least 13 million years of the Cretaceous. The skull anatomy of Sarmientosaurus suggests that multiple titanosaurian species with dissimilar cranial structures coexisted in the early Late Cretaceous of southern South America. Furthermore, the new taxon possesses a number of distinctive morphologies - such as the ossified cervical tendon, extremely pneumatized cervical vertebrae, and a habitually downward- facing snout - that have rarely, if ever, been documented in other titanosaurs, thus broadening our understanding of the anatomical diversity of this remarkable sauropod clade. The latter two features were convergently acquired by at least one penecontemporaneous diplodocoid, and may represent mutual specializations for consuming low-growing vegetation.Fil: Martínez, Rubén Darío. Universidad Nacional de la Patagonia; ArgentinaFil: Lamanna, Matthew C.. Carnegie Museum Of Natural History; Estados UnidosFil: Novas, Fernando Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "bernardino Rivadavia"; ArgentinaFil: Ridgely, Ryan C.. Ohio University College Of Osteopathic Medicine; Estados UnidosFil: Casal, Gabriel. Universidad Nacional de la Patagonia; ArgentinaFil: Martínez, Javier E.. Hospital Regional de Comodoro Rivadavia; ArgentinaFil: Vita, Javier R.. Resonancia Magnética Borelli; ArgentinaFil: Witmer, Lawrence M.. Ohio University College Of Osteopathic Medicine; Estados Unido
    • …
    corecore