Ben Creisler
Some recent non-dino papers:
P. Vincent, A.-S. Grosjean, D. Bert, J.Ferreira, B. SuchÃras-Marx, G. Suan, G. Guinot, V. Perrier, K. Janneau, J.-M. Brazier, E. Sarroca, M.Guiomar & J. E. Martin (2019)
Paleoenvironmental context and significance of a partial elasmosaurid skeleton from the Albian of Haute-Provence, France.
Cretaceous Research (advance online publication)
doi:
https://doi.org/10.1016/j.cretres.2019.104293https://www.sciencedirect.com/science/article/pii/S0195667119302812Highlights
We report an Albian Konzentrat-LagerstÃtte from the Pre-Alps in SE France.
Fossil remains consist of ammonites, chondrichthyans, ichthyosaurs and plesiosaurs.
The most complete plesiosaur specimen from the Albian strata of France is described.
Abstract
The EarlyâLate Cretaceous transition (late Albianâearly Cenomanian; â100 Ma) witnessed marked environmental changes and a deep reorganization of the marine fauna. The impact of these environmental and biotic changes on Tethyan marine vertebrates is poorly understood, due to a fragmentary fossil record. Here we report upper Albian marine vertebrate remains, including a partially articulated plesiosaurian skeleton, from a fossiliferous glauconite-rich bed in the Alpes de Haute-Provence, France. The fossiliferous horizon produced a diversified invertebrate fauna including ammonoids and belemnoids. The ammonite fauna is abundant and diversified, indicating the Mortoniceras fallax ammonite Zone. The calcareous nannofossil biomarkers date the bed to the NC10a Zone. The fossiliferous bed consists of glauconitic marls enriched in planktic foraminifera and occurs amongst a monotonous succession of alternating marlstones and limestone beds. The vertebrate fauna consists of chondrichthyans and marine reptiles. Chondrichthyans are represented by five Lamniformes species (dominated by Sphenodus) and comprise predator taxa probably living in open marine temperate waters. The site yielded a large, partial post-cranial plesiosaurian skeleton with articulated elements, belonging to an elasmosaurid and representing one of the most complete Albian plesiosaurian specimens known from Europe. The abundance and preservation of the collected fossil remains are best explained by their concentration during a basin-scale episode of very low sedimentation corresponding to a major episode of marine transgression, associated with a lower oxygenation of bottom waters. These findings indicate that the newly discovered fossiliferous bed holds promising clues about the evolutionary history of major groups of marine vertebrates and ammonites near the EarlyâLate Cretaceous transition.
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A failed predation against a Late Cretaceous pleurodire turtle is reported.
Distinct trace fossils on the plastron record the bite of the predator.
CT scan indicates bone regeneration and healing of the wound.
Abstract
In the present contribution, we report the evidence of a predation attempt against a semi-aquatic pleurodire turtle who survived the attack. The almost complete specimen of this adult turtle, the holotype of Rionegrochelys caldieroi, was found in the Upper Cretaceous Plottier Formation, El Anfiteatro area, RÃo Negro province, Patagonia. The shell displays two distinct but synchronously produced trace fossils in the anterior right portion of the plastron. One of the trace fossils is semicircular and indicates where the bone has been broken during the attack, as a consequence of a bite. The other one reflects the predatorâs teeth morphology, and suggests a crocodyliform as the best candidate. Computed tomography analysis reveals regenerated tissue associated with both trace fossils, indicating healing of the wound. No vital organ was seriously injured during the attack, and the turtle survived, lacking a fragment of the shell. Taking into account the evidence in the fossil record, the unambiguous predator-prey relationship between crocodyliforms and turtles is present from at least the Late Jurassic, and the Rionegrochelys caldieroi holotype and their trace fossils is a new evidence of this interaction.
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E. Catherine Strickson, ÂJohn R. Hutchinson, ÂDavid M. Wilkinson Â& Peter L. Falkingham (2019)
Can skeletal surface area predict in vivo foot surface area?
Journal of Anatomy (advance online publication)
doi:
https://doi.org/10.1111/joa.13090https://onlinelibrary.wiley.com/doi/10.1111/joa.13090The surface area of feet in contact with the ground is a key morphological feature that influences animal locomotion. Underfoot pressures (and consequently stresses experienced by the foot), as well as stability of an animal during locomotion, depend on the size and shape of this area. Here we tested whether the area of a skeletal foot could predict in vivo soft tissue foot surface area. Computed tomography scans of 29 extant tetrapods (covering mammals, reptiles, birds and amphibians) were used to produce models of both the soft tissues and the bones of their feet. Soft tissue models were oriented to a horizontal plane, and their outlines projected onto a surface to produce twoâdimensional silhouettes. Silhouettes of skeletal models were generated either from bones in CT pose or with all autopodial bones aligned to the horizontal plane. Areas of these projections were calculated using alpha shapes (mathematical tightâfitting outline). Underfoot area of soft tissue was approximately 1.67 times that of skeletal tissue area (~ 2 times for manus, ~ 1.6 times for pes, if analysed separately). This relationship between skeletal foot area and soft tissue area, while variable in some of our study taxa, could provide information about the size of the organisms responsible for fossil trackways, suggest what size of tracks might be expected from potential trackmakers known only from skeletal remains, and aid in soft tissue reconstruction of skeletal remains for biomechanical modelling.
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Free pdf:
Mark Doeland, Aidan M. C. Couzens, Philip C. J. Donoghue and Martin RÃcklin (2019)
Tooth replacement in early sarcopterygians.
Royal Society Open Science 6: 191173
doi:
https://doi.org/10.1098/rsos.191173https://royalsocietypublishing.org/doi/10.1098/rsos.191173Free pdf:
https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.191173Teeth were an important innovation in vertebrate evolution but basic aspects of early dental evolution remain poorly understood. Teeth differ from other odontode organs, like scales, in their organized, sequential pattern of replacement. However, tooth replacement patterns also vary between the major groups of jawed vertebrates. Although tooth replacement in stem-osteichthyans and extant species has been intensively studied it has been difficult to resolve scenarios for the evolution of osteichthyan tooth replacement because of a dearth of evidence from living and fossil sarcopterygian fishes. Here we provide new anatomical data informing patterns of tooth replacement in the Devonian sarcopterygian fishes Onychodus, Eusthenopteron and Tiktaalik and the living coelacanth Latimeria based on microfocus- and synchrotron radiation-based X-ray microtomography. Early sarcopterygians generated replacement teeth on the jaw surface in a pattern similar to stem-osteichthyans, with damaged teeth resorbed and replacement teeth developed on the surface of the bone. However, resorption grades and development of replacement teeth vary spatially and temporally within the jaw. Particularly in Onychodus, where teeth were also shed through anterior rotation and resorption of bone at the base of the parasymphyseal tooth whorl, with new teeth added posteriorly. As tooth whorls are also present in more stem-osteichthyans, and statodont tooth whorls are present among acanthodians (putative stem-chondrichthyans), rotational replacement of the anterior dentition may be a stem-osteichthyan character. Our results suggest a more complex evolutionary history of tooth replacement.
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The monobasal pectoral fins of living coelacanths and lungfishes are homologous to the forelimbs of tetrapods and are thus critical to investigate the origin thereof. However, it remains unclear whether the similarity in the asymmetrical endoskeletal arrangement of the pectoral fins of coelacanths reflects the evolution of the pectoral appendages in sarcopterygians. Here, we describe for the first time the development of the pectoral fin and shoulder girdle in the extant coelacanth Latimeria chalumnae, based on the tomographic acquisition of a growth series. The pectoral girdle and pectoral fin endoskeleton are formed early in development with a radially outward growth of the endoskeletal elements. The visualization of the pectoral girdle during development shows a reorientation of the girdle between the fetus and pup 1 stages, creating a contact between the scapulocoracoids and the clavicles in the ventroâmedial region. Moreover, we observed a splitting of the preâ and postâaxial cartilaginous plates in respectively preâaxial radials and accessory elements on one hand, and in postâaxial accessory elements on the other hand. However, the mechanisms involved in the splitting of the cartilaginous plates appear different from those involved in the formation of radials in actinopterygians. Our results show a proportional reduction of the proximal preâaxial radial of the fin, rendering the external morphology of the fin more lobeâshaped, and a spatial reorganization of elements resulting from the fragmentation of the two cartilaginous plates. Latimeria development hence supports previous interpretations of the asymmetrical pectoral fin skeleton as being plesiomorphic for coelacanths and sarcopterygians.
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The Deccan Volcanic Province has been considered as one of the largest magmatic regions, involving an aerial coverage of ca. 500,000 km2. It is subdivided into four sub-provinces, and holds a unique position in global tectonic models for understanding earth's geodynamics and the impact of voluminous eruptions on the contemporary biosystem and climate system. Published stratigraphic data suggest that volcanic eruption took place from 69 to 64 million years (Ma) ago when the Indian plate passed over the RÃunion hotspot. The main phase of volcanic activity consisting of about 80% of total basaltic lava, erupted rapidly, during a short span (<1 Ma) or even less (two or three hundred thousand years), close to chron 29R, straddling to the CretaceousâPaleogene (KâPg) boundary. Recent high-precision age data show that the main volcanic phase is genetically linked to the Chicxulub impact and plume-head of the hotspot, and largely contributed to the end-Cretaceous mass extinction. To assess the links of the province to the KâPg boundary, Chicxulub impact, RÃunion plume, and Late Cretaceous global climate crisis, it is crucial to have a current state of knowledge of the understanding of its stratigraphy. A review of published data shows a surge in the province research that has considerably advanced the understanding of its stratigraphy. This province is intercalated with numerous infra- and intertrappean sedimentary beds that have yielded diverse biota, providing a reliable relative time control for duration of the volcanic activity. This paper presents a review of the stratigraphic developments of the province (lithostratigraphy, chemostratigraphy, magnetostratigraphy, and chronostratigraphy) from the very beginning to the present, and discusses the role of the RÃunion plume in its formation.