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  • Theropod pre-avian aerial behavior

    From Pandora@21:1/5 to All on Sun Oct 27 09:37:36 2024
    Theropod trackways as indirect evidence of pre-avian aerial behavior

    Open access:
    https://www.pnas.org/doi/10.1073/pnas.2413810121

    Abstract

    Body fossils set limits on feasible reconstructions of functional
    capacity and behavior in theropod dinosaurs, but do not document in-life behaviors. In contrast, trace fossils such as footprints preserve
    in-life behaviors that can potentially test and enhance existing reconstructions. Here, we demonstrate how theropod trackways can be used
    as indirect evidence of pre-avian aerial behavior, expanding the
    approaches available to study vertebrate flight origins. This involved exploring the behavioral implications of a two-toed Cretaceous-aged
    theropod trackway produced by a small, bird-like microraptorine moving
    at high speed. Applying first principle running biomechanics, we were
    able to conclude that the trackway is atypical, indirectly evidencing
    pre-avian aerial behavior. This trackway documents the evidence of wing-assisted aerodynamic force production during locomotion, supporting
    a broader distribution of this behavior than currently known. These
    findings support previously proposed aerial behavior in early bird-like theropods, showing how trackways will help to deepen our understanding
    of theropod flight origins.

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  • From Pandora@21:1/5 to All on Mon Oct 28 20:18:38 2024
    Op 27-10-2024 om 14:32 schreef John Harshman:

    On 10/27/24 1:37 AM, Pandora wrote:
    Theropod trackways as indirect evidence of pre-avian aerial behavior

    Open access:
    https://www.pnas.org/doi/10.1073/pnas.2413810121

    Abstract

    Body fossils set limits on feasible reconstructions of functional
    capacity and behavior in theropod dinosaurs, but do not document in-
    life behaviors. In contrast, trace fossils such as footprints preserve
    in-life behaviors that can potentially test and enhance existing
    reconstructions. Here, we demonstrate how theropod trackways can be
    used as indirect evidence of pre-avian aerial behavior, expanding the
    approaches available to study vertebrate flight origins. This involved
    exploring the behavioral implications of a two-toed Cretaceous-aged
    theropod trackway produced by a small, bird-like microraptorine moving
    at high speed. Applying first principle running biomechanics, we were
    able to conclude that the trackway is atypical, indirectly evidencing
    pre-avian aerial behavior. This trackway documents the evidence of
    wing-assisted aerodynamic force production during locomotion,
    supporting a broader distribution of this behavior than currently
    known. These findings support previously proposed aerial behavior in
    early bird-like theropods, showing how trackways will help to deepen
    our understanding of theropod flight origins.

    Is this really telling us about the origin of flight? Does a running
    takeoff from the ground support a ground-up origin of flight?

    It's suggestive, but the authors state they "cannot make any claim
    linking a specific aerial behavior to the trackway (e.g., launch,
    landing, accelerated downward glides, or wing-assisted stride extension)"
    If it was landing the critter could have come down from the trees.

    And are the tracks really diagnostic at the subfamily level?

    See:

    https://www.nature.com/articles/s41598-018-35289-4

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