Re: [dinosaur] Tyrannosaurus rex cranial kinesis

Some news and blog updates and a video:

T. rex used a stiff skull to eat its prey

https://urldefense.proofpoint.com/v2/url?u=https-3A__phys.org_news_2019-2D09-2Drex-2Dstiff-2Dskull-2Dprey.html&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=HzjeROgnjKCWrLn1--ak4kaCcFRp1W0fq3SdoF584uM&s=Gs3AhlxN_eYx5vh3tiIx_hoYZCw745mf0LaF0zoiA7k&e= 

https://urldefense.proofpoint.com/v2/url?u=https-3A__munews.missouri.edu_news-2Dreleases_2019_0925-2Dt-2Drex-2Dused-2Da-2Dstiff-2Dskull-2Dto-2Deat-2Dits-2Dprey_&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=HzjeROgnjKCWrLn1--ak4kaCcFRp1W0fq3SdoF584uM&s=FLquv5X2FX3JKh0bvIzi7PvXnmRkOofLUuMrBA57FPo&e= 


T. rex's Skull-Shattering Bite

https://urldefense.proofpoint.com/v2/url?u=http-3A__dontmesswithdinosaurs.com_-3Fp-3D2329-26fbclid-3DIwAR388AAu-2Dv-5F8xo8NKYnumTik43gxpi-5F0sYKwmnebyM3w1KHmEGw3ul-2D8cT8&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=HzjeROgnjKCWrLn1--ak4kaCcFRp1W0fq3SdoF584uM&s=0kv5foCpH9W_6oPKWw2FFiFxZzhgck_74vjUzIW0owo&e= 

video:

https://urldefense.proofpoint.com/v2/url?u=https-3A__www.youtube.com_watch-3Ftime-5Fcontinue-3D2-26v-3D-2DSQjv66NOZs&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=HzjeROgnjKCWrLn1--ak4kaCcFRp1W0fq3SdoF584uM&s=WGRN0Weg-mo60HCgeqKhb5Gx9KNMw4GXiJZQ1sBphlU&e= 

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On Mon, Jul 1, 2019 at 9:20 AM Ben Creisler <[email protected]> wrote:

>
> Ben Creisler
> [email protected]
>
>
> A new paper:
>
>
> Ian N. Cost, Kevin M. Middleton, Kaleb C. Sellers, M. Scott Echols,
> Lawrence M. Witmer, Julian L. Davis & Casey M. Holliday (2019)
> Palatal biomechanics and its significance for cranial kinesis in
> Tyrannosaurus rex.
> The Anatomical Record (advance online publication)
> doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1002_ar.24219&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=HzjeROgnjKCWrLn1--ak4kaCcFRp1W0fq3SdoF584uM&s=TkQGbynk9XAmxD1T5fagW_X-uo2YdU69AtZKIeWIWKU&e= 
> https://urldefense.proofpoint.com/v2/url?u=https-3A__onlinelibrary.wiley.com_doi_10.1002_ar.24219&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=HzjeROgnjKCWrLn1--ak4kaCcFRp1W0fq3SdoF584uM&s=2yLBQHCNWy7VVcnnrwenO2AKs_0zD0stpFFtabOSunw&e= 
>
>
> The extinct non‐avian dinosaur Tyrannosaurus rex, considered one of the
> hardest biting animals ever, is often hypothesized to have exhibited
> cranial kinesis, or, mobility of cranial joints relative to the braincase.
> Cranial kinesis in T. rex is a biomechanical paradox in that
> forcefully‐biting tetrapods usually possess rigid skulls instead of skulls
> with movable joints. We tested the biomechanical performance of a
> tyrannosaur skull using a series of static positions mimicking possible
> excursions of the palate to evaluate Postural Kinetic Competency in
> Tyrannosaurus. A functional extant phylogenetic bracket was employed using
> taxa which exhibit measurable palatal excursions: Psittacus erithacus
> (fore‐aft movement) and Gekko gecko (mediolateral movement). Static finite
> element models of Psittacus, Gekko, and Tyrannosaurus were constructed and
> tested with different palatal postures using anatomically‐informed material
> properties, loaded with muscle forces derived from dissection, phylogenetic
> bracketing, and a sensitivity analysis of muscle architecture and tested in
> orthal biting simulations using element strain as a proxy for model
> performance. Extant species models showed lower strains in
> naturally‐occurring postures compared to alternatives. We found that
> fore‐aft and neutral models of Tyrannosaurus experienced lower overall
> strains than mediolaterally‐shifted models. Protractor muscles dampened
> palatal strains, while occipital constraints increased strains about
> palatocranial joints compared to jaw‐joint constraints. These loading
> behaviors suggest that even small excursions can strain elements beyond
> structural failure. Thus, these postural tests of kinesis, along with the
> robusticity of other cranial features, suggest that the skull of
> Tyrannosaurus was functionally akinetic.
>
>
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