Yi qi, which has membranous wings—a flight apparatus that was previously unknown among theropods but that is used by both the pterosaur and bat lineages6. This observation was not universally accepted7. Here we describe a newly identified scansoriopterygid —which we name Ambopteryx longibrachium, gen. et sp. nov.—from the Upper Jurassic period. This specimen provides support for the widespread existence of membranous wings and the styliform element in the ScansoriopterygidaeThe scansoriopterygids (including Ambopteryx) are members of basal Paraves. With their wing skin membrane and longest outermost finger, they are a candidate transitional between pterosaur and later Paraves. They fit right into the pterosaur to bird theory.
On the other hand, there is zero evidence of membrane wings in any claimed dinosaur ancestor. And also, scansoriopterygids have the outermost digit as the longest, which is not found in any claimed dinosaur ancestor.
For details about Yi qi see here:
http://pterosaurnet.blogspot.com/2015/05/another-scansoriopterygid.html
For details about Scansoriopteryx see here:
https://pterosaurnet.blogspot.com/2014/07/scansoriopteryx.html
https://m.phys.org/news/2019-05-jurassic-non-avian-theropod-dinosaur-flight.html
https://pterosaurheresies.wordpress.com/2015/05/03/no-styliform-element-on-yi-qi-thats-just-a-displaced-radius/
ReplyDeletePadian:
ReplyDeletehttps://www.nature.com/articles/nature14392
https://www.researchgate.net/publication/275669107_A_bizarre_Jurassic_maniraptoran_theropod_with_preserved_evidence_of_membranous_wings
ReplyDeleteIn having wings with a well-developed membranouscomponent, Yi would differ from other volant paravians but resemble distantly related groups including pterosaurs, bats and many glidingmammals, representing a striking case of convergent evolution of theaerodynamic apparatus among tetrapods6–10.
https://www.researchgate.net/publication/271658034_Jurassic_archosaur_is_a_non-dinosaurian_bird
ReplyDeleteRe-examination utilizing Keyence 3D digital microscopy and low angled illumination of the fossil Scansoriopteryx, a problematic sparrow-size pre-Archaeopteryx specimen from the Jurassic Daohugou Biotas, provides new evidence which challenges the widely accepted hypothesis that birds are derived from dinosaurs in which avian flight originated from cursorial forms. Contrary to previous interpretations in which Scansoriopteryx was considered to be a coelurosaurian theropod dinosaur, the absence of fundamental dinosaurian characteristics demonstrates that it was not derived from a dinosaurian ancestry and should not be considered as a theropod dinosaur. Furthermore, the combination in which highly plesiomorphic non-dinosaurian traits are retained along with highly derived features, yet only the beginnings of salient birdlike characteristics, indicates that the basal origins of Aves stemmed from outside the Dinosauria and further back to basal archosaurs. Impressionsof primitive elongate feathers on the forelimbs and hindlimbs suggest that Scansoriopteryx represents a basal form of‘‘tetrapteryx’’ in which incipient aerodynamics involving parachuting or gliding was possible. Along with unique adaptations for an arboreal lifestyle, Scansoriopteryx fulfills predictions from the early twentieth century that the ancestors of birds did not evolve from dinosaurs, and instead were derived from earlier arboreal archosaurs which originated flight according to the traditional trees-down scenario