Cheers,
âMike
Sent from my Cybernetic Symbiote
On Apr 26, 2021, at 9:07 PM, Ben Creisler <bcreisler@gmail.com> wrote:
ïA counter article and a response concerning the original paper:====
Francisco J. Serrano & Luis M. Chiappe (2021)
Independent origins of powered flight in paravian dinosaurs?
Current Biology 31(8): R370-R372
DOI: https://doi.org/10.1016/j.cub.2021.03.058
https://www.sciencedirect.com/science/article/abs/pii/S0960982221004310
Feathered dinosaurs discovered during the last decades have illuminated the transition from land to air in these animals, underscoring a significant degree of experimentation in wing-assisted locomotion around the origin of birds. Such evolutionary experimentation led to lineages achieving either wing-assisted running, four-winged gliding, or membrane-winged gliding. Birds are widely accepted as the only dinosaur lineage that achieved powered flight, a key innovation for their evolutionary success. However, in a recent paper in Current Biology, Pei and colleagues disputed this view. They concluded that three other lineages of paravian dinosaurs (those more closely related to birds than to oviraptorosaurs) -- Unenlagiinae, Microraptorinae and Anchiornithinae -- could have evolved powered flight independently. While we praise the detailed phylogenetic framework of Pei and colleagues and welcome a new attempt to understand the onset of flight in dinosaurs, we here expose a set of arguments that significantly weaken their evidence supporting a multiple origin of powered flight. Specifically, we maintain that the two proxies used by Pei and colleagues to assess powered flight potential in non-avian paravians -- wing loading and specific lift -- fail to discriminate between powered flight (thrust generated by flapping) and passive flight (gliding).****News:Researcher questions whether powered flight appeared on non-avialan dinosaurs====Free pdf:
Michael Pittman, Michael B. Habib, T. Alexander Dececchi, Hans C.E. Larsson, Rui Pei, Thomas G. Kaye, Mark A. Norell, Stephen L. Brusatte & Xing Xu (2021)
Response to Serrano and Chiappe.
Current Biology 31(8): R372-R373
doi: https://doi.org/10.1016/j.cub.2021.03.059
https://www.cell.com/current-biology/fulltext/S0960-9822(21)00432-2
https://www.sciencedirect.com/science/article/pii/S0960982221004322
Free pdf:
https://www.cell.com/action/showPdf?pii=S0960-9822%2821%2900432-2
In the recent study in Current Biology by Pei and colleagues, we used two proxies â wing loading and specific lift â to reconstruct powered flight potential across the vaned feathered fossil pennaraptorans. The results recovered multiple origins of powered flight. We respectfully disagree with the criticism raised by Serrano and Chiappe that wing loading and specific lift, used in sequence, fail to discriminate between powered flight and gliding. We will explain this in reference to our original conservative approach.
=====
Also an updated ref in final form:
Rui Pei, Michael Pittman, Pablo A. Goloboff, T. Alexander Dececchi, Michael B. Habib, Thomas G. Kaye, Hans C.E. Larsson, Mark A. Norell, Stephen L. Brusatte & Xing Xu (2020)
Potential for Powered Flight Neared by Most Close Avialan Relatives, but Few Crossed Its Thresholds.
Current Biology 30(20): 4033-4046.e8
DOI: https://doi.org/10.1016/j.cub.2020.06.105
https://www.cell.com/current-biology/fulltext/S0960-9822(20)30999-4
Free pdf:
https://www.cell.com/current-biology/pdf/S0960-9822(20)30999-4.pdf
====On Thu, Aug 6, 2020 at 9:15 AM Ben Creisler <bcreisler@gmail.com> wrote:Ben CreislerA new paper with free pdf:=====
Rui Pei, Michael Pittman, Pablo A. Goloboff, T. Alexander Dececchi, Michael B. Habib, Thomas G. Kaye, Hans C.E. Larsson, Mark A. Norell, Stephen L. Brusatte & Xing Xu (2020)
Potential for Powered Flight Neared by Most Close Avialan Relatives, but Few Crossed Its Thresholds.
Current Biology (advance online publication)
DOI: https://doi.org/10.1016/j.cub.2020.06.105
https://www.cell.com/current-biology/fulltext/S0960-9822(20)30999-4
Support Deinonychosauria as sister taxon to birds and Anchiornithinae as early birds
Powered flight potential evolved â3 times: once in birds and twice in dromaeosaurids
Many ancestors of bird relatives neared thresholds of powered flight potential
Broad experimentation with wing-assisted locomotion before theropod flight evolved
Summary
Uncertainties in the phylogeny of birds (Avialae) and their closest relatives have impeded deeper understanding of early theropod flight. To help address this, we produced an updated evolutionary hypothesis through an automated analysis of the Theropod Working Group (TWiG) coelurosaurian phylogenetic data matrix. Our larger, more resolved, and better-evaluated TWiG-based hypothesis supports the grouping of dromaeosaurids + troodontids (Deinonychosauria) as the sister taxon to birds (Paraves) and the recovery of Anchiornithinae as the earliest diverging birds. Although the phylogeny will continue developing, our current results provide a pertinent opportunity to evaluate what we know about early theropod flight. With our results and available data for vaned feathered pennaraptorans, we estimate the potential for powered flight among early birds and their closest relatives. We did this by using an ancestral state reconstruction analysis calculating maximum and minimum estimates of two proxies of powered flight potential--wing loading and specific lift. These results confirm powered flight potential in early birds but its rarity among the ancestors of the closest avialan relatives (select unenlagiine and microraptorine dromaeosaurids). For the first time, we find a broad range of these ancestors neared the wing loading and specific lift thresholds indicative of powered flight potential. This suggests there was greater experimentation with wing-assisted locomotion before theropod flight evolved than previously appreciated. This study adds invaluable support for multiple origins of powered flight potential in theropods (â3 times), which we now know was from ancestors already nearing associated thresholds, and provides a framework for its further study.
===Video:Most Bird Cousins Neared Powered Flight Potential