Scansorial and aerial ability in Scansoriopterygidae and basal Oviraptorosauria

ABSTRACT

Previously proposed hypothesis that known terrestrial and flightless members of the pennaraptoran clade Oviraptorosauria (Dinosauria: Theropoda) evolved from scansorial and volant ancestors is evaluated by reviewing publications on the phylogenetic position and morphology of the pennaraptoran clade Scansoriopterygidae. Publications on the phylogenetic relationships of basal members of the pennaraptoran clade Paraves and morphology of recently discovered basal paravians were also reviewed to re-evaluate a previously supported hypothesis that terrestrial and flightless members of the paravian clade Deinonychosauria evolved from scansorial and volant ancestors. Uncertainty about the phylogenetic position of Scansoriopterygidae among basal pennaraptorans suggests that scansoriopterygid morphology is close to the ancestral morphology of Pennaraptora. Functional morphology indicates that all known scansoriopterygids were capable of scansorial locomotion and gliding, but not active flight, suggesting that the most recent common ancestor of Pennaraptora was also a scansorial glider and therefore, supports the descent of known terrestrial and flightless Oviraptorosauria from scansorial and volant ancestors. This evolutionary scenario (supported by phylogenetic analyses and functional morphology) supports the evolution of pennaceous feathers as a flight adaptation and the ‘from the trees down’ hypothesis of bird flight evolution.

KEYWORDS:

• Pennaraptora
• Scansoriopterygidae
• Oviraptorosauria
• Paraves
• climbing and flight adaptations
• secondary terrestriality and flightlessness

Acknowledgments

I thank S. Brusatte (University of Edinburgh, UK) and, especially P. Senter (Fayetteville State University, USA) for their suggestions of publications to submit the manuscript to. I also thank two anonymous Historical Biology reviewers for their thoughtful reviews, including extensive constructive criticisms by one of the reviewers that considerably improved the quality and expanded the scope of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the author’s personal funds only.