Yi qi is the infamous scansoriopterygid
preserved in a scattered fashion (Fig. 1) in which some workers mistakenly identify a new long bone, the styliform, arising from the wrist that no other tetrapod has. Earlier one bone was identified as a displaced ulna. The other, straighter bone is a displaced and equally crushed radius. There is no such bone as a ‘styliform’.
Dececchi, Habib and Larsson 2018 imagine
how Yi qi could fly with that bogus styliform and only one bone in each antenbrachium. They erroneously report that among the three vertebrates with the power of flight, only one, birds (in their words: ‘paravian theropods’) “Only in this last group do we have enough of a dataset that we can begin to address the question of what is sufficient to allow flight and did it evolve more than once within the group.”
We’ve known how pterosaurs developed wings since Peters 2000. (See how Dr. Chris Bennett’s threat has come true? “You won’t get published. And if you do get published, you won’t get cited.”)
Over and over this team fails
to understand what they are working with. Dececchi TA, Habib M and Larsson HC 2018 report, “Yi is different from other winged and potential volant pennaraptorans because it built its primary wing structure using a skin based membrane, as opposed to the feathered flight structure seen in birds.” This is a simple misinterpretation. Dececchi, Habib and Larsson will be more or less embarrassed when they look for the displaced antebrachia and reality dawns on them.
Moreover, due to taxon exclusion
Dececchi et al. had no idea that Yi qi and the scanoriopterygidae nest within Aves (Fig. 2), the bird clade that excludes Oviraptor and Deinonychus and includes Archaeopteryx and Passer in the large reptile tree.
Roy et al. 2018
also studied the soft tissue anatomy of Yi qi (Fig. 1). These authors acknowledge, “The
strange membranous wings of this animal are highly disparate from the feathered wings of
avian theropods.” They report, “In this study, all previously identified textured membrane
patches exhibited negligible fluorescence under LSF. However, for the first time, LSF
revealed multiple patches of orange-coloured suspected soft tissue around the cranial bones as well as an ungual sheath. These results appear to have two alternative explanations that deserve further investigation:
- differential, chemical replacement of the soft and hard
tissues of the fossil
- the reported membrane patches are poorly preserved clumped
Roy et al. concluded, “The radiale angle and angle of wing abduction of Yi qi, when compared with orientations of the styliform element proposed in bat, pterosaur, maniraptoran and frog models, indicate that the maniraptoran wing model was least restrictive to bird-like folding of the wings and was probably the most likely
configuration for Yi qi.”
Distinct from most birds,
scansoriopterygids like Yi qi have a longer manual digit 3 than 2.
Dececchi TA, Habib M and Larsson HC 2018. Flights of fancy: modeling powered flight versus gliding in the bizarre theropod Yi qi and its bearing on the question of the origins of flight across Pennaraptora. SVP abstracts.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Roy A, Pittman M, Kaye TG, Wang X, Xu X and Zheng X 2018. Further investigation of the soft-tissue anatomy and wing configuration of the ‘bat-winged’ pennaraptoran dinosaur Yi qi. SVP abstracts.
Pennaraptora = Oviraptor, Deinonychus, Passer, their last common ancestor and all descendants. In the LRT that clade also includes Compsognathus, T-rex, Struthiomimus and other small to giant theropods and Aorum is a sister to the last common ancestor.