Wang, O’Connor, Xu and Zhou 2019
report on another scasoriopterygid with a ‘styliform’ bone creating a bat-like wing membrane in their imaginations. They named this specimen, Ambopteryx longibrachium (Fig. 1). This would be the second such instance, in their opinion, of a bat-wing bird. You might remember the flap over the first such instance, Yi qi (Fig. 2), which turned out NOT to have as styliform bone, just a displaced ulna on one side, a displaced radius on the other.
Well… tracing the elements in color
|reveals no styliform bone. See for yourself (Fig. 1). Again the authors mistook a perfectly good ulna for the invalid and imagined ‘styliform’ bone on the left wing. Turns out Ambopteryx longibrachium has a perfectly normal radius and ulna, just like all of its sisters in the bird clade. The authors do not illustrate a styliform bone on the better articulated right wing. It should have been there, if it was there in life.
The authors tried to make the extraordinary and implausible ordinary
by introducing another example of their previously invalidated observations. Today’s exercise demonstrates the importance of color tracing and using those tracings, as is, to build reconstructions. Do not freehand! The present notes also demonstrate, once again, just because some discovery is published in Nature, and heralded by major publications (see below) it still might not be true.
The news media is all over this:
with gorgeous paintings and glorified reports of a mythical creature with a bird body and bat wings. Unfortunately, like the editors and referees at Nature, they, too, were bamboozled by bombast.
Lead author Wang dramatically reported,
“I was frozen when I realized that a second membranous winged dinosaur was in front of my eyes,” Wang says. The 163 million-year-old fossil confirms that Yi was not an aberration or a one-off. Together, the two species represent an alternate evolutionary path for airborne dinosaurs.”
Not an aberration or a one-off, Dr. Wang…
two similar errors based on wishful thinking and cognitive bias.
Wang M, O’Connor JK.; Xu X and Zhou Z 2019. A new Jurassic scansoriopterygid and the loss of membranous wings in theropod dinosaurs. Nature 569: 256–259. doi:10.1038/s41586-019-1137-z
Xu X, Zheng X-T, Sullivan C, Wang X-L, Xing l, Wang Y, Zhang X-M, O’Connor JK, Zhang F-C and Pan Y-H 2015. A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings. Nature (advance online publication)