No styliform element on Yi qi. That’s just a displaced radius and ulna.

Modified May 3, 2015 with the new identification of the curved ‘styliform element’, as the ulna, not the radius. 

Error alert
Apparently all the fuss and PR over the new batwing dino/bird Yi qi  is based on an error of bone identification. Both antebrachia on the specimen were splintered during crushing. The splinters were misidentified as slender radii. The purported ‘styliform elements’ (Xu et al. 2015) that gave Yi qi such an odd appearance are actually a displaced right radius and left ulna. The pictures below tell the story (Figs. 1-3).

Figure 1. Identification errors (in red) on the original Yi qi diagram from Xu et al. 2015.

Figure 1. Identification errors (in red) on the original Yi qi diagram from Xu et al. 2015.

The digits
were also mislabeled following the pattern in Limusaurus, which we touched on earlier.

The long scapula identified by Xu et al.
appears instead to be a pair of opposing elongate coracoids. Long coracoids make Yi qi a flapper, not a glider, weak though it may have been.

Figure 2. The Yi qi fossil plate and counter plates. Counterplates above and flipped to match plate.

Figure 2. The Yi qi fossil plate and counter plates. Counterplates above and flipped to match plate. Click to enlarge.

Only a few elements
appear on the counter plate (Fig. 2) that are not present on the plate. Putting them together in Photoshop and painting the bones using the methodology of DGS helped sort out the data (Fig. 3).

Figure 3. Closeup of the former 'styliform element' here identified as a radius in Yi qi.

Figure 3. Closeup of the former ‘styliform element’ here identified as a radius in Yi qi. Click to enlarge. Bone splinters led to earlier misidentification.

Reports say
the Xu et al. team struggled for several months to come to grips with this large, never-before-seen bone, the so-called ‘styliform element’. Evidently the left ulna splinters looked enough like a radius that they discounted the possibility that the odd bone was indeed the radius, likewise splintered. Note the odd orientation of the left manus (Fig. 3) in which the lateral digits are medial. The observed membrane may have been the propatagium. Or it could have simply trailed the wing like other bird membranes do. Remember, birds have no scales, as we learned earlier. Birds have naked skin with some feathers later transforming to scales on their legs with few exceptions (like owls).

Figure 4. Yi qi tracing of the in situ specimen using DGS method and bones rearranged, also using the DGS method, to form a standing and flying Yi qi specimen. Note the lack of a styliform element, here identified as a displaced radius and ulna.

Figure 4. Yi qi tracing of the in situ specimen using DGS method and bones rearranged, also using the DGS method, to form a standing and flying Yi qi specimen. Note the lack of a styliform element, here identified as a displaced radius and ulna.

Reconstructions (Fig 4) are also part of the DGS process, making sure that all bones fit together and also match those of closely related taxa (Fig. 5). Odd autapomorphies, like a styliform element, are immediately suspect, but odd autapomorphies do occasionally occur.,, apparently not this time.

Figure 4. Right ulna of Yi (former 'styliform element') compared to right ulna of Epidendrosaurus.

Figure 4. Right ulna of Yi (former ‘styliform element’) compared to right ulna of Epidendrosaurus. Click to enlarge.

DGS has gotten a bad rap.
This is just another example where, without seeing the fossil, a contribution to identification and understanding can be made. Maybe now would be a good time to take down some of those anti-DGS websites and blogposts out there.

References
Padian K. 2015. Paleontology: Dinosaur up in the air. Nature (2015) doi:10.1038/nature14392
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)
doi:10.1038/nature14423

 

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4 thoughts on “No styliform element on Yi qi. That’s just a displaced radius and ulna.

  1. Yi qi looks like a maniraptoran bird to me. I believe you hit the nail on the head! As for DGS being accepted: you need to expose the anti David Peters posts for what they are: pre-emptive strikes, NOT science in any way, shape, or form.

  2. I suppose that they could just as easily have NOT interpreted the styliform element as such, and this would be ‘just another’ scansoriopterygid.

    I’d be interested to see if the team’s interpretations are supported by some sort of penetrative scanning analysis (MRI, x-ray, or whatever is appropriate for fossils), in the way Archaeoraptor was looked at.

      • To clarify, my comment wasn’t about suggesting this was an Archaeoraptor-esqe fake. I just used Archaeoraptor as an example since those techniques seemed to reveal what was going within the matrix/matrices.

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