Shenzhoupterus (Figs. 1-6, Lü et al. 2008) is a wonderfully bizarre derived pterosaur with an outsized skull and long, heron-like limbs, a deep prepubis and a tubby torso. The skeleton is complete and – mostly – articulated.
The big problems are the skull and the sternum. The bones of the cheek region of the skull are all there, they’re just jumbled beyond recognition. The sternum is apparently gone (but wait, there’s more!! ~ and these two problems are interrelated!!)
This is a job for DGS (digital graphic segregation)!
But first the easy stuff. See the tip of the parietal crest (Fig. 1)? It was overlooked by the original authors and illustrators. This long crest is homologous with that of its close relatives Germanodactylus cristatus (Fig. 6) and Sinopterus.
We’ll take this a step at a time. Here (Fig. 2) is a close look at the skull in all its chaos.
Here (Fig. 3) the sternal complex (sternum + clavicles + interclavicle) is illustrated in blue. Yes, it is difficult to see. But it is there, exposed and identified by DGS.
Here (Fig. 4) only one side of the cheek elements and the entire occiput are identified. Even without the other side elements the bones are chaotic. They only make sense when you put them back together, and even then there’s a derived and distinct morphology present (Fig. 5). DGS was able to identify the elements using a photograph and a computer better than the naked eye. Moreover, the elements of the rostrum are better delineated.
Comparisons to related taxa complete the analysis (Fig. 6). Note the original interpretation looks nothing like the related pterosaurs and fails to identify skull elements.
And then there’s the wing ungual.
A closeup photo of the Shenzhoupterus wingtip (Fig. 7) reveals the ungual, hyper-flexed but still articulated. No wonder it was originally overlooked.
Overall a closer examination using every available tool is warranted here. A simple examination using the eyeball alone is not sufficient to segregate the elements of the Shenzhoupterus cheek region. It takes a graphic tool to do so. Identifying one element after another until all elements are accounted for. That’s how the sternal complex beneath the skull was discovered. It wasn’t immediately apparent until all the other skull elements were delineated and identified.
As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.
Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.
Lü J, Unwin DM, Xu L and Zhang X 2008. A new azhdarchoid pterosaur from the Lower Cretaceous of China and its implications for pterosaur phylogeny and evolution. Naturwissenschaften 95 (9): online (preprint). doi:10.1007/s00114-008-0397-5. PMID 18509616.