Dendrorhynchoides – The Real Tail Found

Dendrorhynchoides (Ji and Ji 1988, Fig. 1) was originally described as a rhamphorhynchid pterosaur with a long tail. However, it was immediately apparent that this assignment was an error and that Dendrorhynchoides was an anurognathid due to the round skull. But what about that long tail?

Dendrorhynchoides in situ

Figure 1. Dendrorhynchoides in situ. Click for more info. Note the long, robust tail. It is an implant that has been doctored in.

Unwin et al. (2000) reported that the tail was actually doctored in and belonged to some other sort of creature, likely a tiny dromaeosaurid dinosaur close to birds. On the other hand, I thought the tail could be genuine because Dendrorhynchoides nested close to the MCSNB 3359 specimen of Peteinosaurus and  MCSNB 8950, both of which had a substantial tail of similar shape.

Adding More Taxa Cleared Up the Matter
The embryo anurognathid (IVPP V13758) was found to have a vestigial tail and nested between Peteinosaurus and Dendrorhynchoides. That provided the impetus for a second look. By employing the phylogenetic bracketing concept, you can make predictions about missing parts in transitional taxa. The predictions are not guaranteed, but they do make great guides.

Dendrorhynchoides after DGS (digital graphic segregation).

Figure 2. Dendrorhynchoides after DGS (digital graphic segregation). Click to enlarge. Here the doctored tail is outlined in brown. The real tail is identified with an arrow. Contra published reports and Wikipedia, the sternal complex and m4.4 are both present and all the parts of the skull can be identified.

There It Is. The Real Tail. 
On closer examination the overlooked (by everyone) real tail of Dendrorhynchoides  appeared (Fig. 2). It was tiny and bead-like, as in the IVPP embryo. Stretched out the real tail was actually longer than the chimaera, but much more gracile (Fig. 3).

But Wait, There’s More
Contra earlier reports, the entire skull can be identified using DGS (digital graphic segregation). Manual 4.4 for both wings can be seen hidden among the ribs. Edges of the sternal complex are also visible. It is relatively the widest among all pterosaurs producing a much wider than deep torso, more so than in the flat-head anurognathid. Soft tissue wing membranes and uropatagia can also be delineated. As in other pterosaurs, the wing membrane stretched between the wing tip and the elbow with a fuselage fillet extending back to the femur.

Dendrorhynchoides reconstructed.

Figure 3. Dendrorhynchoides reconstructed. The chimaera tail likely belonged to a tiny dinosaur. Click for more info.

A Second Dendrorhynchoides?
The specimen GLGMV 0002, was attributed to Dendrorhynchoides (Hone and Lü 2010), but it is not related.

Science Is a Process
Several mistakes were made with Dendrorhynchoides over the years, but the process of science finds the errors and rectifies the nestings. First appearances can be deceiving even with phylogenetic bracketing. Sometimes you just have approach a specimen with an open mind and know what you’re looking for before you see it.

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.

Hone DWE and Lü J-C 2010. A New Specimen of Dendrorhynchoides (Pterosauria: Anurognathidae) with a Long Tail and the Evolution of the Pterosaurian Tail. Acta Geoscientica Sinica 31 (Supp. 1): 29-30.
Ji S-A and Ji Q 1998. A New Fossil Pterosaur (Rhamphorhynchoidea) from Liaoning. Jiangsu Geology 4: 199-206.
Unwin DM, Lü J and Bakhurina NN 2000. On the systematic and stratigraphic significance of pterosaurs from the Lower Cretaceous Yixian Formation (Jehol Group) of Liaoning, China. Mitteilngen der Museum für Naturkunde in Berlin, Geowissenschftlichen Reihe 3: 181-206.


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