Tapejarid? or Tupuxuarid?

New Tapejarid-Tupuxuarid skull.

Figure 1. New Tapejarid-Tupuxuarid skull. Click to enlarge.

Sculptor and blogger Helder da Rocha posted this photo of a new Early Cretaceous pterosaur from South America. He wrote: “This fossil was on sale at Paleodirect but not anymore. Either it was sold or (hopefully) acquired by a paleontological institution.”

De Rocha noted the similarity of this specimen to Tapejara (downturned rostrum) and to Tupuxuara (vertically expanded crest and lack of a dentary keel). Th rostral crest was larger than in any tupuxuarid, but the frontal/parietal crest did not extend posteriorly like a tapejarid. So it’s worth examining. The skull appears to be complete lacking a postorbital, bits of crest, a dentary tip and there is a peculiar slit of missing bone anterior to the antorbital fenestra.

Figure 2. Bones colorized in this tapejarid / tupuxuarid with crest hypothetically extended. Interesting that green line representing the maxilla ascending process seems to continue back to over the orbit. Here you can see its the nasals laminated to the premaxilla ascending process that create the rostral crest. Here the rostral crest rises higher than in tupuxuarids, but not as much as in tapejarids. And the crest could serve as a base for an extended soft tissue crest, as in tapejarids.

Figure 2. Bones colorized in this tapejarid / tupuxuarid with crest hypothetically extended. Interesting that green line representing the maxilla ascending process seems to continue back to over the orbit. Here you can see its the nasals laminated to the premaxilla ascending process that create the rostral crest. Here the rostral crest rises higher than in tupuxuarids, but not as much as in tapejarids. And the crest could serve as a base for an extended soft tissue crest, as in tapejarids.

To no one’s surprise, this specimen nests in the large pterosaur tree between the tapejarids and the tupuxuarids, both having descended from a sister to Huaxiapterus, but in different directions.

The new skull compared to other tapejarids. Click to enlarge.

Figure 3. The new skull compared to other tapejarids. Click to enlarge.

And its worthwhile to check out Huaxiapterus (Fig. 2) in greater detail as a starting point and a good guess as to what the post-crania might look like. In Huaxiapterus the mandible is too deep and the premaxilla extends too far back to be ancestral to the new specimen (but perfectly suitable to be ancestral to Tapejara). In our search for ancestors we can only get close and very rarely (almost never) pinpoint an actual ancestor.

 Huaxiapterus, a sister to the ancestor of tapejarids, tupxuarids and the tapejarid / tupuxuarid.

Figure 4. Huaxiapterus, a sister to the ancestor of tapejarids, tupxuarids and the tapejarid / tupuxuarid.

If we go back one step further we find a better ancestor to the new pterosaur skull. Here’s Sinopterus

Sinopterus, sister to the common ancestor of tapejarids and tupuxuarids.

Figure 5. Sinopterus, sister to the common ancestor of tapejarids and tupuxuarids.

No reference for the new skull, which might now reside either with a private collector or  a public institution.

Evolution produces a bush of variation, not just the two lineages (tapejarids and tupuxuarids) we had seen up until this point.

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