as we learned earlier, first achieved their slender proportions in small, sand-piper-like taxa similar to n44 and n42 during the Late Jurassic (Fig. 1). Coeval and later taxa grew larger, some attaining stork-like and then giraffe-like sizes while maintaining their slender proportions.
Figure 1. Click to enlarge. Here’s the 6 foot 1 inch former President of the USA alongside several azhdarchids and their predecessors. Most were knee high. The earliest examples were cuff high. The tallest was twice as tall as a human male.
Extant storks are stalkers
whether wading or on firmer substrates. That analogy brings us, once again, to the Naish and Witton 2017 concept of azhdarchids as terrestrial stalkers. They revisit the subject a third time (after Witton and Naish 2008. 2015), but now freshly armed with the evidence of a large short cervical from Hatzegopteryx, a giant pterosaur from Romania.
The big question is: which cervical is it?
In giant derived azhdarchids.
like Quetzalcoatlus and Hatzegopteryx, half the cervicals (1-3 and 8) are not elongate and the other half (4-7) are elongate.
Unfortunately and earlier
Witton and Naish 2008 mistakenly numbered the cervicals of Phosphatodraco 4-9, when they should have labeled them 3-8 (Fig. 2). They saw that neural spine on #7, which they thought was #8.
Cervical number 8 is always short in azhdarchids
and if correctly identified would have allowed the possibility that Hatzegopteryx had a typical azhdarchid neck. Cervical number 5 is always the longest in giant azhdarchids and Phospatodraco, which gives workers a starting point if the bones are scattered or incomplete at the ends.
But Naish and Witton took it the other way
and with their misidentification of a wide cervical number 7 they imagined a wide cervical series for Hatzegopteryx. And with that they thought they had more evidence for terrestrial stalking instead of aquatic wading, as practiced by all ancestors back to the Late Jurassic. I’m not saying azhdarchids didn’t pick up a few tidbits on land. I am saying they and all their ancestors were built like living sandpipers, stilts and herons, which find their diet in the shallows.
Figure 2. Black images are from Naish and Witton 2017. Cervical series is from Witton and Naish 2008. Purple and red are added here. Improper cervical identity in 2008 led to bigger problems in 2017 where the authors switched real for imaginary in their graphic, which makes it look like they had more data than they really did. BTW, none of these belly-flopping pterosaurs could have taken off in this fashion.
As much as Naish and Witton write about azhdarchids,
they should not be making basic mistakes over and over again. Not only do they misidentify a cervical, they illustrate their pterosaurs doing belly flops in a purported take-off configuration that has no chance of succeeding. See here, here and here for details.) And finally they should no longer consider that pterosaurs had nine cervicals. That goes back to S. Christopher Bennett’s PhD thesis in which he considered vertebrae number 9 to be a cervical since it did not contact the sternum. Even so, it bore long ribs and was located inside the thorax.
(Fig. 3) is the Hatzegopteryx cervical in question. Compared to both Phosphatodraco (Fig. 2) and Quetzalcoatlus sp. (Fig. 3) this is cervical #8, the short one, not cervical #7, the long one.
Figure 3. Hatzegopteryx cervical. If it is number 7, as Naish and Witton suggest, then it is very short and likely would be part of a very short neck. But if it is number 8, then the proportions are typical for azhdarchids. This is where Occam’s Razor might have been useful.
Some azhdarchids and their kin
have a tall neural spine only on cervical #8. Quetzalcoatlus is in this clade. Some, like Zhejiangopterus and Chaoyangopterus, have no tall neural spines. That’s also the case with the tiny basalmost clade members. By contrast, the flightless pterosaur, JME-Sos 2428 has a tall neural spine on cervicals 6-8, which makes me wonder if Phosphatodraco (Fig. 2) is a sister to it, given the present limited amount of data.
The Domino Effect
When Naish and Witton decided that Hatzegopteryx cervical #8 was #7, that mistake unleashed the possibility that they had discovered the first “short neck” azhdarchid! They must have been excited.
What Naish and Witton did not show you…
In lateral view, the Hatzegopteryx cervicals Naish and Witton illustrated actually look normal for an azhdarchid, but in dorsal view the omitted cervicals would have to have been twice as wide as typical and no longer cylinders (Fig. 2). So the “short” neck was really a “wide flat” neck, but that does not have the same headline cache. Such a major departure from the azhdarchid bauplan should have caused Naish and Witton to reconsider that their ‘discovery’ was actually a simple error in identification, now percolating online for the last 8 years. Hope this helps quell the notion!
Naish D and Witton MP 2017. Neck biomechanics indicate that giant Transylvanian azhdarchid pterosaurs were short-necked predators. PeerJ 5:e2908; DOI 10.7717/peerj.2908
Witton MP and Naish D 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLOS ONE 3:e2271 DOI 10.1371/journal.pone.0002271.
Witton MP and Naish D 2015. Azhdarchid pterosaurs: water-trawling pelican mimics or terrestrial stalkers? Acta Palaeontologica Polonica 60:651660 DOI 10.4202/app.00005.2013.
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