“Clash of the Dinosaurs” Quetzalcoatlus Needs Repair

YouTube Video from “Clash of the Dinosaurs” 
Pterosaurs (Flying Dinosaurs) is a relatively new video uploaded in July 2012 from Clash of the Dinosaurs a program, aired in 2009 and produced by Dragons LTD for the Discovery Channel. This episode features the largest of all pterosaurs, Quetzalcoatlus (Figs. 1-13), doing its thang, as described by several paleontologists, some of whom may be (or should be) cringing now based on the way this video was finally put together.

Quetzalcoatlus wing

Figure 1 . Quetzalcoatlus wing. Yes, this title says… Flying Dinosaurs. Obviously the paleontologists listed below did not approve this title, but that’s just the beginning of the long list of sins incorporated here.  They made the wing too long by making m4.2 too long. The fingers should be palmar side down, not forward. More below.

Featuring pterosaur experts Tom Holtz, Pete Larson, Larry Witmer, Mike Habib and Matt Wedel, this video mixes great data (enervated wing membranes connected to enlarged brain tissue) with conjecture without evidence (forelimb takeoff (Fig. 7) and general morphology problems (Figs. 1-10)). Unfortunately the conjecture without evidence now forms much of the conventional thinking embraced by most pterosaur workers. That’s why I’m here, to clear things up and set things straight. Now for the long list of boo-boos.

Quetzalcoatlus pteroid

Figure 2. Quetzalcoatlus pteroid. Unfortunately they put it on the distal carpal, not the proximal one, the radiale. And they forgot the preaxial carpal. We’ll overlook the oversimplification of the rest of the  carpal elements. The depth of the wing is WAY too deep when we compare it to great wing membranes like the dark-wing and Zittel Rhamphorhynchus specimens. Thankfully the radius is in the neutral position here, not the supinated position as championed by Bennett and Hone, but then why are the fingers palmar side foreword? According to conventional thinking, these two go hand-in-hand. Keep the forearm neutral, then the fingers will be palmar side down, exactly as in the human hand pretending to be a wing. (Go ahead and try it, no one is looking)

Quetzalcoatlus fingers

Figure 3. Quetzalcoatlus fingers. Here fingers 1-3 are anchored too far beyond mc4. The metacarpals should all be aligned distally. All the metacarpals should also be connected, as they are in all tetrapods. The palmar sides of fingers 1-3 should be ventral in flight. Looks like finger 2 is missing here. We’re also overlooking the lack of a big cylindrical joint at the distal mc4 than enables wing folding and through which the giant extensor tendon passes. The fingers above don’t allow that tendon the room it requires.

Quetzalcoatlus bones.

Figure 4. Quetzalcoatlus leg bones. The femoral head axis should line up with the lateral acetabulum axis. Here they don’t. The knees should be fully extended. Here they aren’t. When fully extended they create a horizontal stabilizer, a secondary wing that generates its own lift! (See figure 12).

Quetzalcoatlus landing

Figure 5. Quetzalcoatlus landing. Here the wing is way too broad, the humerus is too far anterior and the little fingers point the wrong way.

Quetzalcoatlus walking.

Figure 6. Quetzalcoatlus walking. Note when walking the feet are correctly palmar side down. However, while flying with lateral limbs the feet should be palmar side lateral, but they remain strangely ventral in the video.

On takeoff
Wedel repeated Habib’s original assertions that the takeoff was a sort of “super pushup,” with the “strongest limbs” providing the necessary initial thrust. We looked at that bad hypothesis earlier. The more heavily muscled limbs were the hind limbs. Here (Fig. 7) is the pterosaur takeoff according to the conventional experts and the Clash of the Dinosaurs video in which Q could leap way over twice its height on its tiny triceps and with sufficient forward speed to glide a dozen times its own length before applying the first thrust flap. This pterosaur acts more like an Oz bubble than a 400 lb animal the shape of a giraffe. Not even kangaroos can attain such initial leaps from a standing start. Certainly giraffes can’t do it either despite the similar limb bone segment lengths with Q.

Quetzalcoatlus quadrupedal takeoff

Figure 7. Quetzalcoatlus quadrupedal takeoff. Here the tiny triceps drive this 400 lb pterosaur to heights and lengths that much more strongly muscled kangaroos cannot attain on the first leap. In the video Q appears to be light as a bubble because once aloft, it never descends as it appears to do, but the perspective line reminds us that is not so. Imagine a stork or flamingo in such a wooded setting. Hard to do? That’s because they both prefer water, as does Q.

The better hypothesis, the bipedal hind limb takeoff plan  (Fig. 8), provides wing thrust immediately and tremendous takeoff speed, like a bipedal lizard on steroids!

Quetzalcoatlus running like a lizard prior to takeoff.

Figure 8. Quetzalcoatlus running like a lizard prior to takeoff. Click to animate if not already animated.

Quetzalcoatlus walking

Figure 9. Quetzalcoatlus walking. Way too much wrist bend here. See figure 11 for a better reconstruction. Why doesn’t the wing finger fold up against the forearm? That’s the way other pterosaurs are fossilized and it protects the membrane, which virtually disappears. See figure 11 for the way it should be.

We’ll call this the Jurassic Park syndrome
When film and video makers refuse to add the latest data to their models, feathers for velociraptors and pycnofibers for pterosaurs (Fig. 10), they mark their work as out-of-date on the day it appears.

Quetzalcoatlus no hair

Figure 10. Quetzalcoatlus with no hair? All pterosaurs had a sort of hair. The wings here are also so poorly muscled, Q looks emaciated. The neck, how was it supported? Smaller pterosaurs show tendons holding the neck in a curve, like a horse’s neck, not like a flamingo neck. And where’s the curvature of the wing seen in birds, bats and airplanes. Raise the elbows! That provides the aerodynamic curvature. And shorten that chord! This is pure imagination based on toys, not on fossil evidence.

Quetzalcoatlus and its ancestor, no 42, note scale bars.

Fig. 11. Quetzalcoatlus and its ancestor, no 42, note scale bars. These are not predators of anything but crustaceans and other invertebrates. The video positioned Quetzalocoatlus as a T-rex baby eater?? That’s just showbiz. Q descended from tiny pond waders and was found near an inland lake. So, frogs, little pond reptiles and fish were probably on its diet. Eyesight was not the primary tool for hunting prey. Likely the bill was a sensitive probe and Q never saw its prey, but felt it on the lake floor while wading. We’ll look more at this tomorrow.

Quetzalcoatlus in dorsal view, flight configuration.

Figure 12. Quetzalcoatlus in dorsal view, flight configuration showing the correct wing proportions. The skull was taller than shown in the video and in the inset photo.

So, in the end
whoever guided the construction of Q. in the video did a poor job. As a remedy, imagine a fully muscled Q. running with a blur of lizardy legs and flapping its way into the sky (Fig. 8), like any goose or flamingo. Imagine a wading Q. finding bottom-dwelling invertebrates without seeing them (I’ll show you this tomorrow). Imagine a walking Q standing upright, like a giraffe, or a stork, with an upraised neck and bright colored hair covering its body and an upright crest rising from its skull (Fig. 11). T-rex babies would have been safe from Q with its slender, sensitive, yard-stick-shaped beak capable of handling only food that did not fight back.

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.

References
Witton MP and Naish D 2008. A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology. PLoS ONE 3(5): e2271. doi:10.1371/journal.pone.0002271
Langston W Jr 1981. Pterosaurs. Scientific American 244: 92–102. online
Lawson DA 1975. Pterosaur from the latest Cretaceous of West Texas: discovery of the largest flying creature. Science 187: 947-948.
Nessov LA 1984. Pterosaurs and birds of the Late Cretaceous of Central Asia. Paläontologische Zeitschrift 1: 47–57. online
Paul GS 1987. Pterodactyl habits – real and radio controlled. Nature 328: 481. online
Unwin DM, Bakuhrina NN, Lockley MG, Manabe M and Lü J 1997. Pterosaurs from Asia. Paleontological Society of Korea Special Publication 2: 43–65. online

6 thoughts on ““Clash of the Dinosaurs” Quetzalcoatlus Needs Repair

  1. While a lot of what you say on P.H. does make a lot of sense, I believe you have got this one wrong. If huge Azhdarchid pterosaurs consumed only tiny invertebrates, why do they have such robust beaks with a yard-wide gullet to ingest larger prey, as one would expect of an oversized stork or heron? If an endotherm that size did nothing but sift mud for tiny crustaceans 24 hours a day, I cannot imagine enough of this prey being consumed to sustain such an enormous creature. The largest living wading birds have evolved flat ‘spoonbills’ to maximize the amount of prey they can capture with this feeding strategy, yet ‘Q’ and its kin have pointed, ‘hunting’ beaks, again, like a giant stork or heron. No, those baby T-Rexes and other small dinos would indeed have something to fear if ‘Q’ was in the vicinity.

    • Thanks for your comment, Dan. The premaxilla of Quetz is unknown. The tip of the dentary, however, is known, and it has the dimensions of a yard stick (Kellner and Langston 1996). All sister taxa (see reptileevolution.com) likewise have similar type of flat beak. You may be confusing certain eopteranodontids that otherwise look like azhdarchids, but have that very pointed beak you’re referring to (derived from germanodactylids). Those are indeed the stork/heron analogs, but they did not achieve the same sizes as Quetz. Despite its size, by the way, the torso and stomach were not so large in Quetz, so stirring muddy lake bottoms seems reasonable. I note that current waders, birds of all sizes, have similar proportions and often feed in large multi-genus flocks. So evidently there must be enough food at such sites to feed several dozen birds at a time. Moving on from site to site may have been part of the feeding strategy in Quetz. The premaxilla is known in Zhejiangopterus, but the skull is crushed flat laterally. I’d like to see more details there, too.

  2. On fig 5, you say the wing is too broad. But the amount of membrane you’ve outlined to remove seems like it would leave the animal with hardly any wing to support it at all. I’m just wondering if I’m reading that incorrectly. Seems like it would take away a lot of membrane support from a big animal that could really use it. I’ve never seen a Q depicted this way before.

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