New Quetzalcoatlus northropi skeletal model from Triebold Paleontology

Short one today
… focusing on a tall pterosaur skeleton model.

Figure 1. A Quetzalcoatlus northropi model from Triebold Paleontology scaled up from a Q. sp. sculpture I made and sold to Triebold.

Figure 1. A Quetzalcoatlus northropi model from Triebold Paleontology scaled up from a Q. sp. sculpture I made and sold to Triebold. Maybe it is posed trying to cool itself off, by those wing fingers can fold up against the arms for membrane protection.

First time I’ve seen this. 
Although I heard rumors that Mike Triebold (Triebold Paleontology) had scaled up the Q. sp. model I sold him a few years ago (Fig. 2) to create a 3x taller Quetzalcoatlus northropi model (Fig. 1). Giants are fascinating.

Quetzalcoatlus neck poses. Dipping, watching and displaying.

Figure 2. Quetzalcoatlus neck poses. Dipping, watching and displaying. Yes, that was my living room.

The shorter original was held together by wire
so it could be manipulated into one pose after another, or stuffed away into a small box.

As a reminder,
the brevity of the wings (vestigial distal phalanges) and the top-heavy proportions otherwise mark this as a flightless pterosaur.

Quetzalcoatlus running like a lizard prior to takeoff.

Figure 3. Quetzalcoatlus running like a lizard unable to take off due to vestigial distal wing elements and proportions that sent the center of balance anterior to the wing chord.

Even so, those wings were powerful thrusters
for speedy getaways on land (Fig. 3). I realize this is heresy, but facts are facts. Clipped wings in birds and pterosaurs means they cannot fly. And only flightless birds and pterosaurs are able to achieve such giant sizes (Fig. 4).

Figure 1. Click to enlarge. The largest flying and non-flying birds and pterosaurs to scale.

Figure 1. Click to enlarge. The largest flying and non-flying birds and pterosaurs to scale.

Tricleidus enters the LRT

No surprises here.
Tricleidus seeleyi (Fig. 1; Andrews 1909; Middle Jurassic, Callovian, BMNH R3539) ) enters the large reptile tree (LRT, 1435 taxa) alongside Plesiosaurus.

Figure 1. GIF animation of Tricleidus skull demonstrating both the enormous gape and the filter-feeding teeth that permit water to be pushed out by a constricting throat sac.

Figure 1. GIF animation of Tricleidus skull demonstrating both the enormous gape and the filter-feeding teeth that permit water to be pushed out by a constricting throat sac.

Why such long, slender and closely intermeshing teeth?
Not only do those long teeth provide excellent spiky fish traps, but upon closing they act like whale baleen in trapping food inside the mouth cavity while permitting the expulsion of excess water without losing the fish trapped inside.

As in other plesiosaurs
the large jaw muscles filling the posterior skull ensure a strong bite. A small ridge posterior to the jaw joint blocks over-extension of the mandible.


References
Andrews CW 1909, 1910. A Descriptive Catalogue of the Marine Reptiles of the Oxford Clay, Part I. British Museum (Natural History), London, England: 205 pp.

wiki/Tricleidus

Pteranodon skull evolution movie

Earlier we looked at Pteranodon skulls all to the same scale and in phylogenetic order.  Today there’s a GIF movie that presents the same data (Fig. 1).

Figure 1. Click to animate. Pteranodon skull movie. All the skulls are to the same scale and in phylogenetic order.

Figure 1. Click to animate. Pteranodon skull movie. All the skulls are to the same scale and in phylogenetic order. Each skull appears for 2 seconds and the animation recycles when the page is reloaded. And yes, the long-crested clade does terminate with three smaller taxa.

The first tiny specimen is actually an outgroup Germanodactylus. Long crests and great size evolve from small crests and small size. Learn more about Pteranodon variety here.

Long-crested taxa had digitigrade feet. Tall-crested taxa had flat feet. Other postcranial differences are discussed here.

Hall Train Walking T-rex Model at the AMNH

If you haven’t seen this before, it’s as fascinating as the real thing. This walking model of T-rex, animated with rods and gears is on display at the American Museum of Natural History in NYC.

Figure 1. Click to see video. The famous walking T-rex model at the AMNH created by Hall Train and John Allen.

Figure 1. Click to see video. The famous walking T-rex model at the AMNH created by Hall Train and John Allen.

The Hall Train Studio has produced some of the most spectacular dinosaur museum displays and animation ever. I don’t want to steal too much of their thunder. Check out their website now.

David Attenborough’s Pterosaur Video – “Flying Monsters 3D” review

It’s always good to see pterosaurs on film or video. Too often its a disappointment as we’ve seen earlier with a National Geographic video. Usually it’s the same old dreadful stuff (list below), as archaic in thinking as tail-dragging dinosaurs. But here they toss in some novel ideas that will blow your mind (Fig. 1).

Why have pterosaurs been so singularly disfigured in morphology and behavior?? It’s like everyone involved has decided to discard their thinking caps!

Click here for part 1 of David Attenborough’s Flying Monsters 3D, presented by Serengeti Entertainment, an IMAX presentation now available on YouTube in five parts. The quality is excellent, so be sure to [fill your screen] with the video.

Tapejara using its wings and head crest to sail instead of fly, following hypotheses put forth by Sankar Chatterjee.

Figure 1. Here’s a first: Tapejara using its wings and head crest to sail instead of fly, following hypotheses put forth by Dr. Sankar Chatterjee. These pterosaurs are not flapping. They are holding their wings up like masts (at great strain, I might add). They have no underwater keel, so how they are keeping upright is a mystery. Glad to see someone out there is really out there! Grist for the mill, of course.

The usual anatomical rants:
The animators of FM3D got their data from traditional pterosaur workers, the ones who are holding back real research and continuing to hold fast to bogus data, like:

  1. Deep chord wing membranes attached to the ankles.
  2. In basal pterosaurs, a single uropatagium from leg to leg, not including the tail.
  3. In derived pterosaurs, useless uropatagia not providing lift for posteriorly directed hind limbs.
  4. Flat wings with no camber.
  5. No arm muscles. Too little thigh muscles.
  6. Fingers pointing forward while terrestrial or arboreal.
  7. Pedal digit 5 on basal pterosaurs not being used beneath a digitigrade pes.
  8. No idea where pterosaurs came from or how they developed wings.

Topic 1. How did pterosaurs first take to the air?
Attenborough’s narrative suggests it was the quest for flying insects, or to get from tree to tree in search of crawling insects that drove pre-pterosaurs to develop wings. Draco volans, the rib-gliding lizard, is Attenborough’s analog. Of course, this entirely misses the development of bipedal locomotion and flapping and only hints at the fact that traditional paleontologists are entirely stymied by the origin of pterosaurs. Sadly, today, there are even pterosaur ‘experts’ out there out don’t even know what a pterosaur is, or how pterosaurs fit into the reptile family tree! And there’s no excuse for that ‘nowadays’ with phylogenetic analysis — that is, unless those paleontologists have willfully decided to turn a blind eye toward good data and refuse to test the best working hypotheses for fear of having to retreat from their untenable claims. Of course, there’s motive and opportunity here.

We do get a good view of the rib-gliding lizard, Draco, landing on a tree (this may be CG = computer graphics) with full deployment of the rib membranes in the vertical plane creating maximum drag and a four-point landing right in front of the camera!

Topic 2. Flapping
Attenborough takes us to the white Jurassic cliffs along the coast of Dorset, England, to introduce us to the story of Mary Anning. This is a skillful redirection away from the actual origins of flapping, but allows Attenborough to introduce us to Dimorphodon, his most basic pterosaur complete with pedal digit 5 pointing medially at full extension toward the tail, framing the full uropatagium stretched between the hind limbs beneath the tail. Here the wings are too short and the tail is way-way too short. There are no Triassic pterosaurs featured in the film.

Click here for part 2
Topic 3. Eating
Dimorphodon flies through swarms of insects, gathering them with its (too wide) mouth. A very narrow skull is actually present. Here the hind  legs and feet are improperly positioned in the horizontal plane while flying. That’s because Dimorphodon had dinosaur-like hind limbs, with femoral head at right angles to the shaft, unable to rise to the horizontal plane. Such legs were good for bipedal locomotion on dinosaurs – but evidently the experts hold a prejudice against that activity in pterosaurs.

Crashing into another Dimorphodon on the wing leads to our hero dropping into a river then sinking to the bottom to initiate fossilization.

Topic 4. Finding fossils and the wing joint
From there we segue to the Solnhofen limestone quarry where Attenborough splits limestone hoping to find a specimen. We meet the darkwing specimen of Rhamphorhynchus, famous for preserving so much detail in the wings. Attenborough notes the “miracle joint” (the wing joint) “to move their fingers in any direction,” and that allowed them to fold up their wing when they landed.” Unfortunately, the next scene and all other pterosaur scenes do not show the wings folded as they could be, making the membrane essentially disappear, as shown in fossils, but rather the wing fingers never quite closes up because the too-large deep chord membrane is always present, hanging like a blanket, as it does in virtually all pterosaur movies.     :  (

Topic 5. Darwinopterus and the pterodactyloid transition
David Attenborough next pays a visit to Dr. Dave Unwin who presents Darwinopterus, which he thinks bridges the gap between basal, long-tailed pterosaurs and later, short-tailed forms. Actually, as we have seen earlier here and here, tiny pterosaurs bridge that gap and Darwinopterus is a dead-end pre-scaphognathid pterosaur close to Pterorhynchus leaving no descendants. Darwinopterus simply has a longer neck and longer rostrum than most basal pterosaurs, but the longer skull has its origins with Pterorhynchus at the base of that clade. Dr. Unwin describes Darwinopterus as a “weird mix of characters, primitive and advanced, a little bit like Frankenstein’s monster.” Someone should inform Dr. Unwin that evolution doesn’t work like this. It doesn’t work in modules. That’s why, if you study pterosaur feet, or any other sort of animal feet, you can make a pretty good guess what sort of skull it had. At the time scales involved, every part of the body evolves, not just the head or the tail. Not permitting tiny pterosaurs into his database was Unwins’ downfall, and he’s had many.

Topic 6. Wing design
Very efficient in the air, but they [wings] evolved at a cost,” reports Attenborough. Dr. Unwin shows us a wire-frame model Rhamphorhynchus that flaps then lands, getting quadrupedal ASAP (Fig. 3).

Unwin’s model displays the fingers-forward error, which no tracks ever show. Attenborough tells us, “It’s easy to see that walking on flat surfaces would have been quite difficult for it.” The hands implant at twice or thrice the distance apart from the centerline as do the feet, which again do not match the fossil record. Experimenting with a bipedal pose, Unwin’s model Rhamphorhynchus tail catches or drags on the ground and walks like young Forrest Gump in leg braces. Why this is so is difficult to say because pterosaur tails were very flexible at the base of the pelvis and stiff only some distance beyond that. Clearly any pterosaur could raise its tail over its head Fiig. 2), let alone extend it directly out behind, like a bird. We even have bipedal pterosaur tracks.

The darkwing specimen of Rhamphorhynchus muensteri demonstrating more accurate proportions.

Figure 2. The darkwing specimen of Rhamphorhynchus muensteri demonstrating the ability to raise its tail while bipedal. The wing membrane is shown expanded here, for illustrative purposes, but would have folded much more tightly against the spar in life. And note, there is no awkward and untenable membrane from the forelimb to the ankle here, as in figure 3.

Topic 7. Walking styles
Dr. Unwin argues for a quadrupedal terrestrial locomotion in Rhamphorhynchus, despite the universally acknowledged handicaps it presents and lack of evidence for any basal pterosaur to walk quadrupedally. And this situation is not improved by leaning too far forward (as in Fg. 3), as Unwin proposes. Moreover, Unwin’s Rhamphorhynchus with its leg-to-leg uropatagium and deep chord to the ankle wing membranes creates a three-sided tent beneath the pterosaur that cannot fold away.

Figure 3. Wireframe Rhamphorhynchus by David Unwin. The uropatagium (between the legs) and the deep chord wing membrane combine to produce a three-sided tent, ideal for catching the wing like a parachute.

Figure 3. Wireframe Rhamphorhynchus by David Unwin. The uropatagium (between the legs) and the deep chord wing membrane combine to produce a three-sided tent, ideal for catching the wing like a parachute.

These three fictitious membranes would make great wind catchers should any light breeze or strong storm seek to push a pterosaur off its perch. Such errors would have made pterosaurs virtual open parachutes. The preferred anatomy (Fig. 2) shows any pterosaur could have folded up its wing membrane virtually completely, assisted by the internal fibers, and, of course hunkering down when it really gets windy.

Click here for part 3
Topic 8. Pterodactyls
We get to meet “new style” pterosaurs, or pterodactyls, in Crayssac, France. Attenborough reports “the membrane between the legs split.” Ouch! According to more accurate data, there never was a membrane stretched between the legs. In Sordes that was a displaced ulna and radius together with some displaced wing membrane shown here. The darkwing Rhamphorhynchus clearly shows two uropatagia, but, sadly, like Creationists, traditional pterosaur workers continue to politely ignore such readily seen data.

Topic 9. Crayssac Tracks
Attenborough tells us the manus impressions at Crayssac are made by “the knuckles” and that the wing finger was the “little” finger, rather than digit 4. Both wrong, of course.

Then a little Pterodactylus runs across its own tracks, much as in this animation. Happily the wing is much narrower in chord, but the animators force the poor creature into a hunchback so that it’s wrists are unnaturally bent too far, like an old crone with walking sticks. Straightened up a bit and the walk would have been near perfect. Sadly, even with these narrower chord membranes, the animators continued to extend the wing membrane down the leg, even though this added nothing to the aerodynamics and only served to reinforce an old stereotype that needs to be abandoned. Also unfortunately, the animators paid little heed to the manus tracks and continued to plant the free fingers far outside their path.

Pterodactylus walk matched to tracks according to Peters

Figure 4. Click to animate. Plantigrade and quadrupedal Pterodactylus walk matched to tracks

“The new ability to walk had a profound effect on pterosaur evolution,” Attenborough says. This is the current paradigm???!!! No wonder we’re in trouble. So in pterosaurs, according to Attenborough, first they could walk, then they couldn’t, then they could. Yeah.

Pterodaustro is shown with its sieve-like jaws. Pteranodon should have a sword-like rostrum, but here it is sword-like horizontally as well, creating a sort of box shape. Never saw that before. Hope to never see it again.

Topic 10. Pteranodon soaring
Pteranodon is shown in all of its majesty, with a deep chord membrane soaring above the clouds.

Then Archaeopteryx is introduced as half-reptile, half-bird.

Click here for part 4
Topic 11. Tapejara crests
Dr. Sankar Chatterjee works on Tapejara in Texas. He says the giant soft tissue crest is a steering device, a wind sensor and a rudder in front to be more aerobatic. All this is probable. Attenborough reports that some specimens of Tapejara had fur, which means they were warm-blooded. A little late to be saying that… because we learned earlier that such pycnofibers preceded pterosaurs and go all the way back to Sharovipteryx and Cosesaurus. Then Chatterjee goes out on a limb when he reports pterosaurs used their open and upraised wings as sails when floating on the sea (Fig. 1). Of course, lifting the arms for extended periods during windy conditions is most tiring. Chatterjee reports, “The head crest would be just like a jib.” 

Isn’t it much easier to just fly, with the wings supported by the airstream and without all that hydrodynamic drag? Ducks and geese use water to slow down their landings, after all.  There was one example of a forelimb takeoff, but it was off the side of a cliff. Luckily so, otherwise the ensuing drop would have been a crash before the first wing flap. (See, I told ya!)

Topic 12. Pterosaur eggs
Attenborough shows us a pterosaur egg with well-formed wings, which tells us the chick was able to fly immediately after hatching. “Embryo bones,” Attenborough tells us, “develop differently in pterosaurs than in birds. And this led to some pterosaurs becoming gigantic.” Well, actually we’ve had big birds, too, like elephant birds, much larger than most pterosaurs.

Topic 13. Quetzalcoatlus Introduced
The subject of giants takes us to Big Bend National Park, home of Quetzalcoatlus, which was so big, Attenborough tells, “for years some scientists r to believe that it could have existed.” That’s news to me. I thought everyone accepted it from the start.

We meet Doug Lawson, who found Q. on a sandstone hillside. Later Q is shown scavenging a dead dinosaur, its only competition is another Q. Some rummaging lizards get picked up and slurped down to their dismay in a nod toward the Witton and Naish.

Click here for part 5
Topic 14. Pterosaur Takeoff
How did Quetzalcoatlus get off the ground? A CT scan of the humerus reveals the insides but in CG. The supporting struts are said to line up in one direction for maximum strength in that dimension. Then we meet Mike Habib’s Anhanguera again, catapulting its body skyward at a reported 35 miles per hour. That’s so hard to believe when smaller, more muscular kangaroos can only manage no more than 16 mph on the first hop with better leverage and bigger muscles.  Earlier we looked at the impossibility of a forelimb launch using larger bones but much smaller muscles in the arm compared to the leg.

The precisely engineered sailplane (with narrow-chord wings!) that comes up next is airborne at 46 mph. Of course with the deep chord wing membrane the flaps on Attenborough’s pterosaurs are virtually always extended, creating more lift and drag, especially so during the launch with legs extended down. That’s not the optimal sailplane wing shape that reptileevolution.com champions. There is a better way to get airborne and that is by using those long wings to create something the engineers call, “thrust” which can be directed down and back at the same time.

Topic 15. Asteroid impact? Or the domination of birds?
Part five finishes with a standard asteroid impact, but Attenborough blames the birds for setting pterosaurs on the path toward extinction. He tells us, birds had the advantage of decoupled wings, not attached to the legs. “No pterosaurs, encumbered by their skinny wings could wade like flamingoes, Attenborough reports. Yet that’s exactly what wading pterosaurs, like Ctenochasma, Quetzalcoatlus and Pterodaustro did! We have their footprints! Attenborough is correct, however, if pterosaurs had put on the wrong wing membrane when they got out of bed. If a deep chord membrane got into water, it would have filled up with water. Thankfully that problem never happens with a narrow-chord membrane.

Revised Qiuetzalcoatlus from Flying Monsters 3D with David Attenborough.

Figure 6. Click to enlarge. Revised Qiuetzalcoatlus from Flying Monsters 3D with David Attenborough.

In Summary
So much effort goes into making these animated films. It’s just too bad they’re working from such out-dated blueprints of disfigured pterosaurs.

Mark Witton reported here, “A handful of pterosaur researchers were consulted in the making of the film, too – David Unwin, David Martill, Michael Habib and myself were all involved to ensure the science was on the money. With credentials like that, it’s understandable that expectations were higher for this than for many palaeodocs and, indeed, the programme has caused a stir around the world with palaeobloggers-a-plenty eager for it to land on their cinematic shores this Spring. Problem is, once you’ve taken in how nice everything looks, you start to focus on the story you’re being told and the content of the programme, and that’s where the issues begin.” And Mark lists many issues I glossed over (and ignores others that are not problems according to him.) He summarizes:
 “It really seems that, with a bit more care, this could’ve been as much of an achievement for effective scientific communication as it has been for 3D technology, but it’s really an enormous missed opportunity.”

Donald Duck Dinosaur Skeleton

Just had to share this one (old news (2008) for most, new for me).

Donald Duck skeleton

Donald Duck skeleton. Note the long sacral series and very birdy hips. Pedal digit 1 has never been seen in cartoons, but is appears here. Contrast those with the very human (but lacking one digit) forelimbs and hands. All tongue in cheek, of course.

Follow these links to see the skeletons of other cartoon characters, Tom & Jerry, Roadrunner, Wile E. Coyote and Bugs Bunny.

Link 1 – Link 2 – Link 3

Here are the nephews, Huey, Dewey and Louie (not sure which is which). This caught my eye and brought a big smile.

Huey, Dewey and Louie skeletons

Huey, Dewey and Louie skeletons

South Korean artist, Hyungkoo Lee, created this ‘Animatus’ series with the “intention to analyze anatomical structures and physical forms of animation characters, within the hypothesis to visualize their possible anatomical foundation.” Skeletons are a hybrid mix of animal bones and synthetic materials.

They are also a hybrid mix of avian (dinosaur feet) and human (mammal hands), but note the wishbone, long coracoids and sternum!

Disney (1929) had his own take on animated skeletons here.

Earlier Roadrunner was transformed into Pterorunner here. 

How Experts Have Disfigured Pterosaurs – part 1

The reason and soul of PterosaurHeresies is to reveal the flagrant and untenable errors that continue to float around pterosaurs (in particular) and prehistoric reptiles (in general). We’re not just sniping here. Evidence is always provided when a case is made. And we do provide credit where workers have done their homework.

Here we’ll document some of the worst efforts wrought by experts in the ptero trade.

Case in point:
This YouTube video of an ornithocheirid pterosaur walking (Fig. 1) almost could not be worse. Unfortunately it was based on “expert testimony” from notable experts (see below). It might also owe some due to the Walking With Dinosaurs series from the BBC, which featured a similar giant ornithocheirid.

 Pterosaur walk cycle posted on YouTube. Click to view. While following conventional thinking, this model demonstrates exactly why the hypotheses it is based on are so wrong.

Figure 1. Pterosaur walk cycle posted on YouTube. Click to view. While following conventional thinking, this model demonstrates exactly why the hypotheses it is based on are so wrong.

Problems galore
1. Wing membrane attached to the ankles – not found anywhere in the fossil record. Awkward as hell as you’ll see it in action when you click on the video.
2. Fingers pointing forward – ichnites say laterally to posteriorly.
3. Pteroid pointing forward – all fossils indicate medially, but many papers indicate anteriorly
4. Wing folding – needs to butt up against the metacarpus and ulna as fossils show
5. Convex neck – all fossils show a concave dorsal neck
6. Hind limbs – way too robust. Should be mere sticks with tiny feet, smaller than shown.
7. Skull way too small

Positives
1. Widely splayed femora.
2. Upright torso
3. Elbows back
4. Robust thighs

Don’t Blame the Artist (too much)
He or she was only following the conventional thinking of today’s pterosaur experts, the ones who are ruining pterosaurs right before our eyes by producing visions of walking pterosaurs that do not follow the evidence. In many cases, there is a flagrant disregard and internal inconsistency.

Case in point
In Dr. David Unwin’s book The Pterosaurs From Deep Time (p201), he promotes this image (Fig. 2)  as “Restoration of Anhanguera (Fig. 3) in the posture that pterodactyloids are now thought to have adopted while walking.”

According to Unwin 2006, this is the posture that pterodactyloids are now thought to have adopted while walking. The position of the elbows contradicts his text, which states, "[the humerus] lay nearly parallel to the body."

Figure 2. According to Unwin 2006, this is the posture that “pterodactyloids are now thought to have adopted while walking.” It is based on Bennett (1991, figure 4). However, the position of the elbows here contradicts his text, which states, “[the humerus] lay nearly parallel to the body.” If you put your elbows out, which way to your fingers turn? In, not out. It takes maximum pronation to make them turn out again.

Problems with this figure
1. Lacks metacarpals 1-3. Lacks distinct phalanges on manual digits 2 and 3.
2. Pteroid articulates with tip of preaxial carpal
3. Elbows anterior to shoulders (try it yourself to see how awkward this is)
4. Feet way too big
5. Knees not aligned with prepubes, which are missing
6. Femora not bowed (so that axially aligned head fits into acetabulum socket)
7. Pelvis incorrect (looks like a Germanodactylus pelvis)
8. Humerus too small
9. Sternal complex too flat (looks like a Pteranodon sternal complex)
10. Too few ribs

Here’s what Anhanguera should look like:

Anhanguera

Figure 3. Anhanguera. Note the tiny feet, the bowed femora, the elbows back (the way Unwin described them but did not draw them), etc. etc. In this pose it’s not clear that manual digit 1 would ever touch the substrate, but then only individual pedal ichnites are known for ornithocheirids, no trackways.

Derived from Bennett 1991
Unwin’s 2005 figure was based on Dr. Chris Bennett’s 1991, 2000 reconstruction (Fig. 4) of Pteranodon, which had all of Unwin’s faults and a few of its own. The finger’s on Bennett’s Pteranodon faced palmar side up because Bennett mistakenly reconstructed the metacarpals palmar side forward while flying. We discussed problems with that hypothesis earlier. See a couple of good Pteranodon post-crania here. See some more or less complete Pteranodon here and here.

Bad Pteranodon reconstruction from Bennett 1991, 2000 in which the fingers faced palmar side up and the elbow bent at an impossible angle with regard to the shoulder joint.

Figure 4. Bad Pteranodon reconstruction from Bennett 1991, 2000 in which the fingers faced palmar side up and the elbow bent at an impossible angle with regard to the shoulder joint. Unwin (2005) replaced the skull and flipped the hand. Due to the saddle-like shape of the shoulder joint, rotation should have been impossible, but Bennett ignores this.

Dr. Unwin’s Robodactylus
Unwin (2006) reports that Don Henderson and he “had our first baby.” It was a computer generated walking Anhanguera, they called Robodactylus that was differently configured than his illustration (Fig. 2), but still ignored many morphological traits.

Robodactylus. This is supposed to represent Anhanguera. After tilting the backbone up, "Suddenly it all fell into place," according to Unwin.

Figure 4. Robodactylus. This is one frame in a walking sequence that is supposed to represent Anhanguera. After tilting the backbone up, “Suddenly it all fell into place,” according to Unwin. Note the incorrect parasagittal hind limbs and the improved “elbows back” posture. A careful look reveals the wing fingers are anterior to the forelimbs, which is a result of oversimplification while making the model.

I remember seeing the Henderson/Unwin presentation and shaking my head at how Frankenstein-ish it appeared. The worst aspect of this model is the position of the hind limbs in the parasagittal place. The best aspects include the elbows back and elevated torso. However, the elbows should have been almost straight below the shoulders (fig. 3).

But wait, it gets worse
After tackling Anhanguera, Henderson and Unwin digitized Rhamphorhynchus to create Roborhamphus (Fig. 5). Remember that Unwin (2006) thinks that all basal pterosaurs had a membrane that extended between the hind limbs (including pedal digit 5) and tail based on his misidentification of features in Sordes.  He reported, “Effectively, in these early pterosaurs, all four limbs [and the tail] were linked to one another.” 

Linking the hind limbs to a tibia’s length of tail with uropatagia is how Henderson and Unwin decided the tail was unable to rise at its base. This is their infamous “raincoat test” that shows how awkward and bound up early pterosaurs were in their view. All this disfigurement is all due to Unwin’s misinterpretation of Sordes and the importance he gave it, trumping all other evidence (Fig. 6b).

Roborhamphus. This is how Henderson and Unwin animated Rhamphorhynchus during a walking cycle. Hmm. If this is right, then maybe pterosaurs did indeed share a recent common ancestor with parasuchians.

Figure 5. Roborhamphus. This is how Henderson and Unwin animated Rhamphorhynchus during a walking cycle. Hmm. If this is right, then maybe pterosaurs did indeed share a recent common ancestor with parasuchians. (jess kiddn) Good luck getting Roborhamphus off the ground! They reported they could not raise the torso without “the tail bashing into the ground.”  This pose, to their surprise, worked.  Here the feet appear to be way too small, perhaps cheated to enable a recovery stroke without too much toe drag. Not sure if the wings are foreshortened in this view, but they should be much longer (see fig. 6).

The darkwing specimen of Rhamphorhynchus muensteri demonstrating more accurate proportions.

Figure 6. The darkwing specimen of Rhamphorhynchus muensteri demonstrating more accurate proportions, a little chubbier than Roborhamphus with longer wings and a bendable tail base. The uropatagia do not bind the hind limbs and the wing does not attach to the hind limbs.

Here’s the real darkwing Rhamphorhynchus (Fig. 6, 6b) based on DGS with its torso and tail raised. It’s those little bendable proximal caudals that enable the tail to rise, pulled by sacral muscles that Henderson and Unwin did not consider. In the Henderson/Unwin model (Fig. 5) Unwin (2006) reported, “Remember that the body, neck and head lay in almost a straight line in these animals (as also for example in lizards and crocodiles), and this fitted neatly with the horizontal walking posture of Roborhamphus.” Like birds, that’s not true of any pterosaur, except, perhaps, while flying.

Wing membranes and uropatagia in a basal pterosaur, the darkwing Rhamphorhynchus.

Figure 6b. Wing membranes and uropatagia in a basal pterosaur, the darkwing Rhamphorhynchus. The uropatagia did not connect to the tail, only the pelvis, so the tail could rise as in figure 6. The wing membrane does not attach to the ankle. Those patches that appear to do so are body fluids fossilized by bacterial activity. They have no wing structure to them.

Azhdarchid Problems
Dr. Mark Witton will soon have his pterosaur book out. Previews can be seen here. This is the Witton and Naish (2008) vision of a walking Zhejiangopterus pterosaur (Fig. 7) published in Naish’s blog.

A walking Zhejiangopterus by Mark Witton. Here all four limbs are planted at the same time. The foot-to-foot distance is much larger than the hand-to-hand distance. This configuration also plants the manus anterior to the pes, which is the opposite of what we see in fossil ichnites.

Figure 7. Click to follow link. A walking Zhejiangopterus (Witton and Naish 2008). Here all four limbs are planted at the same time. The foot-to-foot distance is much larger than the hand-to-hand distance. This configuration also plants the manus anterior to the pes, which is the opposite of what we see in fossil ichnites. By elevating the backbone all problems are solved. The outstretched and cantilevered neck is also a potential problem, like the Kent, Stevens sauropod neck in the ONP (osteologically neutral pose) rather than the more biologically followed (OEP) osteologically elevated pose (see fig. 4), promoted, ironically, by Taylor, Wedel and Naish (himself, 2009). The depth of the pelvis is far too shallow here. See figure 5 for an alternative stance. Try walking with your arms at length in front of you while you walk and see how quickly the lactic acid builds up. Then imagine putting the weight of a large skull at the end of six-foot-long arms and you’ll get an idea how quickly tiring this Witton and Naish pose would become for this poor azhdarchid.

Not sure why Witton and Naish (2008, Fig. 7) tried to promote their hypothesis of a walking pterosaur by planting all four feet on the ground in a pattern that does not fit known ichnites or tetrapod walking cycles. Two of those limbs need to be elevated (recovery phase). In order to match tracks that place the manus print just aft of the pedal imprint the backbone needs to be elevated (see animation, fig. 10). The knees need more bend on initial contact. The neck also needs to be elevated, following hypotheses in Naish’s own work (Taylor, Wedel and Naish 2009).

No Bitching Without A Solution
Here (fig. 8) and here (running Quetzalcoatlus) all the problems are solved. The neck is held high. The wings are completely folded. The manus could easily impress behind the pes (as in Fig. 10). The fingers extend laterally to posteriorly. The foot and hand both have recovery phases. The center of gravity is just anterior to each footfall, as in humans. The hands are like ski poles, not contributing to thrust. And this pterosaur (figs. 8, 10) is ready to take off from a standing start. You can see the animated model (fig. 10) matches the tracks in morphology, size and gait.

There are several specimens of Zhejiangopterus.

Figure 8. Click to enlarge. There are several specimens of Zhejiangopterus. Here I am showing the standing pose with that giant skull better balanced over the body and, with bent knees and and upright torso, these feet are able to implant just in front of each hand while walking. And this pterosaur is ready to spread its wings and fly after launching itself with those huge thigh muscles.

Pterodactylus problems

Pterodactylus walking. Note the foot will never plant itself in front of the hand here. And why are both hands on the ground at the same time as the back foot? Hmm.

Figure 9. Pterodactylus walking. Note the foot will never plant itself in front of the hand here. And why are both hands on the ground at the same time as the back foot? Hmm. At least one foot is off the ground here. That’s a positive. Note the wing membrane behind the elbow: nice!! But also look at how far that fuselage fillet has to stretch here. Untenable. See Figure 10 for a more upright solution.

The same problems attend this poor chap (Fig. 9) with the horizontal backbone. At no time in the step cycle of this pterosaur are those forelimbs going to provide thrust, but rather braking. Pterosaurs were secondarily quadrupedal and many could go both ways. Not sure why workers insist on giving pterosaurs a horizontal backbone. Matching the skeleton to tracks (Fig. 4) is easy to do and gives much more tenable results.

Pterodactylus walk matched to tracks according to Peters

Figure 10. Click to animate. Plantigrade and quadrupedal Pterodactylus walk matched to tracks

Ichnites don’t tell how long the implantation of the manus was. Here that time appears shorter than the implantation of the foot. The manus steadied the pterosaur while applying no thrust.

Earlier we covered bipedality and quadrupedality in pterosaurs here. We covered bipedal take-off in pterosaurs here and here. Tomorrow we’ll take on more monstrous reconstructions.

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
Taylor, M. P., Wedel, M. J. & Naish, D. 2009. Head and neck posture in sauropod dinosaurs inferred from extant animals. Acta Palaeontologica Polonica 54, 213-220.
Witton M and Naish D 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS ONE 3 (5): e2271. doi:10.1371/journal.pone.0002271

‘I’m a Dino’ cartoons on YouTube – Sordes and Pteranodon

I’m probably the last to know about this.

YouTube has a few “I’m a Dinosaur” cartoons. These two feature Sordes and Pteranodon talking to the camera and to each other. Click to play.

Click to play. I'm a Dinosaur cartoon - Sordes.

Click to play. I’m a Dinosaur cartoon – Sordes.

Cute and cheeky. Just two minutes long.

Click to play. I'm a dinosaur - Pteranodon.

Click to play. I’m a dinosaur – Pteranodon.