New Tapejara Take-off Video

A bipedal pterosaur video!
Just ran across this Tapejara skeleton take-off, fly and land video from the Huffington Post -and its a bipedal takeoff! The original comes from Texas Tech in November 2012.

Click to animate. Tapejara take-off, flight and landing by the Sankar Chatterjee lab. Red arrows point to morphology problems. 1. Bend humerus back further. 2 Bend elbow more. 3. Pteroid goes to carpals, not the finger joint, unless that's a metacarpal lacking fingers. 4. Knees should be splayed 5. Extend hind limbs laterally.

Figure 1. Click to animate. Tapejara take-off, flight and landing by the Sankar Chatterjee lab. Red arrows point to morphology problems. 1. Bend humerus back further. 2 Bend elbow more. 3. When the elbow is bent, the pteroid angles out from the radius, framing the propatagium.4. Metacarpal lacking free fingers. 4. Knees should be splayed 5. Extend hind limbs laterally in flight.

The headline reads: Pterosaur ‘Runways’ Enabled Huge Prehistoric Flying Animal To Get Airborne, Study Suggests. By: Douglas Main, LiveScience Contributor
Published: 11/08/2012 03:01 PM EST on LiveScience.

How did pterosaurs takeoff and fly?
According to Main, “A new computer simulation has the answer: These beasts used downward-sloping areas, at the edges of lakes and river valleys, as prehistoric runways to gather enough speed and power to take off, according to a study presented Wednesday (Nov. 7) here at the annual meeting of the Geological Society of America.” This is Sankar Chatterjee’s hypothesis. “First the animal would start running on all fours,” Texas Tech University scientist Sankar Chatterjee, a co-author of the study, told LiveScience. Then it would shift to its back legs, unfurl its wings and begin flapping. Once it generated enough power and speed, it finally would hop and take to the air, said Chatterjee, who along with his colleagues created a video simulation of this pterosaur taking flight.

Chatterjee goes over the edge when he reports, “This would be very awkward-looking,” he said. “They’d have to run but also need a downslope, a technique used today by hang gliders. Once in the air, though, they were magnificent gliders.”

Unfortunately, Chatterjee, like the other pterosaur experts, has a built-in bias regarding pterosaurs in that he sees them too weak to run to take-off speed, except downhill, and too weak to flap sufficiently to create enough thrust without a runway, and too weak to flap with vigor while gaining altitude.

Living bipedal lizards are anything but awkward-looking.
In fact they look incredibly like graceful bullets, faster than a rabbit  and impossible to see on film unless greatly slowed down, as shown here in the Bruce Jayne lab films.

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.”

Jaxtasuchus – a new protorosaur, not a doswelliid

A new paper by Schoch and Sues (2013)
introduces a new armored archosauriform with long teeth, Jaxtasuchus salomoni (Fig. 1). It was considered semi-aquatic because it was found in Middle Triassic mudstones along with amphibians, crustaceans, and mollusks. Several incomplete skeletons are known. Schoch and Sues (2013) ran a phylogenetic analysis of 17 taxa that nested Jaxtasuchus with doswelliids, which were similarly armored. Unfortunately, that tree also nested several strange-bedfellows together, including Mesosuchus with Prolacerta, Vancleavea with Chanaresuchus, Parasuchus with Stagonolepis and Scleromochlus with Marasuchus none of whom resemble their putative sisters.

Maybe not a doswelliid
Adding what little is know of Jaxtasuchus to the large reptile tree nests it firmly with Pamelaria, a protorosaur. Protorosaurs are known for their elongated necks, but not for their armor.

In any case, it takes 10 more steps to move Jaxtasuchus to Prolacerta (which was included in the Schoch and Sues (2013) phylogenetic analysis) and 14 steps to move Jaxtasuchus to Doswellia. If valid, the long teeth and armor of Jaxtasuchus would be protorosaur autapomorphies that add new variety to this clade.

Reconstruction and restoration of the skull and neck of Jaxtasuchus, along with scattered armor. The long neck and slender cervical ribs are protorosaur traits. The antorbital fenestra is shared with Pamelaria (fig. 2).

Figure 1. Reconstruction and restoration of the skull and neck of Jaxtasuchus (based on Schock and Sues 2013), along with scattered armor. The long neck and slender cervical ribs are protorosaur traits. The antorbital fenestra is shared with Pamelaria (fig. 2). No other known protorosaur has such long teeth and armor.

A new fifth instance of an antorbital fenestra!
Perhaps even more exciting than armor, Jaxtasuchus was described with an antorbital fenestra lacking a fossa. Doswellia (Heckert et al. 2012) likewise has a tiny antorbital fenestra, but not similar in design. However, a reexamination of Pamelaria reveals a very similar maxilla to Jaxtasuchus, which means it also had a previously overlooked antorbital fenestra (Fig. 2). Together these two up the total number of novel inventions of the antorbital fenestra from four to five. That’s a big deal.

The skull of Pamelaria from Sen 20003, with the maxilla highlighted in green. The maxilla appears similar to that in Jaxtasuchus in having an antorbital fenestra.

Figure 2. The skull of Pamelaria from Sen 20003, with the maxilla highlighted in green. The maxilla appears similar to that in Jaxtasuchus in having an antorbital fenestra. Teeth are only present along the posterior portion of the maxilla.

Restoring the manus and pes
I reconstructed the pes and manus of Jaxtasuchus using PILs (parallel interphalangeal lines). On both the manus and pes proximal phalanges were all longer and distal phalanges were all subequal.

Figure 3. The manus and pes of Jaxtasuchus restored. Along with the cervicals, these are among the most complete segments known of this reptile.

Figure 3. The manus and pes of Jaxtasuchus restored. Along with the cervicals (Fig. 1), these are among the most complete segments known of this reptile.

The osteoderms have a longer history
The osteoderms of Jaxtasuchus were previously interpreted as coming from temnospondyl amphibians or aetosaurs. Remains of Jaxtasuchus have been found in five localities and have been considered common. Now, courtesy of Schoch and Sues (2013) we know enough about it to consider it an armored predator with an antorbital fenestra. Thanks to the large reptile tree, which includes virtually every basal reptile clade, we can consider Jaxtasuchus a new protorosaur, rather than a doswelliid.

Figure 4. Click to enlarge. Jaxtasuchus reconstruction with armor. The small limbs might suggest a sinuous mode of locomotion, but the armor would argue against that. Perhaps this was a sit-and-wait predator, convergent with tanystropheids.

Figure 4. Click to enlarge. Jaxtasuchus reconstruction with armor. The small limbs might suggest a sinuous mode of locomotion, but the armor would argue against that. Perhaps this was a sit-and-wait predator, convergent with tanystropheids. The skull and neck specimen appear to come from a larger one than the post-crania, hence the estimate to match. 

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
Heckert AB, Lucas SG and Spielmann JA 2012. A new species of the enigmatic archosauromorph Doswellia from the Upper Triassic Bluewater Creek Formation, New Mexico, USA”. Palaeontology (Blackwell Publishing Ltd) 55 (6): 1333-1348.
Sen K 2003. Pamelaria dolichotrachela, a new prolacertid reptile from the Middle Triassic of India. Journal of Asian Earth Sciences 21: 663–681.
Schoch RR and Sues H-D (2013). A new archosauriform reptile from the Middle Triassic (Ladinian) of Germany. Journal of Systematic Palaeontology (advance online publication) DOI:10.1080/14772019.2013.781066 online

wiki/Jaxtasuchus

The skull of Azhdarcho restored

The skull of Azhdarcho (Fig.1) is based on several disassociated parts from several individuals of various sizes. So, there’s a bit of estimation going on here.

Restored skull of Azhdarcho based on images in Averianov 2013.

Figure 1. Click to enlarge. Restored skull of Azhdarcho based on images in Averianov 2013. The individual parts belong to several individuals of various sizes.

The dentary (which matches the premaxilla) in dorsal view is narrower and pointier than in Quetzalcoatlus. Even so, there is no tooth at the tip, as in Bakonydraco and other eopteranodontids. The medially fused vomers extend to the premaxilla, which forms a very short part of the rostrum. The maxillary palatal shelves also fuse to the vomers.

The premaxilla and dentary need to align perfectly over a long distance from the glenoids, hence the precise cylindrical articulation at the quadrate/articular.

The portion of the skull just anterior to the antorbital fenestra rises considerably, distinct from Quetzalcoatlus.

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
Averianov AO 2010. The osteology of Azhdarcho lancicollis Nessov 1984 (Pterosauria, Azhdarchidae) from the Late Cretaceous of Uzbekistan. Proceedings of the Zoological Institute RAS. 314(3):264–317.
Averianov AO 2013. Reconstruction of the neck of Azhdarcho lancicollis and lifestyle of azhdarchids (Pterosauria, Azhdarchidae). Paleontological Journal 47 (2): 203-209. DOI: 10.1134/S0031030113020020
http://link.springer.com/article/10.1134/S0031030113020020.
Nesov LA1984. Upper Cretaceous pterosaurs and birds from Central Asia. Paleontologicheskii Zhurnal, 1984(1), 47-57.

Vectidraco daisymorrisae – a new Isle of Wight pterosaur

A new pterosaur from the Isle of Wight, Vectidraco (Naish et al. 2013, Fig. 1) NHMUK PV R36621, has been named for its discoverer, Daisy Morris, all of 9 years old.

Vectidraco daisymorrisae

Figure 1. Vectidraco daisymorrisae from Naish et al 2013.

The partial specimen is represented by a left pelvis and associated partial sacrum is uncrushed and an exciting addition to our knowledge of Early Cretaceous pterosaurs. It’s not very large (see scale bar, fig. 1). Here (Fig. 2) we’ll add some missing parts, colorize vertebrae and try to produce a more understandable specimen.

Affinities
Naish et al. (2013) considered Vectidraco a basal azhdarchoid, which, in their terms meant close to the common ancestor of both azhdarchids and tapejarids (Fig. 2). The large pterosaur family tree, however, indicates that those two clades are not related to one another, despite sharing some traits, including a distinctive expanded posterior process of the ilium.

Figure 2. Vectidraco reconstruction and comparison to other pterosaur pelves with that odd posterior ilium flair. With similarities to the unrelated azhdarchids, the pelvis of Vectidraco appear to belong to a primitive tapejarid, One without a fused pelvis/ischium as in dsungaripterids and germanodactylids. The pelvis of Sinopterus has not been figured, but that is probably where we should look for a closest comparison. That's assuming the model Tupuxuara pelvis is accurate.

Figure 2. Vectidraco reconstruction and comparison to other pterosaur pelves with an odd posterior ilium flair. With similarities to the unrelated azhdarchids, the pelvis of Vectidraco appear to belong to a primitive tapejarid, one without a fused pelvis/ischium as in dsungaripterids and germanodactylids. The pelvis of Sinopterus has not been figured, but that is probably where we should look for a closest comparison. Oddly, many taxa around Sinopterus fail to adequately preserve the pelvis. That’s assuming the model Tupuxuara pelvis is accurate. Tropeognathus is related to neither azhdarchids nor tapejarids, but it likewise has an expanded posterior process of the ilium, but clearly of a different sort of shape.

Matching Morphologies
Here the closest match to the pelvis of Vectidraco is that of Tupuxuara, with the proviso that ancestors (Germanodactylidae) and sisters (Dsungaripteridae) to the Tapejaridae have an open ventral interosseous space and a smaller posterior process of the ilium. Tapejara does not fuse the pubis and ischium, but they are in contact. Earlier we looked at a tapejarid post-cranial specimen with a complete and ventrally fused pelvis (Sayao and Kellner 2006), close to Tupuxuara. For these phylogenetic bracketing reasons I presume the pelvis belongs to a smaller even more basal tapejarid along the lines of Sinopterus.

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
Naish D, Simpson M and Dyke G 2013. A New Small-Bodied Azhdarchoid Pterosaur from the Lower Cretaceous of England and Its Implications for Pterosaur Anatomy, Diversity and Phylogeny. PLoS ONE 8(3): e58451. doi:10.1371/journal.pone.0058451 plosOne link

Sayão JM and Kellner AWA 2006. Novo esquelito parcial de pterossauro (Pterodactyloidea, Tapejaridae) do membro Crato (Aptiano), Formação Santana, Bacia do Araripe, Nordeste do Brasil. Estudos Geológicos 16(2):16-40.

BBC links
Huffington Post link
wik/Vectidraco

Sky Monsters – National Geographic Video Review

All pterosaur videos are eagerly awaited and never fail to disappoint.

Sky Monsters DVD  carrying case featuring Pteranodon on the cover.

Figure 1. Sky Monsters DVD carrying case featuring Pteranodon on the cover. It doesn’t make an appearance inside, but a short-winged version of Nyctosaurus does. Click to go to National Geographic Store webpage.

And this one is no exception. I just became aware of this National Geographic video on pterosaurs called “Sky Monsters.” This DVD was available after Sept 27, 2012.

A little hyperbole, please!
Quotes from the narrator and others, “Their bodies were so bizarre, it’s hard to imagine how they got into the air.” My comments follow: That’s because they were inaccurately modeled and animated.

“The closest thing to living dragons the world has ever seen.” Dragons used to be based on partially exposed plesiosaur fossils, I think. They are known for their great size, wicked teeth, long necks and wing-like flippers, but if you focus on the flying aspect of pterosaurs, well, maybe. But all European pterosaurs were medium to tiny.

‘They’re not birds and they’re not bats, so what in God’s name are they?” Really, do we have to call on The Almighty when Cuvier settled this issue (pterosaurs are flying lizards) two centuries ago?

“Pterosaurs appear abruptly in the fossil record. We don’t have a clue how they evolved.” [buzzer sound] Wrong. No expert wants to admit that pterosaurs were really lizards derived from fenestrasaurs as all the evidence demonstrates. This is problem that continues to fester.

So, you can see, the producers spare no subtlety here in their approach.
Unfortunately, these are the worst 3D animated dinos and pterosaurs I have ever seen, not even counting the various morphological problems: 1) deep wing chords; 2) knees bent down, legs hanging back, not even employing the uropatagia,which are present;  3) free wing finger problems. Here you can see all the classic paradigm problems still employed. Fortunately we see no forward-pointing pteroids and no fore-limb leaping take-offs. Unfortunately the velociraptors have no feathers and no ulnar adduction, only those creepy Nosferatu hands. Also unfortunately, Henodus is identified as a prehistoric turtle.

Scene from Sky Monsters. This ornithocheirid has several "issues" including a deep chord wing membrane attached to the backward-extending hind limb.

Figure 2. Scene from Sky Monsters. This ornithocheirid has several “issues” including a deep chord wing membrane attached to the backward-extending hind limb. The knees are bent like human, not a lizard, which would have produced a sprawl that would have invoked the uropatagia and rotated the fee dorsal side laterally, like horizontal stabilizers. Imagine holding your own legs up  like this without aerial support. That’s what the thighs and uropatagia are for: lift!

Awkward?
Throughout the video we’re often reminded that pterosaurs were awkward on the ground. And of course they are when they are improperly reconstructed with those very wrong and completely imagined deep-chord wing membranes that refuse to fold away (as demonstrated in fossil specimens with narrow chord membranes, like Pterodactylus). Tsk. Tsk. Someone, somewhere should know better by now. I mean, all you have to do is look! WYSIWYG.

Cast of Experts
Wendy Sloboda points out a previously unknown (to me at least) example of a dinosaur tooth lodged in a mid-sized pterosaur shinbone (tibia) in western North America. I’d like to learn more about this.

Dino Frey makes the briefest of appearances.

Phillippe Tacquet replays the moment when Georges Cuvier realized pterosaurs were reptiles.

Kevin Padian and an uncredited Eric Buffetaut examine the Toulouse landing tracks by night.

Archival footage of Paul MacCready, inventor of the Gossamer Albatross, includes a young Kevin Padian as they successfully fly a model Quetzalcoatlus in the 1980s. The model is described as an airplane in pteroaur’s clothing, which sets up the modern model…

Margot Garritsen is a Dutch engineer and Stanford professor who leads a team intent on building a flying pterosaur based on Paul Sereno’s ornithocheirid from the Sahara. They are counting on greater success with lighter materials and a more accurate wing movement with not one, but five wing joints for flight control.

In the new model the shoulders rotate, and sweep forward and back; the wrists rotate and sweep forward and back; and the elbow bends. Funny they didn’t mention the wing finger, the most movable bone in the entire wing. Perhaps five was already too many (see below for successful ptero ornithopters) as there was no successful flight during the filming of this video. If you like crashes, you’ll see two.

David Unwin describes an azhdarchid as a scavenger of dead dinosaurs. He also weighs in on the issue of  ptero babies: born live? or hatched from eggs? (Answer: eggs, as we all have known since 2003.) Then David takes this to the next level asking, “Were they able to fly right after hatching?” Dr. Unwin confirms “yes” because in Solnhofen limestones they find tiny pterosaurs in rocks that were laid down miles out to sea. He demonstrates an ontogenetic sequence (growth series) with three fossils, purportedly and very doubtfully from the same species at three different ages, small, medium and large. Unwin notes that the wing bone proportions don’t change at all from one to another, but the length of the beak does change.

Unfortunately, Dr. Unwin is promoting a false paradigm that refuses to go away.
We looked at this false reasoning earlier and cross-tested it with phylogenetic analysis. Unwin doesn’t use data from actual embryos, the only pterosaurs for which it is possible to find an exact age: zero. Unwin did not discover a phylogenetic series because baby pterosaurs were isometric (virtual exact copies only smaller) of their parents. They did not change beak length, as demonstrated by every one of the embryo pterosaurs, especially the Pterodaustro embryo. Furthermore, tiny Solnhofen pterosaurs with beaks of many lengths are known, but this data evidently continues to evade general acceptance.

Someday someone somewhere
will produce a pterosaur video in which the pterosaurs have the grace and beauty of birds, the aerial agility of bats and the incredible speed and terrestrial locomotion capabilities of bipedal lizards. Until then, pterosaurs remain firmly in control of the experts and producers, who want them slow and ungainly on the ground and slow and ugly/scary in the air.

Here’s another review of the NG pterosaur DVD.

Successful Ptero-Ornithopters
Other than the MacReady Quetzalcoatlus, some good videos of pterosaur-shaped ornithopters (flapping flying machines) can be found here, here and here. They are not anatomically accurate. Nevertheless, they all depend on a horizontal stabilizer, generally pitched up, which keeps the nose up, something lacking in the Gerrittsen model.

There’s also a David Attenborough pterosaur video, which we’ll take a look at sometime in the future.

Carol Abraczinskas – Paul Sereno’s Scientific Illustrator

This is a tribute
to fellow dino artist/illustrator Carol Abraczinskas. I was pleased to find these interviews on the web. Getting to know Carol several years ago was a highlight. Seeing her work is always a delight.

Figure 1. Video interview with scientific illustrator, Carol Abraczinskas.

Scientific illustrator, Carol Abraczinskas. Click image to view video produced by SAIC*. Photo courtesy of Bruce Friedland, FBI.

On a personal note:
I once enjoyed an afternoon running around SVP with Carol as she sought autographs from every contributor to a dinosaur encyclopedia then just published. A few years later I flew into Midway in Chicago in a Cessna just to have a pizza with her. Literally, figuratively and on Google, there is only one Carol Abraczinskas. She has been interviewed many times and a Google search will reveal all.

The early years
After graduation from the School of the Art Institute of Chicago, Abraczinskas began  documenting Egyptian and Nubian artifacts in 1989 at the University of Chicago. That year she joined Paul Sereno on field expeditions to Texas and Niger as a scientific illustrator. She has been with him ever since. Her own work has been exhibited at the Field Museum and the Museum of Science and Industry, both in Chicago. In 2011 she was interviewed by Scientific American, which published this illustration of hers online:

Original caption: Sereno PC (2012) Taxonomy, morphology, masticatory function and phylogeny of heterodontosaurid dinosaurs. ZooKeys 226: 1–225. Fig. 9B.

Original caption: Sereno PC (2012) Taxonomy, morphology, masticatory function and phylogeny of heterodontosaurid dinosaurs. ZooKeys 226: 1–225. Fig. 9B.

The Lanzendorf Prize – x3
Carol Abraczinskas has contributed her expertise to after-school workshops as well as to graduate classes at the University of Chicago, where she teaches advanced courses in scientific illustration. The Society of Vertebrate Paleontology awarded her the John J. Lanzendorf Paleoart Award for Scientific Illustration in 2000, 2005, and 2008. Recent feature articles on Carol and her work have appeared in Scientific American, The Chicago Tribune, The School of the Art Institute of Chicago Alumni Magazine and O, The Oprah Magazine.

*SAIC – The School of the Art Institute of Chicago (SAIC) offers nationally accredited undergraduate, graduate, and post-baccalaureate programs to nearly 3,200 students from across the globe. Carol is an honored alumna.

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. 

Poposaur palates

The palates of poposaurs are poorly known Some have not been described or reconstructed (Fig.1). Others have been wrongly reconstructed or partially reconstructed (Fig. 4). Here (Fig. 1) are two poposaurs, Effigia and Shuvosaurus next to Daemonosaurus (Sues et al. 2011, also largely guessed at from broken pieces) and Thecodontosaurus, which provides more certitude. Most unfortunately, the palate of Lotosaurus has not been described or illustrated despite the presence of several specimens and museum casts. The little question is: On Daemonosaurus, which way do the ectopterygoids go? Long side against the pterygoid, as in rauisuchids? Or short side, as in Effigia and other dinosaurs?

Figure 2. Effigia palate in situ (left) and reconstructed by reassembling colored elements (at right).

Figure 2. Effigia palate in situ (left) and reconstructed by reassembling colored elements (at right).

On rauisuchians, as in ornithosuchians (Fig. 2), the ectopterygoid has a larger contact area with the lateral pterygoid and it produces a small “stem” to contact the jugal (as in Saurosuchus) or the maxilla (as in Riojasuchus). If you flip the ectopterygoid of Daemonosaurus, you get the rauisuchian type of ectopterygoid. Left as is (Fig. 1), however, you get the dinosaurian type,  and that is the preferred reconstruction here based on phylogenetic bracketing.

Click to enlarge. Euparkeriid, ornithosuchian, rauisuchian, aetosaurian, and basal archosaur palates.

Figure 2. Click to enlarge. Euparkeriid, ornithosuchian, rauisuchian, aetosaurian, and basal archosaur palates. Here are Euparkeria and Osmolskina, both euparkeriids. Ornithosuchus and Riojasuchus are ornithosuchids. Saurosuchus and Postosuchus are both rauisuchians. Stagonolepis is an aetosaur. Pseudhesperosuchus is close to the basal archosaur pattern with a much smaller ectopterygoid and smaller ectopterygoid/pterygoid contact. The original configuration is shown on the right side. A possible alternative is shown on the left. Not sure how it was preserved. I’d like to know if you have this data. If the left is correct in figure 2 (Pseudohesperosuchus), and Shuvosaurus is also correct in figure 1, these suggest that Daemonosaurus is correctly drawn in figure 1.

Silesaurus palate with missing elements restored on the right.

Figure 4. Silesaurus palate with missing elements restored on the right. Illustration (without color) from Dzik 2003 who illustrated missing elements on the left.

Silesaurus Palate The missing ectopterygoid and palatine were not illustrated for Silesaurus. Given the palates of related taxa (Fig.1), I have added the missing elements on the right here (Fig. 4) to match them. Thus these restorations are guesses that appear to make sense in context. When better data come along, we’ll make improvements.

This has been a first attempt at reconstructing the palates of several poposaurs at once based on similar morphologies in close kin. The palates should remain somewhat similar. If anyone has good data on the palates of other rauisuchians and basal dinosaurs, please forward them on.

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.

Figure 3 is absent from this post now. Apologies. I had it in my files for several years and thought it had been published by now. It had not. 

 

References Bonaparte JF 1969. Dos nuevas “Faunas” de reptiles Triasicos de Argentina: I. Gondwana Symp., IVGS: 283-306.
Borsuk-Bialynicka M and Evans SE 2009. Cranial and mandibular osteology of the Early Triassic archosauriform Osmolskina czatkowicensis from Poland. Palaeontologia Polonica 65, 235–281.
Brusatte SL, Benton MJ, Desojo JB and Langer MC 2010. The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida), Journal of Systematic Palaeontology, 8:1, 3-47.
Chatterjee S 1985. Postosuchus, a new Thecodontian reptile from the Triassic of Texas and the origin of Tyrannosaurs. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 309 (1139): 395–460. doi:10.1098/rstb.1985.0092.
Chatterjee S 1991. An unusual toothless archosaur from the Triassic of Texas: the world’s oldest ostrich dinosaur? Abstract, Journal of Vertebrate Paleontology, 8(3): 11A.
Chatterjee S 1993. Shuvosaurus, a new theropod: an unusual theropod dinosaur from the Triassic of Texas. National Geographic Research and Exploration 9 (3): 274–285.
Dzik J 2003. A beaked herbivorous archosaur with dinosaur affinities from the early Late Triassic of Poland. Journal of Vertebrate Paleontology 23: 556-574.
Ewer RF 1965. The Anatomy of the Thecodont Reptile Euparkeria capensis Broom Philosophical Transactions of the Royal Society London B 248 379-435. doi: 10.1098/rstb.1965.0003
Rauhut OWM 1997. On the cranial anatomy of Shuvosaurus inexpectatus (Dinosauria: Theropoda). In: Sachs, S., Rauhut, O. W. M. & Weigert, A. (eds) 1. Treffen der deutschsprachigen Palaeoherpetologen, Düsseldorf, 21.-23.02.1997; Extended Abstracts. Terra Nostra 7/97, pp. 17-21.
Long R and Murry P 1995. Late Triassic (Carnian-Norian) Tetrapods from the Southwestern United States. New Mexico Museum of Natural History and Science Bulletin 4, Pp. 153-163.
Sill WD 1974. The anatomy of Saurosuchus galilei and the relationships of the rauisuchid thecodonts. Bulletin of the Museum of Comparative Zoology 146: 317-362.
Sues H-D, Nesbitt SJ, Berman DS and Henrici AC 2011. A late-surviving basal theropod dinosaur from the latest Triassic of North America. Proceedings of the Royal Society Bpublished online
Walker AD 1961. Triassic reptiles from the Elgin area: StagonolepisDasygnathus and their allies. Philosophical Transactions of the Royal Society B 244:103-204.
Walker AD 1964. Triassic reptiles from the Elgin area: Ornithosuchus and the origin of carnosaurs. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 248(744): 53-134.
Yates AM 2003. A new species of the primitive dinosaur Thecodontosaurus (Saurischia: Sauropodomorpha) and its implications for the systematics of early dinosaurs. Journal of Systematic Palaeontology 1(1):1-42. wiki/Daemonosaurus wiki/Shuvosaurus

Poposaur mandibles

There’s still the question of Effigia’s mandible hanging out there.
The question is: “Is that a predentary or a dentary at the tip?” Fig. 1). Nesbitt (2007) says dentary. I say predentaries. Let’s look at the evidence.

To answer that,
I took a comparative survey of poposaur mandibles (Fig. 1), looking for evolutionary patterns and thereby strive to provide an update to the predentary/dentary question. Surprisingly, in the case of Effigia, when you add in the splenials, which neither Nesbitt nor I did before, the mandibular fenestra becomes substantially reduced. That may be similar to what one sees in Lotosaurus, in which the elements are not jumbled. And that provides more substance to the “predentary” argument. Other than Lotosaurus, the closest sister is Shuvosaurus, which is known from an incomplete mandible (Fig.1) showing similar patterns over the remaining portions. Shuvosaurus has something similar to what I saw in Daemonosaurus, that others consider something else. In any case, at some point, something interesting developed in front of the dentaries in certain phytodinosaurs.

The other question is,
when something similar to a predentary appears in front of the dentary, as in Sacisaurus (Figure 1), should it be considered a “beak” rather than a premaxilla? This bone may be paired, as it is in Sacisaurus, rather than a single median bone, as in the predentary of Heterodontosaurus (Fig. 1).

Figure 1. Poposaur (and kin) mandibles. Here are Daemonosaurus, Poposaurus, Pisanosaurus, Heterodontosaurus, Sacisaurus, Lotosaurus, Effigia and Shuvosaurus. The mandibles of Lotosaurus and Effigia appear to share a common heritage of design.  In Effigia the splenial reduces the mandibular fenestra helping to clarify the identify of the dentary and premaxilla (or beak).

Figure 1. Poposaur (and kin) mandibles. Here are Daemonosaurus, Poposaurus, Pisanosaurus, Heterodontosaurus, Sacisaurus, Lotosaurus, Effigia and Shuvosaurus. The mandibles of Lotosaurus, Shuvosaurus and Effigia appear to share a common heritage of design. In Effigia the splenial reduces the mandibular fenestra helping to clarify the identify of the dentary and premaxilla (or beak). The extension of the angular to the predentary is unique to this clade.

If all these other mandibles had a premaxilla or beak (or the possibility of one), is there any reason to suspect that Effigia did not?

The original reconstructions of the Effigia mandible
introduced us to the largest mandibular fenestra I have ever seen relative to the size of the jaw. The new reconstruction reduces the fenestra length and, no doubt, produces a stronger jaw with the splenial (lavendar to iris blue bone) laminated to the medial side and edges.

Typically the mandibular fenestra splits the surangular from the angular,
as it does in Heterodontosaurus. However, in Lotosaurus the mandibular fenestra develops largely below the dentary with very little surangular and angular exposure. In Shuvosaurus the same pattern could play out, but unfortunately the key parts are missing (perhaps due to a very large mandibular fenestra?). This is a different pattern than in ornithischians, saurischians and theropods. And this pattern is also different from rauisuchians. Among euarchosauriforms, only in aetosaurs does the very large mandibular fenestra develop largely below the dentary. In others, the fenestra develops midway or beneath the surangular and it doesn’t get to the size seen in Effigia and Lotosaurus.

One final point
The suture between the two premaxillae in Effigia is convoluted like a puzzle piece. In this way they are locking themselves together, convergent with the central or fused premaxilla of ornithischians, but homologous with the premaxilla in Lotosaurus and Shuvosaurus.

If I’m wrong, show me some data. At this  point, at least it’s worth talking about.

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
Ferigolo J and Langer MC 2006. “A Late Triassic dinosauriform from south Brazil and the origin of the ornithischian predentary bone”Historical Biology 19 (1): 1–11. online pdf.
Nesbitt SJ and Norell MA 2006. Extreme convergence in the body plans of an early suchian (Archosauria) and ornithomimid dinosaurs (Theropoda). Proceedings of the Royal Society B 273:1045–1048. online
Nesbitt S 2007. The anatomy of Effigia okeeffeae (Archosauria, Suchia), theropod-like convergence, and the distribution of related taxa. Bulletin of the American Museum of Natural History, 302: 84 pp. online pdf

AMNH Effigia webpage

wiki/Effigia