Why do pterosaur workers ignore the most basic data?

I don’t know why,
but today’s leading pterosaur experts are actively ignoring the data from the last twenty years while inventing their own fanciful versions of what pterosaurs looked like (Fig. 1) – while claiming to be the latest word on the subject. Today we’ll be looking at a short paper from the latest Flugsaurier book by Hone, Witton and Martill 2017. And we’ll criticize the artwork that crystalizes their latest intentions. This is part 1.

For some reason
Hone, Witton and Martill like to show ancient cartoons that have little to no bearing on the present knowledge base (Fig. 1). I think it’s an English thing since most, if not all of the old engravings are indeed English in origin and easily lampooned. ‘See how far we’ve come!’, they seem to be saying. Doing so only takes up space that could otherwise go to competing current versions – which they want to avoid.

We’ve seen this
earlier when English professor D. Naish preferred to criticize work that preceded (= was not included in) ReptileEvolution.com. He employed cartoons made by others, rather than artwork that was actually posted on the website to show how bad the whole website was.

Evidently
It’s what they like to do. Someday, perhaps, they’ll look in a mirror and see some of the faults I present here… using their own artwork – which will soon enough joint their ancient engravings in a drawer full of foolish ideas they can draw upon in future decades.

Figure 1. Images from Hone, Witton and Martill 2017 showing the 'evolution' of our concept of Dimorphodon. Compare the latest color version to tracings of the several skeletons in figure 2.

Figure 1. Images from Hone, Witton and Martill 2017 showing the ‘evolution’ of our concept of Dimorphodon. Artists are credited in the text. Compare the latest color version to tracings of the several skeletons in figure 2. The long tail is based on a disassociated fossil probably belonging to a campylognathoid.

In figure 1
images of Dimorphodon through time are presented from Hone, Witton and Martill 2017.

  1. Rev. GE Howman 1829. Probably based on the headless holotype BMNH R1034 (Fig. 2). The authors labeled this as ‘monstrous’ when ‘inaccurate’, ‘fanciful’ or ‘medieval’ would do.
  2. Owen 1870. Probably based on the short-skull specimen, BMNH 41212 (Fig. 2), along with the disassociated tail specimen. The authors labeled this rendition as ‘ungainly, bat-like’. Odd word choice when among all the presented illustrations it is the one most like Witton’s 2017 version (#5).
  3. H Seeley 1901. Probably based on the long-skull specimen, BMNH PV R 1035 (Fig. 2) In the their comment Hone, Witton and Martill report, ‘progressive interpretation of D. macronyx as an erect-limbed quadruped’, but note that a biped interpretation was also offered. They thought it best not to show that possibility. 
  4. K Padian 1983. Probably based on the short-skull specimen, BMNH 41212 (Fig. 2). The authors report, ‘a highly active, bird-like digitigrade biped, a controversial interpretation that nevertheless symbolises the reinvention of pterosaurs in the late twentieth century.’ While there are minor issues associated with this figure (the orientation of fingers 1–3 and pedal digit 5, the over-extension of the metatarsophalangeal joint, the great length of the tail), it is the one that is most closely based on the skeleton (Fig. 2). BTW, when authors use the word, ‘controversial’ it usually means it does not fit their world view, but they have no evidence against it, nor any evidence to support their traditional hypothesis. 
  5. M Witton 2017. Not sure which skeleton this one is based on as it appears to have been done entirely freehand from memory and imagination. The authors report, ‘Modern interpretation of D. macronyx adult and speculative juveniles reflecting contemporary interpretations of pterosaur soft tissues, muscle development and ecology.’ Ahem…we’ll run through this illustration step-by-step below.
Figure 2. Images of Dimorphodon from ReptileEvolution.com. The tail attributed to Dimorphodon is shown in figure 3.

Figure 2. Images of Dimorphodon from ReptileEvolution.com. The tail attributed to Dimorphodon is shown in figure 3.

You know, you really can’t go wrong
when you strictly adhere to the bones (Figs. 2,3), soft tissue (Peters 2002) and footprints of the most closely related taxa (Peters 2011), which were made by digitigrade and bipedal pterosaur trackmakers. Unfortunately no such citations appear in this chapter. Those are purposefully omitted.

Dimorphodon model by David Peters

Figur 3. Dimorphodon model by yours truly. The tail is too long based on the disassociated tail.

Witton
fell under the spell of the quad-launch hypothesis (Habib 2008), then took it one step further and made Dimorphodon a galloping hunter (Fig. 4), forsaking its wings and erect, digitigrade hind limbs (according to related ichnite makers) to hunt prey on mossy logs with backward pointing fingers. The finger unguals are again too small here.

While writing this I became aware
of Sangster 2003, a PhD thesis that evidently used computer modeling to show Dimorphodon was a quadruped. I have not seen the thesis and Ms. Sangster can no longer be found online. I wonder about these conclusions because:

  1. PhD theses are, by definition, the work of inexperience workers; and
  2. Sangster may have had to earn her PhD by succumbing to the unveiled interests of her English professors, as we’ve seen before here and here.
Figure 4. Galloping Dimorphodon by Mark Witton.

Figure 4. Galloping Dimorphodon by Mark Witton.

To counter the awkward, dangerous and ultimately unproductive
quad-launch scenario, I proposed the following bipedal launch animation (Fig. 5). It combines the hind limb leap with the first flap of the large wings to provide the maximum thrust at takeoff. In the Habib proposal, you don’t get that wing flap until later in the cycle – maybe too late in the cycle. The quad launch also depends on directing the force of liftoff through the fragile free fingers. They were not strong enough for that, especialy not when there is a better option available using giant muscles in the chest and pelvis. That’s why the sacrum is so strong, to act as a fulcrum on that long, heavy lever!

FIgure 5. Dimorphodon take off (with the new small tail).

FIgure 5. Dimorphodon take off (with the new small tail).

So let’s get back
to Witton’s cover illustration (Fig. 6), which they tout as our contemporary view of Dimorphodon. I will note several inaccuracies (below). See figures 2 and 3 for accurate tracings.

Figure 6. Touted as the contemporary view of Dimorphodon, this Mark Witton illustration suffers from several fancies and inaccuracies.

Figure 6. Touted as the contemporary view of Dimorphodon, this Mark Witton illustration suffers from several fancies and inaccuracies.

  1. No Dimorphodon as this shape of skull.
  2. Needs a longer neck.
  3. Free fingers should be long and the unguals much larger.
  4. Wing appears to be too short with a too narrow wing tip chord.
  5. Witton wants to connect the trailing edge membrane from wing tip to ankle (or lateral toe), but look at the tremendous stretch in the membrane when that happens. Seems to be getting dangerously close to the narrow-at-the-elbow wing design of Zittel, Schaller and Peters, which they want to avoid.
  6. Ouch! This is a set of elongate toe bones with butt metatarsophalangeal joints – where Witton breaks them. This is not a calcar (a novel ossification on bat ankles which enters the uropatagium). One one side of these lateral toes the wing membrane attaches. On the other side the uroropatagium attaches. This is not shown in any fossil! Related taxa, from Langobardisaurus to Sharovipteryx, to Tanystropheus, with this same sort of elongate toe morphology, do not dislocate their bones this way. See Peters 2000 for a description that fits Rotodactylus tracks.
  7. No pterosaur has a uropatagium. This comes from a misinterpretation of Sordes. Pterosaur do have paired uropatagia.
  8. The tail is too large. On the BMNH 41212 fossil the traditionally overlooked tail is very small (Figs. 2, 7) This is in accord with related anurognathids. An unassociated tail has been attributed to Dimorphodon (Fig. 5) but it is robust and much longer. It probably belongs to a eudimorphodontid or campylognathoid. I”m surprised the tiny tail of Dimorphodon has gone unnoticed for so long. The specimen has been in English storage for over a hundred years. It was their responsibility for discovering this, but they chose instead to use their imaginations (Fig. 6).
  9. No tail vane is known for Dimorphodon. Tail vanes are found in pterosaurs like Campylognathoides and Rhamphorhynchus, both with a robust tail. Vestigial tails are unlikely to have had tail vanes.
FIgure 7. The tail of Dimorphodon (BMNH 41212 specimen). See figure 2 for reconstruction.

FIgure 7. The tail of Dimorphodon (BMNH 41212 specimen). See figure 2 for reconstruction.

I’m asking my Engllsh colleagues
|to step up their game and become more professional. Otherwise chaps from across the pond are going to continue pointing out the flaws in their thinking. I’m not going to say their approach is not scientific (as they say about my work), but when you forsake accuracy for artistry, you’re treading very close to that line.

References
Habib MB 2008. Comparative evidence for quadrupedal launch in pterosaurs. Zitteliana B28:159-166.
Hone DWE, Witton MP and Martill DM 2017.
New perspectives on pterosaur paleobiology in Hone DWE, Witton MP and Martill DM (eds) New Perspectives on Pterosaur Palaeobiology. Geological Society, London, Special Publications, 455, https://doi.org/10.1144/SP455.18
Peters D 2000. Description and Interpretation of Interphalangeal Lines in Tetrapods 
Ichnos, 7: 11-41.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist 
Historical Biology 15: 277-301
Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification.
Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605
Sangster S 2003. The anatomy, functional morphology and systematics of Dimorphodon macronyx (Diapsida: Pterosauria)..Unpublished PhD thesis, University of Cambridge.

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Glide analysis in hatchling pterosaurs

Witton et al. 2017 report in their abstract:
We found that hatchling pterosaurs were excellent gliders, but with a wing ecomorphology more comparable to powered fliers than obligate gliders.”

Since hatchling pterosaurs were scale models of adults,
and adults were powered fliers, the logic follows. Oddly, Witton wrote a book in which this was not the case when he imagined a pre-hatchling Pterodaustro with a short rostrum and big eyes.

Witton et al. 2017 continue:
“Size differences between pterosaur hatchlings and larger members of their species dictate differences in wing ecomorphology and flight capabilities at different life stages, which might have bearing on pterosaur ontogenetic niching.”

Big science words here say nothing concrete. 
Dictate different flight capabilities: no. Dictate different prey items: yes.  Note the weasel word: “might have bearing” which acts like a nail in a tire to deflate everything said after it. Try to avoid using weasel words.

References
Witton M, Martin-Silverstone E and Naish D 2017. Glide analysis and bone strength tests indicate powered flight capabilities in hatchling pterosaurs. https://peerj.com/preprints/3216/

Pterosaur wing appearance when quadrupedal

Figure 1. GIF animation (2 frames) showing the original and repaired versions of this Quetzalcoatlus statue and its artisans.

Figure 1. GIF animation (2 frames) showing the original and repaired versions of this Quetzalcoatlus statue and its artisans. Pterosaur wings folded to near invisibility when folded as shown by manipulating bones and observing fossils. Only a narrow chord wing membrane, as in figure 2, works here. Note the unwarranted wrinkles in the original wing membrane. Note in the original the trailing edge of the wing membrane is directed to mid-metacarpal, rather than to the 180º metacarpophalangeal joint as in the repaired version, fossils and other illustrations below. And what is going on with those tiny anterior pteroids? That is wrong, so wrong.

Pterosaur workers
artists and filmmakers have struggled to portray pterosaur wing membrane when the wings are folded and the pterosaur is walking around (Figs. 1, 3–5). Fossils (Fig. 2) that show how the wings looked when folded are too often ignored.

Figure 4. Here's how the wing membrane in pterosaurs virtually disappeared when folded. This is CM 11426 (no. 44 in the Wellnhofer 1970 catalog),

Figure 2. Here’s how the wing membrane in pterosaurs virtually disappeared when folded. This is CM 11426 (no. 44 in the Wellnhofer 1970 catalog), Note: the left wing has been axially rotated during taphoonmy such that the folded portion of the membrane was fossilized posterior to the bony spar.

CM11426
(Fig. 2) shows how wing membranes fold down whenever the wing bones are flexed (folded). Like bats, pterosaur wing membranes fold away to near invisibility. If you think CM11426 looks a bit like Quetzalcoatlus, you’re right! It’s in the lineage in the large pterosaur tree (LPT), but it’s not larger than a typical Pterodactylus (Fig. 9).

Stan Winston Pteranodon suit for Jurassic Park 3.

Figure 3. Stan Winston Pteranodon suit for Jurassic Park 3. Those wrinkled wing membranes are a dead giveaway that Winston was lost when it came to wing folding in Pteranodon. And that’s not to mention the too short metacarpals (see fig. 4 for comparison)

For Jurassic Park 3
Stan Winston’s Pteranodon (Fig. 3) had saggy, baggy wing membranes. So did early paintings by Burian (Fig. 4). These clearly do not reflect what happens in fossils and in life.

Figure 4. Artist Z. Burian also struggled to realistically portray the folded wing membrane in pterosaurs forgetting the fossils and the fact that both birds and bats have no trouble folding their wings without wrinkling them.

Figure 4. Artist Z. Burian also struggled to realistically portray the folded wing membrane in pterosaurs forgetting the fossils and the fact that both birds and bats have no trouble folding their wings without wrinkling them.

Too often 
artists freehand their pterosaurs (Fig 5 purple), ignoring the bone and soft tissue evidence.

wo of the most completely known Pteranodon

Figure 4. Two of the most completely known Pteranodon (UALVP24238 and NMC4138) along with the skull of KUVP2212 to scale. In purple, John Conway’s Pteranodon (purple) with a much smaller skull and an inappropriate  elbow-high walking configuration.

Toy Pteranodon, ca. 1962, from the Marx Company.

Figure 5. Toy Pteranodon, ca. 1962, from the Marx Company.

Toy pterosaurs
also suffer from deep chord wing membranes (Fig. 5). Proportions here are wildly inaccurate for the toddler set. Accuracy is also absent in many professional reconstructions that include skeletons (Fig. 4), so there is enough blame to go around. The fossils (Fig. 6) document how the artists and sculptors should present those folded wing membranes. Too few artists and sculptors who claim accuracy are actually producing accuracy.

Figure 1. Click to enlarge. The plate and counter plate of the BSP AS V 29a/b specimen of Pterodactylus with color overlays of the bones and visible soft tissues.

Figure 6. The plate and counter plate of the BSP AS V 29a/b specimen of Pterodactylus with color overlays of the bones and visible soft tissues.

What do you get when you choose accuracy?
A much less monstrous awkward portrayal and a much more elegant bird-like/bat-like portrayal comes from keeping true to the bones and soft tissues as they are. Deep chord wing membranes that attach to pterosaur ankles are as outdated as tail-dragging dinosaur portrayals. And while we’re at it, keep those pteroids pointing inward, forming straight leading edges for the distal propatagia.

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 7. 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.

Pterodactylus walk matched to tracks according to Peters

Figure 8. Click to animate. Plantigrade and quadrupedal Pterodactylus walk matched to tracks

This animation frame (Fig. 7) from a walking pterosaur movie associated with the Crayssac tracks accurately portrays the wing membrane essentially invisible when folded. Artist unknown.

Another animation matched to Crayssac tracks (Fig. 8) does not include wing membranes, but they would have been nearly invisible here. This version shows a more upright quadrupedal stance, as if the pterosaur wings were used like ski poles. As noted earlier, this is essentially a bipedal pose, enabling wing opening and flapping without shifting the center of balance.

Go with the evidence, not traditional and sometimes current renderings. Follow the evidence.

The Vienna Pterodactylus.

Figure 9. The Vienna Pterodactylus.  Wing membranes in situ (when folded) then animated to extend them. There is no shrinkage here or in ANY pterosaur wing membrane. That is only an “explanation” to avoid dealing with the hard evidence here and elsewhere.

While we’re talking about Quetzalcoatlus
and its flying abilities, it is worthwhile to take another look at gracile m4.2 (second wing phalanx) on the giant Q. northropi vs. the same phalanx on the much smaller and more likely volant Q. species (Fig. 10). Sorry I didn’t bring this up during the earlier discussion, on azhdarchid flight, first published online three years ago here, but I forgot I had it, and it’s more damning evidence against giant pterosaur flight.

Figure 1 Quetzalcoatlus sp. compared to the large specimen wing, here reduced. I lengthened the unknown metacarpus to match the Q. sp. and other azhdarchid metacarpi. I offer the wing finger has reconstructed by the Langson lab and with filler reduced. Note m4.2 is narrower on the larger specimen, which doesn't make sense if Q. northropi was volant.

Figure 10. Quetzalcoatlus sp. compared to the large specimen wing, here reduced. I lengthened the unknown metacarpus to match the Q. sp. and other azhdarchid metacarpi. I offer the wing finger has reconstructed by the Langson lab and with filler reduced. Note m4.2 is narrower on the larger specimen, which doesn’t make sense if Q. northropi was volant.

Figure 1. Freehand wing planform cartoon for Quetzalcoatlus from Witton and Habib 2010. There is no evidence in any pterosaur for this wing plan.

Figure 11. Freehand wing planform cartoon for Quetzalcoatlus from Witton and Habib 2010. There is no evidence in any pterosaur for this wing plan. Such deep chord wings cannot help but create unwarranted wrinkles when folded.

Wing folding
and the muscles that enabled complete flexion (Fig. 12) were covered earlier here.

Figure 1. Pterosaur (Santanadactylus) wing folding. Note when the wing is perpendicular to the metacarpus the flexor must be off axis in order to complete the wing folding process. The insertion must be distal to the joint because the flexor process of m4.1 extends dorsally over the metacarpus during wing folding. Otherwise the ventral (palmar) flexor would be cut off from the swinging dorsal process.

Figure 12. Pterosaur (Santanadactylus) wing folding. Note when the wing is perpendicular to the metacarpus the flexor must be off axis in order to complete the wing folding process. The insertion must be distal to the joint because the flexor process of m4.1 extends dorsally over the metacarpus during wing folding. Otherwise the ventral (palmar) flexor would be cut off from the swinging dorsal process.

References
Witton MP and Habib MB 2010.
On the size and flight diversity of giant pterosaurs, the use of birds as pterosaur analogues and comments on pterosaur flightlessness. PlosOne 5(11): e13982. doi:10.1371/journal.pone.0013982

Azhdarchid pterosaur flight issues

Pterosaurs,
as fenestrasaur tritosaur lepidosaurs matured isometrically. That’s a widely overlooked fact, even by pterosaur workers. Hatchlings had adult proportions with small eyes and long rostra — if their 8x larger parents had small eyes and long rostra. Hatchlings also had adult-proportioned wings. So presumably they were able to fly shortly after hatching (and drying out a bit) — if their parents were able to fly. But not all adult pterosaurs were able to fly…

Figure 1. GIF animation, 4 frames, showing three pterosaurs specimens in 3 sizes (see scale bars) with short, medium and long wings, drawn to the same torso length. The question is: did Quetzalcoatlus fly?

Figure 1. GIF animation, 4 frames, showing three pterosaurs specimens in 3 sizes (see scale bars) with short, medium and long wings, drawn to the same torso length. The question is: did Quetzalcoatlus fly?

Flightless pterosaurs
Earlier we looked at two related pterosaurs, the no. 57 specimen (Sos 2482) and the no. 42 specimen in the Wellnhofer 1970 catalog (Fig. 1). Both are adults. Both are in the azhdarchid lineage that arose from a tiny pterodactyloid-grade dorygnathid, the no. 1 specimen (TM 10341) in the Wellnhofer 1970 catalog and ultimately gave rise to the giant pterosaur, Quetzalcoatlus (also in Fig. 1). A magnitude or more greater in size and with wings only half as long as the flying no. 42 specimen,

Quetzalcoatlus is widely considered a flying pterosaur.
Can that be verified? Other clades of large (larger than a pelican) pterosaurs all have elongate wings, ideal for soaring. Azhdarchids, apparently deep shoreline waders, did not. The distal two long phalanges (sans the ungual) were shorter in azhdarchids, but the wing was not otherwise reduced, as in the flightless pterosaur, no. 57 (Fig. 1). Witton and Naish 2008 provide a history of workers pondering this question. Unfortunately they provided a bat-wing membrane attached to the ankles or shins with anteriorly oriented pteroids, ignoring key references for pterosaur wing shape (Peters 2002, 2009 and references therein) while ignoring fossilized evidence of pterosaur wing tissue, as others have done.

As anything gets larger,
either ontogenetically or phylogenetically, they generally put on weight at the cube of their length. Air-filled pterosaurs were not as solid, so that ratio was undoubtedly lower.  Even so longer, larger wings on larger pterosaurs makes sense, as in living large birds that fly and are also air-filled.

But that is countered by the isometric growth of individual pterosaurs as they mature to adulthood. Whatever works for hatchlings and tiny pterosaurs, is working just as well for giant adults. Could that mean that all ontogenetic stages of Quetzalcoatlus could fly? Or none of them? Or only half-sized juveniles at about ten percent of the adult weight? With flight, it’s always a balancing act: thrust, lift, drag, weight.

Wings can still provide great thrust
for terrestrial excursions even if they cannot get a big pterosaur off the ground (Fig. 2). So that’s a possibility under consideration, too. After all, why not use all the thrust available?

Quetzalcoatlus running like a lizard prior to takeoff.

Figure 10. Quetzalcoatlus running like a lizard prior to takeoff.

To prevent an extant flying bird, like a cockatiel, from flying, or flying well,
it’s surprising how little of the tips of the feathers need to be clipped. Link here. Basically its the difference between no. 42 and Quetzalcoatlus above (Fig. 1). With this in mind, I cannot join those who say giant Quetzalcoatlus could fly or fly between continents, until supporting evidence comes alone. Rather, giant azhdarchids become hippo analogs in this respect: they were probably constant deep waders (Fig. 3) capable of charging or running from danger. Storks, which azhdarchids otherwise resemble, tend to fly away because they have long, not truncated wings and can do so.

Figure 3. In my opinion this saddle-bill stork wading in water appears to be the bird closest to azhdarchid morphology and, for that matter, niche.

Figure 3. In my opinion this saddle-bill stork wading in water appears to be the bird closest to azhdarchid morphology and, for that matter, niche. It can fly from danger on elongate wings. Not so sure that Q could do the same. 

References
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing—with a twist. Historical Biology 15:277-301.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-1330.
Wellnhofer P 1970. 
Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlungen der Bayerischen Akademie der Wissenschaften, N.F., Munich 141: 1-133.
Witton M and Naish D 2008.  A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology. https://doi.org/10.1371/journal.pone.0002271. online here.

Rhamphorhynchus: Zittel wingtip ungual in higher resolution

The Zittel wing
of Rhamphorhynchus preserves a complete and unfolded pterosaur wing (brachiopatagium + propatagium). Because the specimen (B St 1880.II.8) documents a narrow-chord construction it was purposefully omitted from the earlier study by Elgin, Hone and Frey (2010) who wished all their pterosaur wings were of the invalidated and traditional deep chord variety. None are (Peters 2002). Yet the tradition continues as seen in David Attenborough videos and Bennett (2016) papers.

As a scientist,
I prefer cold hard evidence (Figs. 1-3) with regard to pterosaur wing shape. Let’s hope you do, too.

Figure 1. Zittel wing (Rhamphorhynchus) with ungual area color spectrum expanded.

Figure 1. Zittel wing (Rhamphorhynchus) with ungual area color spectrum expanded. Details in figure 2. Note the narrow chord of this nearly perfect specimen with the membrane stretched between the elbow and wingtip, not the hind limb and wing tip. This is hard evidence. This is reality.

Today
we’ll take a closer peek at the typically overlooked wing tip ungual, phalanx 5 of manual digit 4 (m4.5) that we looked at earlier in less detail. Few to no pterosaur workers and other paleontologists recognize the presence of this bone. Rarely workers (Koroljov AV 2017) consider the wing finger to be digit 5 and the pteroid digit 1. Not true (Peters 2009). Just because the wingtip claw is tiny, doesn’t mean it’s not present. You just have to look carefully and use the tools available (Photoshop) to bring it out so others can easily see it (Fig. 2).

Figure 2. Zittel wing m4.5, wingtip ungual in situ, plus with the color spectrum (image levels in Photoshop) expanded.

Figure 2. Zittel wing m4.5, wingtip ungual in situ, plus with the color spectrum (image levels in Photoshop) expanded. Yes, it gets fuzzy when it is enlarged so much, but the hook shape is readily apparent surrounded by excavation.

We nested the Zittel wing
earlier with other Rhamphorhynchus specimens in the large pterosaur tree (LPT, Fig. 3). Although ungual 4.5 is apparent (Figs. 1,2), manual digit 5 is not visible in the Zittel wing due to a ventral exposure of the specimen.

Figure 2. The Zittel wing specimen B St 188 II 8 nests between the 'dark wing' JME specimen and the MTM specimen, both in the Rhamphorhynchus muensteri clade.

Figure 2. The Zittel wing specimen B St 188 II 8 nests between the ‘dark wing’ JME specimen and the MTM specimen, both in the Rhamphorhynchus muensteri clade.

Despite having the specimen in his hands,
Bennett 2016 overlooked the ungual at the wingtip. He proximally extends the propatagium to the neck, rather than the deltopectoral crest. Worse yet, he added lots of proximal wing membrane that was never there in the Zittel wing (Fig. 3). No pterosaur documents wing membranes extending past the knee. No pterosaur documents uropatagia attaching to pedal digit 5. No pterosaur documents a propatagium extending proximally beyond the deltopectoral crest.

Figure 3. Base reconstruction of Zittel wing by Bennett 2016 where he imagined a great deal of patagium between the elbow and knee. Here the hind limbs are rotated laterally, the patagium is stretched between the elbow and wingtip. Femoral and numeral muscles are estimated. 

Figure 3. Base reconstruction of Zittel wing by Bennett 2016 where he imagined a great deal of patagium between the elbow and knee. Here the hind limbs are rotated laterally, the patagium is stretched between the elbow and wingtip. Femoral and numeral muscles are estimated.

Strictly follow your data.
Don’t enhance it with imaginary tissues. And don’t overlook real data.

References
Bennett SC 2016. New interpretation of the wings of the pterosaur Rhamphorhynchus muensteri based on the Zittel and Marsh specimens. Journal of Paleontology 89 (5):845-886. DOI: 10.1017/jpa.2015.68
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56 (1), 2011: 99-111. doi: 10.4202/app.2009.0145
Koroljov AV 2017. The Flight of Pterosaurs.Biol Bull Rev 7: 179. doi:10.1134/S2079086417030045
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.

Another look at a possible pterosaur wingtip ungual

Figure 1. The Yale specimen of Rhamphorhynchus phyllurus with preserved wingtip ungual highlighted. See figure 2 for closeup.

Figure 1. The Yale specimen of Rhamphorhynchus phyllurus with preserved wingtip ungual highlighted. See figure 2 for closeup.

The Yale specimen of Rhamphorhynchus phyllurus (Figs. 1, 2; VP 1001778) has one painted wing tip and one that may include another wingtip ungual.

Figure 2. Closeup of Rhamphorhynchus phyllurus in figure 1 focusing on the preserved wingtip ungual.

Figure 2. Closeup of Rhamphorhynchus phyllurus in figure 1 focusing on the preserved wingtip ungual. Was this carved in? Or is it real? Note the cylindrical tip of the penultimate wing phalanx (m4.4). The wingtip was buried deep within the matrix and had to be exposed.

The wingtip
was buried deep within the matrix and had to be exposed. So the question is: was it carved? Or is it real? If it was carved, why was it carved? Traditionally pterosaurs are not supposed to have wing tip unguals, but I’ve found them in several specimens.

You might remember
we looked at this wing tip earlier with a different provided image. The present one appears to offer more clues.

Douzhanopterus: Not the pterosaur they think it is + overlooked wing membranes.

A new paper by Wang et al. 2017
describes a ‘transitional’ pterosaur (Figs. 1,4) that was purported to link long-tail basal pterosaurs to short-tail derived pterosaurs (Fig. 2).

Unforunately this pterosaur does not do that.
No one single pterosaur can do that (see below, Fig. 3). But the new pterosaur is a new genus with a set of unique traits that nests at the base of the Pterodactylus clade, the Pterodactylidae, not the base of the so-called ‘Pterodactyloidea.’

Figure 1. Douzhanopterus at top in situ compared to scale with related pterosaurs, including Jianchangopterus, Ningchengopterus and the Painten pterosaur, all at the base of the Pterodactylidae.

Figure 1. Douzhanopterus (Wang et al. 2017) at top in situ compared to scale with related pterosaurs, including Jianchangopterus, Ningchengopterus and the Painten pterosaur, all nesting at the base of the Pterodactylidae.

Douzhanopterus zhengi (Wang et al. 2017; STM 19–35A & B; Late Jurassic, Fig. 1) originally nested (Fig. 2) between the Wukongopterids (Wukongopterus, Darwinopterus, Kunpengopterus.) and the Painten pterosaur (Fig. 1) and the rest of the purported clade Pterodactyloidea, beginning with Pterodactylus antiquus. Unfortunately, this is an antiquated matrix based on Wang et al. 2009 modified from Andres et al. 2014 with additional taxa. Unfortunately it includes far too few additional taxa and it produces an illogical cladogram in which clade members recovered by the large pterosaur tree (LPT) become separated from one another.

Figure 2. Basal portion of a cladogram provided by Liu et al. but colorized here to show the division of clades recovered in the LPT.

Figure 2. Basal portion of a cladogram provided by Wang et al. but colorized here to show the division of clades recovered in the LPT. Note that dorygnathids are basal to all derived cyan taxa and Scaphognathids are basal to all derived amber taxa.

As readers of this blogpost know
there was not one origin to the ‘Pterodactyloidea” clade, there were four origins to the pterodactyloid grade: two out of two Dorygnathus specimens and two out of small Scaphognathus descendants (subset of the LPT, Fig. 3). Once again, taxon exclusion is the problem in Wang et al. 2017. Too few taxa were included and many key taxa were ignored.

Should we get excited about the length of the tail
or the retention of an elongate pedal digit 5? No. These are common traits widely known in sister taxa and too often overlooked by pterosaur workers.

I understand the difficulties here.
Wang et al. saw no skull (but see below!) and the rest of the small skeleton is rather plesiomorphic, except for those long shins (tibiae). Even so, plugging in traits to the LPT reveals that Douzhanopterus is indeed a unique genus.

Figure 3. Subset of the LPT focusing on Pterodactylus with Douzhanopterus at its base.

Figure 3. Subset of the LPT focusing on Pterodactylus with Douzhanopterus at its base. Many of these taxa were not included in the Wang et al. 2017 study, but not the proximity of the Painten pterosaur, similar to the Wang et al study.

Here Douzhanopterus nests
in the LPT as a larger sister to Jianchangopterus (Lü and Bo 2011; Middle Jurassic; Fig. 1) at the base of the Pterodactylidae. These are just those few taxa closest to the holotype Pterodactylus and includes the Painten pterosaur, as in the Wang et al. study. Here that pterosaur was likewise demoted from the base of the Pterodactyloidea to the base of the Pterodactylidae.

Figure 4. Douzhanopterus in situ, original drawing and color tracing showing the overlooked soft tissue membranes and skull. Click to enlarge.

Figure 4. Douzhanopterus in situ, original drawing and color tracing showing the overlooked soft tissue membranes and skull. Click to enlarge.

Wang et al. overlooked
the skull and soft tissue membranes (Fig. 4) that are readily seen in the published in situ photo image. Click here to enlarge the image. These shapes confirm earlier findings (Peters 2002) in which the wing membranes had a narrow chord + fuselage fillet and were stretched between the elbow and wingtip, not the knee or ankle and wingtip. The uropatagia were also had narrow chords and were separated from one another, not connected to the tail or to each other, contra traditional interpretations.

DGS
This is what Digital Graphic Segregation is good for. I have not seen the specimen firsthand yet I have been able to recover subtle data overlooked by firsthand observation. The headline for this specimen should have been about the wing membranes, not the erroneous phylogenetic placement.

References:
Andres B, Clark J and Xu X 2014. The earliest pterodactyloid and the origin of the group. Curr. Biol. 24, 1011–1016.
Lü J and Bo X 2011. A New Rhamphorhynchid Pterosaur (Pterosauria) from the Middle Jurassic Tiaojishan Formation of Western Liaoning, China. Acta Geologica Sinica 85(5): 977–983.
Peters D 2002.  A New Model for the Evolution of the Pterosaur Wing – with a twist.  Historical Biology 15: 277–301.
Wang X.Kellner AWA, Jiang S and  Meng X 2009. An unusual long-tailed pterosaur with elongated neck from western Liaoning of China. An. Acad. Bras. Cienc. 81, 793–812.
Wang et al. 2017. New evidence from China for the nature of the pterosaur evolutionary transition. Nature Scientific Reports 7, 42763; doi: 10.1038/srep42763

wiki/Jianchangopterus
wiki/Ningchengopterus
wiki/Douzhanopterus (not yet posted)