Misinformation on the palate of Kunpengopterus

Cheng et al. 2017 present
a new complete but slightly damaged specimen of Kunpengopterus, IVPP V 23674.

The new Kunpegnopterus IVPP V 23674.

The new Kunpegnopterus IVPP V 23674.

Cheng et al. provided a new palate reconstruction
that could use a little DGS to better inform the reader and the the authors (Fig. 2, 3). Cheng et al. think they have found some new medial projections toward the back of the palate. Actually they are looking at broken off lateral pieces of the ecto-palatine (ectopterygoid fused to palatine).

Fig. 2. The skull of IVPP V 23674 colorized using DGS alongside the original description.

Fig. 2. The skull of IVPP V 23674 colorized using DGS alongside the original description.

And
here’s a closeup of the palate in dorsal view (Fig. 3). They relied on Wellnhofer 1978 for palate identification. That was when the anterior palate was considered the palatine as it seems to be here, but perhaps fused to the maxilla??. That must be the revision shown here based on Kellner 2013, which I have not read. Ever since Peters 2000, by comparison with Macrocnemus (acknowledged in Kellner 2013), and later by Osi et al. 2010, looking at Dorygnathus, the entire pterosaur palatal plate has been considered the maxilla, as it is here using colors (Fig. 3).

Fig. 3 Kunpengopterus IVPP V 23674 palate in dorsal view alongside original interpretation. Watch out for those broken bones. They sometimes end up in places a wee bit from their origins.

Fig. 3 Kunpengopterus IVPP V 23674 palate in dorsal view alongside original interpretation. Watch out for those broken bones. They sometimes end up in places a wee bit from their origins. And don’t you just hate 1 point lines telling you where the bones are? Colors are much more informative!

It’s really tough
when the broken bone appears to follow the contours of the unbroken bones, as they do here (Fig. 3). That’s where it helps to know the pattern of the palate in ALL pterosaurs. So exceptions like this can be reexamined, looking for the cracks that should not be there.

In similar fashion, here’s a pelvis
(Fig. 4) from the same specimen that appeared to Cheng et al to have a really deep pubis when the reality is more mundane.

Figure 4 Kunpengopterus pelvis with DGS colors identifying the anterior ilium detached from the posterior ilium and the false deep pubis.

Figure 4 Kunpengopterus pelvis with DGS colors identifying the anterior ilium detached from the posterior ilium and the false deep pubis. Note the original drawing in figure 1 that extends the pubis too deep by incorporating the inverted prepubis that match the contours of the ischium. 

References
Cheng X, Jiang S-X, Wang X-L, Kellner AWA 2017. New anatomical information of the wukongopterid Kunpengopterus sinensis Wang et al., 2010 based on a new specimen. PeerJ 5:e4102; DOI 10.7717/peerj.4102
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Osi A, Prondvai E, Frey E and Pohl B 2010. New Interpretation of the Palate of Pterosaurs. The Anatomical Record 293: 243-258.

Advertisements

Dimorphodon revisited

The odd pterosaur, Dimorphodon
was one of the first taxa included in the large reptile tree (LRT, 1132 taxa). Here I revise earlier errors on the BMNH 41212 specimen (Fig. 1), including adding a short tail discovered a few days ago and also adding more dorsal vertebrae.

Figure 1. The three Dimorphodon specimens traced from the fossils.

Figure 1. The three Dimorphodon specimens traced from the fossils.

Here is the in situ fossil with bones colorized (Fig. 2).

Figure 2. The BMNH 4121 fossil of Dimorphodon here colorized using DGS.

Figure 2. The BMNH 4121 fossil of Dimorphodon here colorized using DGS. Colors match the reconstruction, except for the skull.

Earlier the skull was reconstructed. Here it is again (Fig. 3). This was done to show the mandible did not have a fenestra, only a shifted surangular.

The skull of Dimorphodon macronyx.

Figure 3. The skull of Dimorphodon macronyx. Above: in situ. Middle: Restored. Below: Palatal view. Not settled on the depth of the mandible. The long replaceable teeth suggest a deeper mandible is more appropriate.

References
Buckland W 1829. Proceedings of the Geological Society London, 1: 127
Owen R 1859. On a new genus (Dimorphodon) of pterodactyle, with remarks on the geological distribution of flying reptiles.” Rep. Br. Ass. Advmnt Sci., 28 (1858): 97–103.
Nesbitt SJ and Hone DWE 2010. An external mandibular fenestra and other archosauriform character states in basal pterosaurs. Palaeodiversity 3: 225–233
Padian K 1983. Osteology and functional morphology of Dimorphodon macronyx (Buckland) (Pterosauria: Rhamphorhynchoidea) based on new material in the Yale Peabody Museum, Postilla, 189: 1-44.
Sangster S 2001. Anatomy, functional morphology and systematics of Dimorphodon. Strata 11: 87-88

wiki/Dimorphodon

Were early pterosaurs inept terrestrial locomotors?

Witton 2015 asked:
“Were early pterosaurs inept terrestrial locomotors?” Sorry, this online paper escaped my notice until now. It’s two years old.

The answer is
an unqualified “YES” when Witton turns perfectly good bipeds (supported by morphology, outgroups (Fig. 2), ichnites and omitted citations), into stumbling quadrupeds encumbered by imaginary wing membranes (Fig. 3) that connect the ankles and lateral pedal digits to the wing tips and binds the legs together with a single uropatagium. The Unwin influence is strong in those English youngsters. He also rotates the humerus in a shoulder joint that does not permit rotation (Fig. 1), which would be very bad for a flapping reptile, bird or bat.

Figure 1. Tracings from bones (on left) compared to Witton's freehand quads. Comments in red.

Figure 1. Tracings from bones (on left) compared to Witton’s freehand quads. Comments in red.

From the Witton abstract:
“Pterodactyloid pterosaurs are widely interpreted as terrestrially competent, erect-limbed quadrupeds, but the terrestrial capabilities of non-pterodactyloids are largely thought to have been poor.”

This may be true when you construct pterosaurs that don’t match footprints and you have no idea where ‘early pterosaurs’ came from, even though that has been known for 17 years. Obligate bipeds (Longisquama and Sharovipteryx) are outgroups. Basalmost pterosaur, Bergamodactylus (Fig. 2) , has longer hind limbs and shorter forelimbs (Fig. 2) than other pterosaurs, retaining these plesiomorphic traits.

Figure 2. Updated reconstruction of Bergamodactylus to scale with an outgroup, Cosesaurus.

Figure 2. Updated reconstruction of Bergamodactylus to scale with an outgroup, Cosesaurus. Does this look like a quadruped to anyone? All derived pterosaurs have relatively shorter legs. Outgroups, whether the invalid Scleromochlus, or the valid Sharovipteryx, have long legs like these. Uropatagia are not preserved, but they are on a related taxa one node away, Sharovipteryx. Note the tail is NOT incorporated.

Witton’s abstract continues
“This is commonly justified by the absence of a non-pterodactyloid footprint record,”

(False, see Peters 2011)

“suggestions that the expansive uropatagia common to early pterosaurs”

(False, misinterpretation of Sordes)

“would restrict hindlimb motion in walking or running, and the presence of sprawling forelimbs in some species.”

(sprawling at the top, narrow gauge on the substrate (Fig. 3).

“Here, these arguments are re-visited and mostly found problematic. Further indications of terrestrial habits include antungual sesamoids, which occur in the manus and pes anatomy of many early pterosaur species, and only occur elsewhere in terrestrial reptiles, possibly developing through frequent interactions of large claws with firm substrates.”

Or possibly by grasping branches and tree trunks, but even that possibility is not considered or argued against by Witton.

Getting back to the uropatagium found in bats…
primitive bats extend a membrane from both legs back to the tail. Only in the most derived bats, like Desmodus (Fig. 3), is the tail a vestige to absent. The resulting uropatagium without the tail extends between the legs – while completely avoiding the toes. Thus the pterosaur/bat analog, is also bogus. Final point: basal bats don’t walk or run on their hind limbs. They hang. Only in bats like the vampire do some bats reacquire the ability to actively hop around on horizontal surfaces, like cow buttocks and grassy knolls.

Witton carefully avoids
any mention of papers in which bipedal pterosaur trackways are described (Peters 2011). He fully supports the uropatagium hypothesis proposed by Sharov 1971 and further supported by Unwin and Bakhurina 1994 (disputed by Peters 2002 and here). That uropatagium, found in no other specimens of Sordes or any other pterosaur, is really a displaced wing membrane (Figs. 3–5) along with a displaced radius and ulna as shown here. Note: a few days ago Witton’s latest illustration used pedal digit 5 to frame both the uropatagium and the brachiopatagium. No one else does this. No argument or explanation is given.

Figure 6. Above, from Witton 2017 focusing on the pterosaur uropatagium. Note: even though fanciful, it does not incorporate the tail, but goes from leg to leg, UNLIKE Desmodus the bat, which incorporates what little tail is left.

Figure 3. Above, from Witton 2017 focusing on the pterosaur uropatagium. Note: even though fanciful, it does not incorporate the tail, but goes from leg to leg, UNLIKE Desmodus the bat, which incorporates what little tail is left. Besides, their is NO homology here. Witton is trying to support a bad interpretation with a bad analogy. Not a good idea to support an analogy with invalid drawings. Witton gives no support through testing to the uropatagium controversy, but accepts it with blinders on.

Witton carefully avoids
any mention of other candidate pterosaur outgroups, like fenestrasaurs (Fig. 2), and the assistance they can offer to the questions posed, but supports the basal bipedal crocodylomorph, Scleromochlus, as a potential outgroup. Ironic, isn’t it?

My first question would be, which outgroup taxon has anything resembling a leg-spanning uropatagium?Certainly not phytosaurs. Nor any archosaur. Sharovipteryx has separate uropatagia, but in Witton’s world view those are not the same, nor are they to be mentioned, because that would involve citing some academic paper from Peters, which would be antithetical to Witton’s premise. In good science, all counterarguments are considered, attacked or supported.

The myth of the pterosaur uropatagium

Figure 4. The Sordes uropatagium is actually displaced wing material carried between the ankles by the displaced radius and ulna.

Witton supports
the invalid shrinkage hypothesis of Elgin, Hone and Frey (2011) to explain away narrow-chord wing membranes preserved in the fossil record…which would be ALL of them

The hind limbs and soft tissues of Sordes.

Figure 5. The hind limbs and soft tissues of Sordes. Above, color-coded areas. Below the insitu fossil. Note how insubstantial the illusory uropataigum is compared to the drawing that solidifies the area. Tsk.Tsk.

Witton reports,
“Trackways made by running pterodactyloids indirectly demonstrate how elastic their proximal membranes must have been, allowing track makers to take strides of considerable magnitude (Mazin et al., 2003) despite membranes stretching from the distal hindlimb to their hands (Elgin, Hone & Frey, 2011).” The other explanation is that the wings and hind limbs were always decoupled (as documented in all known fossils). Pterosaurs do not have a membrane extending to the ankles. Witton proposes a bounding gait for pterosaurs, even though no pterosaur tracks document this.

Figure 7. A plesiomorphic bat with the tail incorporated in the uropatagium. This bat, Myotis, cannot walk very well. Desmodus, highly derived, has required the ability to walk, but at the expense of its tail and a vestige uropatagium.

Figure 6. A plesiomorphic bat with the tail incorporated in the uropatagium. This bat, Myotis, cannot walk very well. Desmodus, highly derived, has required the ability to walk, but at the expense of its tail leaving a vestige uropatagium. Everything must be put into a phylogenetic context, even in analogies.

Thankfully Witton supports
“Assessments of pterosaur hindlimb muscle mechanics seem to confirm that the pterosaur pelvic and femoral musculoskeletal system is optimally configured for an erect stance.” 

But then he puts the fingers on the ground (Fig. 1). Why???

Perhaps Witton does not realize
what happens to his uropatagium when the pes is plantigrade, which is how Witton always reconstructs pterosaur pedes. Somehow he avoids drawing the lateral digit reversed toward the pelvis, as he proposed earlier.

Witton has no criticism
for one of his references, Hone and Benton 2007 (but did not cite the setup 2007 paper. Readers know, for many reasons, this is one of the worst papers ever published in this field. The facts will stun even freshmen paleontologists. 

Witton ignores the pterosaur sacrum,
which has more than the typical two sacrals found in a wide range of quadrupedal reptiles. Why does the pterosaur sacrum add and fuse vertebrae phylogenetically and more with larger taxa? For the same reason that humans, apes and theropod dinosaurs do. They are bipedal and the sacrum acts as the fulcrum to a long lever arm.

Earlier we talked about pterosaur workers wearing blinders, ignoring papers with hypotheses that conflicted with pet hypotheses. Now you see that happening in real time.

When workers, like Witton, stopped citing papers
I had published in academic journals is when I took my evidence and arguments online.

Earlier, in a multipart critique,
here, here, here, here and here we talked about Witton’s previously published work combined in a single book. I only wish someone with influence on Witton and his collaborators would remind them that their ideas and papers are going to end up like the Victorian-age cartoons they mock – unless they get back to facts and evidence.

References
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeonntologica Polonica 56(1): 99-111.
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
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.
Witton MP 2015. Were early pterosaurs inept terrestrial locomotors? PeerJ 3:e1018 DOI 10.7717/peerj.1018

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.

National Geographic brings back pterosaurs: Nov. 2017

Years ago,
National Geographic (Monastersky R, May 2001?) put out an article on pterosaurs that marveled at their wonder.

This year,
National Geographic (Conniff R, Nov 2017) put out another article that was supposed to be an update, but turned out to be less than hoped. The entire article and artwork is online and it, too, marvels at their wonder. Reporter Conniff crossed the globe to visit paleontologists in the field at Big Bend National Park seeking Quetzalcoatlus, a house full of footprints in Washington DC, and  to see the latest finds in Beijing, many not yet published. The article features wonderful photographs, of course, and some great information. There was also much to criticize here.

I’m not happy with

  1. the Quetzalcoatlus photo leaning on its tiny fingers and rising to a digitigrade stance. But that’s the fault of the sculptor, following Witton, etc.
  2. re: Darwinopterus with egg, “evidence that for some male pterosaurs, as for some modern birds, big, brightly colored crests probably functioned as a sexual display device.” No. They found a female. Males might have been crestless in that Darwinopterus species, too. No specimen has yet been found to match “Mrs. T” but with the addition of a crest. All Darwinopterus specimens so far are specifically and/or generically distinct.
  3. The gatefold artwork has several errors, including the cladogram nesting pterosaurs between crocs and dinos, deep chord wings, joined uropatagia, and a diagram of Habib’s pole-vaulting takeoff.
  4. Michael Habib, reported, “They (scientific illustrators) basically take a bird model and put a membrane wing and a crest on it, but pterosaur proportions were not birdlike.” Frankly, I have never seen this. Nor do all pterosaurs have certain proportions. Nor do all birds.
  5. Habib reported on the first pterosaurs arising from “light, strong reptiles adapted for running and leaping after prey. Jumping – to catch on insect or dodge a predator – evolved into ‘jumping and not coming down for a while.” He has no idea what pterosaurs are and with this sounds like a Creationist telling a ‘just so’ story lacking evidence.
  6. Habib reiterated his invalid pole-vaulter hypothesis because “taking off from land with an upright, bipedal stance, as other researchers had proposed, would have shattered the femurs of larger species.” Perhaps Habib forgets that most pterosaurs, including the original ones were not ‘larger species’ and that at the same time the flapping wings were producing several times more thrust than the legs. And femurs are not prone to shatter in any tetrapods ‘doing their thing.’ On the same point, Habib reports pterosaurs often had “freakishly small feet”, (only the ornithocheirids), omitting the fact that most pterosaurs had normal feet while some, like Pterodaustro had large feet.
  7. “Pterosaur wings consist of a membrane attached to each flank from shoulder to ankle”. Evidence only supports a wingtip to elbow wing membrane (Peters 2002).
  8. “Changing the angle of a wrist bone called the pteroid may have given them the equivalent of the leading-edge slats on a passenger jet, for increased lift at low speeds.” No. The pteroid was relatively immobile, passively folding the propatagium whenever the wing finger was folded.
  9. “The result is that pterosaurs have begun to look less like a train wreck in the sky and more like sophisticated aviators.” No animal evolves to be a train wreck, no matter how much pterosaur workers try to imagine them that way.
  10. When asked about the giant heads, Habib avoided the right answer and talked about brains and hollow bones. Here Habib is quoted as calling pterosaurs, “giant flying murder heads.” Perfect for Halloween, or comedians. Not so much for the scientifically curious.
  11. Following a discussion of a feud between J-C Lü and X. Wang, who went their separate ways, the following is reported: 

“We’re a very small group, and we don’t really get along,” one pterosaur specialist says. The field, says another, “has a reputation for people who viciously despise one another.” Pterosaur researcher A will readily volunteer that B is “a waste of carbon,” while C independently remarks of A that certain people “would happily see him at the bottom of the ocean.” Their combat is a natural by-product of all those optimistic hypotheses built on fragmentary evidence, and it makes the Chinese rivalry look like a tea party. Lü shrugs off talk of mutual loathing, and Wang manages to avoid talking about it at all.”

There is no reason for this to take place
or to be aired out in public. We’ve seen enough of this. It has to stop. Again, it makes all paleontologists look bad when we demean one another instead of focusing on the work itself. That being said, workers should not hold themselves up as pterosaur experts unless they can tell reporters:

  1. what pterosaurs are (what animals they evolved from)
  2. the only valid wing shape and stance (maybe show evidence)
  3. why certain pterosaurs had big heads (often without a crest)
  4. that they could not know what they know without the collections, data and analyses of their esteemed colleagues
References
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Nat Geo pterosaur article online here

 

 

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/

A new look at Jidapterus (basal azhdarchid pterosaur)

Wu, Zhou and Andres 2017
bring us long anticipated details on Jidapterus (Early Cretaceous, Dong, Sun and Wu 2003) which was previously presented as a small in situ photograph lacking details. Even so a reconstruction could be made (Fig. 1). Coeval larger tracks (Elgin and Frey 2011) have been matched to that reconstruction.

Figure 2. Jidapterus matched to the Gansu, Early Cretaceous pterosaur tracks. The trackmaker was one-third larger than the Jidapterus skeleton.

Figure 1. Jidapterus matched to the Gansu, Early Cretaceous pterosaur tracks. The trackmaker was one-third larger than the Jidapterus skeleton.

Of interest today
is the fact that Jidapterus was originally and, so far, universally considered toothless. Its specific name, J. edentatus, refers to that condition. Wu, Zhou and Andres 2017 produced tracings (Figs. 2, 3) of the rostrum that are also toothless. However, they are crude and appear to miss the premaxilla and maxilla sutures, the palatal elements… and maybe some teeth. Those jaw rims are not slippery smooth like those of Pteranodon. Outgroups in the large pterosaur tree (LPT), all have tiny teeth.

Figure 2. Rostrum of Jidapterus (RCPS-030366CY) and traced according to Wu et al. and colorized using DGS to reveal skull sutures and possible teeth.

Figure 2. Rostrum of Jidapterus (RCPS-030366CY) and traced according to Wu et al. and colorized using DGS to reveal skull sutures and possible teeth. See figure 3 for details. What Wu, Zhou and Andres label the  “low ridge of rostrum” is here identified as the rostral margin above the palatal portion. 

The cladogram of Wu, Zhou and Andres
lacks dozens of key taxa found in the LPT that separate azhdarchids from convergent tapejarids and shenzhoupterids. In the LPT giant azhdarchids arise from tiny toothy azhdarchids once considered Pterodactylus specimens… and these, in turn are derived from tiny and mid-sized dorygnathids in the Middle Jurassic.

What Wu, Zhou and Andres label the  “low ridge of rostrum”
is here identified as the rostral margin rim at the edge of the palate.

Figure 3. Focus on the rostral tip of Jidapterus shown in figure 2. Are these teeth?

Figure 3. Focus on the rostral tip of Jidapterus shown in figure 2. Are these teeth? You decide. I present the data. 

As in all pterosaurs
each premaxilla of Jidapterus has four teeth according to this data.

Are these tiny teeth?
Or are they tiny occlusions and/or chisel marks. Let’s get even better closeups to figure this out. Phylogenetic bracketing indicates either tiny teeth or edentulous jaws could be present here.

References
Dong Z, Sun Y and Wu S 2003. On a new pterosaur from the Lower Cretaceous of Chaoyang Basin, Western Liaoning, China. Global Geology 22(1): 1-7.
Elgin and Frey 2011. A new azhdarchoid pterosaur from the Cenomian (Late Cretaceous) of Lebanon. Swiss Journal of Geoscience. DOI 10.1007/s00015-011-0081-1
Wu W-H, Zhou C-F and Andres B 2017. The toothless pterosaur Jidapterus edentus (Pterodactyloidea: Azhdarchoidea) from the Early Cretaceous Jehol Biota and its paleoecological implications. PLoS ONE 12(9): e0185486.

wiki/Jidapterus