New Quetzalcoatlus northropi skeletal model from Triebold Paleontology

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

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

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

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

Quetzalcoatlus neck poses. Dipping, watching and displaying.

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

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

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

Quetzalcoatlus running like a lizard prior to takeoff.

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

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

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

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

Lepidosaur bipedality and pelvis morphology: Grinham and Norman 2019

Grinham and Norman 2019
brings us a new look at 34 lepidosaur pelves with an emphasis on trends associated with bipedal locomotion. The authors illustrated 11 pelves (Fig. 1, white and yellow areas).
Figure 1. On the left, lepidosaur pelves from Grinham and Norman 2019, reordered phylogenetically here. On the right several tritosaur pelves and prepubes, most of which strongly demonstrate bipedal traits (elongate anterior ilium, increased sacral number). Yellow boxes indicate facultatively bipedal extant lepidosaurs.

Figure 1. On the left, lepidosaur pelves from Grinham and Norman 2019, reordered phylogenetically here. On the right several tritosaur pelves and prepubes, most of which strongly demonstrate bipedal traits (elongate anterior ilium, increased sacral number). Yellow boxes indicate facultatively bipedal extant lepidosaurs.

From the Grinham and Norman abstract:
“Facultative bipedality is regarded as an enigmatic middle ground in the evolution of obligate bipedality and is associated with high mechanical demands in extant lepidosaurs. Traits linked with this phenomenon are largely associated with the caudal end of the animal: hindlimbs and tail. The articulation of the pelvis with both of these structures suggests a morphofunctional role in the use of a facultative locomotor mode. Using a three-dimensional geometric morphometric approach, we examine the pelvic osteology and associated functional implications for 34 species of extant lepidosaur. Anatomical trends associated with the use of a bipedal locomotor mode and substrate preferences are correlated and functionally interpreted based on musculoskeletal descriptions. Changes in pelvic osteology associated with a facultatively bipedal locomotor mode are similar to those observed in species preferring arboreal substrates, indicating shared functionality between these ecologies.”
Unfortunately, Grinham and Norman omitted
tritosaur lepidosaurs from their study. In the Triassic many of them became bipeds and among these, pterosaurs achieved bipedalism supported with four, five and more sacral vertebrae between horizontally elongate ilia, convergent with dinosaurs. The addition of the prepubis virtually extended the anchorage for the puboischial muscles. After achieving flight, beach-combing pterosaurs reverted to a quadrupedal configuration with finger 3 pointing posteriorly. Giant Korean bipedal pterosaur tracks are best matched to large dsungaripterid/tapejarid clade taxa.
Unfortunately, Grinham and Norman reported,
“A recently published molecular-based time-calibrated phylogeny for Squamata was pared down to match the species in our dataset.” Their genomic cladogram bears little to no resemblance to the large reptile tree (LRT, 1635+ taxa), which tests traits, not genes. Once again, genes produce false positives. 
The authors’ principal component analysis of the pelvis failed 
to isolate bipedal lepidosaurs from the rest. Grinham and Norman reported, “The shape of the pelvis in facultatively bipedal extant lepidosaurs falls within the overall morphospace of lepidosaurs generally.” This is also visible in their illustrated pelves (Fig. 1). They also reported, However, it is generally found in a very concentrated area of that morphospace.” And Conclusions can be drawn regarding pelvic morphology and substrate use, although not with the same clarity as for locomotor mode.”
Grinham and Norman 2019 conclude,
“we have used 3D landmark-based geometric morphometrics to demonstrate that the overall morphospace for the lepidosaur pelvis is broad and wide-ranging. Within this overall morphospace, a small region is occupied by facultative bipeds. The vast majority of this smaller morphospace overlaps that occupied by species that show a preference for arboreal habitats. Pelvic morphological adaptations relevant for living in an arboreal environment are similar to those necessary to facilitate facultative bipedality.”
That’s interesting with regard to
the arboreal abilities of volant basal bipedal pterosaurs and their ancestors. Maybe next time Grinham and Norman will expand their study to include tritosaur lepidosaurs.

References
Grinham LR and Norman DB 2019. 
The pelvis as an anatomical indicator for facultative bipedality and substrate use in lepidosaurs. Biological Journal of the Linnean Society, blz190 (advance online publication) doi: https://doi.org/10.1093/biolinnean/blz190
https://academic.oup.com/biolinnean/advance-article-abstract/doi/10.1093/biolinnean/blz190/5687877Â
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Snyder RC 1954. The anatomy and function of the pelvic girdle and hind limb in lizard locomotion. American Journal of Anatomy 95:1-46.

Pterosaur prebubis

 

Meet Mimodactylus, a small ornithocheirid from Lebanon

Figure 1. Mimodactylus in situ from Kellner et al. 2019.

Figure 1. Mimodactylus in situ from Kellner et al. 2019.

Mimodactylus libanensis (Kellner et al. 2019; Late Cretaceous, 95mya; MIM (no number), Lebanon) is known from a virtually complete specimen (Figs. 1, 2), with the top of the skull still buried in the sediment (Fig. 3). Originally it was considered closest to Haopterus, together comprising the Mimodactylidae. This is a pterosaur I was introduced to over ten years ago. Back then Roy Nohra, one of the co-authors, sent me photos of the unprepared slabs from which I created this bipedal reconstruction (Fig. 2) prior to the publication of Kellner et al.

Figure 1. a basal ornithocheirid, undescribed, from Lebanon.

Figure 2. Mimodactylus reconstruction created several years ago, prior to fossil preparation and publication.

Here,
in the large pterosaur tree (LPT, 242 taxa), Mimodactylus nests between Yixianopterus and Haopterus — closer to Yixianopterus. So the LRT does not support the newly erected clade Mimodactylidae. Yixianopterus was omitted from the cladogram of Kellner et al. Once again, taxon exclusion is the number one problem.

Figure 1. Mimodactylus skull in situ and reconstructed. Kellner et al. misidentified the maxillary palate as the palatine. This is repaired in the reconstruction below.

Figure 3. Mimodactylus skull in situ and reconstructed. Kellner et al. misidentified the maxillary palate as the palatine (PL), apparently unaware that this was correctly identified by several authors years ago. This is repaired in the reconstruction below.

Apparently seven co-authors were not enough
to edit out the seven mistakes in the basic understanding of pterosaurs found in this long-awaited paper.

  1. The broad maxillary palate was misidentified as the palatine. This correction was made by Peters 2000 and later by Osi et al. 2010 and Pinheiro and Schultz 2012. The actual tiny pterygoids and ectopalatine (ectopterygoid + palatine) were not identified.
  2. The manual digits are aligned 1–4 palmar side down in flight in pterosaurs, not palm side anterior in flight with #3 on the top as shown in Kellner et al.
  3. All pterosaurs have 8 cervical vertebrae, not 6
  4. The brachiopatagium stretches between the wingtip and elbow, not the tail tip
  5. The feet of ornithocheirid pterosaurs, and Mimodactylus, too, are half the size pictured.
  6. The Kellner et al. cladogram (Supp Data) mistakenly includes the archosauriforms Ornithosuchus, Herrerasaurus and Scleromochlus as outgroup taxa, none of which are related to pterosaurs. Pterosaurs nest within Lepidosauria in the large reptile tree (LRT, 1611+ taxa). Also see Peters 2000, 2007.
  7. Kellner et al. wrote, “dorsal vertebrae not fused into a notarium, it is likely that it was a very young animal at the time of death, having reached an ontogenetic stage between 2 and 32.” No phylogenetic sisters in the LPT have a notarium. Kellner et al. are unaware that as lepidosaurs pterosaurs have a distinctly different ontogenetic pattern of ossification. Their cladogram suffers from massive taxon exclusion.
Figure 1. Original from Kellner et al. 2019 showing the several basic morphology mistakes made by their artist.

Figure 4. Original Mimodactylus illustration from Kellner et al. 2019 showing the several basic morphology mistakes made by their artist.

The cladogram of Kellner et al.
(Fig. 5) continues several myths based on taxon exclusion of the tiny Solnhofen pterosaurs, all of which were outgroups to all known Cretaceous pterosaurs. I have colorized clades that appear in the LPT because they type size they used was way too small to read. Yixianopterus is not present here and Mimodactylus is not closely related to the istiodactylids in the LRT, contra Kellner et al. 2019. These authors simply have no idea what the tree topology of the pterosaur looks like when small taxa are included. Nor do they understand that pterosaurs arose from tritosaur lepidsosaurs, not a scattershot of unrelated and dissimilar archosauriforms.

Figure 3. Cladogram from Kellner et al. 2019. Color overlays show clades recovered in the LPT.

Figure 5. Cladogram from Kellner et al. 2019. Color overlays show clades recovered in the LPT. If you find this difficult to read, you’re in the majority. This cladogram does not include taxa listed in the SuppData in which Anurognathus nests as the basalmost pterosaur.

A subset of the LPT
(Fig. 6) includes several pertinent taxa omitted by Kellner et al. 2019. Even so, Haopterus nests close by, but Pteranodon and kin do not. Not sure if you ask yourself this question, but I do: What does it mean when scientists refuse to test competing hypotheses for twenty years? … and continue traditions they know don’t make sense?

Figure 1. Subset of the LPT with the addition of Mimodactylus within the clade Scaphognathia.

Figure 6. Subset of the LPT with the addition of Mimodactylus within the clade Scaphognathia.

Here’s Haopterus
(Fig. 7) a taxon closely related to Mimodactylus in both cladograms. Note the tiny feet, skull shape, robust tail, and palate morphology, all instructive with regard to Mimodactylus.

Figure 6. Haopterus is close to Mimodactylus and provides a bauplan for a bipedal stance. Note the tiny feet and palate morphology.

Figure 7. Haopterus is close to Mimodactylus and provides a bauplan for a bipedal stance. Note the tiny feet, pelvis, skull and palate morphology.

And here’s Yixianopterus
the basalmost ornithocheirid in the LPT. Mimodactylus is more closely related to this taxon than to Haopterus. Kellner et al. 2019 omitted Yixianopterus from their analysis.

Figure 2. Reconstruction of Yixianopterus. Roadkill fossils really need at least this much reconstruction to make then intelligible. And don't ignore them in phylogenetic studies. Nothing spectacular here, which means it is more likely to be phylogenetically important.

Figure 8. Reconstruction of Yixianopterus. This is the basalmost ornithocheirid in the LPT.

Believe it or not,
Peters 2009 was actually cited in this paper based on the evidence of a ‘clear articulation’ of the pteroid with the radiale and medial orientation of the free end, contra prior studies on pteroid orientation. That shouldn’t be a citation. It’s just the way it has always been.

Figure 8. Artwork in Kellner et al. of Mimodactylus by Julius Csotonyi. Second frame shows repairs to morphology needed to bring this illustration up to date. Figure 8. Artwork in Kellner et al. of Mimodactylus by Julius Csotonyi. Second frame shows repairs to morphology needed to bring this illustration up to date.

Figure 9. Artwork in Kellner et al. of Mimodactylus by Julius Csotonyi. Second frame shows gross repairs to morphology needed to bring this illustration up to date. 

 

References
Kellner AWA et al. (6 co-authors) 2019. First complete pterosaur from the Afro-Arabian continent: insight into pterodactyloid diversity. Nature.com/ScientificReports 9:17875. PDF
Ösi A, Prondvai E, Frey E and Pohl B 2010. New interpretation of the palate of pterosaurs. The Anat Rec 293: 243–258. doi: 10.1002/ar.21053.
Peters D 2000b.
 A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.
Pinheiro FL and Schultz CL 2012. An Unusual Pterosaur Specimen (Pterodactyloidea, ?Azhdarchoidea) from the Early Cretaceous Romualdo Formation of Brazil, and the Evolution of the Pterodactyloid Palate. PLoS ONE 7(11): e50088. doi:10.1371/journal.pone.0050088

wiki/Mimodactylus

Unwin and Martill 2019 find pterosaurs ‘naked’ and ‘ugly’

Unwin and Martill 2019 report:
“With key roles in flight, thermoregulation and protection of the body, the integument was of fundamental importance to pterosaurs. Determination of the basic anatomy of this structure could provide a range of new insights into the palaeobiology of these enigmatic volant reptiles. Presently, however, there are several conflicting hypotheses regarding the construction of the integument, all founded on limited numbers of specimens, and not one of which is fully consistent with the available fossil evidence.

As mentioned yesterday, pterosaurs are not enigmatic. Unwin and Martill have chosen to avoid the scaly lepidosaurian ancestors of pterosaurs cited by Peters (2000, 2007). The integument found on pterosaurs has similar precursor integument on sister fenestrasaurs like Sharovipteryx (Fig. 1) and Longisquama, adding two taxa to their short list of pterosaurs preserving scaly integument and pycnofibers exclusive of the extradermal membranes (wings and uropatagia).

Figure 1. Note the neck skin (integument) of Sharovipteryx, a pterosaur sister.

Figure 1. Note the neck skin (integument) of Sharovipteryx, a pterosaur sister.

Unwin and Martill continue:
“We have developed a new 
model based on investigations of more than 100 specimens all of which show some form of exceptional preservation. This data set spans the entire temporal and systematic ranges of pterosaurs and a wide variety of preservational modes.”

So… “a limited number of specimens” (see above) just turned into “more than 100 specimens.” Did they just want to see if anyone was paying attention?

“The model has three principal components:
(1) A thin epidermal layer. The external surface of the integument was glabrous [= free from hair or down, smooth] with a smooth, slightly granular, or polygonal texture.

Attenuate ‘bristles’ fringed the jaws in two anurognathids and small tracts of filaments may have adorned the posterior cranium in some pterosaurs.

Perhaps these jaw and skull filaments should have been separately numbered because they are different than glabrous tissue.

(2) A layer of reticular and filamentous collagen and of variable thickness and complexity, formed much of the dermis.

Helically wound bundles of collagen fibres (aktinofibrils), were present throughout all flight patagia. Variation of aktinofibrils in terms of their dimensions, packing, orientation and stiffness permitted localized variation in the mechanical properties and behaviour of the flight patagia whichvaried from relatively stiff distally to more extensible and flexible proximally.

‘Feather-like’ structures reported in Jeholopterus appear to be partially unraveled or decayed aktinofibrils.

Again, these are all distinct tissues worthy of their own numbers.

Unwin and Martill have no idea that Jeholopterus was a vampire bat analog (Peters 2008) covered like no other pterosaur with fluffy, silent, owl-like extradermal integument. Neither Unwin nor Martill seem to make reconstructions, so neither has any idea what Jeholopterus looked like, unless they looked here (Fig. 2).

Finally, Unwin and Martill are mixing in flight membranes here. Perhaps THAT is where they get so many examples because otherwise dermal material is exceedingly rare. Integument generally means ‘covering’, so their inclusion of wing membranes is a little misleading, especially considering the ‘naked and hairless’ portion of their abstract headline.

Figure 2. Reconstruction of Jeholopterus. This owl-like bloodslurper was covered with super soft pycnofibers to make it a silent flyer.

Figure 2. Reconstruction of Jeholopterus. This owl-like bloodslurper was covered with super soft pycnofibers to make it a silent flyer.

Collagen fibre bundles were also present in footwebs, and in the integument of the neck and body. These structures have often been mis-identified as ‘hair’ (pycnofibres).

Again, this variety of tissues should have been numbered separately because they are different than tissue forming much of the dermis.

(3) A deep dermal layer with muscles fibres, blood vessels and nerves.

This variety of demal tissues were already described for the flight membranes, but it could also apply to normal tetrapod skin, like our own.

The pterosaur integument was profoundly different from that of birds and bats, further emphasizing the sharp disparity between these volant tetrapods.”

Why didn’t Unwin and Martill compare pterosaur integument to lepidosaur integument, specifically that of Sphenodon and Iguana (Fig. 3)? These are the two closest living relatives of pterosaurs in the large reptile tree. According to the LRT, Unwin and Martill are looking in the wrong places.

The spines of Iguana.

Figure 3. The dorsal and gular spines of Iguana are homologous with those in Sphenodon.

Not sure where Unwin and Martill
are getting data for pterosaur skin exclusive of the extradermal membranes. They don’t say. The dark wing Rhamphorhychus (Fig. 4) has the most incredible preservation of extradermal membranes, but the skull, neck and torso were prepared down to the bone.

Figure 1. The darkwing specimen of Rhamphorhynchus. Top: in situ. Middle: Soft tissues highlighted. Bottom: Neck and forelimb restored.

Figure 4. The darkwing specimen of Rhamphorhynchus. Top: in situ. Middle: Soft tissues highlighted. Bottom: Neck and forelimb restored.

So, why do Unwin and Martill think the Mesozoic got ugly?
Their abstract does not seem to answer their click-bait headline, which describes naked, hairless and featherless pterosaurs without giving one example of same based on evidence. On the contrary, employing phylogenetic bracketing, between Sharovipteryx (Fig. 1), Scaphognathus and Sordes (the hairy devil, Fig. 5), basal pterosaurs were not naked. Their fibers were not the same as hair or feathers, but unique to fenestrasaurs.

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.

Finally…
Why were pterosaurs considered naked by Unwin and Martill when hairy Sordes (Fig. 5) was studied by Unwin, known to Martill, and not mentioned in the abstract? Very strange, indeed coming from these two.


References
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Unwin D and Martill D 2019. When the Mesozoic got ugly – naked, hairless, (and featherless) pterosaurs. SVPCA abstracts.

New pterosaur skull from China: Nurhachius luei

Riley Black (formerly Brian Switek) wrote:
in the subhead of her Scientific American blogpost, “New pterosaur was fossilized with a ridiculous grin.”

Well… maybe,
but in situ (Fig. 1) it’s not the first or only one. And when reconstructed (Fig. 2) the grin is gone.

On the plus side,
the Aptian (Early Cretaceous) skull attributed to Nurhachius is complete, which is always wonderful, especially for such fragile skulls.

Figure 1. New Nurhachius skull in situ. Bone colors added using DGS methods. BPMC-0204

Figure 1. New Nurhachius skull in situ. Bone colors added using DGS methods. BPMC-0204. The little curved pink ridge ventral to the jugal is the displaced descending nasal process found in sister taxa. Tiny cervical ribs are present, but overlooked.

Then Black’s subhead reports, 
“A skull found in China reveals a previously unknown flying reptile.” Well, if you read the text, not really. The authors consider the new specimen congeneric with the holotype Nurhachius (Fig. 3).

FIgure 2. New Nurhachius reconstruction. Sorry,Riley, no grin. The tiny, slit-like nostril and anterior extensions of the nasal and jugal following it are shown here.

FIgure 2. New Nurhachius reconstruction. Sorry,Riley, no grin. The tiny, slit-like nostril and anterior extensions of the nasal and jugal following it are shown here.

The teeth are like those of other istiodactylids in shape and distribution,
but when you put the two Nurhachius skulls together (Fig. 3), the two are not congeneric, so far as can be determined from available data. The mandible is not as robust in the new specimen, the rostrum is not as long. There in indication of the broader rostral tip found in Istiodactylus and other istiodactylids, nor is the orbit subdivided by circumorbital processes. The referred specimen preserves post orbital and cranial bones unknown in the holotype.

Figure 3. Nurhachius ignaciobritol reconstructed to scale alongside N. luei skull. These two do not look congeneric. The authors should have shown the two together like this.

Figure 3. Nurhachius ignaciobritol reconstructed to scale alongside N. luei skull. These two do not look congeneric. The authors should have shown the two together like this.

 

The genus holotype is
Nurhachius ignaciobritoi 
(Wang, Kellner, Zhou & Campos 2005; Fig. 3) IVPP V-13288, Early Cretaceous, skull length ~30 cm, ~2.5 m wingspan). The wings are long. The free fingers and toes are tiny. The sternum portion of the sternal complex is deep.

From the abstract:
“A revised diagnosis of the genus Nurhachius is provided, being this taxon characterized by the presence of a slight dorsal deflection of the palatal anterior tip, which is homoplastic with the Anhangueria and Cimoliopterus. N. luei sp. nov. shows an unusual pattern of tooth replacement, with respect to other pterodactyloid species.”

Istiodactylus model by David Peters

Figure 4. Istiodactylus model

The phylogenetic analysis presented by Zhou et al. 2019
is not worth showing or discussing due to the inclusion of Scleromochlus (a basal bipedal croc) and the exclusion of dozens of relevant pterosaur and fenestrasaur taxa. The new Nurhachius nests in the large pterosaur tree (LPT, 240 taxa), basal to other istiodactylids, next to, but not with Nurhachius. Proximal outgroup taxa include Coloborhynchus and Criorhynchus.


References
Zhou X, Pegas RV, Leal MEC and Bonde N 2019. Nurhachius luei, a new istiodactylid pterosaur (Pterosauria, Pterodactyloidea) from the Early Cretaceous Jiufotang Formation of Chaoyang City, Liaoning Province (China) and comments on the Istiodactylidae. PeerJ 7:e7688 DOI 10.7717/peerj.7688

https://peerj.com/articles/7688/

scientificamerican.com/laelaps/new-pterosaur-was-fossilized-with-a-ridiculous-grin

The Times (UK) declares: proof for ‘winged dinosaurs’ vaulting

According to The Times.co.uk,
“Isle of Wight find proves winged dinosaurs took off by ‘vaulting’ into the air. Following the discovery of a fossilised giant pterosaur, scientists may have resolved how the 650lb beasts took flight. The sheer size of such creatures has long baffled scientists because they seem too heavy to take off. Now research with a computerised 3D model suggests they used their massive leg and wing muscles to catapult themselves into the air.”

Figure 1. Image from The Sunday Times (UK) showing the Isle of Wight and an ornithocheird filled with helium on a smaller planet taking off by vaulting.

Figure 1. Image from The Sunday Times (UK) showing the Isle of Wight and an ornithocheird filled with helium on a smaller planet taking off by vaulting. See figure 2 for the 650 lb Hatzegopteryx. The human silhouette (gray at left) is way too small for this ornithocheirid, so they got their pterosaurs mixed-up.

“Robert Coram, a professional fossil hunter who made the find, said: “It might have been the largest flying creature that had ever lived up to that time.”

“Mr Habib explained: “Mathematical modelling indicates that launching from a quadrupedal stance — pushing off first with the hind limbs and then with the forelimbs — would have provided the leaping power giant pterosaurs required for takeoff.”

FIgure 2. From The Sunday Times (UK) showing a human to scale with a restoration of Hatzegopteryx.

FIgure 2. From The Sunday Times (UK) showing a human to scale with a restoration of Hatzegopteryx.

This article appears to follow a Witton 2019 SVPCA abstract
(coincidence?) discussing the flight capabilities of the giant azhdarchid, Hatzegopteryx, using Graphic Double Integration and Principal Component Analysis. AND this article coincides with a Scientific American cover story on pterosaurs by Dr. Habib, discussed earlier here.

The pterosaur experts talking to The Times are still not discussing
the much smaller phylogenetic ancestors of azhdarchids with longer wings, nor do they consider the reduced to vestigial distal phalanges that essential clip the wings of azhdarchids over 1.8 m (6 ft) tall, nor do they recognize the traits that attend small flightless pterosaurs.

Let’s stop promoting giant volant pterosaurs
until these objections are met and resolved. Perhaps a little backtracking and apologizing for earlier grand standing is in order here.

Figure 1. Estimating giant azhdarchid weight from estimated height and comparables with similar smaller taxa.

Figure 3. Estimating giant azhdarchid weight from estimated height and comparables with similar smaller taxa.

Let’s define giant pterosaurs
as those at least 2m or 7ft tall at the eyeball (sans crest if present). The rest are large (more or less human-sized) pterosaurs (comparable to Pelagornis, Fig. 4) or smaller pterosaurs comparable to some other extant bird (e.g. goose-, robin- or hummingbird-sized).

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

Figure 4. Click to enlarge. The largest flying and non-flying birds and pterosaurs to scale.

You might remember
an earlier post featuring a classified ad from U of Leicester, (UK) seeking a student to prove the vaulting pterosaur hypothesis by finding appropriate pterosaur tracks. The Isle of Wight includes several strata with dinosaur tracks. Perhaps someday they will deliver giant pterosaur tracks that suddenly end. Then we can argue if the pterosaur flew from that point on and how it did so.


References
Witton M 2019. You’re going to need a bigger plane: body mass and flight capabilities of the giant pterosaur. SVPCA abstracts.
Counter arguments based on facts appear here:

Cryodrakon boreas: new Canadian azhdarchid: pt. 2

Hone, Habib and Therrien 2019
bring us news of several bones from several individuals of various sizes of a new mid-sized Canadian azhdarchid, Cryodrakon boreas (Fig. 1). Earlier today we looked at the promotional materials for this paper. Now, praise and criticism for the authors.

The name is excellent.
“Cryodrakon derived from the Ancient Greek for ‘cold’ and ‘dragon,’ boreas from the Greek god of the north wind. This is therefore the ‘cold dragon of the north winds.’”

The authors uncritically cite Wellnhofer 1970 who,
“suggested that the cervical vertebrae of azhdarchids elongate during ontogeny (i.e., show positive allometry). If correct, this can make identification of positions of individual vertebrae, and comparisons between specimens and taxa, difficult when specimens are small.” 

Figure 1. Click to enlarge. There are several specimens of Zhejiangopterus. The two pictured in figure 2 are the two smallest above at left. Also shown is a hypothetical hatchling, 1/8 the size of the largest specimen.

Figure 1. There are several specimens of Zhejiangopterus. The two pictured in figure 2 are the two smallest above at left. Also shown is a hypothetical hatchling, 1/8 the size of the largest specimen.

Unfortunately,
this reliance on citation shows the authors’ lack of understanding about pterosaur isometric (lepidosaur-like) growth patterns, proven by the several growth series demonstrated in the azhdarchid, Zhejiangopterus (which they cite, Fig. 1), Rhamphorhynchus (the subject of a rejected paper), and Pterodaustro (not to mention the several pterosaur embryos known).

The authors discuss a very large cervical mid-shaft,
TMP 1980.16.1367, but do not show it. Dang.

The most complete specimen of Cryodrakon
TMP 1992.83 includes several disarticulated bones (Fig. 2) here reduced to x.70 to match tibias to scale with Quetzalcoatlus sp.

Figure 2. The most complete Cryodrakon compared to the most complete Q. sp. Most elements are identical in size when scaled x.70 to match tibia lengths, but the cervical, metatarsal and humerus are relatively smaller in Cryodrakon.

Figure 2. The most complete Cryodrakon compared to the most complete Q. sp. Most elements are identical in size when scaled x.70 to match tibia lengths, but the cervical, metatarsal and humerus are relatively smaller in Cryodrakon.

Bone thickness
The authors report, “A break in the humerus of Quetzalcoatlus sp. (TMM 47180) reveals that cortical bone thickness [1.07mm] is near identical to that of Cryodrakon [1.1-1.3mm] (for which cortical bone thickness data were obtained by computed tomography [CT] imaging).” Note that the cortical thickness ratio (x 0.82) nearly matches the scale difference x 0.70). Fact: Large flightless azhdarchids are not evolving more solid bones, distinct from giant flightless birds.

Back to the humerus
The authors report, “Overall, the humeri of Cryodrakon and Quetzalcoatlus are quite similar, varying in most proportions within the range that would be expected for intraspecific comparisons.” The images of both (Fig. 2) do not support that statement. The authors conclude, “The greatest difference in overall shape is the slightly exaggerated flaring of the humerus distally in Quetzalcoatlus.” 

You decide what the differences are.
The authors should have showed the two humeri side-by-side.

Flight
The authors report, “These similarities confirm that Cryodrakon and Quetzalcoatlus were likely of very similar size and build, and the two species likely shared similar flight performance characteristics and flight muscle fractions.” This assumes that azhdarchids of this size could fly, regardless of the vestigial distal wing phalanges (= clipped wings) that argue against that hypothesis in Q. sp. (Fig. 2; wingtip unknown in Cryodrakon).

Weight
The authors report, “Combined with the somewhat greater length of the humerus in Cryodrakon, it is likely that Cryodrakon was slightly heavier than Quetzalcoatlus but that their overall mass was likely similar.” Yes! True? But not so fast. Scaled to a similar tibia, pteroid and metacarpal length, the feet, neck and humerus were all smaller (Fig. 2). Then remember: to achieve that scale Cryodrakon was reduced to x 0.70 from its original size. So Cryodrakon had big legs, big hands, small feet (used as twin rudders in smaller taxa), a slender humerus… not really the traits you’re looking for in a volant pterosaur (by comparison, see Jidapterus below). Finally, weight is never the issue if you have plenty of thrust and lift. But those two factors are reduced in large azhdarchids, all of which had clipped wings (vestigial distal phalanges).

Cervical comparisons and bauplan
The authors report, “The cervical vertebrae of Cryodrakon are absolutely more robust than those of Quetzalcoatlus.” No. They are relatively smaller (Fig. 2). See for yourself.

It really does help to follow the scale bars,
placing the bones upon a good Bauplan (blueprint) to see how incompletely known taxa compare to more completely known taxa. This last graphic step is something the authors did not provide or experiment with. If they had done so, they would not come to such conclusions. The referees (Drs. Martill, Naish and Bever) could also have raised these issues or suggested graphic experiments (Fig. 2).

Cladistic analysis
The authors report, “The fragmentary nature of the material available, and possible ontogenetic trajectories, prevents us from conducting a cladistic analysis to determine the phylogenetic relationships of Cryodrakon boreas. Nevetheless, certain characteristics permit a preliminary assessment of the phylogenetic position of the taxon within Azhdarchidae. For example, it does lack distinct cervical zygapophyses for the middle cervicals, a trait that suggests that it does not lie within basal-most Azhdarchidae, but instead within the Jidapterus-Quetzalcoatlus clade.”

Figure 1. Jidapterus compared to the new Lower Cretaceous pterosaur tracks. It's a pretty close match.

Figure 3. Jidapterus compared to the new Lower Cretaceous pterosaur tracks. It’s a pretty close match.

Since the authors brought up Jidapterus
it is worth our while to see for ourselves the relative size of its humerus and wing in this small azhdarchid (Figs. 3,4). Note the relatively larger humerus in Jidapterus. Only wing phalanx 4.4 is shorter here, with a folded wing that extends higher than the shoulder girdle, distinct from the much larger flightless azhdarchids.

Azhdarchids and Obama

Figure 4. Click to enlarge. Here’s the 6 foot 1 inch President of the USA alongside several azhdarchids and their predecessors. Most were knee high. The earliest examples were cuff high. The tallest was twice as tall as our President. This image replaces an earlier one in which a smaller specimen of Zhejiangopterus was used.

Jidapterus and Chaoyangopterus represent the transitional ‘end of the road’
for flying in azhdarchids. What follows (Fig. 4) are shorter distal wings and much larger flightless taxa.

Let’s put an end to the myth
that large azhdarchids were the largest flying animals of all time, a myth promoted by pterosaur paleontologists who should know better, but have staked their professional reputations on showmanship (rather than science).  We still have long-winged pteranodontids and ornithocheirids to compete with long-winged Pelagoris, among the largest bird aviators. That’s the Bauplan nature insists on if you’re a big flyer.


References
Hone DWE, Habib MB and Therrien F 2019. Cryodrakon boreas, gen. et sp. nov., a Late Cretaceous Canadian azhdarchid pterosaur. Journal of Vertebrate Paleontology Article: e1649681 DOI: 10.1080/02724634.2019.1649681

www.nationalgeographic.com
www.newsweek.com

Cryodrakon boreas: new Canadian azhdarchid

Hone, Habib and Therrien 2019
bring us news of several bones from several individuals of various sizes of a new Canadian azhdarchid, Cryodrakon boreas (Fig. 1).

From the NatGeo webpage:
“For a long time [30+ years] paleontologists had instead assumed that the fossils belonged to a pterosaur called Quetzalcoatlus northropi [Figs. 1, 2], says study coauthor Dave Hone, a paleontologist at Queen Mary University of London.”

Figure 1. Cryodrakon humerus compared to Q sp. specimen (the small one). Yes, they are different. Zhejiangopterus also has a straight humerus shaft.

Figure 1. Cryodrakon humerus compared to Q sp. specimen (the small one). Yes, they are different. Zhejiangopterus also has a straight humerus shaft.

Here it took less than 2 minutes
to compare the humerus of Cryodrakon to that of Quetzalcoatlus (Fig. 1). Yes, they are different. Zhejiangopterus (Fig. 3) also has a straight humerus, like that of Cryodrakon.

Figure 1. Estimating giant azhdarchid weight from estimated height and comparables with similar smaller taxa.

Figure 2. Estimating giant azhdarchid weight from estimated height and comparables with similar smaller taxa.

From the Royal Tyrrell Museum webpage:
“The partial skeleton represents a young animal with a wingspan of about five metres, but one isolated giant neck bone from another specimen suggests that Cryodrakon could have reached a wingspan of around 10 metres when fully grown.”

Partial skeleton =
part of the wings, legs, neck and a rib. So, not a lot, but enough.

Figure 2. The large azhdarchid pterosaur, Zhejiangppterus. is shown walking over large pterosaur tracks matched to its feet from Korea (CNUPH.p9. Haenamichnus. (Hwang et al. 2002.)

Figure 3. The large azhdarchid pterosaur, Zhejiangppterus. is shown walking over large pterosaur tracks matched to its feet from Korea (CNUPH.p9. Haenamichnus. (Hwang et al. 2002.) On second look, perhaps less elbow and knee bend here.

Looking forward to learning more
about Cryodrakon after reading the paper. All the above comes from online promotional materials.


References
Hone DWE, Habib MB and Therrien F 2019. Cryodrakon boreas, gen. et sp. nov., a Late Cretaceous Canadian azhdarchid pterosaur. Journal of Vertebrate Paleontology Article: e1649681 DOI: 10.1080/02724634.2019.1649681

www.nationalgeographic.com
www.newsweek.com

Meet Seazzadactylus, the newest Late Triassic pterosaur

Dalla Vecchia 2019 introduces us to
Seazzadactylus venieri (Figs. 1–3; MFSN 21545), a small Late Triassic pterosaur known from a nearly complete, disarticulated skeleton (Fig. 2). The tail is supposed to be absent, but enough is there to show it was very gracile. The gracile feet are supposed to be absent, but they were overlooked. The rostrum was artificially elongated, but a new reconstruction (Fig. 3) takes care of that. A jumble of tiny bones in the throat (Fig. 4) were misidentified as a theropod-like curvy ectopterygoid, but the real ectopterygoid fused to the palatine as an L-shaped ectopalatine was identified (Figs. 3,4). 

Figure 1. Seazzadactylus nests between the two Austriadactylus specimens in the LPT.

Figure 1. Seazzadactylus (at far right) nests between the two Austriadactylus specimens in the LPT.

Seazzadactylus is a wonderful find,
and DGS methodology (Fig. 1) pulled additional data out of it than firsthand observation, which was otherwise quite thorough (with certain exceptions).

Figure 2. Seazzadactylus in situ and tracing from Dalla Vecchia 2019. Colors added here.

Figure 2. Seazzadactylus in situ and tracing from Dalla Vecchia 2019. Colors added here.

Dalla Vecchia reports

  1. The premaxillary teeth are limited to the front half of the bone. Dalla Vecchia did not realize that is so because, like other Triassic pterosaurs, the premaxilla forms the ventral margin of the naris, dorsal to the maxilla (Fig. 3).
  2. A misidentified theropod-like ectopterygoid and pterygoid. Dalla Vecchia should have known no pterosaur has an ectopterygoid shaped like this. Rather the curvy shape represents a jumble of bones (Fig. 4). The real ectopalatine in Seazzadactylus has the typical L-shape (Figs. 3, 4) found in other pterosaurs.
  3. The scapula is indeed a distinctively wide fan-shape.
  4. The proximal caudal vertebrae are present, as are several more distal causals. All are tiny.
Figure 3. Seazzadactylus reconstructed using DGS methods.

Figure 3. Seazzadactylus reconstructed using DGS methods. No such reconstruction was produced by Dalla Vecchia. This is a primitive taxon precocially and by convergence displaying several traits found in more derived taxa.

Figure 4. Seazzadactylus bone jumble, including the L-shaped ectopalatine (orange + tan).

Figure 4. Seazzadactylus bone jumble, including the L-shaped ectopalatine (orange + tan). No pterosaur has a theropod-like ectopterygoid. That’s a loose jumble of bone spurs and shards.

It is easy to see how mistakes were made.
Colors, rather than lines tracing the bones, would have helped. Using a cladogram with validated outgroup taxa and more taxa otherwise were avoided by Dalla Vecchia for reason only he understands.

Figure 5. Seazzadactylus pectoral girdle.

Figure 5. Seazzadactylus pectoral girdle.

Phylogenetically Dalla Vecchia reports,
Macrocnemus bassaniiPostosuchus kirkpatricki and Herrerasaurus ischigualastensis were chosen as outgroup taxa.” (Fig. 6)

Funny thing…
none of these taxa are closely related to each other or to pterosaurs (Macrocnemus the possible distant exception) in the large reptile tree (LRT, 1549 taxa) where no one chooses outgroup taxa for pterosaurs. PAUP makes that choice from 1500+ candidates.

Figure 5. Cladogram by Dalla Vecchia 2019 showing where Seazzadactylus nests

Figure 6. Cladogram by Dalla Vecchia 2019 showing where Seazzadactylus nests. Their is little to no congruence between this cladogram and the LPT (subset Fig. 7), exception in the anurognathids. This cladogram needs about 200 more taxa to approach the number in the LPT.

Within the Pterosauria,
Dalla Vecchia nests his new Seazzadactylus between Austriadraco and Carniadactylus within a larger clade of Triassic pterosaurs that does not include Preondactylus, Austriadactylus or Peteinosaurus. Dalla Vecchia’s cladogram includes 27 taxa (not including the above mentioned outgroup taxa). In the large pterosaur tree (LPT, 239 taxa) Austriadraco (BSp 1994, Fig. 8) is a eudimorphodontid basal to all but two members of this clade. Carniadactylus (Fig. 8) is a dimorphodontid closer to Peteinosaurus. So there is little to no consensus between the two cladograms.

Figure 7. Subset of the LPT focusing on Triassic pterosaurs.

Figure 7. Subset of the LPT focusing on Triassic pterosaurs and their many LRT validated outgroups.

Publishing in PeerJ may cost authors $1400-$1700 (or so I understand).
Dalla Vecchia asked his Facebook friends for monetary help to get this paper published. I offered $900, but only on the proviso that the traditional outgroup taxa (listed above and unknown to me at the time) not be employed. You can understand why I cannot support those invalidated (Peters 2000) outgroups. Dr. Dalla Vecchia’s rejected my offer with a humorless invective of chastisement that likened my offer to one traditionally made by the Mafia. A more polite, ‘no thank-you,’ would have sufficed. Just today I learned of Dalla Vecchia’s ‘chosen’ outgroups (see list above). Kids, that’s not good science.

Figure 6. Seazzadactylus sister taxa in the Dalla Vechhia 2019 cladogram to scale.

Figure 8. Seazzadactylus sister taxa in the Dalla Vechhia 2019 cladogram to scale.

Bottom line:
A great new Triassic pterosaur! We’ll hash out the details as time goes by.


References
Dalla Vecchia FM 2019. Seazzadactylus venieri gen. et sp. nov., a new pterosaur (Diapsida: Pterosauria) from the Upper Triassic (Norian) of northeastern Italy. PeerJ 7:e7363 DOI 10.7717/peerj.7363
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.

A new cat-sized flightless azhdarchoid from Canada

Martin-Silverstone, Witton, Arbour and Currie 2019 bring us
news of a humerus and several vertebrae (some fused into a notarium) they taxonomically narrow down to a cat-sized Campanian (Late Cretaceous) azhdarchoid pterosaur. It was found on Hornsby Island, close to the much larger Victoria Island in Southwestern Canada.

The authors report,
“the individual was approaching maturity at time of death.”

In their discussion, the authors state:
“The thin bone walls, gracile bone construction and humeral morphology of RBCM.EH.2009.019.0001, indicate it clearly belonged to a volant Mesozoic animal, a pterosaur or avialan.”

There’s not much to see or reconstruct here.
The few bones found are fragments still in the matrix. The link below will take you to the online PDF.

On closer inspection,
the small triangular deltopectoral crest is smaller than in flightless pterosaurs (e.g. Sos2428 in Fig. 1) and the bone is thicker than one might expect of a volant pterosaur. The authors do not consider the possibility that their specimen had a volant ancestry, but was itself no longer volant, as happens often enough in the azhdarchid line of wading pterosaurs. Some were tiny (Fig. 1), some cat-sized, some man-sized and others much larger. Some were volant. Others were not, convergent with birds of all sizes.

Figure 2. The flightless pterosaur, Sos 2428, along with two ancestral taxa, both fully volant. Note the reduction of the wing AND the expansion of the torso. We don't know the torso of Q. northropi. It could be small or it could be very large.

Figure 1. The flightless pre-azhdarchid pterosaur, Sos 2428, along with two ancestral taxa, both fully volant. Note the reduction of the wing AND the expansion of the torso. This deltopectoral crest is at least twice the size of the new Canadian specimen

Dr. Witton has invested much time and treasure
in telling us giant azhdarchids were volant, despite the facts that weigh against that hypothesis. He also omits the data on three flightless pterosaurs, including Sos2428 (Fig. 1). Now we can add a fourth, his new cat-sized Hornby Island pterosaur.

Earlier co-author Witton
and Habib 2010 discussed hypothetical flightlessness in giant azhdarchids from many angles, but never introduced actual flightless taxa, two of which were known at the time. This online paper included infamous illustrations of an ornithocheirid manus in the process of a quadrupedal launch that had been cheated to implant the wing finger on the substrate, something that never happens according to the ichnite record. They did this by shrinking the free fingers.

Quetzalcoatlus running like a lizard prior to takeoff.

Figure 2. Quetzalcoatlus running like a bipedal lizard with no need or ability to fly.

Postscript
Interesting blog post here on an unfortunate bone misidentification on a paper earlier by one of the co-authors. Thank goodness Witton chose not to vilify his co-author.


References
Martin-Silverstone E, Witton MP, Arbour VM and Currie PJ 2019. A small azhdarchoid pterosaur from the latest Cretaceous, the age of flying giants. Royal Society open science 3: 160333. http://dx.doi.org/10.1098/rsos.160333
Witton MP, Habib MB 2010. On the Size and Flight Diversity of Giant Pterosaurs, the Use of Birds as Pterosaur Analogues and Comments on Pterosaur Flightlessness. PLoS ONE 5(11): e13982. https://doi.org/10.1371/journal.pone.0013982