First pterosaur basihyal (Gladocephaloideus?, Gallodactylidae?)

Jiang, Li, Cheng and Wang 2020 bring us
the first evidence of a tiny medial hyoid bone, the basihyal (Fig.1; IVPP V 14189). Comparisons were made to “scavenger crows rather than chameleons.” Other pterosaurs have hyoids, but, until now, not a basihyal. Really, that’s all the authors needed to say. The rest of what they presented was filler, little of it accurate or valid.

Figure 1. Images from Zheng et al. 2020 scaled, rotated and layered. This is all that is known of this specimen. Micro -CL image shows hollow basihyal.

Figure 1. Images from Jiang et al. 2020 scaled, rotated and layered. This is all that is known of this specimen. Micro -CL image shows hollow basihyal.

Overlooked by the authors,
Cosesaurus (Fig. 2), Sharovipteryx, Kyrgyzsaurus and Longisquama also have hyoids  The authors considered their specimen close to Gladocephaloideus (Fig. 3), which they considered a gallodactylid. Here Gladocephaloides nests with Gegepterus, a ctenochasmatid.

Figure 2. Cosesaurus nasal crest (in yellow).

Figure 2. Cosesaurus hyoids in bright green.

Jiang et al. 2020 presented a greatly simplified cladogram
of pterosaur interrelationships… so simplified that it bears little resemblance to a more complete pterosaur cladogram. Kryptodrakon (junior synonym for Sericipterus) was misspelled Kryptondrakon.

Figure 1. Gladocephaloideus (the holotype) compared to the new specimen referred to Gladocephaloideus and its two sister taxa in the large pterosaur tree. Long necks in ctenochasmatids made several appearances by convergence.  Of particular interest, note the size of the pelvis in the JPM specimen, no larger than that of the much smaller MB.R. specimen. Lü et al considered the pelvis incomplete and it may be. Sister taxa are illustrated here from figure 2.

Figure 3. Gladocephaloideus (the holotype) compared to the new specimen referred to Gladocephaloideus and its two sister taxa in the large pterosaur tree. Long necks in ctenochasmatids made several appearances by convergence.  Of particular interest, note the size of the pelvis in the JPM specimen, no larger than that of the much smaller MB.R. specimen. Lü et al considered the pelvis incomplete and it may be. Sister taxa are illustrated here from figure 2.

According to Jiang et al.
“The hyoids of primitive non-pterodactyloids only include the preserved ceratobranchials; this rod-like element is slender and quite long relative to the skull length. The ceratobranchial/skull length ratio is similar to most extant reptiles.” OK. Good to know.


References
Jiang S-X, Li Z-H, Cheng X and Wang X-L 2020. The first pterosaur basihyal, shedding light on the evolution and function of pterosaur hyoid apparatuses. DOI 10.7717/peerj.8292

Could this azhdarchid eat this baby dinosaur?

Artist and paleontologist Mark Witton, U of Portsmouth,
published an iconic image of an azhdarchid pterosaur biting a baby sauropod prior to eating and digesting it (Fig. 1, Witton and Naish 2008). While biting a baby dinosaur in this fashion certainly was possible, could this azhdarchid swallow and digest it? Let’s see.

Figure 1. Above: original art from artist M Witton showing azhdarchid biting baby sauropod. Below: Azhdarchid organs including stomach (green) do not appear to be able accommodate such a large meal. Gastralia prevent ventral expansion.

Figure 1. Above: original art from artist M Witton (Witton and Naish 2008) showing azhdarchid biting baby sauropod. Below: Azhdarchid organs including stomach (green) do not appear to be able accommodate such a large meal. Gastralia prevent ventral expansion.

A skeletal view of the same azhdarchid
to the same scale (Fig. 1 below) shows the approximate lungs (blue), heart (red), liver (brown), stomach (green), intestines (pink), kidneys (red brown) and bladder (yellow) along with the same  baby dinosaur reduced slightly due to perspective. The wing membranes are also repaired. The tiny sternum is shown on the chest of the biting azhdarchid, another factor in giant azhdarchid flightlessness.

Based on the given parameters
the azhdarchid stomach (green) does not appear to be able to accommodate such a large meal all at once.

The analogous saddle-billed stork
(Ephippiorhynchus senegalensis, Fig. 2) eats what appears to be a similar-sized meal, but note the abdomen of the bird is relatively much larger than that of the azhdarchid and the meal is relatively smaller, much more flexible, without limbs, largely meat/muscle content and wet. Unfortunately Witton and Naish did not consider stomach size in their PlosOne paper.

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 2. In my opinion this saddle-bill stork (genus: Ephippiorhynchus) wading in water appears to be the bird closest to azhdarchid morphology and, for that matter, niche.

An alternative wading lifestyle,
(Figs. 2, 3) dismissed by Witton and Naish 2008, appears to be more appropriate, based on the stomach size and other wading stork-like traits evidenced by azhdarchids. In LiveScience.com writer Jeanna Bryner (link below) wrote, ‘Witton and Naish learned that more than 50 percent of the azhdarchid fossils had been found inland. Other skeletal features, including long hind limbs and a stiff neck, also didn’t fit with a mud-prober or skim-feeder. All the details of their anatomy, and the environment their fossils are found in, show that they made their living by walking around, reaching down to grab and pick up animals and other prey,” Naish said.

“Their tiny feet also ruled out wading in the water or probing the soft mud for food. “Some of these animals are absolutely enormous,” Witton told LiveScience. “If you go wading out into this soft mud, and you weigh a quarter of a ton, and you’ve got these dinky little feet, you’re going to just sink in.”

Quetzalcoatlus neck poses. Dipping, watching and displaying.

Figure 3. Quetzalcoatlus neck poses. Dipping, watching and displaying.

We don’t know how soft the mud was
wherever azhdarchids fed. Analogous herons and storks seem to deal with underwater mud very well with similarly-sized feet. Witton and Naish report, Some storks with relatively small feet are known to wade indicating that azhdarchids may have been capable of some wading activity, but the high masses of large azhdarchids may have limited their ability to wade on soft substrates. Moreover, other pterodactyloids with larger pedal surface areas (most notably ctenochasmatoids) were almost certainly better adapted waders than azhdarchids. In view of this evidence, we suggest that azhdarchids were not habitual, although perhaps faculatative, waders.”

Don’t you wish the authors had performed some sort of test
to show azhdarchids were not like storks? Perhaps they could have employed a tank full of water and a variety of mud-like, sand-like and pebble-like substrates with a model azhdarchid foot and hand (btw, halving the weight of the azhdarchid directed through the feet) pressed with increasing weight to gauge the amount of sink. Instead they relied on their imaginations and made suggestions based on their initial bias. Nor did they discuss the factor of the hands supporting half the weight, nor the possibility of floating on the surface, polling with the hands and feet (Fig. 4), producing manus-only tracks, which are documented.

Witton and Naish did not attempt to show the maximum size of an object an azhdarchid stomach could handle, shown above (Fig. 1). In hindsight, that would have negated their dinosaur-killer hypothesis and the reason for their paper.

Figure 1. The azhdarchid pterosaur Quetzalcoatlus floating and poling producing manus only tracks.

Figure 4. The azhdarchid pterosaur Quetzalcoatlus floating and poling producing manus only tracks.

Witton and Naish 2008 report,
“Scavenging storks and corvids manage to open carcasses quickly and bite off pieces of flesh without the aid of curved jaw tips. Therefore, it seems almost certain that azhdarchids would have been capable of feeding upon at least some elements of large carcasses, although their long skulls and necks would inhibit their ability to obtain flesh from the deepest recesses of a corpse. However, although carrion was a likely component of azhdarchid diets, they possess no anatomical features to suggest they were obligate scavengers.”

Now you can ask,
did this azhdarchid (Fig. 1) kill this baby sauropod and then pick the meat from the bone? It is important to consider this and other possibilities. If so, the best meat would have come from the base of the tail and proximal limbs, not the neck or ‘breast.’

Azhdarchids and Obama

Figure 5. 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.

Phylogenetically
what azhdarchids did ever since they were the size of tiny pterodactylids (Fig. 5) in the Late Jurassic is nibbling on bottom-dwelling prey. Larger, older, later azhdarchids were able to feed further out from shore in deeper ponds than smaller taxa and younger azhdarchids.  Witton and Naish did not discuss azhdarchids in a phylogenetic context evolving from tiny wading taxa. That is unfortunate because phylogeny is the backstory that informs every taxon. Phylogeny solves so many issues. That’s why the LRT and LPT (large pterosaur tree) could be so important for paleo workers, but, so far, they prefer not to use it.

Still struggling,
Witton and Naish began their 2015 introduction with, “Azhdarchids are among the most aberrant and remarkable of pterodactyloid pterosaurs.” Not really, As figure 5 shows, azhdarchids were simply larger versions of their small to tiny Late Jurassic ancestors, some of whom were also flightless waders.


References
Witton MP and Naish D 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS ONE 3(5): e2271. https://doi.org/10.1371/journal.pone.0002271
Witton MP and Naish D 2015. Azhdarchid pterosaurs: water-trawling pelican mimics or “terrestrial stalkers”?. Acta Palaeontologica Polonica, 60(3), 651-660

Seems everyone bought into this invalid hypothesis:
https://www.livescience.com/
https://www.theguardian.com

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

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

Quetzalcoatlus wingspan compared to other azhdarchids

There are those who think
the giant azhdarchid pterosaur, Quetzalcoatlus (Fig. 1), was flightless. Almost all others think Quetzalcoatlus was the largest flying animal of all time. The question is: were the wings of Quetzalcoatlus large enough to initiate and sustain flight?

Sometimes it just helps to compare
azhdarchids to azhdarchids to azhdarchids. In this case we’ll compare Quetzalcoatlus in dorsal view to two azhdarchids so small that traditional paleontologists don’t even consider them to be azhdarchids. BSPG 1911 I 31, (Figs. 2, 3) is a traditional, small volant pterosaur with a long neck and a standard pterosaur wingspan. JME-Sos 2428 (Fig. 2) is an odd sort of flightless pterosaur with a very much reduced wingspan. Neither of these taxa seems to ever make it to the cladograms of other workers.

Figure 1. Quetzalcoatlus in dorsal view compared to two much smaller azhdarchids from the Solnhofen formation, JME-Sos 2428, a flightless pterosaur, and BDPG 1911 I 31, a volant pterosaur. The wingspan of Quetzalcoatlus does not match that of the much smaller azhdarchid, so perhaps the giant was unable to fly. At least, this is the evidence for flightlessness.

Figure 1. Quetzalcoatlus in dorsal view compared to two much smaller azhdarchids from the Solnhofen formation, JME-Sos 2428, a flightless pterosaur, and BDPG 1911 I 31, a volant pterosaur. The wingspan of Quetzalcoatlus does not match that of the much smaller azhdarchid, so perhaps the giant was unable to fly. At least, this is the evidence for flightlessness.

When you compare azhdarchids to azhdarchids to azhdarchids
you get the overwhelming impression that IF Quetzalcoatlus was volant, it would not have reduced the distal wing phalanges so much. And yet it did, just like other flightless pterosaurs did. Since weight increases by the cube as size in dorsal view increases by the square, the wings of the giant should actually be larger than those of the smaller azhdarchid to handle the relatively larger mass.

So what did Quetzalcoatlus use its flightless wings for?
Thrust (Fig. 2).

Quetzalcoatlus running like a lizard prior to takeoff.

Figure 2. Quetzalcoatlus running like a lizard prior to takeoff. Click to animate.

Quetzalcoatlus and its ancestor, no 42, note scale bars.

Fig. 3. Quetzalcoatlus and its ancestor, BSPG 1911 I 31, note scale bars. At 72dpi, the pterosaur on the left is nearly full scale on a monitor. The one on the right is as tall as a tall human, with giant relatives more than doubling that height. 

Contra tradition, the azhdarchid bauplan
was initiated with Late Jurassic small pterosaurs like BSPG 1911 I 31, so misbegotten  that traditional paleontologists have forgotten to give it its own generic and specific name distinct from the wastebasket taxon Pterodactylus, with which it is not related, as we learned earlier here.


References
Kellner AWA and Langston W 1996. Cranial remains of Quetzalcoatlus (Pterosauria, Azhdarchidae) from late Cretaceous sediments of Big Bend National Park, Texas. – Journal of Vertebrate Paleontology 16: 222–231.
Lawson DA 1975. Pterosaur from the latest Cretaceous of West Texas: discovery of the largest flying creature. Science 187: 947-948.
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. PloS one, 5(11), e13982.

More data here: why-we-think-giant-pterosaurs-could-fly-not/

wiki/Quetzalcoatlus

New pterosaur: Keresdrakon. Old cladogram.

Kellner et al. 2019
bring us a new desert pterosaur, Keresdrakon (Fig. 1). The bone is exceptionally preserved, similar to red bed Gobi Desert specimens from the Late Cretaceous. The exact age of the strata is “controversial.”  Kellner et al. nest their new specimen between Dsungaripteridae + Shenzhoupterus and Tapejaridae (omitting the unrelated Chaoyangopteridae + Azhdarchidae, see below).

From the abstract:
“Here we present a new tapejaromorph flying reptile from this site, Keresdrakon vilsoni gen. et sp. nov., which shows a unique blunt ridge on the dorsal surface of the posterior end of the dentary. Morphological and osteohistological features indicate that all recovered individuals represent late juveniles or sub-adults. This site shows the first direct evidence of sympatry in Pterosauria. The two distinct flying reptiles coexisted with a theropod dinosaur, providing a rare glimpse of a paleobiological community from a Cretaceous desert.”

Sympatry: “Occupying the same or overlapping geographic areas.” I have used the term ‘coeval’ to represent taxa from a similar formation (location and strata).

The same desert strata ‘cemetary of pterosaurs’
produced many partial specimens and several ontogenetic ages of the tapejarid, Caiuajara, which we looked at earlier here.

Figure 1. The larger bits and pieces of Keresdrakon. The bone is like bone, clearly distinct from the matrix.

Figure 1. The larger bits and pieces of Keresdrakon. The bone is like bone, clearly distinct from the desert matrix.

Unfortunately
Kellner et al. have excluded so many pterosaur taxa from their cladogram that it does not recover the four origins of pterodactyloid-grade pterosaurs known for the last 12 years (Peters 2007) and documented online in the large pterosaur tree (LPT, 239 taxa). Instead the authors follow the traditional, invalidated hypothesis that includes a monophyletic and awkward ‘Pterodactyloidea.’ that is only recovered by taxon exclusion.

Remember, 
dsungaripterids, tapejarids and pteranodontids all arise from various germanodactylids, which arise from pterodactylids, which arise from a branch of tiny scaphognathids. Ornithocheirds + cycnorhamphids arise from other tiny scaphognathids. Ctenochasmatids arise from one branch of dorygnathids. Azhdarchids arise from yet another branch of dorygnathids. All had tiny transitional pterosaur ancestors. Sadly, this is completely lost on the Kellner team, who have chosen to omit pertinent taxa from their analyses.

Otherwise
their topology is similar enough to the LPT. I have not yet entered Keresdrakon into the LRT. If the nesting differs from that of Kellner et al. (above), I will post that.


References
Kellner AWA, Weinschuütz LC, Holgado B, Bantim RAM and Sayão JM  2019. A new toothless pterosaur (Pterodactyloidea) from Southern Brazil with insights into the paleoecology of a Cretaceous desert. Anais da Academia Brasileira de Ciências (2019) 91(Suppl. 2): e20190768 (Annals of the Brazilian Academy of Sciences).
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.

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 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