Liaodactylus, a new gnathosaurine pterosaur

Figure 1. Liaodactylus (in color in in situ compared to Gnathosaurus.

Figure 1. Liaodactylus (in color in in situ compared to Gnathosaurus. The portion of the rostrum above the antorbital fenestra remains unknown. A short crest may or may not have been present.

Liaodactylus primus (Zhou et al. 2017) was considered the earliest filter-feeding pterosaur. Here it nests with the Solnhofen specimen of Gnathosaurus. Distinctly, Liaodactylus has short premaxillary teeth and longer dentary teeth than maxillary teeth. The skull was small, only half the length of Gnathosaurus, but with similar proprotions. The jugal was not elevated and so did not shrink the orbit.

FIgure 2. Subset of the large pterosaur cladogram focusing on the clade Dorygnathia and the clade within it, the Ctenochasmatidae.

FIgure 2. Subset of the large pterosaur cladogram focusing on the clade Dorygnathia and the clade within it, the Ctenochasmatidae. Here Liaodactylus nests as a sister to Gnathosaur, a basal ctenochasmatid.

Zhou et al. did not provide
a specimen-based phylogenetic analysis. but used only one taxon for each genus and so missed out on the gradual accumulation of traits that nested Liaodactylus with Gnathosaurus. Instead they nested it with Ctenochasma.

Zhou et al. used the data matrix
of Andres, Clark and Xu 2004, which nested Kryptodrakon as the basalmost pterodactyloid. As we learned earlier, those authors reconstructed the few bits and pieces of Kryptodrakon as a small Pterodactylus-like pterosaur, when it should have been reconstructed as a larger, but very gracile Sericipterus, which was found in the same deposits, but would not have made so many headlines.

References
Andres B, Clark JM and Xu X 2010.A new rhamphorhynchid pterosaur from the Upper Jurassic of Xinjiang, China, and the phylogenetic relationships of basal pterosaurs, Journal of Vertebrate Paleontology 30: (1) 163-187.
Andres B, Clark J and Xu X 2014. The Earliest Pterodactyloid and the Origin of the Group. Current Biology (advance online publication)
DOI: http://dx.doi.org/10.1016/j.cub.2014.03.030
Zhou C-F, Gao K-Q, Yi H, Xue J, Li Q and Fox RC 201. Earliest filter-feeding pterosaur from the Jurassic of China and ecological evolution of Pterodactyloidea. R. Soc. open sci. 4: 160672. http://dx.doi.org/10.1098/rsos.160672

 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

You heard it here first: no gender differences detected in pterosaur pelves

A new paper on wukongopterid crests
(Cheng et al. 2017) reports, “We also show that there is no significant variation in the anatomy of the pelvis of crested and crestless specimens. We further revisit the discussion regarding the function of cranial structures in pterosaurs and argue that they cannot be dismissed a priori as a valuable tool for species recognition.”

The subject of gender differences
in pterosaur pelves was examined here, here and here. While the subject of gender differences in pterosaur crests was examined here, here and here in previous posts going back several years (Fig. 1).

Female Pteranodon?

Figure 3. Pteranodon (left) and Nyctosaurus (right) pelves. KUVP 933 (I)  is closer to Nyctosaurus in morphology. It is not a female Pteranodon. It belongs to a big Nyctosaurus. Note the HUGE individual variation presented here among putative congeneric specimens.

Nice to see published work
rejecting the hypotheses by Bennett 1992 that linked crest size to pelvic canal size. Bennett did not realize the large opening pelvis was that of a large nyctosaurid (Fig. 1), as in all specimens of Nyctosaurus. Cheng et al. report, “there is no direct association of the skulls and pelves that could back this hypothesis (e.g., Kellner and Tomida 2000). Re-evaluation of several specimens attributed to Pteranodon has shown that in some cases there are sufficient morphological differences other than the shape and size of the cranial crest, supporting a larger taxonomic diversity within what can be called the Pteranodon-complex (Kellner 2010).” Here (Fig. 2) smaller more primitive Pteranodon specimens have smaller crests, just as smaller more primitive tapejarids do.

Figure 2. The Tanking-Davis specimen compared to other forms. Specimen w and specimen z appear to be the closest to the Tanking-David specimen. Specimen 'w' = Pteranodon sternbergi? USNM 12167 (undescribed). Specimen 'z' = Pteranodon longiceps? Dawndraco? UALVP 24238. Click to enlarge.

Figure 2. The Tanking-Davis specimen compared to other forms. Specimen w and specimen z appear to be the closest to the Tanking-David specimen. Specimen ‘w’ = Pteranodon sternbergi? USNM 12167 (undescribed). Specimen ‘z’ = Pteranodon longiceps? Dawndraco? UALVP 24238. Click to enlarge.

Then there is the Hamipterus association…

According to Cheng et al. “Hamipterus tianshanensis bears a  premaxillary crest that, in similar sized individuals, showed consistently two distinct morphotypes: one with larger and more robust crests, and the second with smaller and more delicate crests. These morphotypes were tentatively regarded as males and females, respectively (Wang et al. 2014a). This occurrence constitute, to our knowledge, the best argument favoring sexual dimorphism expressed by cranial crests.” Of course these could be different ages, alpha and beta individuals (= individual variation leading to rapid phylogenetic changes), tribes (familial clades), or male and female. Pterosaurs have been competing for mating privileges since before they had wings, in Cosesaurus, for instance.

And there is Caiuajara
where Cheng et al. report, “Caiuajara (admittedly very distantly related to the Wukongopteridae), there seems a continuum in the appearance and development of the cranial crest, present in this taxon at a very young ontogenetic stage (Manzig et al. 2014).”

Cheng et al. conclude: “the variation in shapes and sizes of cranial crests that are found in pterosaurs, associated with other morphological features, should not be understated as being a powerful tool for understanding their diversity.”

No images or reconstructions
were offered of the pelves under study (as provided in Fig. 3). Precise measurements in a series of tables were presented. No phylogenetic analysis was attempted by Cheng et al., but you can see the results of such a test here, at the large pterosaur tree where five specimens attributed to Darwinopterus and additional others attributed to other wukongopterids lump and separate without loss of resolution.

As reported earlier
I have not found two Rhamphorhynchus specimens that score the same, except for a juvenile of the largest species. That goes the same for Pterodactylus, Germanodactylus, Pteranodon (Fig. 2), Darwinopterus (Fig. 3) or any other genus represented by a large number of individual specimens. They all nest in phylogenetic order, lumped and split by a variety of traits. Note the HUGE individual variation presented here among putative congeneric specimens.

Figure 1. Click to enlarge. The five specimens of Darwinopterus to scale and in phylogenetic order preceded by six more primitive taxa. The ZMNH 8802 specimen is a female associated with an egg. The others genders shown are guesses by Lü et al. 2011a. Note the skull did not elongate, it actually shrank in the vertical dimension, probably reducing its weight. The female is crestless because it is the most primitive of the five known Darwinopterus specimens. The odds that the remaining four specimens are all males is relatively small.

Figure 3. Click to enlarge. The five specimens of Darwinopterus to scale and in phylogenetic order preceded by six more primitive taxa. The ZMNH 8802 specimen is a female associated with an egg. The others genders shown are guesses by Lü et al. 2011a. Note the skull did not elongate, it actually shrank in the vertical dimension, probably reducing its weight. The female is crestless because it is the most primitive of the five known Darwinopterus specimens. The odds that the remaining four specimens are all males is relatively small.

References
Cheng X, Jiang S-X, Wang X-L and Kellner AWA 2017. Premaxillary crest variation within the Wukongopteridae (Reptilia, Pterosauria) and comments on cranial structures in pterosaurs. Anais da Academia Brasileira de Ciencias. http://dx.doi.org/10.1590/0001-3765201720160742

Hatzegopteryx: one error in cervical identification leads to trouble

Azhdarchid pterosaurs
as we learned earlier, first achieved their slender proportions in small, sand-piper-like taxa similar to n44 and n42 during the Late Jurassic (Fig. 1). Coeval and later taxa grew larger, some attaining stork-like and then giraffe-like sizes while maintaining their slender proportions.

Azhdarchids and Obama

Figure 1. Click to enlarge. Here’s the 6 foot 1 inch former 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 a human male.

Extant storks are stalkers
whether wading or on firmer substrates. That analogy brings us, once again, to the Naish and Witton 2017 concept of azhdarchids as terrestrial stalkers. They revisit the subject  a third time (after Witton and Naish  2008. 2015), but now freshly armed with the evidence of a large short cervical from Hatzegopteryx, a giant pterosaur from Romania.

The big question is: which cervical is it?

In giant derived azhdarchids.
like Quetzalcoatlus and Hatzegopteryx, half the cervicals (1-3 and 8) are not elongate and the other half (4-7) are elongate.

Unfortunately and earlier
Witton and Naish 2008 mistakenly numbered the cervicals of Phosphatodraco 4-9, when they should have labeled them 3-8 (Fig. 2). They saw that neural spine on #7, which they thought was #8.

Cervical number 8 is always short in azhdarchids
and if correctly identified would have allowed the possibility that Hatzegopteryx had a typical azhdarchid neck. Cervical number 5 is always the longest in giant azhdarchids and Phospatodraco, which gives workers a starting point if the bones are scattered or incomplete at the ends.

But Naish and Witton took it the other way
and with their misidentification of a wide cervical number 7 they imagined a wide cervical series for Hatzegopteryx. And with that they thought they had more evidence for terrestrial stalking instead of aquatic wading, as practiced by all ancestors back to the Late Jurassic. I’m not saying azhdarchids didn’t pick up a few tidbits on land. I am saying they and all their ancestors were built like living sandpipers, stilts and herons, which find their diet in the shallows.

Figure 2. Black images are from Naish and Witton 2017. Cervical series is from Witton and Naish 2008. Purple and red are added here. Improper cervical identity in 2008 led to bigger problems in 2017.

Figure 2. Black images are from Naish and Witton 2017. Cervical series is from Witton and Naish 2008. Purple and red are added here. Improper cervical identity in 2008 led to bigger problems in 2017 where the authors switched real for imaginary in their graphic, which makes it look like they had more data than they really did. BTW, none of these belly-flopping pterosaurs could have taken off in this fashion.

As much as Naish and Witton write about azhdarchids,
they should not be making basic mistakes over and over again. Not only do they misidentify a cervical, they illustrate their pterosaurs doing belly flops in a purported take-off configuration that has no chance of succeeding. See here, here and here for details.) And finally they should no longer consider that pterosaurs had nine cervicals. That goes back to S. Christopher Bennett’s PhD thesis in which he considered vertebrae number 9 to be a cervical since it did not contact the sternum. Even so, it bore long ribs and was located inside the thorax.

Pictured here
(Fig. 3) is the Hatzegopteryx cervical in question. Compared to both Phosphatodraco (Fig. 2) and Quetzalcoatlus sp. (Fig. 3) this is cervical #8, the short one, not cervical #7, the long one.

Figure 3. Hatzegopteryx cervical. If it is number 7, as Naish and Witton suggest, then it is very short and likely would be part of a very short neck. But if it is number 8, then the proportions are typical for azhdarchids. This is where Occam's Razor might have been useful.

Figure 3. Hatzegopteryx cervical. If it is number 7, as Naish and Witton suggest, then it is very short and likely would be part of a very short neck. But if it is number 8, then the proportions are typical for azhdarchids. This is where Occam’s Razor might have been useful.

Some azhdarchids and their kin
have a tall neural spine only on cervical #8. Quetzalcoatlus is in this clade. Some, like Zhejiangopterus and Chaoyangopterus, have no tall neural spines. That’s also the case with the tiny basalmost clade members. By contrast, the flightless pterosaur, JME-Sos 2428 has a tall neural spine on cervicals 6-8, which makes me wonder if Phosphatodraco (Fig. 2) is a sister to it, given the present limited amount of data.

The Domino Effect
When Naish and Witton decided that Hatzegopteryx cervical #8 was #7, that mistake unleashed the possibility that they had discovered the first “short neck” azhdarchid! They must have been excited.

What Naish and Witton did not show you…
In lateral view, the Hatzegopteryx cervicals Naish and Witton illustrated actually look normal for an azhdarchid, but in dorsal view the omitted cervicals would have to have been twice as wide as typical and no longer cylinders (Fig. 2). So the “short” neck was really a “wide flat” neck, but that does not have the same headline cache. Such a major departure from the azhdarchid bauplan should have caused Naish and Witton to reconsider that their ‘discovery’ was actually a simple error in identification, now percolating online for the last 8 years.  Hope this helps quell the notion!

References
Naish D and Witton MP 2017. Neck biomechanics indicate that giant Transylvanian azhdarchid pterosaurs were short-necked predators. PeerJ 5:e2908; DOI 10.7717/peerj.2908
Witton MP and Naish D 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLOS ONE 3:e2271 DOI 10.1371/journal.pone.0002271.
Witton MP and Naish D 2015. Azhdarchid pterosaurs: water-trawling pelican mimics or terrestrial stalkers? Acta Palaeontologica Polonica 60:651660 DOI 10.4202/app.00005.2013.

Brian Switek blog
wiki/Hatzegopteryx

Forfexopterus: a Huanhepterus sister

Boy, it’s been a long time
since we’ve looked at a new pterosaur. Several months, perhaps… maybe longer…

Figure 1. Forfexopterus reconstructed. Note the metacarpals: 1>2>3, shared with Ardeadactylus. The rostrum tip is off the matrix.

Figure 1. Forfexopterus reconstructed. Note the metacarpals: 1>2>3, shared with Ardeadactylus. The rostrum tip is off the matrix. Note the difference between the actual fingers and the traced fingers by Jiang et al. The lack of precision in the Jiang et al. tracing, despite it being traced from a photograph, is a little disheartening.

Jiang et al. 2016
present a new disarticulated, but largely complete Early Cretaceous pterosaur, Forfexopterus jeholensis (Figs. 1–3). Jiang et al. consider their new find an ‘archaeopterodactyloid’ based on the ‘long metacarpus and reduced mt5’–but those are convergent traits in four pterodactyloid-grade clades. The large pterosaur tree (LPT) nests Forfexopterus near the base of the azhdarchid clade, which arises from the Dorygnathus clade, specifically nesting between Ardeadactylus and Huanhepterus + Mesadactylus (BYU specimen, not the anurognathid with the same name).

Figure 1. Forfexopterus original tracing, colors added.

Figure 2. Forfexopterus original tracing, colors added. See how simple colors ease the chaos of the roadkill fossil.

Unfortunately 
the Jiang et al. phylogenetic analysis suffers from taxon exclusion. They consider the Archaeopterodactyloidea to be composed of Germanodactylidae, Pterodactylus, Ardeadactylus. Gallodactylidae and Ctenochasmatidae. Those members are only monophyletic if the clade also includes Dorygnathus in the LPT, which was not the intention of the authors. It’s been awhile, but let us recall that the former clade “Pterodactyloidea” had four separate origins in the LPT, two from Dorygnathus (Ctenochasmatidae and Azhdarchidae) and the rest from Scaphognathus which was, in turn, also derived from Dorygnathus through several intervening transitional taxa.

Figure 2. Forfexopterus compared to sisters Huanhepterus and Ardeadactylus and the BYU specimen of Mesadactylus.

Figure 3. Forfexopterus compared to sisters Huanhepterus and Ardeadactylus and the BYU specimen of Mesadactylus.

Forfexopterus
has the slender proportions of Huanhepterus and Ardeadactylus. The rostrum was longer and lightened with several fenestra, one of which was likely a naris. Metacarpals 1–3 were longer medially, the opposite of basal pterosaurs. That trait lines up the joints in m1-3. Manual 4.2 is sub equal to m4.1, unique to this clade and atypical for pterosaurs in general.  Atypical for smaller members of this clade, but typical for larger members (like Jidapterus, but evidently not Huanhepterus (data comes from awkwardly produced original drawing)), the scapula was subequal to the coracoid and would have articulated with a notarium, which is not preserved, or is still largely buried (Fig. 2).

Shorthand suggestion (again)
There are two ways you can label a tetrapod phalanx:

  1. ph3d4 = phalanx 3, digit 4 (manus or pes? as shown in figure 2 above) or
  2. m4.3 = manual 4th digit, 3rd phalanx

Jiang et al. labeled their illustration using #1. You may find that method cumbersome and space consuming. I use and encourage others to use #2, the shorthand version.

When you check out the
Wikipedia page on Forfexopterus, the link to Archaeopterodactyloidea references three papers with Dr. Brian Andres as a co-author including his dissertation on
Sytematics of the Pterosauria. It’s great that PhD candidates tackle large projects. It’s hard work that makes them study their subject and prove their mettle. However, by definition, PhD candidates are not experts. They want to become experts by creating a dissertation, but they come to their projects naive, trusting the literature and beholding to their professors. These are all potential problems, as we talked about earlier.

In like manner, 
for my second paper (Peters 2000) I came to the project naive and trusting the literature. Judging from a vantage point, 17 years later, my observations were not those of an expert. Even so, I hit the mark with regard to pterosaur origins despite the many errors in that paper that have been corrected here and at ReptileEvolution.com. The nesting of pterosaurs apart from archosaurs and close to Macronemus, Tanystropheus, Langobardisaurus, Cosesaurus, Sharovipteryx and Longisquama has been validated and cemented by the large reptile tree (LRT). No other candidate taxa have ever been shown to be closer (= produce a gradual accumulation of derived traits). Attempts at correcting the observational errors in academic publications have been rejected by the referees who don’t want any more evidence published that pterosaurs are not dinosaur kin — or that tiny Solnhofen pteros are not babies.

Unfortunately
the Andres dissertation fails to produce a cladogram in which a gradual accumulation of traits can be traced in all derived taxa. For instance, anurognathids are basal to pterodactyloids in the Andres cladogram and the clade Archaepterodactyloidea was recovered. The Andres dissertation shortcoming can be attributed to taxon exclusion. By contrast, the LPT minimizes taxon exclusion by including many specimens ignored by Andres and other prior workers including multiple species within several genera and all those sparrow- and hummingbird-sized Solnhofen specimens. I know pterosaur workers are loathe to admit it, or recognize it, but those extra specimens are key to understanding pterosaur interrelations.

If you don’t look, you’ll never see.
If you don’t ask, you’ll never find out. Fellow pterosaur workers, don’t keep your blinders on. Expand your taxon lists to include a wider gamut of specimens.

This is Science.
When workers publish and referee allow manuscripts to be published they are judging the work fit for print. At that point they have stated their case. If the work stands up to rigorous scrutiny, then it will be cherished. If the work has flaws, then it’s up to fellow workers to expose those flaws for the good of Science.

References
Andres BBB 2010. Systematics of the Pterosauria. Dissertation. Yale University. p. 366.
Jiang S, Cheng X, Ma Y and Wang X 2016. A new archaeopterodactyloid pterosaur from the Jiufotang Formation of western Liaoning, China, with a comparison of sterna in Pterodactylomorpha. Journal of Vertebrate Palaeontology: e1212058.
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.

wiki/Forfexopterus
wiki/Archaeopterodactyloidea

Dr. David Unwin on pterosaur reproduction – YouTube

Dr. David Unwin’ talk on pterosaur reproduction 
was recorded at the XIV Annual Meeting of the European Association of Vertebrate Palaeontologists, Teylers Museum, Haarlem, Netherlands and are online as a YouTube video.
Dr. Unwin is an excellent and engaging speaker.
However, some of the issues Dr. Unwin raises have been solved at www.ReptileEvolution.com
The virtual lack of calcite in pterosaur eggs were compared to lepidosaurs by Dr. Unwin, because pterosaurs ARE lepidosaurs.  See: www.ReptileEvolution.com/reptile-tree.htm
Lepidosaurs carry their eggs internally much longer than archosaurs, some to the point of live birth or hatching within hours of egg laying. Given this, pterosaurs did not have to bury their eggs where hatchlings would risk damaging their fragile membranes while digging out. Rather mothers carried them until hatching. The Mrs. T external egg was prematurely expelled at death, thus the embryo was poorly ossified and small.
Dr. Unwin ignores the fact that hatchlings and juveniles had adult proportions as demonstrated by growth series in Zhejiangopterus, Pterodaustro and all others, like the JZMP embryo (with adult ornithocheirid proportions) and the IVPP embryo (with adult anurognathid proportions).
Dr. Unwin also holds to the disproved assumption that all Solnhofen sparrow- to hummingbird-sized pterosaurs were juveniles or hatchlings distinct from any adult in the strata. So they can’t be juveniles (see above). Rather these have been demonstrated to be phylogenetically miniaturized adults and transitional taxa linking larger long-tailed dorygnathid and scaphognathid ancestors to larger short-tailed pterodactyloid-grade descendants, as shown at: www.ReptileEvolution.com/MPUM6009-3.htm
Thus the BMNH 42736 specimen and Ningchengopterus are adults, not hatchlings. And the small Rhamphorhynchus specimens are also small adults.

It looks A LOT like Gladocephaloideus, but it’s not one

Among the long-necked ctenochasmatids
close to Gegepterus, is Gladocephaloideus (Lü et al. 2012), a taxon originally considered a cycnorhamphid. A new, smaller specimen with an equally impressive set of long cervicals was recently assigned to the same genus (Lü et al. 2016, Fig. 1) as a juvenile.

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 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.

Unfortunately
the two specimens do not nest together in the large pterosaur tree (Fig. 2). Close, but separated by several nodes.

Before leaving Figure 1,
note the size of the relatively tiny pelvis in the JPM specimen, no larger than that of the much smaller MB.R. specimen with a relatively large pelvis of similar shape. This reconstruction was built from scraps that give the appearance of complete bones. Lü et al. 2016 considered the pelvis incomplete and did not attempt a reconstruction. No sacrum is associated with the pelvic elements to confirm or refute the present size reconstruction. New conspecific specimens will help.

Figure 2. Ctenochasmatids arise from these dorygnathids.

Figure 2. Ctenochasmatids arise from these dorygnathids.

Lü et al. amended the diagnosis of Gladocephaloideus
to accommodate the new smaller specimen. That’s not a good idea before determining that they are indeed conspecific. In order to obviate that prospect, in phylogenetic analysis Lü et al. created a chimaera of the two specimens eliminating any possibility of testing one against the other and against all other pterosaur taxa. In my experience it is extremely rare to find conspecific pterosaurs. That is why I try to nest only specimens, not chimaeras.

The pes of Gladocephaloideus

Figure 3. (Left) The pes of Gladocephaloideus compared to (right) the pes of Ctenochasma elegans (a smaller, more primitive Ctenochasma with fewer teeth). Compare to the pes in figure 1.

The feet
of the holotype and referred specimen are similar but not the same in proportion or appearance. They score differently. In pterosaurs, feet are like fingerprints, enabling one to lump conspecific taxa and split convergent look-alikes.

Figure 4. The JPM specimen in situ along with a reconstruction of its skull compared to the holotype of Gladocephaloides.

Figure 4. The JPM specimen in situ along with a reconstruction of its skull compared to the holotype of Gladocephaloideus. The anterior mandible was glued on in the wrong direction, as noted by Lü et al. 2016.

Lü et al. did not test
the MBR stem ctenochasmatid. Lü et al.  nest ctenochasmatids with cycnorhamphids, among other odd yet traditional nestings. This may be due to the low number of included taxa (67) vs. 215 in the large pterosaur tree.

The taxonomy and systematics get a little confusing….
the original Gladocephaloideus was assigned by Lü et al. 2012 to the Gallodactylidae (cycnorhamphids), but in consideration of the smaller specimen Lü et al. 2016 shifted it to the Ctenochasmatidae where it nests with Pterofiltrus, which nests as a cycnorhamphid in the large pterosaur tree. Moreover, Lü et al. include as related taxa, Elanodactylus (a derived germanodactylid, basal to pteranodontids), Beipiaopterus (a basal azhdarchid), Feilongus and Moganopterus (both cycnorhamphids). At the next level of closest kin Lü et al. include Pterodactylus longicollum (a pterodactylid), Gnathosaurus (a ctenochasmatid) and Cearadactylus (an ornithocheirid nesting far from other ornithocheirids).

This buckshot phylogeny only get worse, but I’ll stop here.

I applaud Lü et al.
for re-identifying the holotype Gladocephaloideus as a ctenochasmatid, as first reported here several years ago. But the rest of their phylogenetic analysis has to add taxa to get up to speed with current research. Their pterosaur tree recovered over 3000 MPTs compared to the fully resolved single tree at ReptileEvolution.com.

Juvenile? Big question that needs new insight to answer:
Lü et al. 2016 report, “The unfused contact between the extensor tendon process and the proximal end of wing phalange 1, as well as the poorly ossified epiphyses of the wing phalanges, indicates that JPM-2014-004 is an early juvenile individual.” It is hard to consider the JPM specimen a juvenile because in phylogenetic analysis it is larger than both proximal adult taxa. The more primitive MB.R. specimen, despite its size is an adult having undergone phylogenetic miniaturization from larger Dorygnathus and Angustinaripterus ancestors, an evolutionary process that often gives rise to new morphologies, in this case, the clade Ctenochasmatidae with all of its synapomorphies. Phylogenetically miniaturized pterosaurs retain, through neotony, juvenile bone microstructure. Lü et al. 2016 report woven bone structure and no LAGs or zones. This may occur in rapidly growing tiny (sparrow-to-hummingbird-sized) adults less than one year in age. Tiny pterosaurs, like tiny birds may have matured in far less than a year, just like small birds. Lü et al. 2016 note that LAGs are uncommon in pterodactyloids, but may be seen in larger specimens that presumably lived longer. Size matters in a phylogenetic context. This has to be considered before making statements about ontogenetic age estimates.

Tibial bone wall thickness
With a radius of 16 units (holding a cm scale up to my monitor) the tibial bone thickness was 5 units, leaving 11 units of hollow cavity. That is same cortex ratio as in the 2x larger (9x heavier) holotype specimen.

But wait! What’s this?? A long rostrum on a juvenile??? 
That can’t be so, IF you follow the work of Bennett, Witton, Wellnhofer and others. That would be internally inconsistent! However, if you follow ReptileEvolution.com and the Pterosaur Heresies you’ll note that many tiny adults AND embryos had long rostra and small eyes. No problem under the isometric growth hypothesis, which I hope will someday gain a little acceptance because it is demonstrably factual. 

References
Lü J-C, Ji Q, Wei X-F and Liu Y-Q 2012. A new ctenochasmatoid pterosaur from the Early Cretaceous Yixian Formation of western Liaoning, China. Cretaceous Research in press. doi:10.1016/j.cretres.2011.09.010.
Lü J, Kundrát M, Shen C 2016. New Material of the Pterosaur Gladocephaloideus Lü et al., 2012 from the Early Cretaceous of Liaoning Province, China, with Comments on Its Systematic Position. PLoS ONE 11(6): e0154888. doi:10.1371/ journal.pone.0154888