Geographic cladogram of pterosaurs

So many pterosaurs come from so few places.
And those places are spread around the world. So, here (Fig. 1) is the large pterosaur tree (LPT, 239 taxa) with color boxes surrounding Solnhofen, Chinese, North American, South American and other geographic areas where they are found.

Figure 1. LPT with pterosaurs colorized according to geography.

Figure 1. LPT with pterosaurs colorized according to geography.

As before,
the traditional clades ‘Pterodactyloidea’ and ‘Monofenestrata‘ become polyphyletic when traditionally omitted taxa are included. Here (Fig. 1) four clades achieve the pterodactyloid-grade by convergence. Other pterosaur workers (all PhDs) omit or refuse to include most of these taxa, leading to false positives for the tree topologies they recover. Moreover, none recognize, nor cite literature for, the validated outgroup members for the Pterosauria (Fig. 1) preferring to imagine pterosaurs arising from unidentified and/or invalidated archosaurs or archosauriforms. Here we get to peak beneath the curtain.

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.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.

Latest pterosaur cladogram fails on many levels

Buchmann and Rodrigues 2019
studied skeletal pneumatization in pterosaurs then mapped their results on a painfully antiquated pterosaur cladogram (Fig. 1, based on their mentor, Kellner 2003) that includes the basal crocodylomorph, Scleromochlus, and the basal dinosaur, Herrerasaurus as outgroup taxa.

Figure 1. Invalid cladogram of the Pterosauria from Buchmann and Rodrigues 2019. Colors are clades confirmed by the LRT.

Figure 1. Invalid cladogram of the Pterosauria from Buchmann and Rodrigues 2019. Colors are clades confirmed by the LRT. Note the lack of resolution at several nodes, the inappropriate outgroup taxa and the small number of included taxa, eliminating all small taxa except Nemicolopterus.

It is embarrassing
when pterosaur experts do not know what pterosaurs really are: fenestrasaur tritosaur lepidosaurs (not archosaurs). Scleromochlus has vestigial hands that lack digit 4 and feet that lack digit 5. These traits alone do not invalidate Scleromochlus as an appropriate ancestor, and Herrerasaurus is just as bad. Pterosaur ‘experts’ are strangely content with ignoring the four cladograms in Peters 2000 that nested tiny Cosesaurus, Sharovipteryx and Longisquama closer to pterosaurs than any archosaur, simply by taxon inclusion.

When you add more pterosaurs to your cladogram
(link to cladogram here) you recover Bergamodactylus and other Triassic pterosaurs (missing in Fig. 1) at the base. The first dichotomy splits dimorphodontids + anurognathids from eudimorphodontids + all other pterosaurs. After several nodes four clades produce ‘pterodactyloid’-grade pterosaurs by convergence after phylogenetic miniaturization. Two (azdarchids and ctenochasmatids) arise from distinct tiny Dorygnathus specimens. Two others (cycnorhamphids + ornithocheirids and pterodactylids + germanodactylids) arise from tiny Scaphognathus descendants. Darwinopterus and kin are strangely absent from Fig.1 (probably because it was based on Kellner 2003). The Pterodactylus clade + the Nyctosaurus clade arise directly from Rhamphorhynchuswhile the toothy Ornithocheiridae arise from the toothless Nyctosaurus and Nemicolopterus.

Buchmann and Rodrigues break the first rule of cladogram building:
1. All sister taxa must demonstrate and document a gradual accumulation of derived traits.

And they break the second rule:
2. Outgroup taxa at every node must have plesiomorphic traits capable of evolving into the derived traits of derived members.

Clearly these two authors did not check their results.
Their referees and editors also bear part of the blame here. Putting out invalid data gives PhDs in paleontology a bad name. Their peers should have pointed this out before an amateur with no academic background in science exposed those blatant errors. At least the authors did not include the phytosaurs as outgroup taxa, as recovered by so many other workers, like Nesbitt 2011.

It goes without saying:
without a valid family tree the work Buchmann and Rodrigues did with pneumatic foramina was largely a waste of time. If they were looking for patterns they were starting with disorder. These two should redo their study with a valid and comprehensive tree topology.

The large pterosaur tree (LPT) currently includes 238 taxa, validated outgroups, several embryos/hatchlings and dozens of tiny pterosaurs, only some of which are juveniles. The LPT does not break the rules of cladogram building.

Buchmann R and Rodriques T 2019. The Evolution of Pneumatic Foramina in Pterosaur Vertebrae.Anais da Academia Brasileira de Ciências 91: e20180782.
DOI 10.1590/0001-3765201920180782.
Kellner AWA 2003. Pterosaur phylogeny and comments on the evolutionary history of the group. Geological Society Special Publications 217: 105-137.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.

Flugsaurier 2018: Los Angeles County Museum

is a meeting of those interested in pterosaurs that happens in another part of the world every few years. I went to the first few. Saw a lot of specimens. Met a lot of colleagues. Produced a few abstracts and gave some presentations.

Over the next few days
there’s a Flugsaurier meeting taking place in Los Angeles. Many well-known and not-so-well known speakers are giving presentations this year. I will not be among them. Why?

So far as I know,
all of the conveners and many of the presenters continue to ignore a paper I wrote 18 years ago on the origin of pterosaurs from fenestrasaurs, not archosaurs. Other papers followed on wing shape, trackmaker identification and other topics, all supporting that phylogenetic hypothesis of relationships. Evidently workers would prefer to hope that pterosaurs arose from archosaurs close to dinosaurs. This is not where the data takes anyone interested in the topic who is not a party to taxon exclusion.

In addition, several of the conveners

  1. subscribe to the invalid quad-launch hypothesis
  2. the bat-wing reconstruction of the brachiopatagium.
  3. they believe that pedal digit 5 framed a uropatagium.
  4. They refuse to add tiny Solnhofen pterosaurs to their cladograms.
  5. They refuse to add several specimens of each purported genus to cladograms—and because of this they don’t recognize the four origins of the pterodactyloid-grade (not clade).
  6. They still don’t recognize that pterosaurs grew isometrically.
  7. They still don’t accept that pterosaur mothers retained their egg/embryo within the body until just before hatching (a lepidosaur trait).
  8. They still don’t accept that pterosaur bone fusion patterns follow lepidosaur, rather than archosaur patterns.
  9. They accept the idea that giant eyeballs filled the anterior skulls of anurognathids, not realizing that the supposed ‘scleral ring’ on edge of the flathead anurognathid is actually the mandible and tiny teeth.
  10. They reject any notion that all basal and some derived pterosaurs were bipedal, despite the footprint and morphological evidence proving bipedal locomotion.
  11. They all hold out hope that the largest azhdarchids could fly.
  12. I was going to say that all workers believe that crest size and hip shape identify gender, when the evidence indicates these are both phylogenetic markers, but then I found an abstract in 2018 that casts doubt on the gender/crest/pelvis hypothesis. So there’s hope.

That’s a fairly long list of ‘basics’
that most pterosaur workers ‘believe in’ despite the fact that there is no evidence for these false paradigms — but plenty of evidence for the lepidosaur origin of pterosaurs, from which most of the above hypotheses follow.

I am not attending Flugsaurier 2018
because the convening pterosaur workers deny and suppress the data listed above. Plus, I can more actively and thoroughly test assertions made during the conference from ‘my perch’ here in mid-America.

Good luck to those attending. 
Test all assertions and hypotheses, no matter their source.

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.

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)
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.


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
The virtual lack of calcite in pterosaur eggs were compared to lepidosaurs by Dr. Unwin, because pterosaurs ARE lepidosaurs.  See:
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:
Thus the BMNH 42736 specimen and Ningchengopterus are adults, not hatchlings. And the small Rhamphorhynchus specimens are also small adults.

What is Orientognathus? Nest it with Changchengopterus and Sordes.

Earlier on January 24, 2015 we looked at a description of Orientognathus chaoyngensis (Lü et al. 2015. Fig.1) a new Late Jurassic rhamphorhynchoid pterosaur known then from a series of comparative descriptions only. No images. Now that I’ve seen a low-resolution photograph (Fig. 1), let’s review the data we had to work with on the 24th of January.

Figure 1. Orientognathus in situ, tracing moved to live position, comparisons to sisters Changchengopterus and Sordes.

Figure 1. Orientognathus in situ, tracing moved to live position, comparisons to sisters Changchengopterus and Sordes. Click to enlarge. More resolution is needed to get more out of this. The wings and tail are not very long here. The sternum is a small triangle.

Data provided:

  1. toothless tip of dentary, slightly pointed – True
  2. mc4/humerus ratio = 0.38 – True and precise
  3. ulna < each individual wing phalanx – False, the ulna is quite long
  4. tibia subequal to femur – False, tibia is longer, both tibia are broken.
  5. deltopectoral crest more developed than in Qinlongopterus – True, but not as much as in Sordes.
  6. anterior teeth stouter and longer than in Pterorhynchus – True, but Pterorhynchus has pretty short anterior teeth.
  7. teeth are straight and longer than in Jianchangnathus Subequal actually. 
  8. pteroid/humerus ratio = 0.21; pteroid has expanded distal end True enough (0.23)
  9. larger than other rhamphorhynchine pterosaurs from Late Jurassic NE China (measurements not indicated). Did not check, but seems pretty big (Fig. 1).

The specimen is nearly complete and partly disarticulated. 
The antebrachium (forearm) is broken. Put them back together and that’s a long forearm.

It turns out the the tibia is not equal to the femur in length
So all of the prior candidates become rejects.

Step two: ulna is not smaller than each individual wing phalanx
Orientognathus has a large antebrachium, subequal to m4.2 and longer than m4.1.

Figure 2. The original nesting of Orientognathus from Lü et al. 2014. Note the lack of resolution in that clade. Changchengopterus is not listed, but should be.

Figure 2. The original nesting of Orientognathus from Lü et al. 2014. Note the lack of resolution in that clade. Changchengopterus is not listed, but should be.

Step three: Phylogenetic Analysis
The prior cladogram lost resolution when Orientognathus was added (Fig. 2) .

A new analysis of the large pterosaur tree (not yet updated) nests Orientognathus between Changchengopterus and the primitive specimen of Sordes (Fig. 1) with no loss of resolution.

These three (Sordes, Orientognathus and Changchengopterus) are the metaphorical ‘plain brown sparrows’ among pterosaurs from which all later spectacular specimens are derived. It’s that lack of any ‘distinctive’ traits that is actually their own distinctive trait.

Thus Orientognathus is basal to the several specimens of Sordes and the many specimens of Dorygnathus, from which arise darwinopterids (wukongopterids), scaphognathids and ultimately all the pterodactyloids. Orientognathus may have been hard to nest and caused so little stir because it is indeed plesiomorphic. Getting that antebrachium and tibia right would have helped. If anyone has access to high resolution imagery of the skull and foot, that would be very helpful.

Lü J, P H-Y, We X-F, Chan H-L and Kundrat GM 2014. A new rhamphorhynchid pterosaur (Pterosauria) from Jurassic deposits of Liaoning Province, China.

Pterosaur tails tell tales… Unwin et al. 2014 JVP abstract

Unwin et al. (2014)
describe an increasing number of tail vertebrae in a purported ontogenetic series (hatchling to juvenile to adult in a series of purported Darwinopterus specimens.) Although this is unheard of elsewhere among vertebrates, Unwin et al. link this trait to the origin of pterodactyloid-grade pterosaurs. And it should be mentioned that Unwin et al. are the only workers who nest darwinopterids basal to pterodactyloids. Andres nests anurognathids there. Kellner nests Rhamphorhynchus there. I nest tiny dorygnathids and scaphognathids there by convergence (e.g. Fig. 1) four times.

From the Unwin et al. 2104 abstract:
“The evolution of pterodactyloids from basal pterosaurs in the Early-Middle Jurassic involved a complex series of anatomical transformations that affected the entire skeleton. Until recently, almost nothing was known of this major evolutionary transition that culminated in the Pterodactyloidea, a morphologically diverse and ecologically important clade that dominated the aerial environment throughout the mid-late Mesozoic. The discovery of Darwinopterus, a transitional form from the early Late Jurassic of China, provided the first insights into the sequence of events that gave rise to the pterodactyloid bauplan and hinted at an important role for modularity, but was largely silent regarding the anatomical transformations themselves, or the evolutionary mechanism(s) that underlay them. A series of recent finds allowed us to construct a complete postnatal growth sequence for Darwinopterus. By comparing this sequence with those for Rhamphorhynchus and Pterodactylus, pterosaurs that phylogenetically bracket Darwinopterus, it is possible to map key anatomical transformations such as the evolution of the elongate, complex tail of basal pterosaurs into the short, simple tail of pterodactyloids. In Darwinopterus hatchlings the tail is shorter than the dorsal-sacral series (DSV) and consists of around 18 simple vertebral ossifications. The tail is longer (1-2 x DSV) in juveniles and has a normal complement of about 30 caudals, but only reaches its full length (2-3 x DSV) and complexity in adults. Basal pterosaurs largely conform to this pattern, although some species, including Rhamphorhynchus, have longer tails with up to 40 caudals. Generally, the tail of adult pterodactyloids, including Pterodactylus, resembles that of Darwinopterus hatchlings (≤18 ossified vertebrae; tail ≤0.7 x DSV; vertebrae simple, blocky), but occasionally develops a little further (e.g. in Pterodaustro) corresponding to the condition seen in early juveniles of Darwinopterus and paralleling the developmental pattern observed in long-tailed pterosaurs. The short tail of adult pterodactyloids, and anurognathids, basal pterosaurs that also have relatively short tails, appears to be neotenic, resulting from a sharp decrease in growth rate compared to the rest of the skeleton. This mechanism, heterochrony acting upon a distinct anatomical module to effect a large-scale morphological transformation, can be applied to other modules to generate the derived features (e.g. elongate neck and metacarpus, reduced fifth toe) that typify the pterodactyloid bauplan.”

Problem #1
Among professional pterosaur workers, only Unwin et al. nest Darwinopterus as the stem pterodactyloid. No one else does. Andres nests anurognathids with pterodactyloids. Kellner nests Rhamphorhynchus with pterodactyloids. Readers of this blog and reptile know that when you add the sparrow- to hummingbird-sized Solnhofen pterosaurs, you get four clades of pterodactyloid-grade pterosaurs.

Figure 1. Scaphognathians to scale. Click to enlarge.

Figure 1. Scaphognathians to scale. Click to enlarge.

Problem #2
Are the specimens truly juvenile Darwinopterus? Or do they represent smaller genera or species, perhaps closely related, or not? Currently no two Darwinopterus specimens are conspecific. No two are identical. See them here. By comparing purported Rhamphorhynchus and Pterodactylus juveniles to putative adults I’m afraid Unwin et al. are playing with a pack of Jokers. Those smaller specimens are distinct species and genera, as recovered in the large pterosaur tree. Everyone should know by now that pterosaur juvenile pterosaurs are isometric matches to their adult counterparts, from several well-known examples. Any differences in Darwinopterus likewise mark phylogenetic, not ontogenetic differences.

Problem #3
Rhamphorhynchus and Pterodactylus only phylogenetically bracket Darwinopterus if the inclusion set is reduced to these three taxa. Otherwise they nest several nodes away from each other with lots of intermediate taxa as you can see here.

Problem #4
Unwin et al. claim the caudal count increases with maturity in Darwinopterus (18 in hatchlings, 30 in juveniles and adults). Put these into a cladogram and they probably become disparate taxa. Where else does the vertebral count nearly double during ontogeny? Nowhere. Those caudal counts for the larger specimens have to be estimates. Not every tail is complete. It appears as if the caudal count could vary among the larger specimens as well.

Problem #5
I see no mention of a phylogenetic analysis with regard to the various Darwinopterus specimens. This is a problem as Unwin et al. do not want to test their observations with the only method known to lump and split taxa. In the large pterosaur tree IVPP V 16049 nests with YH2000. 41H111-0309A nests with ZMNH M 8782. All four Darwinopterus taxa nest as a sister clade to Kunpengopterus + Archaeoistiodatylus and this combined clade is a sister to Wukongopterus, then the PMOL specimen of Changchengopterus, then Pterorhynchus. This major clade nests between Dorygnathus and Scaphognathus, both of which ultimately give rise to the two pairs of basalmost pterodactyloids.

Possible Solution 
I noted earlier that the Darwinopterus clade left no descendants. They also did not produce any small taxa like Dorygnathus and Scaphognathus did. Other workers thought the smaller Scaphognathus specimens were juveniles, despite the morphological differences. I can only wonder if the same situation is happening in the Darwinopterus clade? Perhaps what the Unwin team found are the smaller specimens previously missing from their clade branch. Even so, and sadly, this clade was not able to survive into the Cretaceous, small or not, because no known Cretaceous pterosaurs share darwinopterid traits. They are all accounted for with presently known tiny ancestors.

Unwin D, Lü J-C, Pu H-Y, Jim X-S  2014. Pterosaur tails tell tails of modularity and heterochrony in the evolution of the pterodactyloid bauplan. JVP 2014 abstracts