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.

Some things you learn are not found in any textbooks…yet.

No current discoveries are found in the latest textbooks. 
That’s because it takes time (years typically) for textbooks to be (in reverse order) assigned, accepted, distributed, printed, edited, written and illustrated, researched and concepted. Textbook publishers are out to sell the maximum number of books, so they write to the current consensus, which may be in flux on several points and hypotheses. The current consensus may also be wrong–but it remains the consensus.

There are no courses
at any colleges entitled, PTEROSAURS 101, 102 or 103. Who would attend? There are only two dozen people in the world who have an interest, who study them, or contribute to what we know about them. And where is the consensus? On some points, there is no consensus!! And all too often “the consensus” is holding on to outmoded, invalid and unverifiable paradigms (see below).

Every new fossil specimen is really a new chapter
in an ever expanding textbook on paleontology. And all paleontologists who publish are contributing authors to that future textbook.

Striiving for veracity
It is important for all workers to see things as they are in specimens, and not to reinterpret them to fit an established paradigm, no matter the temptation to do otherwise. For instance, narrow chord wing preservation in pterosaurs is not the result of ‘shrinkage’ as some workers report. Rather it is what it is, universal. All pterosaur specimens have narrow chord wings. If you know one that is different, please tell me. I know one that appears different, but that’s because part of its arm was ripped away and displaced. Look closely. That’s the way it is.

If Galileo
went to school as a teenager and found the following question on a test: “If object A at ten pounds and object B at 10 ounces both fall from 1000 feet at the precisely the same moment, how many seconds ahead of B will A strike the ground?” He’d would not have even had the opportunity to choose answer E. “zero seconds.” Common knowledge at the time, based on Aristotle, would not have allowed it, no matter the facts of this case, proven by experiment. This went on for centuries.

if you were in college today and were given the multiple choice question, “Which one of the following taxa is most closely related to pterosaurs? A. Dinosaurs. B. Scleromochlus. C. Proterochampsids (including Lagerpeton). D. Euparkeria. E. Erythrosucids. F. We don’t know.” You would have to pick “F” to get a good score, because that’s the current consensus… unless your professor had recently written a paper espousing one of the other answers (see below). “G. None of the above” is the better answer according to the large reptile tree where fenestrasaurs are more closely related to pterosaurs. But each one of the above (A-E) has been proposed by recent authors, not caring if they made sense or not.

Imagine the plight of the poor student in Paleontology 101 today
when he or she asks the professor about that website, “repitleevoluton.com” The professor is going to have to say, “If you want a good grade, you’ll ignore that website and provide the same answers that are in your textbook.” That’s what Dr. Darren Naish  reported online. Don’t consider, test or discuss other possibilities. Best to ignore them — if you want to advance in paleontology and get your Masters or PhD.

Take, as an example,
David Hone’s dissertation that was later published in two papers in which he proposed comparing two competing pterosaur origin hypotheses, one by Peters 2000 (Cosesaurus, Sharovipteryx, Longiasquama) and one by Bennett 1996 (Scleromochlus) using the supertree method of analysis (combining several published analyses without actually examining any fossil specimens). Aware that his professor, Michael Benton, had earlier written a paper (Benton 1999) celebrating Scleromochlus as the sister to pterosaurs, Hone decided to delete and diminish the taxa proposed by Peters. He somehow created several typos in the Peters data and then deleted the entire Peters dataset because of those typos (references and the full story here). Then Hone and Benton (2008) gave credit for both competing hypotheses to Bennett while deleting all reference to Peters 2000. As a result, Hone received his PhD, two associated papers (Hone and Benton 2007, 2008) were published and Hone gained the ability to referee pterosaur manuscripts (like mine) submitted to academic journals. I wrote to Dr. Benton about the inconsistencies and leaps of logic between the two parts of their two part paper. His reply was a sheepish, “whoops. :  )”

See how it works? 
That’s how you crush an opposing hypothesis. And that’s just the tip of the iceberg of current readily solvable problems, as Pterosaur Heresies readers are well aware. No PhD wants to admit he/she was wrong. On some problems consensus will likely never be achieved — because in order to do so all invalid candidate hypothesis writers would have to admit they were wrong.

And that’s just not going to happen.
Not without a fight or a dismissal. Let me know if you know of any instances of someone admitting they were wrong (I know of one semi-wrong situation regarding Dr. Padian and his fight with pterosaur tracks). In the origin of snakes, pterosaurs, turtles and dinosaurs there are lots of ‘right’ answers out there, but few challenges to the weaker hypothesis and no one admits to being wrong.

As history tells us, in paleontology it takes decades to turn the boat around. And paleontologists don’t want anyone else, even other paleontologists, solving their mysteries for them… even when solutions are published in the literature.

Thanks for your interest.
I will continue to study and make informed comment on new fossil specimens, (many that haven’t made the textbooks yet). I will throw a spotlight on problems and celebrate solutions as they are verified or not in the large reptile tree. And I encourage you to do the same. If I can do it, anyone can do it.

There are too many paleontologists who
matrices, textbooks and papers blindly
and not enough paleontologists who have the balls to say, “Hey, there’s something wrong here.”

We’ll help fix the world of paleontology someday.
Unfortunately, it’s not going to happen this year. After four years of working with the large reptile tree, and improving it, and enlarging it year after year, it still has not been accepted for publication or gained intrigue among basal reptile workers. They don’t like it. It rocks the boat.

Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoolological Journal of the Linnean Society 118: 261–308.
Benton MJ 1999. Scleromochlus taylori and the origin of the pterosaurs. Philosophical Transactions of the Royal Society London, Series B 354 1423-1446. Online pdf
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008. Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.

News on the Origin of Pterosaurs on YouTube

I just uploaded a pterosaur origins video on YouTube. Click here to view it.

Click to view this "Origin of Pterosaurs" video on YouTube.

Click to view this “Origin of Pterosaurs” video on YouTube. 17 minutes long. 

Palaeontology [online]

Header for website paleontology online.

Header for website paleontology online. Click to go to the website.

A website (new to me, but looks like it’s been around for awhile) palaeontologyonline.com is, in their own words,

“Palaeontology [online] is a website covering all aspects of palaeontology. The site is updated with articles about the cutting edge of research, by the researchers themselves. These are usually written by experts in the field, but are aimed at non-specialists. Articles vary widely in their content: some serve as an introduction to palaeontological or interdisciplinary fields, while others outline events in the history of palaeontology. Some contributions include summaries of recent findings and advances in rapidly evolving disciplines, and some focus on a particular geographic region or time period. Finally, some of our articles are based on the experience of being a palaeontologist – what life and work is really like as a fossil worker.  Our online format allows researchers to explain their work with the aid of an unlimited number of figures and videos.”

Commissioning editors (who are responsible for inviting contributions and overseeing the website) are:

Russell Garwood: Invertebrate palaeontologist; Peter Falkingham: Postdoctoral research fellow in the fields of vertebrate palaeontology and ichnology (trace fossils); Alan Spencer: Palaeobotanist; Imran Rahman: Postdoctoral researcher in invertebrate palaeontology and evolutionary genetics.

Some great pages here. Check out this placodont page.

The pterosaur page was written by Dr. David Hone, who states, “The origins and the relationships of the pterosaurs have long been contentious, although a consensus is forming on both issues. Often confused with dinosaurs, pterosaurs are members of their own clade, but are close relatives of their more famous cousins.

Over the years, palaeontologists have hypothesized that pterosaurs originated from various parts of the reptile evolutionary tree. Very early researchers considered them to be the ancestors of birds or even bats, and for a long time it seemed that they were probably basal archosaurs (the clade that contains dinosaurs, birds, crocodilians and some other groups). More recently evidence has begun to stack up that they are a separate group to the dinosauromorphs (dinosaurs and their closest relatives) but that the two groups evolved from a common ancestor. Most researchers now support this position. This makes pterosaurs reasonably close relatives to birds, but they are not bird ancestors as is sometimes wrongly reported.”

Well, par for the course…
Sad to see when there actually is a verifiable better relationship out there, but then that would involve actually acknowledging the literature (Peters 2000, 2002, 2007, 2009, 2011) and/or testing candidates one vs. another. But nobody wants to do this without fudging the data or reducing the inclusion set. It’s time to either recognize the literature or argue with it. The large reptile tree found a long line of pterosaur ancestors between Ichthyostega and Longisquama. Almost any one will do, as we learned earlier with turtles and pterosaurs.

Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 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.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.
Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification
Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605

Pterosaur origins according to Wikipedia

Not sure
who has established him/herself as the editor of the “Pterosaur” article in Wikipedia, but there was a falsehood in there that had to be edited.

With regard to the “Origins” section, as I read it, the author reported that I did not view the fossils themselves. However, the author approved the Hone and Benton 2007 supertree analysis and the 2011 Nesbitt 2011 archosaur family tree.

The opposite is actually true. 
I had first hand access to Longisquama, Sharovipteryx, Cosesaurus, Langobardisaurus and Macrocnemus, taxa that are related to pterosaurs in order of  increasing phylogenetic distance (Longisquama is the closest). Hone and Benton, as in all authors of supertree analyses, did not even look at these specimens, but reported they were going to join together previous pertinent trees. Instead they only combined the trees they liked. They deleted Peters (2000) from their analysis and added a few typos to the scores to justify their deletion, as we discussed earlier. So there was no Bennett vs. Peters “contest.” W.C. Fields echoed their feelings when he said, “Go away, boy… you bother me.”

So, kids, this is what we’re dealing with.
No one wants to look at fenestrasaurs and there are people out there who are willing to flip the truth.

Not sure
how long the edit will stand. Wikipedia can edited by anyone. Just thought you should know…

Benton 1985 on pterosaurs

Benton 1985 was an early cladistic analysis done without a published matrix. Benton nested pterosaurs between Rhynchosaurs and Younginiforms + Lepidosaurs (that’s a stretch!). He did not report which pterosaur(s) he used in analysis.

Benton wrote: “Pterosaurs have typically been regarded as archosaurs that had their ancestry among the thecodontians (e.g. Romer, 1966; Wellnhofer, 1978). However, Wild (1978) has described two late Triassic genera on the basis of good material (Eudimorphodon, Peteinosaurus) , and he has made the proposal that the pterosaurs arose directly from ‘eosuchians’ and are not true archosaurs. Pterosaurs possess an antorbital fenestra, but Wild (1978: 247) considered that this may be a convergence. Further, Wild ( 1978: 246-253) reviewed numerous similarities between the early pterosaurs and various ‘eosuchians’ and differences from early thecodontians. The characters shared with Youngina, Prolacerta and others are all primitive to diapsids as a whole, except for the reduced quadratojugal, the ossified sternum, the ‘hooked’ 5th metatarsal, and the 3-pointed teeth seen in Eudimorphodon.

Until Peters 2000, Wild (1978) was the sole voice doubting the affinity of pterosaurs with archosaurs. Neither Wild nor Benton realized that the diapsid configuration arose twice in reptile phylogeny, as shown by the large reptile tree because their test did not include primitive reptiles.

Benton wrote: “Pterosaurs display all of the characters of the Neodiapsida as far as can be determined, except B2 (ventral processes on parietals) and B6 (emarginated quadrate). They show some archosauromorph synapomorphies (C4-10), but lack others: C1-3, 11-14. Pterosaurs share two characters with the Lepidosauromorpha: the single ossified sternum, and specialized sternal attachments for the ribs. The most parsimonious position for the pterosaurs at present is within the Archosauromorpha, as sister-group to all other archosauromorphs. Further work is needed on this question as well as on the suggestion that Pterosauria are the sister-group of Aves (Gardiner, 1982).”

Benton, to his credit, at least gave a nod to the lepidosauromorph traits. He noted pterosaurs shared 6 archosauromorph traits, but lacked 7 others.

According to Benton, archosauromorph traits shared with pterosaurs:

C4. Loss of tabulars. Benton notes they are also lost in lepidosaurs.

C5. Stapes without a foramen. I don’t think stapes have ever been identified in pterosaurs, but living lepidosaurs retain a heavier stapes with a foramen, according to Benton. Huehuecuetzpalli, at the base of the Tritosauria, does not show a foramen, but then it is only partly exposed.

C6. Vertebrae not notochordal. Benton notes that Sphenodon and geckos retain notochordal verts. Reynoso (1998) reports that Huehuecuetzpalli had amphicoelous verts, a trait shared with pterosaurs.

C7. Transverse processs on dorsal vertebrae project as distinct narrow elongate processes. Benton’s samples are all large reptiles. We don’t see these on pterosaur ancestors until Macrocnemus and all of its descendants among the tritosaurs.

C8. Cleithrum absent. Also absent on Huehuecuetzpalli. 

C9. No entepicondylar foramen in the humerus. Benton notes that lizards lose this too. Huehuecuetzpalli retains one. Cosesaurus does not have one.

C10. Loss of foramen in carpus between ulnare and intermedium. Benton notes this is lost in Squamata.

So that’s his list. Not much to say the least. I was hoping for more.

According to Benton, archosauromorph traits lacked in pterosaurs include:

C1. Premaxilla extends behind naris. Benton is wrong here, but Huehuecuetzpalli shares this trait.

C2. Nares elongate and close to midline. Benton is wrong here. Huehuecuetzpalli shares this trait.

C3. Quadratojugal (if present) located mainly behind the lower temporal fenestra. Benton is wrong here, but the same morphology is present in Cosesaurus.

C11. Presence of a lateral tuber on the calcaneum. Benton is correct! But no lateral tuber is found on Huehuecuetzpalli. 

C12. Complex concave-convex articulation between the astragalus and calcaneum. Correct, but the same is found on Huehuecuetzpalli.

C13. Fifth distal tarsal lost. Correct, but the same is found in Huehuecuetzpalli.

C14. Fifth metatarsal hooked without lepidosaur specializations. These include: ‘hooked’ in two planes. According to Benton mt5 bears specialized plantar tubercles, and it passes into the tarsus over the proximal end of the 4th metatarsal. Benton may be right. In any case pterosaurs and Huehuecuetzpalli have the same kind of mt5. In Pteranodon the metatarsus is reduced to being hooked in one plane.

Benton did not realize the rampant homoplasy in the reptilia.
The HI (Homoplasy Index) of the large reptile tree is over 0.90. So, exceptions and convergences abound within the reptilia. Very few traits are found in one and only one clade.

Benton mentioned Cosesaurus briefly, noting in the original description a long antorbital fossa (but he quoted the original French). He lumped it with Malerisaurus in “Prolacertiformes, incertae serdis”, not realizing that Cosesaurus was a tritosaur, along with Macrocnemus, Tanystropheus and Tanytrachelos, which he also considered prolacertiformes. Longisquama and Sharovipteryx, the two taxa closest to pterosaurs, were not considered.

The Gardiner (1982) paper mentioned by Benton has been largely ignored, and for good reason. Not sure why it was even included, but then, we’re talking about 1985 here. We’ll look at Gardiner 1982 tomorrow.

Bottom line:
With wrong, tenuous and convergent evidence Benton 1985 found pterosaurs nested outside the archosauromorpha. Later workers, who merely looked at the conclusions without questioning the evidence, accepted Benton’s conclusion. And look where that has brought us.

Later Hone and Benton (2007, 2009) applied the same lax interest and disposal of data to show that pterosaurs probably nested close to archosauromorphs after deleting the only competing candidate taxa. We looked at those problems in detail here.

I think it all comes down to conservatism. The same sort of conservatism that dismissed Wagner’s (and others) hypothesis on continental drift, Heyerdahl’s hypothesis on western migration to Polynesia and the static, earth-centered universe. Those days are not yet over.

Benton MJ 1985. Classification and phylogeny of the diapsid reptiles. Zoological Journal of the Linnean Society 84: 97-164.
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008. Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Reynoso V-H 1998. Huehuecuetzpalli mixtecus gen. et sp. nov: a basal squamate (Reptilia) from the Early Cretaceous of Tepexi de Rodríguez, Central México. Philosophical Transactions of the Royal Society, London B 353:477-500.

New Pterosaur Tree – Andres and Myers 2013

Pterosaur worker, Brian Andres, has produced a larger pterosaur tree than prior efforts by combining those prior efforts (Fig. 1). This was part of his 2010 PhD dissertation. The Wiki version (easier to read) can be seen here. I understand this tree will appear in a forthcoming (2014) volume entitled, “The Pterosauria.” Hope it avoids all past pitfalls, but judging by this tree (Fig. 1) and the description of the volume (“important new finds such as Darwinopterus“) we are due for another few years in the “dark ages.”

Sorry about that, kids. l’m really trying to fix things here by pointing out obvious errors.

According to Wikipedia
Andres’ phylogenetic analysis combines data mainly from three different matrixes: Kellner’s original analysis (2003) and its updates (Kellner (2004), Wang et al. (2005) and Wang et al. (2009)), Unwin’s original analysis (2003) and its updates (Unwin (2002), Unwin (2004), Lu et al. (2008) and Lu et al. (2009)) and previous analyses by Andres et al. (2005), Andres and Ji (2008) and Andres et al. (2010). Additional characters are taken from DallaVecchia (2009), Bennett’ analyses (1993-1994) and various older, non-phylogenetic, papers.

Figure 1. Click to enlarge. Pterosaur family tree produced by Andres 2010 and in press. Color added to show clades according to the large pterosaur tree that included several specimens of certain genera and included tiny pterosaurs, lacking here.

Figure 1. Click to enlarge. Pterosaur family tree produced by Andres 2010 and in press. Color added to show clades according to the large pterosaur tree (that included several specimens of certain genera and included tiny pterosaurs, lacking here). The indigo bar by Eosipterus indicates one specimen is indeed a ctenochasmatid, but the other is a germanodactylid, as we covered earlier. So, specimens are needed here, not just genera.

It’s big but still incomplete
Andres’ taxon list excludes distinct variations within certain genera, like Dorygnathus and Scaphognathus, that proved important in the large pterosaur tree. Andres’ taxon list also excludes all tiny pterosaurs. Those likewise proved important in the large pterosaur tree.

Strange bedfellows
The Andres’ tree nested several taxa that also nest together in the large pterosaur tree. However, the Andres tree also produces several nesting partners that don’t look alike. They don’t share many traits. For instance, Andres tree nests the basal anurognathid Dendrorhynchoides with the germanodactylids (Fig. 2) at the base of the “pterodactyloidea.” Few pterosaurs are so different from one another. It seems improbable that one would evolve from the other. In the large pterosaur tree this transition actually was several convergent transitions — and all sister taxa document a gradual accumulation of derived traits — not the skull-jarring leap shown here (Fig. 2).

Figure 3. According to Andres these two pterosaurs are sisters. This, obviously, is erroneous.

Figure 2. According to Andres these two pterosaurs are sisters. This, obviously, is erroneous.

Andres tree also nests the dorygnathid, Parapsicephalus (= Dorygnathus) purdoni with Dimorphodon (Fig. 3). Again, these two share very few traits. Click on the links above to see and read about pterosaurs that are more similar to these two, and you’ll see what I mean.

Figure 4. According to Andres, these two pterosaurs are close sister taxa. According to the large pterosaur tree, they nest far apart.

Figure 3. According to Andres, these two pterosaurs, Dorygnathus and Dimorphoson, are close sister taxa. According to the large pterosaur tree, they nest far apart.

There are several other misfits in the Andres tree, as shown by the various color codes (Fig. 1) that represent clades in the large pterosaur tree. For instance, Andres tree doesn’t recognize that azhdarchids and chaoyangopterids evolved from protoazhdarchids, like Beipiaopterus and Huanhepterus.

Some highlights
Andres tree does not put darwinopterids at the base of the “pterodactyloidea” but between Sordes and Changchengopterus and close to Scaphognathus. This is very close to results of the large pterosaur tree (Fig. 4).

Figure 1. Click to enlarge. Unwin and Lü note a resemblance between Darwinopterus and Germanodactylus. And that is certainly so, but only by convergence. Phylogenetic analysis indicates a closer relationship between the descendants of Scaphognathus and Germanodactylus. Arrows indicate phylogenetic order. Here the long neck evolved first with a smaller skull. Then the skull became longer in the lineage of Darwinopterus.

Figure 4. The evolutionary lines that gave rise to Germanodactylus and Darwinopterus according to the large online pterosaur tree by yours truly. Small changes, gradual accumulations of derived traits are shown here. No strange bedfellows.

Andres nests the Triassic Raeticodactylus and Preondactylus at the base of the Pterosauria. While MPUM6009 is ancestral to both, these nestings are not bad (Fig. 5).

The origin of the Pterosauria from basal Fenestrasauria

Figure 5. The origin of the Pterosauria from basal Fenestrasauria. This image is not current, but will update when enlarged. Note: Euparkeria is not involved here.

Some lowlights
Andres tree nests most ornithocheirids following the pteranodontids (Fig. 6). This means large teeth reappeared on a broad rostrum evolving from a toothless sword-like rostrum. Sharp rostrum germanodactylids make better ancestors for pteranodontids and scaphognathids make better ancestors for ornithocheirids via Yixianopterus (Fig. 6). The warp in the humerus deltopectoral crest is distinct in ornithocheirids and pteranodontids and evolved convergently.

Figure 6. Left - evolutionary lineage according to Andres in which toothless pteranodontids give rise to toothy ornithocheirids. On the right, corrected lineages for each.

Figure 6. Click to enlarge. Left – evolutionary lineage according to Andres in which toothless pteranodontids give rise to toothy ornithocheirids. Right –  corrected lineages for each clade.

At the base of the pterosaurs Andres uses the derived erythrosuchid, Euparkeria, which shares no traits with pterosaurs. He would have been better off using a tritosaur or fenestrasaur, but chose to ignore the literature on pterosaur origins (Peters 2000, 2002, 2007).

Andres nests anurognathids with darwinopterids in a false clade, “monofenestrata” in which the naris and antorbital fenestra are supposed to be confluent, evidently based on the bogus reconstruction of Anurognathus by Bennett 2007, which we dismantled earlier here and here.

Some thoughts
Since so many pterosaurs are preserved in a crushed fashion it is imperative that they be reconstructed in order to ascertain the identification of bony elements. Few other workers attempt this and Andres is not known for doing so.

It is also imperative that pterosaur workers know what a pterosaur is. Phylogenetic analysis (Peters 2000, 2007 and online studies) and character analysis (Peters 2013) demonstrate pterosaurs are not related to archosaurs, like Euparkeria, but to tritosaur fenestrasaurs.

Finally it is imperative that pterosaur workers employ the tiny pterosaurs in their analyses. The family tree will never make sense and will never produce gradual accumulations of derived characters unless the tiny pterosaurs are included.

Andres BB 2010. Systematics of the Pterosauria PhD dissertation. Yale University, 2010, 366 pages; 3440534
Andres B and Myers TS 2013. Lone Star Pterosaurs. Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 103: Issue 3-4, p 383-398.
Bennett SC 2007. A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift 81(4):376-398.
Peters D 2000. 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.
Peters D 2013. A gradual accumulation of pterosaurian traits within a series of Lepidosauriformes. Rio Ptero Symposium 2013.