Enigma pterosaur wing bone from Late Campanian Utah

Farke 2021
brings us a large ‘pterosaur limb bone’ (Fig. 1) from the Late Cretaceous of Utah. The author guessed the bone was an ulna, but could not determine which end was proximal.

Figure 1. Radius RMA 22574 from Farke 2021.

Figure 1. Ulna RMA 22574 from Farke 2021. Distal is at bottom.

From the abstract
“A large pterosaur bone from the Kaiparowits Formation (late Campanian, ~76–74 Ma) of southern Utah, USA, is tentatively identified as an ulna, although its phylogenetic placement cannot be precisely constrained beyond Pterosauria. The element measures over 36 cm in preserved maximum length, indicating a comparatively large individual with an estimated wingspan between 4.3 and 5.9 m, the largest pterosaur yet reported from the Kaiparowits Formation.”

That tentative identity as an ulna is confirmed here.  
Other than its more robust width and overall size, the bone is a good match for the ulna in the more completely known Triebold specimen of Pteranodon, NMC41-358 (Fig. 3). The overall size and relative length vs. width of RMA 22574 identifies this as a large Pteranodon (Fig. 2), perhaps the largest by a few percent, rather than a small azhdarchid (Fig. 4).

So, contra Farke 2021,
this specimen can be precisely constrained rather precisely beyond Pterosauria. It just takes a little comparative anatomy and taxon inclusion. Farke employed only one Pteranodon specimen (FHSM 184) for comparison, perhaps not realizing that no two known taxa are identical, even in the post-crania (Fig. 2), and others demonstrate a wide variation in size and morphology. By the way, FHSM 184 is a large solitary metacarpal 4.

Figure 2. The largest Pteranodon post-crania compared to RMA 22574, slightly larger than the largest.

Figure 2. The largest Pteranodon post-crania compared to RMA 22574, slightly larger than the largest.

A little repair work
to the broken proximal end (elbow) helps complete the match between RMA 22574 and NMC41-358 (Fig. 3).

Figure 2. Comparing RMA 22574 with the smaller and more gracile NMC41-358.

Figure 3. Comparing RMA 22574 with the smaller and more gracile NMC41-358 scaled to the same length.

A selection of Pteranodon post-crania
can be seen to scale here and one of the largest is shown here (Fig. 2). Note the relatively shorter, broader antebrachia (= radius + ulna) in the largest, latest Pteranodon species relative to the humerus (Fig. 2 upper right). The relatively shorter, more robust, largest antebrachium with the characters of RMA 22574 is restricted to large, late Pteranodon specimens.

Figure 3. RMA 22754 compared to Quetzalcoatlus sp. which has a more slender radius.

Figure 4. RMA 22754 compared to Quetzalcoatlus sp. which has a more slender radius.

Comparisons to appropriately sized azhdarchids
(Fig. 4) do not match as well. These tend to have a more gracile, hourglass appearance.


References
Farke AA 2021. A large pterosaur limb bone from the Kaiparowits Formation (late Campanian) of Grand Staircase-Escalante National Monument, Utah, USA. PeerJ 9:e10766 https://doi.org/10.7717/peerj.10766

reptileevolution.com/pteranodon-skulls.htm
reptileevolution.com/pteranodon-postcrania.htm

Pterosaur tooth scratches and diets

Bestwick et al. 2020 wrote:
“Pterosaurs, the first vertebrates to evolve active flight, lived between 210 and 66 million years ago. They were important components of Mesozoic ecosystems, and reconstructing pterosaur diets is vital for understanding their origins, their roles within Mesozoic food webs and the impact of other flying vertebrates (i.e. birds) on their evolution.

Vital? Is that what they call ‘hyperbole?’ For their outgroup, the authors employ the basal bipedal crocodylomorph with tiny hands and no toe 5, Scleromochlus, so… so far tooth scratches are not proving ‘vital for understanding their origins.‘ They ignored citations, scratches and common sense. Not a good start.

“However, pterosaur dietary hypotheses are poorly constrained as most rely on morphological-functional analogies. Here we constrain the diets of 17 pterosaur genera by applying dental micro wear texture analysis to the three-dimensional sub-micrometre scale tooth textures that formed during food consumption. We reveal broad patterns of dietary diversity (e.g. Dimorphodon as a vertebrate consumer; Austriadactylus as a consumer of ‘hard’ invertebrates) and direct evidence of sympatric niche partitioning (Rhamphorhynchus as a piscivore; Pterodactylus as a generalist invertebrate consumer).

That’s refreshing! Delivering results in an abstract. Unfortunately, there’s nothing new here and Nature papers usually break new ground.

“We propose that the ancestral pterosaur diet was dominated by invertebrates and later pterosaurs evolved into piscivores and carnivores, shifts that might reflect ecological displacements due to pterosaur-bird competition.”

Again, nothing new here.

The authors downplay fossilized stomach contents 
due to their limited preservation, so they put greater emphasis on the scratched enamel of pterosaur teeth. Comparisons are made to extant reptile tooth scratches from crocs and monitor lizards. Iguanids are not mentioned. The word ‘arboreal’ is likewise not found in the text.

Figure 3. Dsungaripterus single teeth at the tips of the jaws. Phylogenetically these began with Germanodactylus (Fig. 4).

Figure 1. Dsungaripterus single teeth at the tips of the jaws. Phylogenetically these began with Germanodactylus (Fig. 4).

Those tooth scratches are rather indistinct.
Odd that the authors downplay stomach contents in pterosaurs (based on their rarity) given the headline of their paper. So-called toothless pterosaurs are ignored despite the fact that the tips of beaks are teeth (Fig. 1). Oddly, so are dsungaripterids (Fig. 1) and ctenochasmatids, both of which have marginal teeth.

Pterodaustro adult with manual digit 3 repaired.

Figure 2. Pterodaustro adult with manual digit 3 repaired.

Juvenile diets are not mentioned appropriately
Rather phylogenetically miniaturized adult basal Rhamphorhynchus specimens are considered juveniles, forgetting the fact that all pterosaurs mature isometrically, as demonstrated by Pterodaustro (Fig. 2) and Zhejiangopterus ontogenetic series. We also have one juvenile Rhamphorhynchus, identical to larger adult.


References
Bestwick J, Unwin DM, Butler RJ and Purnell MA 2020. Dietary diversity and evolution of the earliest flying vertebrates revealed by dental micro wear texture analysis. Nature Communications https://doi.org/10.1038/s41467-020-19022-2

Bestwick J, Unwin DM, Butler RJ, Henderson DM and Purnell MA 2018. Pterosaur dietary hypotheses: a review of ideas and approaches. Biological Reviews https://doi.org/10.1111/brv.12431

Caupedactylus ybaka (Kellner 2012) enters the LPT

Kellner (2012, 2013) described
the skull of an Early Cretaceous sinopterid pterosaur, Caupedactylus ybaka (MN 4726-V, Fig. 1). The skull is about forty-six centimetres long. (Hope I got this right this time).

Earlier the same skull was posted online.

Figure x. Caupedactylus in situ and restored by sculptors.

Figure x. Caupedactylus in situ and restored by sculptors. Or a different specimen.

New Tapejarid-Tupuxuarid skull.

Figure 1. New Tapejarid-Tupuxuarid skull now named Caupedactylus.

Bones colorized in this tapejarid / tupuxuarid.

Figure 2. Bones colorized in this tapejarid / tupuxuarid, named Caupedactylus.

Abstract
“A new unusual tapejarid pterosaur from the Early Cretaceous Romualdo Formation (Araripe Basin, Brazil) is described, based on a skull, lower jaw and some postcranial elements. Caupedactylus ybaka gen. et sp. shows the typical high nasoantorbital fenestra of the Thalassodrominae but lacks a palatal ridge, and shares with the Tapejarinae several features, including a downturned rostral end, allowing its allocation to that clade.”

The new skull compared to other tapejarids. Click to enlarge.

Figure 2. Click to enlarge. The rising size of the tapejaridae.

Abstract continues
“Furthermore, the new species differs in having an anteriorly and posteriorly expanded premaxillary sagittal crest, the lacrimal process of the jugal strongly inclined, and a slit-like postpalatine fenestra, among other characters. The region of the left jugal-quadratojugal-quadrate shows a pathology that is likely the result of an infection. The lateral surface of the premaxillary crest presents grooves that were interpreted in other pterosaurs as impressions of blood vessels, corroborating growing evidence that cranial crests could have been involved in thermoregulation.”

“Also, the new species has a well-preserved palate with a large palatine forming the anterior region of the choanae and the postpalatine fenestra and a secondary subtemporal fenestra. Since the latter has been regarded as unique to non-pterodactyloids, its occurrence in Caupedactylus demonstrates that the evolution of palatal region in pterosaurs is more complex than previously thought.”

Perhaps to no one’s surprise, this specimen nested in 2013 in the large pterosaur tree (LPT) between Sinopterus dongi and Tupandactylus.


References
Campos HBN and Headden JA 2013. A review of Tupuxuara deliradamus (Pterosauria, Azhdarchoidea, Thalassodromidae) from the Early Cretaceous Romualdo Formation of Brazil. International Symposium on Pterosaurs – Rio Ptero 2013.
Elgin RA 2015. Paleobiology, Morphology and Flight Characteristics of Pterodactyloid Pterosaurs. Dissertation, University of Heidelberg.
Kellner AWA 2012. A new unusual tapejarid (Pterosauria, Pterodactyloidea) from the Early Cretaceous Romualdo Formation, Araripe Basin, Brazil. Cambridge University Press 103 (3-4) The Full Profession: A Celebration of the Life and Career of Wann Langston, Jr., Quintessential Vertebrate Palaeontologist September 2012 , pp. 409-421.
Kellner AWA 2013. A new unusual tapejarid (Pterosauria, Pterodactyloidea) from the Early Cretaceous Romualdo Formation, Araripe Basin, Brazil. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 103(3-4): 409-421.
Manzig PC et al. (10 co-authors) 2014. Discovery of a Rare Pterosaur Bone Bed in a Cretaceous Desert with Insights on Ontogeny and Behavior of Flying Reptiles. PLoS ONE 9(8): e100005.
Martill DM and Naish D 2006. Cranial Crests Development in the Azhdarchoid Pterosaur Tupuxuara, With Review of the Genus and Tapejarid Monophyly. Palaeontology 49(4): 925-941.

wiki/Caupedactylus
pterosaurheresies.wordpress.com/2013/06/06/tapejarid-or-tupuxuarid/

SVP abstracts 6: Dsungaripterus palate

This October 2020 abstract is identical
to one published in April 2020 as Chen et al. described the same Dsungaripterus palate (Fig. 1) in PeerJ. The following is a brief synopsis of that earlier post.

Figure 1. Dsungaripterus palate from Chen et al. 2020 with colors and diagrams (above) from Peters 2000 added. Note only a vestige remains of the lateral process of the palatine. The extent of the jugal is a guess here. Pink = pterygoid. Blue = palatine. Gold = ectopterygoid.  In Chen et al. the line leading toward the abbreviation pl points to the maxilla.

Figure 1. Dsungaripterus palate from Chen et al. 2020 with colors and diagrams (above) from Peters 2000 added. Note only a vestige remains of the lateral process of the palatine. The extent of the jugal is a guess here. Pink = pterygoid. Blue = palatine. Gold = ectopterygoid.  In Chen et al. the line leading toward the abbreviation pl points to the maxilla.

Chen et al. April 2020 cited
Osi et al. 2010, which we looked at earlier here. You might remember, Osi et al. thought they had discovered the true identity of palatal elements, but parenthetically acknowledged that Peters 2000 (Fig. 1) had done so a decade earlier. They did not realize others had also done so over a century before.

Prior to Peters 2000  
and ever since Williston (1902) and continuing through Huene 1914, Wellnhofer (1978, 1991) and Bennett (1991, 2001a,b), the solid palatal plate in pterosaurs had been traditionally considered the palatine. That was the orthodox point-of-view.

Virtually ignored,
Newton (1888), Seeley (1901 and Woodward (1902) reported that the solid palatal plate was an outgrowth of the maxilla, not the palatine. Unfortunately, I did not know those citations when Peters 2000 reported that the palatal plate actually originated from the maxilla. I thought I had discovered something! Rather, I had only confirmed work from a century earlier. Workers: it is important to expand your citation list so future workers will not overlook important papers, be they 20 years old or 120 years old.


References
Chen et al. (7 co-authors) 2020 (April). New anatomical information on Dsungaripterus weii Young, 1964 with focus on the palatal region. SVP Abstracts
Chen et al. (7 co-authors) 2020 (October). New anatomical information on Dsungaripterus weii Young, 1964 with focus on the palatal region. PeerJ 8:e8741 DOI 10.7717/peerj.8741

https://pterosaurheresies.wordpress.com/2020/04/03/dsungaripterus-palate-news-chen-et-al-2020/

Prior References from April 2020:
Bennett SC 1991. Morphology of the Late Cretaceous Pterosaur Pteranodonand Systematics of the Pterodactyloidea. [Volumes I and II]. – Ph.D. thesis, University of Kansas [Published by University Microfilms International/ProQuest].
Bennett SC 2001a, b. The osteology and functional morphology of the Late Cretaceous pterosaur Pteranodon. Part I and 2. General description of osteology. – Palaeontographica, Abteilung A, 260: 1-153.
Chen et al. (7 co-authors) 2020. New anatomical information on Dsungaripterus weii Young, 1964 with focus on the palatal region. PeerJ 8:e8741 DOI 10.7717/peerj.8741
Newton ET 1888. On the skull, brain and auditory organ of a new species of pterosaurian (Scaphognathus Purdoni) from the Upper Lias near Whitby, Yorkshire. Philosphoical Transaction of the Royal Society, London 179: 503-537.
Osi A, Prondvai E, Frey E and Pohl B 2010. New Interpretation of the Palate of Pterosaurs. The Anatomical Record 293: 243-258.
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Seeley HG 1901. Dragons of the air. An account of extinct flying reptiles. – London, Methuen: 1-240.
Wellnhofer P 1978. Pterosauria. Handbuch der Paläoherpetologie, Teil 19.– Stuttgart, Gustav Fischer Verlag: 1-82.
Wellnhofer P 1991. The Illustrated Encyclopedia of Pterosaurs. London, Salamander Books, Limited: 1-192.
Williston SW 1902. On the skull of Nyctodactylus, an Upper Cretaceous pterodactyl. Journal of Geology 10:520–531.
Woodward AS 1902. On two skulls of Ornithosaurian Rhamphorhynchus. Annals of the Magazine Natural History 9:1.
Young CC 1964. On a new pterosaurian from Sinkiang, China. Vertebrata PalAsiatica 8: 221-256.

wiki/Dsungaripterus

Hone 2020 reviews anurognathid pterosaurs

Here’s a new paper from Dr. DWE Hone (2020).
Quoting Hone’s own publicity sheet regarding the paper, “there’s not a huge amount to talk about here since as it’s a review, it doesn’t contain too much that’s new.”

Even so,
Hone manages to promote invalid pterosaur myths, like the pushup-takeoff (Fig. 1) and the presence of a giant eyeball in the front of the skull (Bennett 2007, Fig. 1). That was repaired here and here (Fig. 1) several years ago. The purported scleral (eyeball) ring is in fact the maxilla in the smaller flat-head SMNS 81928 specimen (Fig. 1) incorrectly referred to the genus Anurognathus (Figs. 3a, b) by Bennett 2007 and repeated by Hone 2020. Correcting the eyeball problem resulted in a traditional dimorphodontid/ anurognathid-type skull (Fig. 1 top figures) despite the skull being flatter than tall, a morphology repeated several times in later anurognathid discoveries.

Bennett presented a unique morphology
(not shared with any other pterosaur) that was copied and embraced by Witton and Hone without question. Both PhDs should have done their own scientific research instead of trusting anyone under this simple rule: “Extraordinary claims require ordinary evidence.” Yes, ordinary evidence. Just confirm or refute Bennett’s bizarre observation with your own tracing of the specimen and compare that with other similar taxa. That’s what PhDs are paid to do. To trust unique claims like Bennett 2007 without a second examination is not scientific.

Figure 1. The SMNS 81928 anurognathid specimen.

Figure 1. The SMNS 81928 anurognathid specimen, two interpretations shown slightly larger than life size. This was the first of several ‘flathead’ anurognathids to be discovered. Let’s hope the blue one can open its wings and start flapping before the eventual face plant. And how did such a take-off configuration evolve from bipedal ancestors?

In summary, Hone 2020
reviews the history of anurognathid research and renames a specimen. Hone promotes previous mistakes (Fig. 1) as valid without support from new, confirming tracings or any tracings whatsoever. Only one taxon is reconstructed (Fig. 1). No phylogenetic analysis appears. The IVPP transitional anurognathid embryo is ignored along with several other basal anurognathids (Fig. 4). Some citations are omitted (see way below). All the above shortcomings and mistakes were resolved online here and at links therein several years ago.

From the Hone 2020 Abstract:
“The anurognathids are an enigmatic and distinctive clade of small, non‐pterodactyloid pterosaurs with an unusual combination of anatomical traits in the head, neck, wings and tail.”

No. After precise tracings and phylogenetic analysis in the large pterosaur tree (LPT, 251 taxa), anurognathids are not enigmas, not all are small, the traditional clade Pterodactyloidea is invalid because it is polyphyletic (Peters 2007, LPT) and there is no reason to trust Hone’s description of the head, neck, wings and tail given his use of M Witton’s invalid illustration (Figs. 1, 2).

Compare Hone and Witton’s published anurognathids
(Figs. 1, 2) with more precise tracings (Figs. 1, 3) of the skeletal and soft-tissue elements of the Anurognathus holotype (Figs. 3a, 3b) distinct from the smaller disc-head SMNS 81928 specimen (Figs. 1, 3b), both from Solnhofen limestones.

Figure 1. From Hone 2020, illustration by M Witton of Jeholopterus. Compare to figure 2.

Figure 2. From Hone 2020, illustration by M Witton of Anurognathus, not the holotype, but the SMNS 81928 as in figure 1.

Witton and Bennett 9007 place the eyeball over the maxilla
in the large antorbital fenestra, rather than further back in the orbit, as in all other pterosaurs, over the jugal (Fig. 3a cyan), behind the lacrimal (Fig. 3a pink).

Figure 2. Click to enlarge. DGS tracing of Anurognathus ammonia. Note the placement of the lacrimals in the skull, behind the large antorbital fenestra. That is not the orbit. The small jugal (bright light blue) also indicates the placement of the small orbit in the back half of the skull, as in all other anurognathids. Also note the disappearance of the cervicals beneath the matrix. That may be an embryo by the tail. More on that tomorrow.

Figure 3a. Click to enlarge. DGS tracing of Anurognathus ammonia. Note the placement of the lacrimals in the skull, behind the large antorbital fenestra. That is not the orbit. The small jugal (bright light blue) also indicates the placement of the small orbit in the back half of the skull, as in all other anurognathids. Also note the disappearance of the cervicals beneath the matrix. That may be an embryo by the tail. More on that tomorrow.

Figure 1. The flat-head pterosaur, a private specimen (on the left) attributed by Bennett (2007) to Anurognathus ammoni (on the right).

Figure 3b. The flat-head pterosaur, a private specimen (on the left) attributed by Bennett (2007) to Anurognathus ammoni (on the right). Pedal digit 5 does not frame a membrane. Rotodactylus and other bipedal Jurassic pterosaur  tracks show how it impresses.

Hone 2020 abstract continues:
“They [anurognathids] are known from very limited remains and few have been described in detail, and as a result, much of their biology remains uncertain.

If pterosaur expert, Dr. Hone, doesn’t want to go to the effort, and wants to ignore workers who have gone to the effort years earlier (Figs. 1-4), before too long Dr. Hone will not be known as the expert he trained to be and thinks he is.

“This is despite their importance as potentially one of the earliest branches of pterosaur evolution or even lying close to the origins of pterodactyloids.

Well, which is it? Basal or transitional? A bit of effort, like creating a cladogram, would have resolved this issue. Hone has a PhD in paleontology. He should not leave things vague and unanswered. This is his passion and his job and he is not doing his job or following his passion.

“This review covers the taxonomy and palaeoecology of the anurognathids, which remain an interesting branch of pterosaurian evolution.”

Hone defined the Anurognathidae,
“as all taxa more closely related to Anurognathus than Dimorphodon, Pterodactylus or Scaphognathus.” That would include all of the taxa (and a few more recent ones) shown in figure 4. Many of these did not appear in the Hone 2020 review, which was intended to be comprehensive.

Figure 2. Click to enlarge. Anurognathids to scale. The adult of the IVPP embryo is 8x the size of the embryo, as in all other tested adult/embryo pairings.

Figure 4. Click to enlarge. Anurognathids to scale. The adult of the IVPP embryo is 8x the size of the embryo, as in all other tested adult/embryo pairings.

See below for comments
on Hone’s self-published publicity statement, which summarizes his paper and arrived a few days before the PDF became available.


References
Bennett SC 2007. A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift 81(4):376-398.
Hone DWE 2020. A review of the taxonomy and palaeoecology of the Anurognathidae (Reptilia, Pterosauria). Acta Geologica Sinica (English edition)
https://onlinelibrary.wiley.com/doi/epdf/10.1111/1755-6724.14585?saml_referrer

From DWE Hone’s publication announcement:
“Revising the frog-mouthed pterosaurs: the anurognathids”

Oops. This paper is not a revision. Hone 2020 is titled, “A review of the taxonomy and palaeoecology of the Anurognathidae”. A revision would revise present thinking. Hone himself notes he makes no attempt to do this. Let’s imagine Hone was thinking of the word ‘reviewing’ when he wrote the PR piece, but inserted the more exciting word ‘revising’ by accident.

“The anurognathids are a wonderful group of small non-pterodactyloid pterosaurs known from Europe and various parts of Asia that are perhaps the most distinctive of the early pterosaur groups and probably the latest survivors.

According to the large pterosaur tree (LPT) and simple logic, several clades of Middle and Late Jurassic pterosaurs gave rise to four pterodactyloid-grade clades, some of which extended to the last day of the Cretaceous. You don’t get Cretaceous pterosaurs without Jurassic and Triassic ancestors. Anurognathids also invaded North and South America, according to phylogenetic analysis and footprints.

“They had bizarrely short and broad skulls made of tiny spars of bone and with few teeth and remarkably short tails for non-pterodactyloids. They were mostly small and are interpreted as having been hawking for insect prey on the wing. There are few specimens (even with the recent discoveries) that are hard to tell apart because they are all so similar and yet almost every different specimen has been named as a new species.”

Hone puts no effort (no tracings, a single borrowed reconstruction, no original cladograms) into understanding, reconstructing, modeling, lumping and splitting the several known anurognathid specimens. As in prior studies, Hone stands back when scientific work is required. Hone’s writing is only in service and support to his traditional bias. He avoided citing several peer-reviewed studies that included other anurognathid materials (see below). Bottom line: Hone is supposed to be a scientist, not a journalist. He should be shedding new light on anurognathids, resolving the enigmas, not repeating what others have already published. That’s what journalists do.

“So they are both really unusual and not very well known and that means even if this has taken time to come to fruition, a review of them would be rather handy. And so as you might imagine, this post coincides with a new paper doing exactly that. Somewhat inevitably there’s not a huge amount to talk about here since as it’s a review, it doesn’t contain too much that’s new – the primary role is to bring things together and synthesise them so most of what is there is already known (at least to people who keep up with the pterosaur literature). Reading the review will bring you up speed if you want all the basics, but I do want to talk here about a couple of the more interesting things I have added.”

“The first one is the validity of the various taxa. It’s hardly unknown for pterosaur clades to be made up of lots of species each represented by only a single specimen but the anurognathids are pushing even that. While I can’t immediately think of any calls for synonymy of any taxa, the fact that so few specimens have been described in detail and the poor quality of the preservation of many means that the available lists of diagnoses have been pretty weak to date.

In counterpoint, detailed tracings and reconstructions have been online for every known anurognathid (Fig. 4) for several years. Hone omitted several of these taxa. A cladogram would have helped him separate in-groups from out-groups.

“They are not much better now, but I have at least revised and updated the diagnosis of every taxon. There are two consequences of this that are important. First off, all the current taxa seem valid, and moreover, some of the recently illustrated, but not yet named, specimens also look like they are distinct taxa and there’s probably several new names needed. Secondly, the second species of Dendrorhynchoides, D. mutodongensis is as distinct, if not more so, than many other anurognathid genera and as such needs to be elevated to the genus level… I erected the new genus Luopterus to house the species.

That’s a good name for a specimen needing a new generic name. Well done, Dave!

“Next up, the variation in the different species is quite odd. Anurognathids are weirdly conservative, even compared to other pterosaur groups and while the poor preservation of the specimens hasn’t helped up find distinguishing traits between them, once you sit down and really look it’s hard to find the kinds of traits that you might normally use to separate out genera and species.”

Seeking traits to separate specimens is “Pulling a Larry Martin“. Don’t do that. It leads to madness due to convergence, or, in this case, backing away from what must be done: a comprehensive phylogenetic analysis with all the anurognathid taxa and parts thereof laid out, lumped and separated.

“That said, there are some bits of variation which while commented on before are quite notable in this context (and there is more coming on this in a future paper that I’m involved in). The length of the tail is really variable and while these are as a whole short-tailed (even the longest of them is much shorter than other non-pterodactyloids) there is really quite some difference between the longest and the shortest. I don’t know what this means but it’s an area worthy of greater attention.

Unfortunately, Hone only crudely illustrates the variety found in anurognathid humerus shapes, but omits doing the same for the tails, or any other body parts, especially the skulls. If an amateur can do it (Figs. 1–4), a paid professional and a PhD should be able to do it that much better.

“Similarly, the smaller anurognathids tend to have extraordinarily large heads and the larger ones rather small ones.

This needed to be illustrated and documented. Reconstructions (see Fig. 4) do not reflect and confirm Hone’s observation.

“There could be ontogentic effects here since many of the smaller specimens are juveniles but it stands in contrast with the more general isometry of other pterosaurs, and could be linked to prey sizes or even eye size. If they are, any [sic] many people suspect, nocturnal then juveniles need huge heads to house huge eyes.”

Hone is correct with regard to pterosaur isometry, so why then does he label some pterosaurs ‘juveniles’, rather than small adults of distinct genera? The huge eyes guess is easily resolved by tracing each specimen and locating the eyes, none of which are ‘huge”, with the exceptions of Batrachognathus (Fig. 5) having the most owl-like eyes and most binocular. Even so, those eyes remain in the back half of the skull, as in ALL other pterosaurs.

Dorsal and lateral views of three anurognathid pterosaurs.

Figure 5. Dorsal and lateral views of three anurognathid pterosaurs. From left to right, Dendrorhynchoides, Batrachognathus and Jeholopterus, all crushed dorsoventrally, due to the skull’s greater width.

Hone continues
“Finally, there is the issue of the ‘folded’ wings. While some disarticulation can occur in decaying pterosaurs unless the specimen has disintegrated the various bones of the wing finger stay together. Presumably they are held together by numerous strong ligaments or they would not be able to hold up the forces of flight. It’s a very derived condition since of course all other archosaurs (indeed tetrapods generally) can flex their fingers.

Pterosaurs are not archosaurs. This is yet another myth Hone promotes without citing competing studies. He tried to do so once, but choked on the attempt, kowtowing to the agenda of his professor and mentor, Mike Benton. Hone has not been under the influence of Benton for over a decade, so he should show a little independence now. As a PhD pterosaur expert, knowing what a pterosaur is… that is his job and he is not doing his job. More on the wing issue below.

Anurognathids however, despite having some exquisitely preserved specimens, and nearly all of them being basically articulated, show the joints of the wing finger being flexed. This suggests that they are doing something really rather different with their wings, when flying or even when on the ground.

Not at all. The small size of most anurognathids means the wing finger did not need to be as robust as in the larger clades. That alone could account for the flexion seen in many anurognathid wing phalanges (Figs. 4, 6). There’s also taphonomy. And speaking of wings, no pterosaur fossil shows the wing membrane extending down the thigh to the ankle, as shown in the Witton illustrations (Figs. 1, 2).

Tracing of Jeholopterus using DGS.

Figure 6. Click to enlarge. Tracing of Jeholopterus using DGS. Dorsal view of Jeholopterus based on the tracing. Lower left images include an unidentified pair of semi-circles too large to be embryo upper temporal fenestrae (that was the first guess). The tail is not particularly short when stretched to its full length, despite the reduced length of the individual caudals. The red ellipse represents a hypothetical egg shape. The abdomen was not so wide. The ribs would have had a ventral component and direction, which they do not have here. Note the right angle femoral head, ideal for parasagittal locomotion, like a dinosaur.

“One thing to note is that this is also seen in one other set of pterosaur specimens – embryos. That implies that either anurognathids have inherited this trait from their ancestors (if they are, as some suggest, the first branching group of pterosaurs) or have secondarily acquired what is essentially a paedomorphic trait of wing flexion.”

If Hone had produced a valid cladogram, like the LPT, he would have been able to find a solution to his own problem. See figure 4 for a quick graphic review.

“I’ll leave it there for now. There’s plenty more in the paper that you can read and there is obviously more research to come (indeed I’m working on another anurognathid paper that’s come about in part through this work) so don’t want to go over this in detail when it’s already a review. Hopefully this does sort out a few issues and pave the way for a better understanding of these most interesting of pterosaurs.”

In counterpoint, and allowing for a little verbal showmanship on Hone’s part (e.g. using “revising” instead of “reviewing” in his PR ), all pterosaurs should be equally interesting because taxon omission by PhDs is a traditional sin. Granted, Hone is infatuated with anurognathids, like the proud father of any new paper generally should be. Unfortunately, because this paper is already in print, it is now too late to give it the care and attention it should have had when still in his mind and on his monitor.

David Hone is still a young man.
I hope that someday he will see the light, crawl out of Benton’s shadow, do the work he is paid to do, stop hiding behind taxon and citation omission, and ultimately become the pterosaur expert he trained to be.


Papers and abstracts omitted by Hone 2020
Peters D 1995. Wing shape in pterosaurs. Nature 374, 315-316.
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 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 2003. The Chinese vampire and other overlooked pterosaur ptreasures. ournal of Vertebrate Paleontology, 23(3):87.
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 2010. In defence of parallel interphalangeal lines.
Historical Biology iFirst article, 2010, 1–6 DOI: 10.1080/08912961003663500
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

See a pattern here?
Kids, if you want to get cited, get your PhD and go with the traditional bias and flow. Be willing to ignore competing citations if they come from outsiders who are willing to do the work and go the extra mile without getting paid [heavy on the sarcasm here, for those who are thinking about quote-mining this paragraph].

Development and evolution of the notarium in Pterosauria: notes and review

Aires et al. 2020
plotted the evolution of the notarium (= fused dorsal vertebrae anchoring the scapulae; Fig. 1) in pterosaurs. “The notarium is the structure formed by fusion of the dorsal vertebrae which occurred independently in pterosaurs and birds. This ankylosis usually involves two to six elements and in many cases, also includes the last cervical vertebra.

I have not seen incorporation of the most proximal of eight cervical vertebra into the notarium of pterosaurs yet. The authors note, “Vertebral fusion can be observed among contiguous centra, neural spines, and transverse processes, sometimes forming a ventral plate.” Not mentioned by the authors, dorsal vertebral fusion can occur independent of scapulocoracoid fusion and/or sacral fusion.

“Fusion can occur in different degrees, uniting the vertebral centra, the neural spines, the transverse processes, the ventral processes, or a combination of these sites. A detailed assessment of the fusion process of pterosaur dorsal vertebrae is still lacking. Here we identify the fusion sequence of pterosaur notarial elements, demonstrating the order of ossification in vertebral bodies and neural spines based on fossils and extant birds. In both Pterosauria and Aves, the notarium generally develops in a antero‐posterior direction, but the actual order of each fusion locus may present slight variations. Based on our data, we were able to identify seven developmental stages in the notarium formation, with broad implications for the prediction of ontogenetic stages for the Pterosauria.”

These ontogenetic implications do not pan out. They are based on an incorrect archosaur model of ontogeny, not the lepidosaur model of pterosaur ontogeny.

“In addition, we report the occurrence of a notarium in Ardeadactylus longicollum (Kimmeridgian, Southern Germany), the oldest occurrence of this structure in pterosaurs.”

That notarium was first published here (Fig. 1) in 2013 when that specimen was known as Pterodactylus longicollum, a taxon that nests in the Pterodactylidae far from the holotype of Ardeodactylus (Fig. 2) nesting with pre-azhdarchids.

Figure 1. Cladogram from Aires et al. 2020 suffering greatly from taxon exclusion to such an extent that unrelated pterosaurs are nested with one another.

Figure 1. Cladogram from Aires et al. 2020 suffering greatly from taxon exclusion to such an extent that unrelated pterosaurs are nested with one another. Black dot = notarium. White dot = no notarium. N = origin of notarium?

A collection of notarium data is good to have.
However the Aires et al. cladogram (21 taxa, Fig. 1) suffers greatly from taxon exclusion when compared to the large pterosaur tree (LPT, 251 taxa, Fig. 2 click to enlarge) where taxa with a notarium are highlighted in yellow.

As the outgroup Aires et al. mistakenly used 
a bipedal crocodylomorph with tiny fingers, Scleromochlus when the validated outgroups have been known for 20 years. This is an ongoing embarrassment for traditional pterosaur workers blindly supporting academic textbooks and lecturers.

Problems in the above illustration
(Fig. 1) begin with a sharp snouted Pteranodon nested with toothy, broad-snouted ornithocheirids (Scaphognathus descendants), rather than the sharp-snouted taxa with crests like tapejarids and dsungaripterids (Germanodactylus descendants). Excluding pertinent taxa in pterosaur cladograms is another ongoing embarrassment, where PhDs have let amateurs take the lead by simply adding taxa irregardless of bias, tradition and academic pressure.

Figure x. LPT. Taxa with notarium in yellow.

Figure 2. LPT. Taxa with notarium in yellow. Click to enlarge.

Oddly the Aires et al. conclusions do not place
a minimum size on notarium development. Principally large pterosaurs (and their juveniles) fuse vertebral spines (Figs. 1, 2) in the LRT.

Germanodactylus
Aires include a specimen of duck-sized  Germanodactylus (BSP 1892) among taxa with a notarium, citing the observations of others as evidence. The dorsal vertebrae in that specimen are exposed ventrally. No sister taxa in the LPT have a notarium, making that second-hand observation questionable for several reasons.

Nyctosaurus
The same holds true for the only Nyctosaurus listed (FHSM VP 2148) by Aires et al. 2020. The potential notarium is buried in the matrix, ventral surface exposed, each centrum distinct from the others. No other Nyctosaurus specimens have a notarium, including the UNSM 93000 specimen, which is exposed dorsally and the vertebrae are scattered. That’s why neither is marked with a notarium in the LPT (Fig. 2).

Diopecephalus = P. longicollum = Ardeadactylus. Normannognathus is in the box in the lower left.

Figure 1. Goose-sized Diopecephalus = P. longicollum = Ardeadactylus. Normannognathus is in the box in the lower left. Santanadactylus GIUA M 4895 at upper right. Note the unfused scapulocoracoid.

I found 16 pterosaur taxa with a notarium
out of 251 taxa in the LPT. One can add UNSM 50036, a postcranial Pteranodon of great size, which is not listed among the skull-only taxa. Several other post-cranial Pteranodon specimens (e.g FHSM VP 2062, UUPI R197) likely had a notarium given the morphology of the proximal scapulae. All are large specimens as adults. Taxa with a notarium nest in five separate clades in the LPT.

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

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

By contrast
some equally large pterosaurs (e.g. Arthurdactylus, Anhanguera) do not have a distinct notarium bar (fused and ossified parasagittal ligaments), but are reported to fuse the complete dorsal series. In the former, the sacrum was likewise fused to the dorsal series. In the later, 3 cervicals were fused to the dorsal series. Neither had a notarial bar (fused and ossified parasagittal ligaments).

Figure 2. FHSM 17956 compared to Ptweety. They are virtually identical, though Ptweety looks like a juvenile of a more robust variety of Pteranodon, thus a younger specimen because adults would be larger.

Figure 3. FHSM 17956 compared to Ptweety. They are virtually identical, though Ptweety looks like a juvenile of a more robust variety of Pteranodon, thus a younger specimen because adults would be larger.

Some inappropriate name changes are present in Aires et al.
Coloborhynchus spielbergi has been renamed Anhanguera spielbergi. Coloborhynchus robustus has been renamed Anhanguera robustus. Not sure why Aires et al. are promoting  this inappropriate lumping.

Figure 1. The new small Pteranodon wing, FHSM 17956, compared to Ptweety and the adult NMC41-358 specimen.

Figure 4. The new small Pteranodon wing, FHSM 17956, compared to Ptweety and the adult NMC41-358 specimen.

The juvenile Pteranodon
unnumbered and privately owned ‘Ptweety‘ also has a notarium, as expected. Pterosaurs, like all tritosaur lepidosaurs, developed isormetrically during ontogeny with phylogenetic ossification patterns traditionally misunderstood by pterosaur workers and their professors.

Figure 2. Gallus, the chicken, nests as a sister to the Early Cretaceous, Eogranivora, also a seed-eater.

Figure 5. Gallus, the chicken, fuses the entire backbone and sacrum, but note the scapula is not involved.

Bottom line
Colleagues, let’s all add taxa to your in-groups and out-groups so conclusions will not be undermined by an improper phylogenetic context. Let’s not cite the questionable observations of others unless confirmable by phylogenetic bracketing. There have been so many false positives published by pterosaur workers unchecked by other pterosaur referees and professors that interested amateurs are able to stand up and point the finger noting errors and omissions. Let’s fix this, together.


References
Aires AS, Reichert LM, Müller RT, Pinheiro FL and Andrade MB 2020. Development and evolution of the notarium in Pterosauria. Jounal of Anatomy. https://doi.org/10.1111/joa.13319

 

Reconstructing the Cretaceous azhdarchid Keresdrakon

Kellner et al. 2019
presented a new Early or Late Cretaceous (Aptian or Campanian) toothless pterosaur preserved as several 3D bones, far from complete (Fig. 1). Keresdrakon vilsoni (CP.V 2069) was considered an “azhdarchoid pterodactyloid.” Unfortunately, neither clade is monophyletic when more taxa are added in the large pterosaur tree (LPT, 251 taxa). The authors report, “Keresdrakon vilsoni gen. et sp. nov. was recovered as a sister taxon of the tapejaridae.”

Figure 1. All that is known of Keresdrakon layered on top of a Quetzalcoatlus sp. specimen and the same ghosted and reduced to the size of Keresdrakon.

Figure 1. All that is known of Keresdrakon layered on top of a Quetzalcoatlus sp. specimen and the same ghosted and reduced to the size of Keresdrakon.

Perhaps too little of Keresdrakon is preserved
to add it to the LPT, but layering elements atop a previously completed image of the six-foot-tall Quetzalcoatlus specimen results in a pretty close match (Fig. 1). Overall Keresdrakon is about 64% the size of Q. sp. Proportionately manual 4.1 is longer than in Q. sp.

Ontogeny
The authors note, “the presence of these growth marks suggests that this bone belongsto an ontogenetically less developed individual compared to others.”

Figure 8 in Kellner et al. 2019 has a few identification errors.

  1. a is the left ilium, not the left ischium
  2. b and c are ischia, not pubes
  3. d and e are pubes, not ischia

The coracoid identified in Kellner et al. 2020
is not co-osified to the scapula and is relatively small (Fig. 1). In pterosaurs ossification or lack thereof is phylogenetic, not ontogenetic. It’s also worth noting that basal taxa in the Azhdarcho clade also have an unfused scapula and coracoid with the coracoid often much smaller than the scapula. The tiny BSPG 1911 I 31 Solnhofen specimen is one such taxon.

Co-author, Alex Kellner, along with Wann Langston
published Q. sp. in 1996, so it’s a bit surprising that Q. sp. was not immediately seen as a close match to Keresdrakon.

Sympatry
Keresdrakon were found close to the tapejarid Caiuajara in desert sandstone.


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.
Kellner AWA, Weinschütz 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 Ciencias 91: e20190768. DOI 10.1590/0001-3765201920190768

wiki/Quetzalcoatlus
wiki/Keresdrakon

Naked pterosaurs–or feathered? PhDs clash

Earlier Yang et al. 2019
argued that pterosaurs, like the disc-headed unnamed anurognathids, CAGS-Z070 (Fig. 1) and NJU-57003 (Fig. 2), had protofeathers and thus they were related to dinosaurs with feathers.

Figure 2. CAGS Z020 anurognathid reconstructed in lateral view. As in other disc-head anurognathids the frog-like eyeballs likely rose above the flat skull.

Figure 1. CAGS Z020 anurognathid reconstructed in lateral view. As in other disc-head anurognathids the frog-like eyeballs likely rose above the flat skull.

Figure 2. NJU-57003 insitu. Even though the photo is fuzzy, so is this pterosaur apart from the wing membranes.

Figure 2. NJU-57003 insitu. Even though the photo is fuzzy, so is this pterosaur apart from the wing membranes.

Yesterday Unwin and Martill 2020 
argued that pterosaurs did not have protofeathers. They said, any feathery-looking remains are decomposing fibers shed from the wings. They note that bristle-like integumentary structures do fringe the jaws of CAGS-Z070, but they do not concede any sort of homology other than to call the bristles ‘bristles’.

Yesterday Yang et al. 2020
replied to Unwin and Martill 2020, defending their hypothesis. “In our [2019] paper, we explored the morphology, ultrastructure and chemistry of the dermal structures of pterosaurs and showed that they probably had a common evolutionary origin with the integumentary structures seen widely in dinosaurs (including birds), their close relatives.” 

Their first sentence is wrong. As long-time readers are tired of hearing by now, Peters 2000, 2007 tested the pterosaur – dinosaur relationship by adding taxa. The added taxa attracted pterosaurs away from dinosaurs and nested them in a new and overlooked third clade of lepidosaurs, the Tritosauria, of which late surviving Huehuecuetzpalli is a basal member.

Yang et al. 2020 remind us,
“all four pycnofibre types are morphologically identical to structures already described in birds and non-avialan dinosaurs, not only in terms of gross morphology but also in their ultrastructure and chemistry, including melanosomes and chemical evidence for keratin; collectively, thesefeatures are consistent with feathers.”

Or hair. Or scales. Does anyone else see Yang et al. “Pulliing a Larry Martin“? The first thing Yang et al. should do is establish the relationship of pterosaurs with more parsimonious outgroups. They should know convergence is rampant within the Vertebrata and pterosaurs have never nested with dinosaurs whenever other candidates have been offered.

“Mapping these data onto a phylogeny yields a single evolutionary origin for feathers minimally in the avemetatarsalian ancestor of both pterosaurs and dinosaurs.”

That’s what happens when you omit data and citations. Professor Michael Benton is on the list of authors. This is not the first time Benton has omitted data and citations. You might remember when Hone and Benton 2008, 2009 were going to test competing hypotheses of relationship of pterosaurs. They reported they would test the archosaur hypothesis of Bennett 1996 versus the non-archosaur hypothesis of Peters 2000. Peters tested four prior hypotheses (including Bennett 1996) by simply adding Longisquama (Fig. 5), Cosesaurus, Sharovipteryx, and Langobardisaurus (Fig. 6), all of which attracted pterosaurs to their clade. Several of these added taxa have pterosaur-like fibers on their bodies (Fig. 5). When the anticipated results did not go their way, Hone and Benton 2009 deleted all reference to Peters 2000 and wrote that Bennett 1996 had come up with both competing hypotheses.

Getting back to the Reply from Yang et al. 2020:
“In their comment, Unwin and Martill [2020] assert that the branched integumentary structures that we identified are not feathers or even pycnofibres. They make five arguments in favour of their point of
view:”

  1. “superposition or decomposition of composite fibre-like structures or aktinofibrils yields branched structures similar to those in the anurognathids;
  2. the anatomy and anatomical distribution of the anurognathid integumentary structures are consistent with aktinofibrils, but not pycnofibres;
  3. evidence for keratin and melanosomes is not indicative of pycnofibres but rather reflects contamination from epidermal tissue;
  4. the branching we reported is not consistent with exclusively monofilamentous coverings in other anurognathids; and
  5. homology of the branched integumentary structures with feathers cannot be demonstrated conclusively owing to the simple morphology of the former.”

“We refute all five of their arguments.”

The view from ReptileEvolution.com:
Apparently no one has noticed that anurognathids, like Jeholopterus (Fig. 3), are decidedly different than other pterosaurs in terms of the length and quantity of their feathery fluff. In this way, and many others, anurognathids resemble modern owls, predator birds capable of silent flight due to the fluffiness of the pelage.

It is also worth noting
that anurognathids leave no descendants after the Early Cretaceous. In any case, pterosaurs are not related to birds or dinosaurs or archosaurs or archosauriformes or archosauromorphs, as demonstrated in the large reptile tree (LRT, 1740+ taxa) which tests all candidates for dinosaur, bird and pterosaur ancestry back to headless Cambrian chordates.

Figure 4. Jeholopterus in dorsal view. Here the robust hind limbs, broad belly and small skull stand out as distinct from other anurognathids. Click to enlarge.

Figure 3. Jeholopterus in dorsal view. Here the robust hind limbs, broad belly and small skull stand out as distinct from other anurognathids. Click to enlarge.

A figure caption from Unwin and Martill 2020
(Fig. 4) reports, “The inner region of the cheiropatagium adjacent to the body anterior to the pelvis. The dark, slightly granular epidermal surface of the integument (et) covering the torso (t) contrasts with the remarkably thin epidermal surface (ep) of the integument forming the proximal region of the cheiropatagium (c). Much of the epidermis covering the cheiropatagium has been lost, exposing closely packed and aligned aktinofibrils (ak) now slightly decayed. On the far left, much of the cheiropatagium has been pulled away, leaving a few incomplete aktinofibrils and numerous fine fibrils (fb) from which they were composed.”

This is the PIN–2585/36 specimen of Sordes pilosus, which Unwin has not shown in its entirety—ever. The proximal membrane (yellow) is the left fuselage fillet (see Fig. 3), which disproves the batwing hypothesis championed by Unwin and other PhDs. Unwin and Martill say the fine fibrils at left have been ‘pulled away’. I know of no fossil processes that ‘pull’ fine fibrils away from their original insertion points.

Other Sordes specimens have been misinterpreted by Unwin since Unwin & Bakhurina 1994. Peters 1995 argued against the bat-wing interpretation offered by Unwin & Bakhurina 1994 further described nine years ago here.

Figure 4. From Unwin and Martill 2020, colors, arrows and inset added. This is all that has ever been published of PIN-2585/36, a purported Sordes specimen. Given the few clues this appears to be the left fuselage fillet (see Fig. 3), which means this is why Unwin is only showing part of it because, if so, this disproves the batwing hypothesis championed by Unwin and other PhDs.

Figure 4. From Unwin and Martill 2020, colors, arrows and inset added. This is all that has ever been published of PIN-2585/36, a purported Sordes specimen. Given the few clues this appears to be the left fuselage fillet (see Fig. 3), which means this is why Unwin is only showing part of it because, if so, this disproves the batwing hypothesis championed by Unwin and other PhDs.

Yang et al. 2020 conclude:
“In light of this, the most parsimonious interpretation of the simple and branched integumentary appendages in the anurognathid pterosaurs remains our original conclusion that they are feathers.”

This conclusion is not supported by the LRT. Taxon inclusion would have helped Yang et al. 2020. Unwin and Martill 2020 are likewise not correct. They should have shown the same evidence that Yang et al. presented was incorrect, rather than showing their own evidence, which does not support their position.

An online article posted on Phys.org
cites U of Leicester and U of Portsmouth (England) workers. David Unwin and David Martill who claim pterosaurswere in fact bald.”

The article reports, “Feathered pterosaurs would mean that the very earliest feathers first appeared on an ancestor shared by both pterosaurs and dinosaurs, since it is unlikely that something so complex developed separately in two different groups of animals.”

Unlikely ≠ impossible. Just cite the LRT where convergence is rampant. Adding taxa is something paleontologists have been loathe to do for the last twenty years since Peters 2000 moved pterosaurs away from dinosaurs and 13 years since Peters 2007 moved pterosaurs into lepidosaurs. But let’s move on…

The article then states, 
“It would also suggest that all dinosaurs started out with feathers, or protofeathers but some groups, such as sauropods, subsequently lost them again—the complete opposite of currently accepted theory.” 

Once again, add taxa to determine where feathers, or protofeathers, first appeared in tetrapods and if there was a second genesis within the clade.

The article then states,
“The evidence rests on tiny, hair-like filaments, less than one tenth of a millimeter in diameter, which have been identified in about 30 pterosaur fossils. Among these, Yang and colleagues were only able to find just three specimens on which these filaments seem to exhibit a ‘branching structure’ typical of protofeathers.”

Evidence from 30 or just 3 pterosaurs is considerable. Nevertheless, all prior authors omit the pre-pterosaurs (Cosesaurus, Oculudentavis, Sharovipteryx, Longisquama, Fig. 5) most of which have epidermal membranes and fibers. These taxa (Fig. 6) nest between pterosaurs and the lepidosaur Huehuecuetzpalli.

Longisquama in situ. See if you can find the sternal complex, scapula and coracoid before looking at figure 2 where they are highlighted.

Figure 5. Longisquama in situ. See if you can find the sternal complex, scapula and coracoid before looking at figure 2 where they are highlighted.

The Phys.org article then states,
“Unwin and Martill propose that these are not protofeathers at all but tough fibers which form part of the internal structure of the pterosaur’s wing membrane, and that the ‘branching’ effect may simply be the result of these fibers decaying and unraveling.”

Professor Unwin said:
“The idea of feathered goes back to the nineteenth century but the fossil evidence was then, and still is, very weak. Exceptional claims require exceptional evidence—we have the former, but not the latter.”

The evolution of the pterosaur tail beginning with a basal lizard, Huehuecuetzpalli.

Figure 6. The evolution of the pterosaur tail beginning with a basal lizard, Huehuecuetzpalli.

Professor Martill noted:
that either way, palaeontologists will have to carefully reappraise ideas about the ecology of these ancient flying reptiles. Martill said, “If they really did have feathers, how did that make them look, and did they exhibit the same fantastic variety of colors exhibited by birds. And if they didn’t have feathers, then how did they keep warm at night, what limits did this have on their geographic range, did they stay away from colder northern climes as most reptiles do today. And how did they thermoregulate? The clues are so cryptic, that we are still a long way from working out just how these amazing animals worked.”

As a final note, let’s remember, that when it comes to pterosaur origins, 
workers have been keeping their blinders on for decades. Not sure why, but what results is the current misunderstanding expressed by Yang et al. 2020 AND Unwin and Maritill 2020.


References
Peters D 1995. Wing shape in pterosaurs. Nature 374, 315-316.
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.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-1330
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371, 62–64.
Unwin DM and Martill DM 2020. No protofeathers on pterosaurs. Nature Ecology & Evolution. https://doi.org/10.1038/s41559-020-01308-9
Yang Z et al. 2019. Pterosaur integumentary structures with complex feather-like branching. Nature Ecology & Evolution 4, 24–30 (2019).
Yang Z et al. 2020. Reply to: No protofeathers on pterosaurs. Nature Ecology & Evolution. https://doi.org/10.1038/s41559-020-01308-9

https://phys.org/news/2020-09-naked-prehistoric-monsters-evidence-reptiles.html?fbclid=IwAR0YSjtIfZRBUiD6W3b1jwnhzWPFe_eXBE4ABFa2D8QXRCI8GNIfxNQEEs4

From today’s dml.cmnh.org:

“If you can’t cope with the idea of naked pterosaurs, don’t watch my SVP presentation…”

––––––––––––––––––––––––––––––––––––––––––––––
Dr David M Unwin
Associate Professor (Museum Studies)
School of Museum Studies, University of Leicester
t: +44 116 252 3947   e: dmu1@le.ac.uk

What is Leptostomia? So little to work with…

A new genus and species of little pterosaur
from the Early Cretaceous of Morocco, Leptostomia begaaensis (Smith et al. 2020; Figs. 1–3), is based on two, little 3D pieces of rostrum (FSAC-KK 5075) and mandible (FSAC-KK 5076) originally considered to belong to a new kind of azhdarchoid (an invalid polyphyletic clade in the large pterosaur tree; LPT, 251 taxa), that traditionally, but mistakenly includes unrelated tapejarids and azhdarchids. As usual, simply adding traditionally or specifically omitted taxa clarifies interrelationships.

Figure 1. At about twice life size, these are jaw portions from Leptostomia in several views.

Figure 1. At about twice life size, these are jaw portions from Leptostomia in several views.

The affinities of the jaw segments remain ‘unclear’
according to the authors. Once again this was due to taxon exclusion.

Figure 2. Photo of the Leptostomia rostrum fragment in several views. Colors added here.

Figure 2. Photo of the Leptostomia rostrum fragment in several views. Colors added here. Premaxilla = yellow. Maxilla = green. Vomer = purple.

Unfortunately 
Smith et al. omitted the tall, slender ctenochasmatid, Gegepterus (Fig. 3,4) from their comparables list. Gegepterus has a similar rostrum and mandible. Both are similar in size and (Fig. 4) both are from Early Cretaceous strata, one from Morocco, the other from China.

Figure 3. Leptostomia compared to coeval Gegepterus (see figure 4).

Figure 3. Leptostomia compared to coeval Gegepterus at the same scale  (see figure 4).

Most pterosaurs,
including azhdarchids and tapejarids, have a taller than wide rostrum along with a narrow premaxilla ascending process that extends to the dorsal orbit.

Figure 4. Similar to azhdarchids, Gegepterus was a tall, slender ctenochasmatid with long jaws, neck and legs.

Figure 4. Similar to azhdarchids, except for size, Gegepterus was a tall, slender ctenochasmatid with long jaws, neck and legs for an overall small pterosaur. Here it is shown 3/5 original size.

By contrast,
the Leptostomia rostrum has a wider rostrum and a wider premaxilla overlapping it. Worth remembering: both the rostrum and mandible fragments are less than 1cm wide on this small specimen and genus.

Figure 5. Leptostomia rostrum palatal view. Vomer = purple ridge. Mx = maxilla. Tiny remnant alveoli appear to be present on the lateral palatal ridge.

Figure 5. Leptostomia rostrum palatal view. Vomer = purple ridge. Mx = maxilla. Tiny remnant alveoli appear to be present on the lateral palatal ridge, overlooked by Smith et al.

Most ctenochasmatids
have long slender teeth arising from the jaw rims. No such teeth are preserved with or were collected with Leptostomia, A close view (Fig. 5) shows a line of small ovals that could be slender tooth alveoli. Or teeth may indeed be absent in this taxon.

Wiki authors describing Gegepterus in Wikipedia note:
“This is the first uncontroversial report of the Ctenochasmatidae from the Yixian Formation, as the fossils of other assumed ctenochasmatids have not preserved the dentition.”

Smith et al. note,
Leptostomia differs from other edentulous pterosaurs in possessing a remarkably low rostral lateral angle, endowing it with a very long and slender beak. Its lateral angle is also very low when compared with toothed pterosaurs with only some ctenochamatids having a similarly low lateral angle.”

Smith et al. propose a poorly informed guess,
“The new pterosaur adds to the remarkable diversity of pterosaurs known from the mid-Cretaceous, and suggests that pterosaur diversity remained under sampled.” No it doesn’t. Leptostomia looks like an omitted taxon, Gegepterus.

In the LPT there are few to no morphological gaps largely because it employs a much larger taxon list than any published by PhD workers and their students who refuse to include small taxa, more than one specimen assigned to a genus and valid pterosaur outgroups in their analyses. Same for the LRT.

Quetzalcoatlus scraping bottom while standing in shallow water.

Figure 6. Quetzalcoatlus scraping bottom while standing in shallow water.

Smith et al. state,
“The proposed probe-feeding strategy suggested by the rostrum morphology of Leptostomia has not previously been documented for the Pterosauria.” This is false. Just google, “pterosaur + probe” and a long list will appear. And there’s always this image (Fig. 6) of the man-sized Quetzalcoatlus probing, which has been online for awhile, following ‘suggestions’ from Langston 1981.


References
Langston W Jr 1981. Pterosaurs. Scientific American: 244,:122–126.
Smith RE, Martill DM, Kao A, Zouhri S and Longrich N 2020. A long-billed, possible probe-feeding pterosaur (Pterodactyloidea: ?Azhdarchoidea) from the mid-Cretaceous of Morocco, North Africa, Cretaceous Research, https://doi.org/10.1016/j.cretres.2020.104643.

wiki/Leptostomia
wiki/Gegepterus

New Quetzalcoatlus northropi skeletal model from Triebold Paleontology

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

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

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

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

Quetzalcoatlus neck poses. Dipping, watching and displaying.

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

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

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

Quetzalcoatlus running like a lizard prior to takeoff.

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

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

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

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