First pterosaur basihyal (Gladocephaloideus?, Gallodactylidae?)

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

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

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

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

Figure 2. Cosesaurus nasal crest (in yellow).

Figure 2. Cosesaurus hyoids in bright green.

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

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

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

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


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

Could this azhdarchid eat this baby dinosaur?

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

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

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

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

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

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

Figure 3. In my opinion this saddle-bill stork wading in water appears to be the bird closest to azhdarchid morphology and, for that matter, niche.

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

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

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

Quetzalcoatlus neck poses. Dipping, watching and displaying.

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

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

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

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

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

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

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

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

Azhdarchids and Obama

Figure 5. Click to enlarge. Here’s the 6 foot 1 inch President of the USA alongside several azhdarchids and their predecessors. Most were knee high. The earliest examples were cuff high. The tallest was twice as tall as our President. This image replaces an earlier one in which a smaller specimen of Zhejiangopterus was used.

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

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


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

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

Quetzalcoatlus wingspan compared to other azhdarchids

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

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

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

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

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

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

Quetzalcoatlus running like a lizard prior to takeoff.

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

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

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

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


References
Kellner AWA and Langston W 1996. Cranial remains of Quetzalcoatlus (Pterosauria, Azhdarchidae) from late Cretaceous sediments of Big Bend National Park, Texas. – Journal of Vertebrate Paleontology 16: 222–231.
Lawson DA 1975. Pterosaur from the latest Cretaceous of West Texas: discovery of the largest flying creature. Science 187: 947-948.
Witton MP and Habib MB 2010. On the size and flight diversity of giant pterosaurs, the use of birds as pterosaur analogues and comments on pterosaur flightlessness. PloS one, 5(11), e13982.

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

wiki/Quetzalcoatlus

New pterosaur: Keresdrakon. Old cladogram.

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

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

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

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

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

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

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

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

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


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

A paper model of the ‘Discodactylus’ skull

Earlier a flat, but layered Adobe Photoshop plan of the skull of Discodactylus’ was presented (Fig. 1) and nested with the very similar anurognathid pterosaur, Vesperopterylus.

Figure 3. The skull of NJU-57003 reconstructed in animated layers for clarity. This is something the print media just cannot do as well. All elements are similar to those found earlier in other anurognathids.

Figure 1. The skull of NJU-57003 reconstructed in animated layers for clarity. This is something the print media just cannot do as well. All elements are similar to those found earlier in other anurognathids.

Here
a paper, paste and tape model of this plan is presented (Figs. 2, 3), made from a print out of the elements in figure 1.

Figure 1. Paper reconstruction of the Discodactylus skull and mandibles.

Figure 2. Paper reconstruction of the Discodactylus skull and mandibles. Yes, the dentary teeth don’t make sense. They are scattered in situ and this is not corrected here.

The extremely fragile skull
held together from below by slender palatal bones (maxillary palatal rods and hyoids not shown) provides a solution for a flying animal with a wide, rattlesnake-like gape.

Figure 3. Another view of the paper reconstruction of the skull and mandibles of Discodactylus.

Figure 3. Another view of the paper reconstruction of the skull and mandibles of Discodactylus.

Discodactylus megasterna (Yang et al. 2018; Middle-Late Jurassic; NJU-57003) is a complete skeleton of a disc-skull anurognathid with soft tissue related to Vesperopterylus (below). The sternal complex is quite large to match the wider than tall torso. Distinct from other anurognathids, m4.1 does not reach the elbow when folded.

This specimen was featured in a report (Yang et al. 2018) on pterosaur filaments that incorrectly aligned pterosaurs with feathered dinosaurs, rather than their true ancestors, the filamentous fenestrasaurs, Sharovipteryx and Longisquama.

Figure 4. Vesperopterylus skull reconstructed from color data traced in figure 3.

Figure 4. Vesperopterylus skull reconstructed 

Figure 2. Vesperopterylus reconstructed using original drawings which were originally traced from the photo. Manual digit 4.4 is buried beneath other bones and reemerges to give its length. Pedal digit 1 turns laterally due to metacarpal arcing and taphonomic crushing. There is nothing reversed about it. 

Figure 5. Vesperopterylus reconstructed using original drawings which were originally traced from the photo. Manual digit 4.4 is buried beneath other bones and reemerges to give its length. Pedal digit 1 turns laterally due to metacarpal arcing and taphonomic crushing. There is nothing reversed about it.

References
Yang et al. (8 co-authors) 2018. Pterosaur integumentary structures with complex feather-like branching. Nature ecology & evolution.

 

 

Another disc-head anurognathid from Jurassic China

Yesterday Yang et al. 2018 presented NJU-57003 (Figs. 1–3), a small anurognathid pterosaur with a great deal of soft tissue preservation, including feather-like filaments, said to be homologous with feathers. That was shown to be invalid by taxon exclusion here.

Today we’ll reconstruct
the crushed skull using DGS and nest this specimen in a cladogram using phylogenetic analysis (Fig. 4) in a few hours. Yang et al. were unable or unwilling to do either, even with firsthand access to the fossil and nine co-authors.

Figure 1. The NJU-57003 specimen and outline drawing, both from Yang et al. 2018. Various membranes and the overlooked sternal complex are colored in here.

Figure 1. The NJU-57003 specimen and outline drawing, both from Yang et al. 2018. Various membranes and the overlooked sternal complex and prepubes are colored in here. Clearly the uropatagia are separated here, as in Sharovipteryx. No wing membrane attaches below the knee.

Overlooked by Yang et al.
the sternal complex is quite large beneath the wide-spread ribs, a trait common to anurognathids. The torso, like the skull, would have been much wider than deep in vivo.

Figure 2. The skull elements of NJU-57003 colored to help alleviate the chaos of the crushed specimen. See figure 3 for the same elements reconstructed.

Figure 2. The skull elements of NJU-57003 colored to help alleviate the chaos of the crushed specimen. I can’t imagine betting able to interpret this skull without segregating each piece with a different color. See figure 3 for the same elements reconstructed with these colors.

As in other disc/flathead anurognathids
the palatal processes of the maxilla (red in Figs. 2, 3) radiate across the light-weight palate.  Yang et al. mislabeled these struts the ‘palatine’ (Fig. 1) following in the error-filled footsteps of other pterosaur workers who did not put forth the effort to figure things out.

The skull
is likewise supported by relatively few and very narrow struts. Contra Yang et al. 2018, who once again, mistakenly identify the toothy maxilla as an scleral ring (Fig. 1), the actual scleral rings (Figs. 2, 3) are complete and smaller within a large squarish orbit bounded ventrally by a deep jugal.

Figure 3. The skull of NJU-57003 reconstructed in animated layers for clarity. This is something the print media just cannot do as well. All elements are similar to those found earlier in other anurognathids.

Figure 3. The skull of NJU-57003 reconstructed in animated layers for clarity. This is something the print media just cannot do as well. All elements are similar to those found earlier in other anurognathids. Note the eyes, as in ALL pterosaurs, are in the back half of the skull.

Discodactylus megasterna (Yang et al. 2018; Middle-Late Jurassic, Yanlio biota, 165-160mya; NJU-57003) is a complete skeleton of a disc-skull anurognathid with soft tissue related to Vesperopterylus. The sternal complex is quite large to match the wider than tall torso. Distinct from other anurognathids, m4.1 does not reach the elbow when folded.

Figure 4. Subset of the LPT nesting Discodactylus with Vesperopterylus within the Anurognathidae.

Figure 4. Subset of the LPT nesting Discodactylus with Vesperopterylus within the Anurognathidae.

This specimen was introduced without a name
in a paper that incorrectly linked pterosaur filaments to dinosaur feathers (Yang et al. 2018), rather than with their true ancestor/relatives, the filamentous fenestrasaurs, Sharovipteryx and Longisquama, taxa omitted in Yang et al. and all workers listed below. Details here. The authors were unable to score traits for the skull and did not mention Vesperopterylus in their text.

Apparently the same artist
who originally traced the skull of Jeholopterus in 2003 (Fig. 5) also traced the present specimen (Fig. 1) with the same level of disinterest and inaccuracy. Compare the original image (Fig. 5 left) to a DGS image (Fig. 5 right). 

Figure 5. The original 2003 tracing of Jeholopterus (upper left) was inaccurate, uninformed and uninformative despite first hand access compared to the more informative and informed tracing created using DGS methods.

Why did these anurognathids have such long filaments?
Owls use similar fluffy feathers to silence their passage through air, first discussed earlier here.

The pterosaur experts weigh in the-scientist.com/news:
“I would challenge nearly all their interpretations of the structures. They are not hairs at all, but structural fibers found inside the wings of pterosaurs, also known aktinofibrils,” says pterosaur researcher David Unwin at the University of Leicester in the UK who was not part of the study. “They discovered lots of hair-like structures, but [don’t report any] wing fibers. I find that problematic.” Unwin suspects these fibers are likely to be present but have been mislabeled as feathers.  

This is a very important discovery,” says Kevin Padian, a palaeontologist at the University of California, Berkeley, “because it shows that integumentary [skin] filaments evolved in both dinosaurs and pterosaurs. That’s not surprising because they are sister groups, but it is good to know.”  

Padian draws attention to the pycnofibers’ “hair-like structure” as illustrating that they served as insulation. This is yet another characteristic of dinosaur and pterosaurs, along with high growth rate, pointing to their common ancestor as warm blooded.  “I wish the illustrations in the paper were better, but there is no reason to doubt them,” he adds.

Dr. Padian knows better.
He’s keeping the family secret by not mentioning fenestrasaurs (Peters 2000).

“The thing that is cool is that it bolsters the idea that pterosaurs and dinosaurs are sister taxa, if they are correct in interpreting these structures as a type of feather,” writes paleobiologist David Martill of the University of Plymouth in the UK, in an email. 

Dr. Martill knows better.
He’s keeping the family secret by not mentioning fenestrasaurs.

The specimens described in the paper are very interesting, agrees Chris Bennett, a palaeontologist at Fort Hays State University in Kansas, but in an emailed comment he describes the interpretation of the structures as problematic. “The authors’ characterization of the integumentary structures as ‘feather-like’ is inappropriate and unfortunate,” he writes. Some of the structures look like they could be from fraying or other decomposition, rather than feathers. Bennett adds that filamentous structures for insulation and sensation are fairly common, from hairy spiders to caterpillars to furry moths. “It seems to me to be premature to use filamentous integumentary structures to support a close phylogenetic relationship between pterosaurs and dinosaurs,” says Bennett. 

Dr. Bennett knows better.
He’s keeping the family secret by not mentioning fenestrasaurs.

Benton stands by his conclusion that pterosaurs wore plumage. Asked about the suggestion that the feathers could be wing fibers, he writes in an email, “Actinofibrils occur only in the wing membranes, whereas the structures we describe occur sparsely on the wings, but primarily over the rest of the body.”

Dr. Benton knows better.
He’s keeping the family secret by not mentioning fenestrasaurs. More details here.

References
Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoological Journal of the Linnean Society 118:261-308.
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 2009.
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.
Yang et al. (8 co-authors) 2018. Pterosaur integumentary structures with complex feather-like branching. Nature ecology & evolution doi:10.1038/s41559-018-0728-7

 

SVP 2018: Resolving the Mesadactylus complex of individual bones

Figure 1. Mesadactylus restored from available data as an anurognathid.

Figure 1. Mesadactylus restored from available data as an anurognathid.

The BYU specimens attributed to 
Mesadactylus 
nest with anurognathids like ?Dimorphodon weintraubi (coeval and also from North America) in the large pterosaur tree (LPT). The specimen is Late Jurassic (Morrison Formation) in age.

Sprague and McLain 2018 conclude, “the taxonomic affinity of the genus is uncertain.” So why did they title their talk “Resolving…”

All they had to do
was Google “Mesadactylus.” Or run a phylogenetic analysis. The affinities of this specimen have been known here at the LPT since 2012.

References
Spratue M and McLain MA 2018. Resolving the Mesadactylus complex of Dry Mesa Quarry, Morrison Formation, Colorado. SVP Abstracts.