The ‘feathery’ anurognathid repaired with higher resolution

No one likes to trace and reconstruct
small, crushed anurognathid pterosaurs. That’s where Digital Graphic Segregation (DGS; Fig. 1) comes into play. Come to think of it, it’s rare that any pterosaur worker attempts to trace an anurognathid in precise detail before going straight to freehand (Fig. 1 upper left by Wang, Zhou, Zhang and Xu 2002; Bennett 2007).

Figure 1.  Comparing data gathering results using first-hand observation with the DGS method on the skull of Jeholopterus.. The digital outlines were then transferred into the reconstruction.

Back in 2006 I made a first attempt
at reconstructing this specimen (CAGS Z070, originally CAGS IG 02-81, Figs. 2–6), back when it was considered Jeholopterus sp. (Lü et al., 2006). That was before any other disc-head anurognathids were known and early in my studies using low-resolution images.

Those mistakes are corrected here
(Figs. 2, 3) with higher resolution images provided by Yang et al. 2018 and a fair amount of practice during the intervening years from several other disc-head pterosaurs, like SMNS 81928 (Bennett 2007) Discodactylus and Vesperopterylus.

Figure 1. The skull of the fuzzy anurognathid CAGS Z020 under DGS.

Figure 2. The skull of the fuzzy anurognathid CAGS Z070 under DGS. This is a ventral exposure. Elements match those of other anurognathids. Colors enable rapid and easy identification of every bone. The mandible is blue, shown together with the palate elements. Below in red are the quadrates. Note how low and wide the skull is.

DGS comes in handy
to segregate and reconstruct the bones of the CAGS Z070 specimen exposed in ventral view. (Fig. 2). All the elements are similar to those in other disc-head anurognathids.

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

Note: There are no giant eyeballs in the front half of the skull here,
nor in any anurognathid pterosaurs (Fig. 4). When Bennett 2007 mistook a maxilla for a giant scleral ring, that became gospel to a generation of lazy anurognathid workers and artists. No giant eye rings have ever been found since in any pterosaur. No matching giant eye ring was ever found on the original Bennett 2007 specimen. Better still, try to trace the bones yourself — because in science anyone can repeat a valid observation.

That being said, this is a difficult skull to trace.
Fortunately evolution works in micro steps and we’ve had several other disc-head anurognathids to look at for the Bauplan (= blueprint). You may need to practice on a few before tackling the CAGS specimen preserved in palatal / ventral view.

FIgure 3. A selection of anurognathid skulls. All follow the pattern of a small eye ring in the posterior half of the skull, except Bennett's 2007 freehand reconstruction.

FIgure 4. A selection of anurognathid skulls from 2013. All follow the pattern of a small eye ring in the posterior half of the skull, except Bennett’s 2007 freehand reconstruction.

You might remember, Yang et al. 2018
used this CAGS specimen to say pterosaurs had something like feathers all over their body. New Scientist  and The Scientist quotes several pterosaur experts in their handling of this story. All of them fell prey to ‘Pulling a Larry Martin‘ by focusing on one trait while ignoring a long list of missing taxa and all their traits. None of the following pterosaur experts traced the materials nor performed the necessary phylogenetic analyses.

  1. “I think it’s now case closed, pterosaurs had feathers.” —Steve Brusatte
  2. “Our interpretation is that these bristle-type structures are the same as the feathers on birds and dinosaurs,” —Mike Benton
  3. “This is a very important discovery, 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.” —Kevin Padian
  4. ”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,” —David Martill

Surprisingly taking a more critical point-of-view is Chris Bennett, “The authors’ characterization of the integumentary structures as ‘feather-like’ is inappropriate and unfortunate. It seems to me to be premature to use filamentous integumentary structures to support a close phylogenetic relationship between pterosaurs and dinosaurs.”

The CAGS specimen

Figure 5. The CAGS specimen attributed to Dendrorhyncoides and then to Jeholopterus, but is distinct from both.

In the large reptile tree
(LRT, 1707+ taxa) pterosaurs are fenestrasaur, tritosaur lepidosaurs. In other words, pterosaurs are closer to lizards than to dinosaurs. Overlooked by Benton and the others, several pterosaur outgroups (e.g. Cosesaurus, etc.) also have furry, fuzzy, feathery coverings. Perhaps thinking of the status quo, scientists who collect a paycheck have preferred not to test this twenty-year-old hypothesis of interrelationships (Peters 2000). Sometimes it takes an outsider with gobs of retirement time to expose the fallacies of traditional textbooks (= secondary profit generators).

Figure 2. Interpretation of bony and soft tissue elements in the CAGS specimen. Click to see rollover image.

Figure 6. Interpretation of bony and soft tissue elements in the CAGS specimen. Click to see rollover image.

A note on the ventral view of the CAGS skull:
The reduction of the maxillary palate bones to slender Y-shaped structures (green in Fig. 2) has not been noticed by other workers content with freehand illustrations. Earlier in 2013 the hypothesis was proposed that these slender Y-shaped bones acted like sensors in flight while feeding on flying insects. Once the fly touched the sensor, the open jaws would snap shut. Flies and mosquitos were radiating during the Triassic alongside these aerial insect eaters.

Phylogeny
Despite these several skull score changes, no shift in topology toward the other flat-head anurognathids was recovered.


References
Bennett SC 2007. A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift 81(4):376-398.
Lü J-C, Ji S, Yuan C-X and Ji Q 2006. Pterosaurs from China. Geological Publishing House, Beijing, 147 pp.
Wang X, Zhou Z, Zhang F and Xu X 2002. A nearly completely articulated rhamphorhynchoid pterosaur with exceptionally well-preserved wing membranes and “hairs” from Inner Mongolia, northeast China. Chinese Science Bulletin 47(3): 226-230.
Yang et al. (8 co-authors including Benton MJ) 2018. Pterosaur integumentary structures with complefeather-like branching. Nature ecology & evolution

wiki/Jeholopterus

The sculpture shown on the Jeholopterus wiki page is based on my model, but they changed the skull to reflect the Bennett 2007 type skull… which is a mistake.

https://pterosaurheresies.wordpress.com/2018/12/18/pterosaur-pycnofibres-revisited-yang-et-al-2018/

https://pterosaurheresies.wordpress.com/2014/02/13/anurognathid-eyes-the-evidence-for-a-small-sclerotic-ring/

https://pterosaurheresies.wordpress.com/2013/06/21/anurognathids-and-their-snare-drum-palates/

https://www.newscientist.com/article/2188405-stunning-fossils-show-pterosaurs-had-primitive-feathers-like-dinosaurs/

https://www.the-scientist.com/news-opinion/pterosaurs-sported-feathers–claim-scientists-65220

 

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