Vesperopterylus (aka: Versperopterylus, Lü et al. 2017) did not have a reversed first toe

And this specimen PROVES again
that anurognathids DID NOT have giant eyeballs in the anterior skull.

Figure 1. Vesperopterylus in situ. There is nothing distinct about pedal digit 1.

Figure 1. Vesperopterylus in situ. There is nothing distinct about pedal digit 1.

Lü et al. 2017 bring us a new little wide-skull anurognathid
Vesperopterylus lamadongensis (Lü et al. 2017) is a complete skeleton of a wide-skull anurognathid. It was considered the first pterosaur with a reversed first toe based on the fact that in digit 1 the palmar surface of the ungual is oriented lateral while digis 2–4 the palmar surfaces of the unguals are medial. That is based on the slight transverse curve of the metatarsus (Peters 2000) and the crushing which always lays unguals on their side. In life the palmar surfaces were all ventral and digit 1 radiated anteriorly along with the others.

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 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.

Lü et al were unable to segregate the skull bones.
Those are segregated by color here using DGS (Digital Graphic Segregation). See below. Some soft tissue is preserved on the wing. Note: I did not see the fossil first hand, yet I was able to discern the skull bones that evidently baffled those who had this specimen under a binocular microscope. Perhaps they were looking for the giant sclerotic rings in the anterior skull that are not present. Little ones, yes. Big ones, no.

Figure 1. Vesperopterylus skull with bones identified by DGS (digital graphic segregation). Lü et al. were not able to discern these bones and so left the area blank in their tracing. Note the complete lack of a giant eyeball in the front of the skull. Radius and ulna were removed for clarity and to show a complete lack of giant eyeballs (sclerotic rings) in the anterior skull. 

Figure 1. Vesperopterylus skull with bones identified by DGS (digital graphic segregation). Lü et al. were not able to discern these bones and so left the area blank in their tracing. Note the complete lack of a giant eyeball in the front of the skull. Radius and ulna were removed for clarity and to show a complete lack of giant eyeballs (sclerotic rings) in the anterior skull.

This skull reconstruction
(Fig. 4) is typical of every other anurognathid, because guesswork has been minimized here. After doing this several times with other anurognathids, I knew what to look for and found it. No giant sclerotic rings were seen in this specimen.

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

Figure 4. Vesperopterylus skull reconstructed from color data traced in figure 3. Due to the angled sides of the skull some foreshortening was employed  to match those angles. Original sizes are also shown.

With regard to perching
all basal pterosaurs could perch on branches of a wide variety of diameters by flexing digit 1–4 while extending digit 5, acting like a universal wrench (Peters 2000, FIg. 5). This ability has been overlooked by other workers for the last two decades,

Figure 1. The pterosaur Dorygnathus perching on a branch. Above the pes of Dorygnathus demonstrating the use of pedal digit 5 as a universal wrench (left), extending while the other four toes flexed around a branch of any diameter and (right) flexing with the other four toes. As in birds, perching requires bipedal balancing because the medially directed fingers have nothing to grasp.

Figure 1. The pterosaur Dorygnathus perching on a branch. Above the pes of Dorygnathus demonstrating the use of pedal digit 5 as a universal wrench (left), extending while the other four toes flexed around a branch of any diameter and (right) flexing with the other four toes. As in birds, perching requires bipedal balancing because the medially directed fingers have nothing to grasp.

I have not yet added Vesperopterylus
to the large pterosaur tree.

References
Lü J-C et al. 2017. Short note on a new anurognathid pterosaur with evidence of perching behaviour from Jianchang of Liaoning Province, China. From: Hone, D. W. E., Witton MP and Martill DM(eds) New Perspectives on Pterosaur Palaeobiology.
Geological Society, London, Special Publications, 455, https://doi.org/10.1144/SP455.16
Peters D 2000. Description and Interpretation of Interphalangeal Lines in Tetrapods. 
Ichnos, 7: 11-41

 

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What lies beneath: SMNS ‘Flathead’ anurognathid wingtips

Earlier and here we looked at deciphering the crushed skull of the ‘flathead’ anurognathid. You might remember in the original description Bennett (2007) mistook a maxilla for a giant sclerotic ring (with teeth!) and a long list of other problems. DGS was able to find a pair of every skull bone and reconstruct them into a skull similar in all respects (except for its exceptional width) to all other anurognathids. Bennett (2007) unfortunately was not able to do this and even had to resort to making up some parts. More unfortunately, the Bennett model has been adopted as correct by a wide variety of pterosaur workers and artists.

Today
we’ll look at the wing membranes and distal wing phalanges that were overlooked in the original description (Fig. 1, Bennett 2007). On a similar note, you might recall yesterday we looked at another Solnhofen pterosaur and fish that betrayed ‘what lies beneath’ by large surface bulges. Similar, but more subtle clues are present here for the careful observer.

Figure 1. Clck to enlarge and animate. Here the buried wing phalanges are shown along with more tail vertebrae and wing membranes. Boosting the contrast brings some close-to-the-surface parts to more prominence.

Figure 1. Clck to enlarge and animate. Here the buried wing phalanges are shown along with more tail vertebrae and wing membranes. Boosting the contrast brings some close-to-the-surface parts to more prominence. If the wing attached to the ankles, there should have been a lot more material folded around the knee. And if there was material around each tibia, I can’t imagine any preparator chipping it away. If you look closely in hi-rez around the left ankle you can see a wing phalanx cross section entrance and exit in the excavated areas. 

These new wing tips
bring this specimen in line with other anurognathids and most other pterosaurs that have four wing phalanges plus a wingtip ungual. Left and right sides match, of course.

I saw this specimen first hand
a few years ago and noticed the left m4.3 was diving beneath the surface, like the English Channel ‘chunnel‘. I showed that to Chris Bennett standing beside me. He didn’t see it that way. Or wouldn’t… not after publishing it with three wing phalanges. The right m4.3/m4.4 knuckle nearly reaches the surface and the distal end of the right m4.4 is broken and clearly visible after surfacing near the right posterior pelvis, but that two was overlooked originally.

Narrow chord wing membrane readily visible here,
not marred by all the prep that removed all the surface matrix within a half inch of the leg bones. As wonderful as this specimen is, it could have used both less prep and more.

References
Bennett SC 2007. A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift 81(4):376-398.

 

The AMNH animated Jeholopterus

Updated March 3, 2015 with the addition of a dorsal view of Jeholopterus.

About a year ago
the American Museum of Natural History (AMNH) in New York City (NYC) put on a pterosaur display, both in their halls and online.

Their animated portrayal
of the Late Jurassic Chinese pterosaur, Jeholopterus, caught my eye (Fig. 1).

Figure 1. Animated GIF created by the AMNH for their web page on Jeholoopterus. Note the complete lack of an airfoil in the wing, the lack of muscles in the limbs, the presence of a uropatagium between the hind limbs, the lack of a tail, eyes set on the sides of a blockhead skull, and no care to reproduce the wide ribcage. In short, there is little that is accurate about this otherwise wonderfully animated pterosaur. And where is all the long hair that should be there?

Figure 1. Animated GIF created by the AMNH for their web page on Jeholoopterus. Note the complete disregard for its preserved anatomy, the  lack of an airfoil in the wing, the lack of muscles in the limbs, the presence of a uropatagium between the hind limbs, the lack of a tail, eyes set on the sides of a blockhead skull, and no care to reproduce the wide ribcage. In short, there is little that is accurate about this otherwise wonderfully animated pterosaur. And where is all the long hair that should be there? The animator was gifted, but the blueprint was largely imaginary.

One wonders what the animators used for reference… certainly not the fossil.
This animation lacks all the traits that make Jeholopterus unique: the up-curved jawline, the forward angled eyes, the very hairy body, the broad ribcage and belly, the deep chest, the low attachment of the wing, the large-boned limbs, the surgically curved claws, the huge feet with a very large digit 5, a longish tail and longer wings. Also lacking here is a wing with a decent airfoil section, a proper trailing edge stretched between the wing tip and elbow, large limb muscles and paired uropatagia behind each hind limb. And where does that box-like skull come from??

This is an old-school pterosaur cartoon,
lacking almost everything we know about this complete and articulated fossil. For comparison, a reconstruction is offered here (Fig. 2) based on precise tracings.

Figure 3. Click to enlarge. The Jeholopterus holotype (left) alongside the referred specimen (right). No doubt they were related, but were likely not conspecific. The one on the right was an insect eater. The one on the left was specialized for drinking dinosaur blood.

Figure 3. Click to enlarge. The Jeholopterus holotype (left) alongside the referred specimen (right). No doubt they were related, but were likely not conspecific. The one on the right was an insect eater. The one on the left was specialized for drinking dinosaur blood.

Jeholopterus had so many traits distinct from those of other anurognathid pterosaurs, that it deserves more respect than the AMNH gave it. Seems they purposely avoided describing it for what it is… a vampire pterosaur (details here). Would have been a bigger draw and a more accurate presentation had they just paid attention to the details.

The genesis of this post
came from an Ask.MetaFilter.com post on binocular vision in pterosaurs posted by Hactar, who wrote: “I am trying to find any information about binocular vision in pterosaurs. This past weekend, I went to the Museum of Natural History’s exhibition on pterosaurs. Their illustrations for Jeholopterus varied greatly in the placement of they eyes from on the sides of the head to facing forward (third picture on the page). (The second image caused me to dub it “freaky monkey pterosaur.”)  So how much binocular vision did pterosaurs have? I have found a couple of scattered references to family Anurognathus (of which Jeholopterus is a genus) having binocular vision, based on the structure of ear [sic] canals. Were these pterosaurs unique in having binocular vision, or did pteranodons and other pterosaurs have vision like a raptors instead of like a tern or pigeon? Links to academic articles are acceptable, I have confederates who can access articles for me. Please nothing by David Peters. From what I can read, his work on pterosaurs is at best somewhat wrong and generally completely inaccurate, which is a shame as he seems to be the only one who has posted anything online about this. (If the site mentions Jeholopterus as a vampire, skip it).”

Several things jump out here: 

  1. The AMNH did not edit their artwork. As noted above, one piece of artwork had lateral eyes. The other had anterior eyes.
  2. Science is a process that can be repeated by anyone. Therefore, Hactar could have taken a skull photo of Jeholopterus (or any other binocular pterosaur, like Batrachognathus), and traced the elements to arrive at his/her own skull reconstruction.
  3. If my work on pterosaurs varies from “somewhat wrong to completely inaccurate,” then I am at a loss as to how to explain the internal consistency of sister taxa that not only nest in complete resolution, but gradually evolve from one to another, apparently modeling the actual evolution of the group with stone cold logic. I also note that no one else is producing accurate tracings AND reconstructions based on those tracings. The alternative, of course, is to accept hopeful monsters, like Bennett’s anurognathid, or Andres’ hypothesis that anurognathids begat pterodactyloids, or Unwin’s uropatagium and other such fanciful hypotheses.

And like I said earlier,
this is Science, so you don’t have to accept anyone’s word for whatever you’re trying to figure out. You can find out for yourself by tracing the specimen and creating your own reconstruction. If my observations and hypotheses cannot be replicated, please send me your interpretations so they can be repaired here.

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 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.

Don’t just repeat the propaganda ad nauseum.
The data is set in stone. Go get it and you’ll find the process rewarding.

References
Cheng X, Wang X, Jiang S and Kellner AWA 2014. Short note on a non-pterodactyloid pterosaur from Upper Jurassic deposits of Inner Mongolia, China. Historical Biology (advance online publication) DOI:10.1080/08912963.2014.974038
Kellner AWA, Wang X, Tischlinger H, Campos DA, Hone DWE and Meng X 2010. The soft tissue of Jeholopterus (Pterosauria, Anurognathidae, Batrachognathinae) and the structure of the pterosaur wing membrane. Proc Royal Soc B 277: 321–329.
Peters D 2003. The Chinese vampire and other overlooked pterosaur ptreasures. Journal of Vertebrate Paleontology 23(3): 87A.
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.

wiki/Jeholopterus

The vampire pterosaur has a new sister: Daohugoupterus

Cheng et al. (2014)
present a new small, late Jurassic pterosaur, Daohugoupterus. They were not quite sure what it was, assigning it to Pterosauria incerta sedis. The specimen is represented by an articulated skeleton lacking hind limbs, the anterior skull and two proximal wing phalanges (Fig. 1). Wing tip soft tissue was preserved. I believe the ulna and radius are just beneath the surface based on the positions of the humerus and carpus/metacarpus. The rest of the wing is likely twisted beneath these elements as the distal two wing phalanges frame the soft tissue.

Figure 1. Click to enlarge. Daohugoupterus in situ, colorized (left) and as originally traced (right). You'll note that DGS pulled out more details than firsthand tracing.

Figure 1. Click to enlarge. Daohugoupterus in situ, colorized (left) and as originally traced (right). You’ll note that DGS pulled out more details than firsthand tracing.

From their abstract:
“Daohugou is an important locality of the Jurassic Yanliao Biota, where
only two pterosaurs have been described so far (Jeholopterus and
Pterorhynchus). Here we report a new genus and species, Daohugoupterus
delicatus gen. et sp. nov. (IVPP V12537), from this region, consisting
of a partial skeleton with soft tissue. The skull is laterally
compressed, differing from Jeholopterus. The antorbital fenestra is
larger than in Pterorhynchus. The upper temporal fenestra is unusually
small. The short cervical vertebrae bearing cervical ribs indicate
that it is a non-pterodactyloid flying reptile. The sternal plate is
triangular, being much wider than long. The deltopectoral crest of
humerus is positioned proximally and does not extend further down the
shaft, a typical feature of basal pterosaurs. Daohugoupterus also
differs from the wukongopterids and scaphognathids from the Tiaojishan
Formation at Linglongta, regarded to be about the same age as the
Daohugou Bed. The new specimen increases the Jurassic
non-pterodactyloid pterosaur diversity of the Yanliao Biota and is the
smallest pterosaur from Daohugou area so far.”

DGS
Digital Graphic Segregation was used to pull details out of the skeleton. While the original paper described small upper temporal fenestra (that are indeed there) the figure did not show this detail. No skull bones were identified. The vertebrae were outlined without details. Color tracing and reconstruction (fig. 2) help bring this specimen ‘back to life.’ The length of the rostrum is unknown, but after phylogenetic analysis nesting with Jeholopterus, the rostrum was reconstructed like it’s sister taxon.

Reconstruction
A reconstruction of all available elements resulted in a sister to Jeholopterus, sharing many traits including the strong reduction of anterior cervical vertebrae, robust cervical vertebrae posteriorly, wide ribs creating a pancake-like torso, and a fragile skull with very large orbit (Fig. 2). Notably, Jeholopterus was a contemporary from the same Late Jurassic formation.

Figure 2. Click to enlarge. Daohugoupterus reconstructed.

Figure 2. Click to enlarge. Daohugoupterus reconstructed.

If you take a bone-by-bone survey
of the the DGS tracing vs. the original tracing (Fig. 1), you’ll find many differences. This is a difficult fossil and the accuracy of my tracings depending to a large part on testing each part within an evolving reconstruction (Fig. 3). Attempting reconstructions of roadkill pterosaurs is something conventional paleontologists are loathe to do, and they never ask me to help. Hence this blog.

Figure 1. Jeholopterus in lateral view. Note the extreme length of the dermal fibers, unmatched by other pterosaurs.

Figure 3. Jeholopterus in lateral view. Note the wide ribs.

In a side-by-side comparison (Fig. 4)
Jeholopterus and Daohugoupterus do share many traits and are roughly the same size. Daohugoupterus does not have the robust limbs and surgically curved claws that Jeholopterus has, but Daohugoupterus does have enormous eyes, probably for night vison. They share a wider than deep torso which enables them to cram their bellies, but still keep an aerodynamic disc-like shape (also see Sharovipteryx for something similar). They also share a very robust neck that gets very gracile close to the skull. I presume this gives both pterosaurs a wider range of motion at the skull/neck juncture. But why does most of the neck have to be stronger than the dorsal vertebrae?

Figure 3. Jeholopterus and Daohugoupterus in side-by-side comparison to scale. The wings were relatively short in Daohugoupterus and the pelvis was small. The skull was relatively narrower, but the torso was just as broad.

Figure 3. Jeholopterus and Daohugoupterus in side-by-side comparison to scale. The wings were relatively short in Daohugoupterus and the pelvis was small. The skull was relatively narrower, but the torso was just as broad.

On a side note
Experiment.com has accepted by submission and my first crowd-source funding project has started today. See details at:
https://experiment.com/projects/the-reptile-evolution-project

References
Cheng X, Wang X, Jiang S and Kellner AWA 2014. Short note on a non-pterodactyloid pterosaur from Upper Jurassic deposits of Inner Mongolia, China. Historical Biology (advance online publication) DOI:10.1080/08912963.2014.974038

 

Two really big anurognathids

Yesterday we looked at the adult sisters to the JZMP embryo. Today we’ll do the same with the IVPP embryo.

Figure 1. Large anurognathids and their typical-sized sisters. Here the IVPP embryo enlarged to adult size is larger than  D. weintraubi and both are much larger than more typical basal anurognathids, Mesadactylus and MCSNB 8950.

Figure 1. Large anurognathids and their typical-sized sisters. Here the IVPP embryo enlarged to adult size is larger than D. weintraubi and both are much larger than more typical basal anurognathids, Mesadactylus and MCSNB 8950.

The IVPP embryo pterosaur (Wang et al. 2004), the first ever described, was wrongly considered a juvenile ornithocheirid based on its small tail and short rostrum. At the time pterosaur juveniles were purported to have a short rostrum, but this has been proven wrong at every turn. First on that list: the JZMP embryo is an ornithocheirid and it has a long rostrum.

Phylogenetic analysis nests the IVPP embryo pterosaur together with Mesadactylus, a poorly known anurognathid. Both are sister to another large anurognathid, the misnamed “Dimorphodon” weintraubi. And all three were derived from a sister to MCSNB 8950, wrongly considered a juvenile “Eudimorphodon.

It’s a wonder to see a giant anurognathoid with an embryo the size of other anurognathoids. Only D. weintraubi approaches the embryo enlarged to adult size. Can’t wait for someone in China to come out with the big news of the discovery of the adult.

References
Wang X-L and Zhou Z 2004. Palaeontology: pterosaur embryo from the Early Cretaceous. Nature 429: 623.

Anurognathid eyes: the evidence for a small sclerotic ring

Ever since Bennett 2007, pterosaur workers have been following like sheep to a shepherd and putting a giant sclerotic ring in the antorbital fenestra. That’s a problem. Andres et al. (2010) even reported the confluence of the naris and antorbital fenestra (but to his eye, by placing the sclerotic ring in the antorbital fenestra, there was only one opening ahead of it, the naris). And this he used as a character to unite pterodactyloids with anurognathids in phylogenetic analysis. (I’m not sure it can get any worse than this.)

Figure 1. The flathead anurognathid in visible light (above) and UV (below). Sclerotic rings n pink. Maxillae in blue.

Figure 1. Click to enlarge. The flathead anurognathid in visible light (above) and UV (below). Sclerotic rings n pink. Maxillae in blue. Nasals highlighted in upper left image.

Sclerotic rings are bones formed in the scleral portion of the eyeball. They form a disc around the iris. Then everything rots, they usually fossilize as a ring or the scattered remnants thereof. I have never seen such a ring fossilized standing on edge in a crushed fossil. But this is what you have to believe you get if you follow the Bennett 2007 hypothesis in the flathead anurognathid (Fig. 1, SMNS 81928a & b). Witton, Andres and others bought into this.

When I took a look at that fossil, I found two small sclerotic rings in the back half of the skull (Fig. 1), where they are in all other pterosaurs and anurognathids. What Bennett took to be a giant sclerotic ring on the left is actually the maxilla, convex ventrally. It is difficult to make out the bones of the skull in that fossil, but I have provided a guide here.  Putting the bones back together in a reconstruction seals the deal (Fig. 6). Everything fits and there’s only gradual, not radical, change between sister taxa.

Figure 2. Click to enlarge. Batrachognathus with sclerotic ring impressions highlighted.

Figure 2. Click to enlarge. Batrachognathus with sclerotic ring impressions highlighted. This specimen has the largest eyes known among anurognathids.

In Batrachognathus (click this link to see all bones identified) some of the bones are red/brown. Others are represented by impressions. Such is the case with the sclerotic rings. Here they are larger and more owl-like than in other anurognathids. Nevertheless, a skull reconstruction (Fig. 6) is fairly standard in most aspects.

Figure 3. Click to enlarge. The GLGMV 0002 specimen attributed to Dendrorhynchoides. Sclerotic rings highlighted.

Figure 3. Click to enlarge. The GLGMV 0002 specimen attributed to Dendrorhynchoides. Sclerotic rings highlighted.

The GLGMV 0002 specimen (Fig. 3, Hone and Lü 2010) has two small sclerotic rings at the back of its skull. See the reconstruction (Fig. 6) to make sense of this roadkill.

Figure 4. Click to enlarge. Sclerotic rings on Jeholopterus.

Figure 4. Click to enlarge. Sclerotic rings on Jeholopterus.

Jeholopterus, the vampire pterosaur, also has two small sclerotic rings at the back of its skull. Nothing big filling the front half here.

Figure 5. Click to enlarge. Anurognathus holotype with bones identified. Here the sclerotic ring is not so clear, but the jugal is. And the jugal carries the sclerotic ring.

Figure 5. Click to enlarge. Anurognathus holotype with bones identified. Here the sclerotic ring is not so clear, but the jugal is. And the jugal carries the sclerotic ring. Orange = nasal. Yellow = pmx. Pink = lacrimal. Green = maxilla. Blue = jugal. Digital graphic segregation helps locate and identify elements here. That mass of green is wing membrane.

Ironically, Anurognathus has a very small sclerotic ring over its small jugal. While there is a large antorbital fenestra here, which Bennett and Andres would call the orbit, there is no sclerotic ring in there. It should be very easy to see if present. Trouble is, it’s not present. Observations should be repeatable. Bennett called the flathead pterosaur a juvenile Anurognathus. If they are conspecific, they should have the same bones. So, where is the giant sclerotic ring?

Figure 1. Anurognathid skulls in phylogenetic order.

Figure 6. Anurognathid skulls in phylogenetic order.

The variety in anurognathid skulls is a wonder to behold, but the little monster created by Bennett (20078) stands out as an outlier in this group of skull reconstructions (Fig. 6). Clearly something is wrong here (not duplicated in any other anurognathid).

References
Andres B, Clark JM and Xing X 2010. A new rhamphorhynchid pterosaur from the Upper Jurassic of Xinjiang, China, and the phylogenetic relationships of basal pterosaurs, Journal of Vertebrate Paleontology 30: (1) 163-187.
Bennett SC 2007. A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift 81(4):376-398.
Hone DWE and Lü J-C 2010. A New Specimen of Dendrorhynchoides (Pterosauria: Anurognathidae) with a Long Tail and the Evolution of the Pterosaurian Tail. Acta Geoscientica Sinica 31 (Supp. 1): 29-30.

Anurognathid flying abilities – Rio Ptero Symposium

Earlier we talked about various Rio Ptero Symposium abstracts here, here, here, and here.

Today we look at anurognathids
Habib and Witton wrote, “The ration of humeral to femoral section modulus in Anurognathus ammoni is significantly lower than that for pterosaurs.” Habib is famous for reporting the humerus in pterosaurs was much stronger than the femur and so concluded that pterosaurs launched by leaping with their hind limbs to compress their forelimbs in preparation for a forelimb launch. This odd and, so far, unsupported by footprint evidence, hypothesis was covered earlier here and here.

But getting back to that ratio
Here are the two specimens attributed to Anurognathus (Fig. 1) in which the humerus is no thicker at its smallest diameter than the femur. In most pterosaurs the humerus is thicker. There are other notable exceptions here.

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

Figure 1. The flat-head pterosaur, a private specimen (on the left) attributed by Bennett (2007) to Anurognathus ammoni (on the right). There are several generic differences here, readily observed.

Habib and Witton report that:

  1. Anurognathids had short faces – this is based on the bad reconstruction of the flathead anurognathid (Bennett 2007) which was misinterpreted with a giant orbit (actually a maxilla) in the front half of the skull, different than ALL other pterosaurs.
  2. Anurognathids had a wingspan up to .9m (Habib and Witton did not consider the IVPP embryo, 8x larger than most other anurognathids and Dimorphodon? weintraubi, which nests with anurognathids in the large pterosaur tree).
  3. Anurognathids include only 4 species (the large pterosaur tree found 9 + 3 more protoanurognathids)
  4. Much of anurognathid osteology has been documented (actually only the post-crania has been accurately traced, the skulls have not been successfully reconstructed in the literature, but can be found here).
  5. Anurognathids are the only probable pterosaurian aerial insectivores, ignoring the many small to tiny pterosaurs (and their 8x smaller juveniles!) that could only have fed on the tiniest of insects.
  6. Their estimate for the wingspan of [the small, flathead] Anurognathus ammoni at 22 cm deletes the distal wing phalanges.
  7. Habib and Witton note “the average humeral breadth at midshaft relative to body mass is greatest in those birds and bats that habitually sustain hovering and feed on nectar, but the relative humeral diameter also tends to be greater than average in those species that hawk insects on the wing” – but this can’t pertain to pterosaurs as giant ornithocheirids greatly exceed those ratios when compared to anurognathids.
  8. Anurognathids had “dorsally-facing eyes” – wow, that’s weird and unsupported by ANY fossil reconstructions.  Even the bad Bennett (2007) reconstruction had a broad skull roof with laterally-facing eyes.
  9. Anurognathids probably performed “perch and chase” methods of hunting, as well as, or instead of sustained hunting flights. – This idea may come from deleting the distal wing phalanges (Bennett 2007), making the pterosaur less of a long-wing nighthawk analog. Odd that Habib and Witton do this because Jeholopterus and Batrachognathus, the two most derived anurognathids have a full complement of four wing phalanges plus the ungual.

Habib and Witton compare the gape of anurognathids to the freckled nightjar (Caprimulgus tristigma) as we did earlier with the common swift (Apus apus). That’s valid.

The skull and skeleton of Apus apus,

Figure 2. The skull and skeleton of Apus apus, the Common Swift.

Habib and Witton omitted any reference to the vampire anurognathid, Jeholopterus, or any reference to its unique morphology, including its incredible long curved hand claws, the super strong feet and, of course, the fangs, but do note that anurognathids “would have been competent leapers and ground launchers that may indicate a unique life history or ecology.” That I can agree with.

Too bad Habib and Witton did not touch on the right angle, dinosaur-like, femoral articulations to the pelvis, their extraordinarily long feet and even longer fifth toes. They didn’t discuss their unique and sensitive palatal bones or their extremely wide bodies.

As readers know, I have not been charitable with the works of Mike Habib and Mark Witton, but rather critical. I only wish they would start making accurate reconstructions from precise tracings and then create their own phylogenetic analyses over a wide gamut of pterosaurs so these problems would go away.

References
Bennett SC 2007. A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift 81(4):376-398.
Habib MB and Witton M 2013. Functional morphology of anurgnathid pterosaurs and the evolution of insectivore in the Pterosauria. Rio Pterosaur Symposium 2013:74-76.