Flugsaurier 2018: ‘Young istiodactylid’ nests with tall pterodactylids in the LPT

Flugsaurier 2018 opens today, August 10,
and the abstract booklet is out. So it’s time to take a look at some of the news coming out of that Los Angeles pterosaur symposium. Since the purpose of the symposium is increase understanding of pterosaurs, I hope this small contribution helps.

Figure 1. The Erlianhaote specimen attributed by Hone and Xu 2018 to istiodactylidae nests in the LPT with the large derived pterodactylids.

Figure 1. The Erlianhaote specimen attributed by Hone and Xu 2018 to the clade Istiodactylidae (within Ornithocheiridae) nests in the LPT with the large derived pterodactylids. Note the un-warped deltopectoral crest and lack of a deep cristospine, along with the long legs and short wings.

Hone and Xu at Flugsaurier 2018
describe, “An unusual and nearly complete young istiodactylid from the Yixian Formation, China (Fig. 1). The specimen shows the characteristic istiodactylid cranial features of tooth shape and enlarged nasoantorbital fenestra. However, it has proportionally large hindlimbs and wing proportions that are similar to those of azhdarchids. This has led to suggestion that the specimen may be a composite and that only the cranial material is istiodactylid. Preparation work around some key parts revealed no inconsistencies in the matrix or evidence of glue. The specimen is held in the Erlianhaote Dinosaur Museum, Erlianhote, China.”

Figure 2. The Erlianhaote specimen nests with these pterodactylids in the LPT, not with Istiodactylus (Fig. 3).

Figure 2. The Erlianhaote specimen nests with these pterodactylids in the LPT, not with Istiodactylus (Fig. 3). Note the antorbital fenestra becomes longer with larger size in this clade. The teeth are similar to those in istiodactylids.

Reconstructed as is
(Fig. 2) and added to the large pterosaur tree (LPT, 233 taxa, not yet updated due to no museum number nor genus name) the young ‘istiodactylid’ nests as a large derived pterodactylid. 13 steps separate this taxon from the Istiodactylus clade.

Ornithocheirids,
like Istiodactylus (Figs. 3, 4) and the SMNL PAL 1136 specimen (Fig. 5), share a very large wing finger, a short metacarpus, a warped deltopectoral crest, small free fingers and deeply keeled sternal complex not found in the Erlianhote specimen.

Figure 3. Istiodactylus has a shorter neck, longer wing finger and deep cristospine, among other traits not found in the new Erlianhaote specimen.

Figure 3. Istiodactylus has a shorter neck, longer wing finger and deep cristospine, among other traits not found in the new Erlianhaote specimen.

Figure 4. Istiodactylus sinensis is an istiodactylid from China sharing few traits with the new Erlianhaote specimen. Note the warped deltopectoral crest not warped in the new specimen.

Figure 4. Istiodactylus sinensis is an istiodactylid from China sharing few traits with the new Erlianhaote specimen. Note the warped deltopectoral crest not warped in the new specimen. Manual 4.1 is shorter than in other well-known istiodactylids.

The largest ornithocheirid

Figure 5. The unnamed largest ornithocheirid, SMNK PAL 1136, nests with Istiodactylus.

Figure 6. The Erlianhaote pterodactylid reconstructed in several views.

Figure 6. The Erlianhaote pterodactylid reconstructed in several views. The imagined (gray) areas of the skull here were imagined as an istiodactylid, but the better restoration is shown in figure 2.

It’s better not to eyeball certain specimens.
Sometimes you have to run them through a phylogenetic analysis to find out what they are. That’s what the LPT is for. It minimizes taxon exclusion and handles convergence.

Pterosaurs are still lepidosaurs.
So they follow lepidosaur fusion patterns, which follow phylogeny. Hone and Xu made the mistake of imagining pterosaurs might have archosaur fusion patterns that follow ontogeny.

Why am I not at Flugsaurier 2018?
In addition to about a dozen reasons that I can list later, or your can guess now, I can be more helpful and timely here.

References
Andres B and Ji Q 2006. A new species of Istiodactylus (Pterosauria, Pterodactyloidea) from the Lower Cretaceous of Liaoning, China. Journal of Vertebrate Paleontology, 26: 70-78.
Bowerbank JS 1846. On a new species of pterodactyl found in the Upper Chalk of Kent P. giganteus). Quarterly Journal of the Geological Society 2: 7–9.
Bowerbank JS 1851. On the pterodactyles of the Chalk Formation. Proceedings of the Zoological Society, London, pp. 14–20 and Annals of the Magazine of Natural History (2) 10: 372–378.
Bowerbank JS 1852. On the pterodactyles of the Chalk Formation. Reports from the British Association for the Advancement of Science (1851): 55.
Hone DWE and Xu 2018. An unusual and nearly complete young istiodactylid from the Yixian Formation, China. Flugsaurier 2018: the 6th International Symposium on Pterosaurs. Los Angeles, USA. Abstracts: 53–56.
Hooley RW 1913. On the skeleton of Ornithodesmus latidens. An ornithosaur from the Wealden shales of Atherfield (Isle of Wight)”, Quarterly Journal of the Geological Society, 69: 372-421
Howse SCB, Milner AR and Martill DM 2001. Pterosaurs. Pp. 324-335 in: Martill, D. M. and Naish, D., eds. Dinosaurs of the Isle of Wight, The Palaeontological Association
Wang X, Rodrigues T, Jiang S, Cheng X and Kellner AWA 2014. An Early Cretaceous pterosaur with an unusual mandibular crest from China and a potential novel feeding strategy. Scientific Reports 4 : 6329, pp. 1-9. | DOI: 10.1038/srep06329
Witton MP 2012. New Insights into the Skull of Istiodactylus latidens (Ornithocheiroidea, Pterodactyloidea). PLoS ONE 7(3): e33170. doi:10.1371/journal.pone.0033170

wiki/Istiodactylus

Advertisements

Anhanguera animation at the NHM (London)

This one started off with so much promise
as the animators at the National History Museum (NHM) in London assembled their version of the ornithocheirid pterosaur, Anhanguera, bipedally (Fig. 1), as you’ll see when you click on the video under ‘References’.

Figure 1. Animated by the NHM, Anhanguera is bipedal and flapping its literally oversize wings.

Figure 1. Animated by the NHM, Anhanguera is bipedal and flapping its literally oversize wings standing on oversize feet with an undersized skull and hyperextended elbows and unbalanced stance.

Unfortunately there were some morphology issues (compared in Fig. 2):

  1. wings too long
  2. sternal complex missing
  3. gastralia missing (but rarely preserved in ornithocheirids)
  4. feet way too big
  5. skull too small
  6. tail too short
  7. not sprawling
  8. free fingers too big
  9. wing fingers should tucked tight against elbows (in the same plane)
  10. one extra cervical
  11. anterbrachia too short and gracile
  12. elbows overextended (in Fig. 1)
  13. too much weight put on forelimbs, center of balance (wing root) should be over the toes
  14. Prepubes are extremely rare in ornithocheirds, but when present they are tiny, putter-shaped and oriented ventrally in line with the bent femora, not anteriorly
Figure 2. NHM Anhanguera compared to skeletal image from ReptileEvolution.com.

Figure 2. NHM Anhanguera compared to skeletal image from ReptileEvolution.com. There are at least 10 inaccuracies here. See text for list.

Also unfortunately, the video quickly devolved
to the invalid and dangerous quad launch, when (doggone it!) it was all set up to do a more correct and  much safer bird-like launch. The laws of physics and biomechanics are ignored here, but at least David Attenborough narrates.

Figure 3. NHM Anhanguera quad launch select frames.

Figure 3. NHM Anhanguera quad launch select frames. The laws of physics and the limitations of biomechanics are ignored here.

Attempts to convince readers and workers
that the quad-launch hypothesis cheats morphology and physics (as recounted here and at links therein) have so far failed. But I’m not giving up. So, if anyone has a connection to the NHM in London, please make this post available to alert them of their accidental foray into wishful thinking and inaccurate morphology.

References
National History Museum (NHM) in London

Azhdarcho restored (from bits and pieces)

Earlier
we looked at the neck and skull of Azhdarcho… Today we’ll put all the bits and pieces we know (from several individuals, unfortunately) to see what we get, following the Q. sp. bauplan (Fig. 1).

Figure 1. Azhdarcho to scale with more complete smaller Quetzalcoatlus specimen and in proportion to the bauplan of Q. sp. Note the robust femur and gracile humerus. These together with the small sternal complex and short distal wing elements indicate a flightless condition.

Figure 1. Azhdarcho to scale with more complete smaller Quetzalcoatlus specimen and in proportion to the bauplan of Q. sp. Note the robust femur and gracile humerus. These together with the small sternal complex and short distal wing elements indicate a flightless condition.

Azhdarcho lancicollis (Nesov 1984, Averianov 2010) is the namesake for the clade Azhdarchidae. This species is known from several individuals of various sizes and very few complete bones. That is why reconstructions of this genus are rare. This reconstruction is based on the more complete Q. sp., but about half as tall.

Given these limitations,
(no complete long bones), the femur appears to be more robust than in other azhdarchids, while the humerus is more gracile. Only in Huanhepterus is the femur so relatively short. The sternal complex is quite small, but with a deep cristospine, distinct from other azhdarchids. (Perhaps the rest of the sternal complex is missing.) Manual 4.4 was identified by Averianov, but it appears to be the distal portion of m4.3. The scale bars for the distal femur appear to be in error, or apply to a much larger individual (see Fig. 1).

The invisible aid in this reconstruction
is the observation that in nearly all post-Huanhepterus azhdarchids, the metacarpus, manual digit 4 and tibia are similar in length (Fig. 1), no matter how small or tall… probably to facilitate terrestrial locomotion.

Unfortunately,
not enough is known of Azhdarcho to add it to the LRT. So much has to be imagined.

References
Averianov AO 2010. The osteology of Azhdarcho lancicollis Nessov, 1984 (Pterosauria, Azhdarchidae) from the Late Cretaceous of Uzbekistan. Proceedings of the Zoological Institute of the Russian Academy of Sciences, 314(3): 246-317.
Nesov LA 1984. Upper Cretaceous pterosaurs and birds from Central Asia. Archived 17 March 2012 at the Wayback Machine. Paleontologicheskii Zhurnal, 1984(1), 47-57.

wiki/Azhdarcho

Battle of the giant Quetzalcoatlus sculptures

Bigger is better
especially when it comes to pterosaurs in museum exhibits. To wit: The Field Museum (Chicago, IL, USA) is installing a flying Quetzalcoatlus (Fig. 3) and a standing Quetzalcoatlus (largely imagined and restored, based on an almost complete wing bone, Fig. 1).

The artist/professors in Southern England
have one as well (Fig. 1). And full scale Q. northropi sculptures can be found worldwide! (See links and images at the end of this post.)

Figure 1. Field Museum Quetzalcoatlus (tan) vs. English Quetzalcoatlus (gray) vs. a tracing of the real Q. sp. and Q. northropi scant remains.

Figure 1. Field Museum Quetzalcoatlus (tan) vs. English Quetzalcoatlus (gray) vs. a tracing of the real Q. sp. and Q. northropi scant remains. Yes, the skull on the Field Musuem model is too long, evidently following the invalid archosaur hypothesis of origin. Pterosaurs, like other tritosaurs, do not change their proportions during growth as fossils demonstrate.

These models arrive on the heels
of a recent post on flightless giant pterosaurs. The Field Museum model (Fig. 1) appears to have a more precisely modeled skull, though about 50% too long (but really, without a skull, who knows?). Perhaps the skull was elongated (based on the smaller ?species) based on the invalid archosaur hypothesis of pterosaur origins. We know from the evidence of fossils that hatchlings and juvenile pterosaurs had adult proportions, not longer skulls.

Both models suffer
from putting too much weight on the tiny free fingers. The feet should be beneath the shoulder joint, as in birds, to take the weight off the tiny hyperextended fingers, acting more like ski poles, not providing thrust, only some sort of support.

The folded wing membrane should tend to disappear
(Fig. 2), but it shows in both models. The wing finger should flex closer to the elbow, but it doesn’t (probably to let the wing membrane show). The wing membrane chord should be shorter, to the elbow, but in both models the brachiopatagium blends with the leg, always awkwardly and in defiance of the data preserved in all pterosaur fossils (Fig. 2) that preserve soft tissue.

Here's how the wing membrane in pterosaurs virtually disappeared when folded.

Figure 2. Here’s how the wing membrane in pterosaurs virtually disappeared when folded. This is a tiny pre-azhdarchid, CM 11426.

Over at the Carnegie Museum (Pittsburgh, PA, USA)
they have a tiny pre-azhdarchid, CM 11426 (Fig. 2), with real wing membranes, as described above, matching those of other pterosaur soft tissues.

Figure 3. Field museum flying Quetzalcoatlus model has the invalid deep chord wing that attaches to the tibia.

Figure 3. Field museum flying Quetzalcoatlus model has the traditional but invalid deep chord wing that attaches to the tibia and makes this sort of pterosaur untenably awkward.

Figure 2. Quetzalcoatlus recreated as a digital model by Henderson 2010 compared to a bone reconstruction. No wonder the results were odd. The math was wrong.

Figure 4. Quetzalcoatlus recreated as a digital model by Henderson 2010 compared to a bone reconstruction. This is a possible slightly deeper wing chord. Compare this one to figure 5, which is more typical. And look at those hind limbs, like those of Sharovipteryx, forming a horizontal stabilizer, just like a typical airplane. And it matches the evidence (Fig. 2).

Not sure why pterosaur paleontologists
keep insisting that evidence (Fig. 2) can and should be ignored. It’s disheartening to see this and leaves them open to criticism.

Quetzalcoatlus running like a lizard prior to takeoff.

Figure 5. Quetzalcoatlus running like a lizard prior to takeoff. Click to animate. Giant azhdarchids gave up flying by reducing the lenth of their wings, following the patterns of other flightless pterosaurs. There is no awkwardness with this narrow chord wing design, which follows fossils like CM 11426 (Fig. 2).

Other online Quetzalcoatlus models/sculptures:

Low Poly Quetzalcoatlus model

https://www.alamy.com/stock-photo-muenchehagen-germany-10th-apr-2017-a-sculpture-of-the-quetzalcoatlus-138149396.html

https://blog.everythingdinosaur.co.uk/blog/_archives/2014/07/07/collecta-quetzalcoatlus-with-prey-model.html

If some of these seem to defy the ability to fly based on
a too far aft center of lift and a too far forward center of balance, or too small of a wing for such a large mass, no worries mate! If the imagination can soar, then so can these giants (NOT!) In the above YouTube video, the invalid, but traditional batwing shape of the brachiopatagium is best seen in the pterosaur’s shadow.

Quetzalcoatlus northropi

Tierra de dinos - Quetzalcoatlus Northropi

IF the wing membranes seem encumbering
awkward, liable to trip up the pterosaur or catch on some low lying shrub, no worried, mate! As these pterosaurs once wandered, let your imagination wander. There’s no need to precisely follow the evidence (Fig. 2) that shows the wing membranes essentially disappearing while flexed/folded.

Quetzalcoatlus at the Toledo Zoo

It’s going to be difficult to raise the wings for flight
given some of these awkward quadrupedal poses. Much better to have the center of balance over the toes at all static times (see below), shifting the balance forward while running at full speed (Fig. 5), like birds.

http://www.iaapa.org/DigitalShowDaily/2016/wed/Billings.asp

https://hiveminer.com/Tags/quetzalcoatlus

Why is this Houston Museum Quetzalcoatlus posed like this? Very strange.

Why is this Houston Museum Quetzalcoatlus posed like this? Very strange.

Quetzalcoatlus neck poses. Dipping, watching and displaying.

Quetzalcoatlus neck poses from David Peters Studio. Dipping, watching and displaying. Yes, the third finger is wrong here. It should be pointing posteriorly.

With what we know about pterosaurs
this should be a golden age of restoration. Instead, these models will someday be seen for what they are… near misses. They replace elegance with awkwardness, facts with fancy, and precision with tradition.

References
https://blog.everythingdinosaur.co.uk/blog/_archives/2018/06/01/pterosaur-models-go-on-display.html

Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist 
Historical Biology 15: 277-301

Pterosaur brain cavities vs. posture (Unwin 2003, Witmer et al. 2003)

Unwin 2003
reviewed views on pterosaur posture (Fig.1 ) from the Witmer et al. 2003 paper on pterosaur brains and ‘smart’ wings. Unfortunately, Unwin illustrated his Nature review with freehand illustrations from Wellnhofer 1991 (Fig. 1) that bear little resemblance to traced bone sizes and proportions.

And no one raised a finger in protest.

Figure 1. Images from Unwin 2003 compared to fossil tracings and reconstructions from ReptileEvolution.com. Dashed line above toes in Rhamphorhynchus indicates center of balance, below the wing root, as in birds. Note the imaginative illustrations Unwin uses with little to no basis in reality. The skulls display the appropriate rostral tilt.

Figure 1. Images from Unwin 2003 compared to fossil tracings and reconstructions from ReptileEvolution.com. Dashed line above toes in Rhamphorhynchus indicates center of balance, below the wing root, as in birds. Note the imaginative illustrations Unwin uses with little to no basis in reality. The skulls display the appropriate rostral tilt.

Inaccuracies are permitted for some workers. 
Some have license to misrepresent, to advance bogus concepts, and to omit taxa. Then again, mistakes do happen. If so when were these mistakes (Fig. 1) noted and corrected by pterosaur workers over the past 15 years? After all… this is science and accuracy should be paramount. Fact should not be confused with fantasy.

Pterosaur workers
have advanced competing hypotheses and reconstructions, but I rarely if ever, have seen them specifically criticizing competing hypotheses and reconstructions. (Send examples or citations of this if you have them.) Instead, pterosaur workers seem to avoid criticizing the work of colleagues, leaving that to bloggers.

Ironically
Unwin is of the mind set that pterosaurs were dinosaur relatives — but gave Rhamphorhynchus a sprawling, lizard-like posture (Fig. 1), with fingers pointing anteriorly. I gave Rhamphorhynchus an erect posture in the knowledge that some lepidosaurs were occasional bipeds while others, like Sharovipteryx (Fig. 2), Longisquama and Bergamodactylusdid not employ their forelimbs at all during terrestrial locomotion.

Figure 2. Cosesaurus was experimenting with a bipedal configuration according to matching Rotodactylus tracks and a coracoid shape similar to those of flapping tetrapods. Long-legged Sharovipteryx was fully committed to a bipedal configuration.

Figure 2. Cosesaurus was experimenting with a bipedal configuration according to matching Rotodactylus tracks and a coracoid shape similar to those of flapping tetrapods. Long-legged Sharovipteryx was fully committed to a bipedal configuration.

Caption to Unwin’s 2003 figures:
“The horizontal alignment of the lateral semi-circular canal, indicated by the red line, is consistent with a crouching posture and forward-directed head in basal pterosaurs, represented by Rhamphorhynchus. b, In derived forms such as Anhanguera, the reorientation of the canal can be interpreted in terms of an upright position and a downward-pointing head. (Pterosaurs redrawn from Wellnhofer 1991 and not to scale.)”

Back to the abstract of Witmer et al. 2003.
“Comparison of birds and pterosaurs, the two archosaurian flyers, sheds light on adaptation to an aerial lifestyle. The neurological basis of control holds particular interest in that flight demands on sensory integration, equilibrium, and muscular coordination are acute. Here we compare the brain and vestibular apparatus in two pterosaurs based on high-resolution computed tomographic (CT) scans from which we constructed digital endocasts. Although general neural organization resembles birds, pterosaurs had smaller brains relative to body mass than do birds. This difference probably has more to do with phylogeny than flight, in that birds evolved from nonavian theropods that had already established trends for greater encephalization. Orientation of the osseous labyrinth relative to the long axis of the skull was different in these two pterosaur species, suggesting very different head postures and reflecting differing behaviours. Their enlarged semicircular canals reflect a highly refined organ of equilibrium, which is concordant with pterosaurs being visually based, aerial predators. Their enormous cerebellar floccular lobes may suggest neural integration of extensive sensory information from the wing, further enhancing eye- and neck-based reflex mechanisms for stabilizing gaze.”

References
Unwin DM 2003. Smart-winge pterosaurs. https://www.nature.com/articles/425910b.pdf
Witmer LM, Chatterjee S, Franzosa J. and Rowe T 2003. Neuroanatomy of flying reptiles and implications for flight, posture and behavior. Nature 425, 950–953.

 

Germanodactylus sp. 6592 plate and counterplate

Matching a fossil plate to a counterplate is easy.
Matching a photo of a plate to a photo of counterplate (Fig. 1) requires Photoshop, even if the differences are minute.

Figure 1. Plate and counterplate of the SMNS 6592 specimen referred to Germanodactylus matched in Photoshop.

Figure 1. Plate and counterplate of the SMNS 6592 specimen referred to Germanodactylus matched in Photoshop.

This is the first time I’ve seen
the counterplate to the SMNS 6592 specimen attributed to Germanodactylus. And I think this counterplate is composed of painted plaster. Photoshop was used to match the plate to the counterplate and to trace the resulting elements. As you can see, the pelvis is in an atypical position due to taphonomy (crash landing on its butt?), but everything else seems to be naturally posed with the exception of the displaced and overlapping femora (another results of the crash landing, perhaps).

A giant Romanian pterosaur mandible fragment

FIgure 1. LPB R 2347 largest pterosaur mandible compared to Bakonydraco.

FIgure 1. LPB R 2347 largest pterosaur mandible compared to Bakonydraco.

Vremir et al. 2018
describe a pterosaur mandible fragment (Figs. 1, 2), “This specimen represents the largest pterosaur mandible ever found and provides insights into the anatomy of the enigmatic giant pterosaurs.”

Figure 2. LPR pterosaur mandible compared to related taxa, like Eopteranodon, and to the largest known pterosaur, Quetzalcoatlus. Figure 2. LPR pterosaur mandible compared to related taxa, like Eopteranodon, and to the largest known pterosaur, Quetzalcoatlus.

Figure 2. LPR pterosaur mandible compared to related taxa, like Eopteranodon, and to the largest known pterosaur, Quetzalcoatlus to scale.

It’s worthwhile
to place the jaw fragment in context with other pterosaurs. We don’t have a similar jaw fragment for the big Quetzalcoatlus (Fig. 2), which likely stood twice as tall as the giant eopteranodontid owner of the jaw fragment. Bakonydraco is a likely eopteranodontid, larger than Eopteranodon, but much smaller than the jaw fragment owner.

Earlier this jaw fragment was used as the basis for restoring the rest of this pterosaur as a giant azhdarchid nicknamed, ‘Dracula’ (with beaucoup errors, Fig. 2).

Figure 1. Dracula the giant azhdarchid pterosaur museum mount. Hopefully it's not too late to fix the problems here.

Figure 2. Dracula the giant pterosaur model built and based on the jaw fragment in today’s post. That’s a lot of imagination!

References
Vremir M et al. 2018. Partial mandible of a giant pterosaur from the uppermost Cretaceous (Maastrichtian) of the HaÈeg Basin, Romania. Lethaia doi: https://doi.org/10.1111/let.12268 https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12268