Largest ‘flying reptile’ from the Crato formation? Maybe not.

Cheng et al. 2018
report on a partial wing finger (MPSC R 1221, Fig. 1) that they say represents, “The largest flying reptile from the Crato Formation, Lower Cretaceous, Brazil.”

But is it? 

Figure 1. The as yet undescribed SMNS PAL 1136 specimen is much larger than comparable bones in the new specimen, MPSC R 1221.

Figure 1. The as yet undescribed SMNS PAL 1136 specimen is much larger than comparable bones in the new specimen, MPSC R 1221. If the scale bars are correct, the SMNS specimen is much larger.

No…
if the scale bars are correct. The larger, as yet undescribed, and very impressive SMNS PAL 1136 specimen (Fig. 1) is not mentioned in the text. I do not know if the SMNS specimen is from the Crato or Roualdo formation (I have not gone back to look up that datum). In any case, the authors overlooked this specimen, because it is not mentioned in the text or charts that list a few dozen other large pterosaurs. It should have been included. Of course, then the headline would have read, “…second largest…” and no one wants that.

So was this oversight intentional?
We’ll never know. The SMNS specimen has been in the literature for 24 years (Frey and Martill 1994).

Addendum several days later
The Crato Formation was not erected until 13 years after the 1994 paper by Martill, Bechly and Loveridge. Therefore all layers were considered Santana Formation in 1994. So the SMNS specimen from the Santana formation might have come from the upper or lower layers. It should have been included in the 2018 survey.

The authors conclude
“Based on the fusion of the extensor tendon process and the first wing phalanx and bone histology, MPSC R 1221 presents a subadult individual of a late ontogeny stage (OS5) at time of death, whichmeans that the final maximized wingspan might have been larger. This is corroborated by the osteohistological sections since this individual did not present an external fundamental system.” Look how eager the authors are to hang on to that superlative, ‘largest’, even though we know of at least one that is so much larger.

The authors do not realize
or continue to deny data, that pterosaurs do not follow archosaur fusion patterns during ontogeny—because pterosaurs are not archosaurs, and their fusion patterns follow phylogenetic patterns.

I never heard the term,
“external fundamental system” before. So, I looked it up: “A closely spaced series of lines of arrested growth that is called the External Fundamental System (EFS) indicates that adult size has been reached.” Now we all know!

I hope this blog post
will one day turn out dozens of young paleontologists who will read every paper they see with a seasoned and skeptical eye. If so, a few of you may someday become editors of academic journals or manuscript referees. When that happens, don’t let mistakes like this slip out. Having a website, like ReptileEvolution.com, that is full of data and illustrations, makes it easy to fact-check superlative claims, like this one, with just a few clicks.

On that note:
here (Fig. 2) is a published illustration of a pterosaur wrist from Duque and Barret 2018 with labels that were a little mixed up with regard for the ulna and radius. The referees should have caught this.

Figure 1. From figure 9 from Duque and Barreto 2018 with corrections noted and digit 5 colorized

Figure 2. From figure from Duque and Barreto 2018 with corrections noted and digit 5 colorized. This mistake should have been caught by the authors and referees, not me.

References
Cheng X, Bantim RAM, Sayão JM, Kellner AWA, Wang X and Saraiva AAF 2018. The largest flying reptile from the Crato Formation, Lower Cretaceous, Brazil. Historical Biology. https://doi.org/10.1080/08912963.2018.1491567
Duque RRC and Barret AMF 2018. New exceptionally well-preserved Pterosauria from the lower Cretaceous Araripe Basin, Northeast Brazil. Cretaceous Research 10.1016/j.cretres.2018.05.004
Frey E and Martill DM 1994. A new Pterosaur from the Crato Formation (Lower Cretaceous, Aptian) of Brazil. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 194: 379–412.

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Largest birds and pterosaurs to scale (finally!)

Question: Could the largest azhdarchids fly?
Tradition says: Yes! Most pterosaur workers say: Yes! Flying azhdarchid models say: Yes!

Heresy:
We looked at that question earlier and came to another conclusion based on comparable vestigial wingtip phalanges in flightless pterosaurs. Today there’s more to consider.

Let’s take another look at that same problem,
this time comparing the largest flying bird to the largest flying pterosaurs, and the largest non-flying bird to a giant pterosaur (Fig. 1). Since the largest flying birds and pterosaurs had the longest wing/neck and wing/torso ratios, the reduction of wing span/neck length points toward flightlessness—if analogous.

As reported yesterday,
lacking the ability to fly removes the constraints for multiple increases in size. We know of no pterosaurs that had vestigial wings, only vestigial distal wing phalanges. Three of the four flightless pterosaurs we looked at earlier were pterodactyloid-grade quadrupeds, so their free fingers had to contact the substrate. Moreover, all flightless pterosaurs could still flap vigorously, whether to ward off threats by display and/or increase thrust while fleeing.

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

Figure 1. Click to enlarge. The largest flying and non-flying birds and pterosaurs to scale. Are large soaring birds analogs to large flying pterosaurs. If so, then are large non-flying birds analogs to large non-flying pterosaurs. Does giving up flight enable giantism in birds and pterosaurs?

While recognizing obvious differences
between the largest pterosaurs and birds, which are more alike?

On the one hand
we have pterosaurs and birds with shorter necks, shorter legs and longer wings.

On the other hand
we have a pterosaur and a bird with a longer neck, longer legs and a relatively shorter wing (compared to those of volant pterosaurs). Is it really as simple as that?

Or did I cherry-pick taxa?

Figure 2. Azhdarchids are stork-like waders, so Ciconia, the stork, is a good analog. It is notably smaller than the smallest known Quetzalcoatlus.

Figure 2. Azhdarchids are stork-like waders, so Ciconia, the stork, is a good analog. It is notably smaller than the smallest known Quetzalcoatlus, about the size of flying azhdarchids.

Azhdarchids are often compared to storks.
And they do have similar proportions (Fig. 2). But all storks fly and some of the largest (e.g. Ciconia) are only half as tall as the smallest Quetzalcoatlus sp. We know of no giant storks. Even so, at half as tall, the legs of Ciconia were equal in length to the larger Q. sp, the torso was similar in size, and the neck and skull were only half as long. All this would appear to make azhdarchids top heavy relative to the volant stork (Fig. 3), despite a longer wing span, even with reduced distal elements.

Figure 3. Q. northropi and Q. sp. compared to Ciconia, the stork, and Pelagornis, the extinct gannet, to scale. That long neck and large skull of Quetzalcoatlus would appear to make it top heavy relative to the volant stork, despite the longer wingspan. Pteranodon and other flying pterosaurs do not have such a large skull at the end of such a long neck (Fig. 1). The longer wings of pelagornis show what is typical for a giant volant tetrapod, and Q. sp. comes up short in comparison.

Figure 3. Q. northropi and Q. sp. compared to Ciconia, the stork, and Pelagornis, the extinct albatross/gannet, to scale. That long neck and large skull of Quetzalcoatlus would appear to make it top heavy relative to the volant stork and gannet, despite the longer wingspan compared to the stork. Pteranodon and other flying pterosaurs do not have such a large skull at the end of such a long neck (Fig. 1). The longer wings of Pelagornis show what is typical for a giant volant wide-ranging tetrapod, and Q. sp. comes up short in comparison.

What about those wings?
Compared to the stork, Q sp. had longer wings. Compared to albatrosses and pterosaurs, Q. sp. had shorter wings. In any case, that long neck is strikingly different in azhdarchids. Such a long lever arm had to affect the center of balance (Fig 3 red line).

Figure 3. Quetzalcoatlus model ornithopter by Paul Macready getting walked to its take-off point.

Figure 4. Quetzalcoatlus model ornithopter by Paul Macready getting walked to its take-off point. The wing chord extends to the posterior pelvis, which is invalid. The demonstrated wing chord is shown in figure 3.

What about that mechanical flying Q. sp?
Paul Macready built and flew a gliding Q. sp., (Fig. 4) not a Q. northropi. It did not have a long enough neck or large enough skull. As it was, it was well-engineered and all the mechanics in the torso were unlikely duplicated in the Late Cretaceous taxon.

Figure 5. The Macready flying model compared to Q. sp. Perhaps it has always been overlooked that the neck proportions were changed and heavy mechanical motors and batteries filled the torso.

Figure 5. The Macready flying model compared to Q. sp. Perhaps it has always been overlooked that the neck proportions were changed and heavy mechanical motors and batteries filled the torso. The hind limbs are unnaturally tucked in in the model, following Kevin Padian’s invalidated view that pterosaurs were close to dinosaurs.

The question(s) comes down to:
If large soaring birds are analogs to large flying pterosaurs, then are the largest non-flying birds analogs to the largest pterosaurs? Does giving up flight enable and promote gigantism in birds AND pterosaurs?

At present, the evidence says: yes.

However, it’s not that giant pterosaurs were “too big to fly”.
Here’s the working hypothesis: Smaller pterosaurs that stopped flying were then able to grow much bigger, with less constraint for maintaining a center of balance at the shoulders.

Quetzalcoatlus running like a lizard prior to takeoff.

Figure  6. Quetzalcoatlus running like a lizard prior to takeoff. Leaning forward while running fast is what humans do to. Perhaps the neck was held more erect, like an ostrich or giraffe, back in the Late Cretaceous.

Not sure why it took so long
to put large pterosaurs and birds together. This should have been posted years ago.

 

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

Once a children’s book, now an academic paper on PeerJ.

The children’s book,
GIANTS of Land, Sea & Air – Past & Present (Fig. 1 PDF) came out in 1986 and featured all of the largest animals to scale on dozens of pages alongside humans for scale.

Figure 1. The cover of Giants, the book that launched my adult interest in dinosaurs, pterosaurs and everything inbetween.

Figure 1. The cover of Giants, the book that launched my adult interest in dinosaurs, pterosaurs and everything inbetween.

The PeerJ online academic paper
(McClain et al. 2015) featured many of the same sea creatures and many more (Fig. 2) to scale with a human swimming alongside. Lacking are any of the terrestrial, aerial and prehistoric creatures you’ll find in GIANTS.

Figure 2. Poster turned on end illustrating the largest creatures in the sea to scale from McClain et al. 2015,

Figure 2. Poster turned on end illustrating the largest creatures in the sea to scale from McClain et al. 2015,

Sorry I didn’t see this online paper when it first came out a few years ago. 
It just came to my attention today. I suppose the inspiration was by convergence, but 1986 was long enough ago that a 10-year-old reader then would have been close to forty in 2015.

PS.
I just got a thumb’s down from the PeerJ voters for wondering if any of the authors were aware of the earlier children’s book. First bad review I’ve had! Or was I not supposed to mention it at PeerJ?

References
McClain et al. (15 co-authors) 2015. Sizing ocean giants: patterns of intraspecific size variation in marine megafauna. PeerJ 3:e715; DOI 10.7717/peerj.715

The origin of giant birds: Jianianhualong, a giant Jurapteryx (formerly Archaeopteryx)

We looked at this one
earlier here. Among the Solnhofen birds is Jurapteryx recurva (Figs. 1,2) and it nests with the many times larger Serikornis (Fig. 2) and the even larger Jianianhualong (Fig. 2).

Figure 3. The Eichstätt specimen, Jurapteryx recurva, nests with the living ostrich, Struthio, presently in the LRT.

Figure 3. The Eichstätt specimen, Jurapteryx recurva, nests with the living ostrich, Struthio, presently in the LRT.

Achaeopteryx (Jurapteryx) recurva (JM2257; the Eichstätt specimen; Howgate 1985) is one of the smaller Solnhofen birds. Here it nests as the last common ancestor of all extant birds. A gap spanning the entire Cretaceous separates this taxon from extant taxa and their kin. As in other bird lines, the loss of tail length, the fusion of the pygostyle and the fusion of manus elements are convergent.

Figure 2. Jianianhualong, Serikornis and Jurapteryx to scale.

Figure 2. Jianianhualong, Serikornis and Jurapteryx to scale.

 

Serikornis sungei (Lefèvre et al. 2017; Late Jurassic; 50cm long) was originally considered a pre-bird sister to Eosinopteryx. Here it nests with Jurapteryx, the Eichstätt specimen first attributed to ArchaeopteryxSerikornis is larger than its sister, had larger teeth and was flightless. 

Jianianhualong tengi (Xu et al. 2017; Early Cretaceous; DLXH 1218) originally considered a non-avian troodontid, Jianianhualong nests bertween Sapeornis and Archaeopteryx recurva. It is a troodontid-like bird, not a bird-like troodontid. Note the odd scapula shape, like that in Sapeornis. Note the retrovered pedal digit 1, showing this taxon was derived from perching birds. The tall naris and long tibia are autapomorphies.

Xu et al. 2014 made a headline out of the asymmetric feathers found with Jianianhualong. In the present context, Jianianhualong is derived from volant ancestors. So asymmetry is not exceptional, but expected. This is the earliest known large flightless bird.

References
Howgate ME 1985. Problems of the osteology of Archaeopteryx: is the Eichstätt specimen a distinct genus?. In Hecht, Ostrom, Viohl, and Wellnhofer (eds.), The Beginnings of Birds: Proceedings of the International Archaeopteryx Conference, Eichstätt 1984. Freunde des Jura-Museums Eichstätt, Eichstätt 105-112.
Lefèvre U, Cau A, Cincotta A, Hu D-Y, Chinsamy A, Escuillié F and Godefroit P 2017.A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers. Sci Nat 104:74. DOI 10.1007/s00114-017-1496-y
Xu X, Currie P, Pittman M, Xing L, Meng QW-J, Lü J-C, Hu D and Yu C-Y 2017. Mosaic evolution in an asymmetrically feathered troodontid dinosaur with transitional features. Nature Communications DOI: 10.1038/ncomms14972.

wiki/Jurapteryx
wiki/Jianianhualong
wiki/Serikornis

Who else has telescopes and wonders about the existence of us?

NatGeo ‘elephant bird’ embryo

Updated November 13 with a new skull from an 1896 academic journal,
evidently the best data available at present… better than a commercially available restored skull cast.

Strangely enough, 
today’s topic fits in nicely with our current ‘giant birds‘ series.

While looking for data
on the palate of Aepyornis (the last data was published in Andrews 1896 and the palate, still unknown, was not recovered with the other skull pieces), I found a paper (Balanoff and Rowe 2007) and a Digimorph.org link that reconstructed the skull of an embryo (Fig. 4) found within a huge Aepyornis-sized egg (Figs. 1, 2) found in Madagascar and currently on display at the National Geographic Society.

Balanoff and Rowe report:
“The referral of this specimen to Aepyornithidae, including both Aepyornis and Mullerornis, is based largely on a geographical argument. No other ratites are known from the island of Madagascar, the source area for the National Geographic egg. The large size of the egg, provides a character with which this specimen may be diagnosed to Aepyornis. The length of the egg is 315 mm, and it is 224 mm at its widest point. The difference in the sizes of the eggs is large enough to distinguish between other ratite eggs and this particular Aepyornis egg.”

Alright… so what’s true here?
So far, only elephant birds (genus: Aepyornis, Fig. 1) are known to have eggs as large as the NatGeo egg (Fig. 1) and elephant birds are indeed from Madagascar. The large reptile tree (LRT, 1120 taxa) nests Aepyornis with the ostrich, Struthio, not the kiwi, Apteryx, which DNA suggests is the closest relative.

Figure 1. Aepyornis maximus along with eggs, the largest known. The new skull replaces the original one.

Figure 1. Aepyornis maximus along with eggs, the largest known. The new skull replaces the original one.

But more importantly,
what is inside the egg trumps size and location. With the earlier restored skull, analysis, nested the NatGeo embryo with the ostrich (genus: Struthio, Fig. 4) and the adult with the corn crake, Crex. The new skull nests Aepyornis with Struthio. Elephant birds have long been considered ratites, and this new data returns the elephant bird to the ratites, but not with the kiwi.

Figure 1. NatGeo egg compared to ostrich and chicken eggs. It is well within the size of a typical Aepyornis (elephant bird) egg, but what's inside is more like an ostrich. Balanoff and Rowe provided an inaccurate scale bar based on their in text measurement of the egg.

Figure 2. NatGeo egg compared to ostrich and chicken eggs. It is well within the size of a typical Aepyornis (elephant bird) egg, but what’s inside is more like an ostrich. Balanoff and Rowe provided an inaccurate scale bar based on their in text measurement of the egg.

As in Struthio
and unlike other tested birds, the skull sutures of the NatGeo embryo are not fused.

As in Struthio and Aepyornis (with the new Andrews 1896 data) 
and unlike other tested birds, the scapula and coracoid are fused.

Figure 2. Ostrich hatchling compared to NatGeo egg and skull with hatchling imagined. The skull, as found is premature, based on its size.

Figure 3. Ostrich hatchling compared to NatGeo egg and skull with hatchling imagined. The skull, as found is premature, based on its size. If the adults were also twice as tall, we’re looking at a 13- to 18-foot tall ostrich.

 

The premaxilla + maxilla
are fused in the NatGeo embryo. These elements were misidentified originally as the premaxilla alone. As a result, Balanoff and Rowe also misidentified the palatines as the maxillae (Fig. 4) and, of course, did not identify any palatines despite the fact they could not be lost within the intact egg shell.

Furthermore, the skull of the NatGeo embryo
has the large, puffy squamosals found in Struthio and lacking in Aepyornis and other birds. The NatGeo embryo looks like Struthio (Fig. 4) and Aepyornis (Fig. 1). Note the flaring prefrontals (orange), the shape of the mesethmoid (light green) and the matching domed crania. All are strongly distinct from the restored commercial cast of Aepyornis, but are similar to the Andrews 1896 data.

Figure 4. NatGeo embryo compared to Struthio and adult Aepyornis. The original maxilla is reinterpreted as the palatine. The original premaxilla is a fused premaxilla + maxilla. The original Nat Geo skull was put together in computer software from scattered parts. Mesethmoid inverted in revision. Aepyornis does not have bulbous squamosals found in Struthio and the NatGeo embryo. Not to scale.

Figure 4. NatGeo embryo compared to Struthio and adult Aepyornis. The original maxilla is reinterpreted as the palatine. The original premaxilla is a fused premaxilla + maxilla. The original Nat Geo skull was put together in computer software from scattered parts. Mesethmoid inverted in revision. Aepyornis does not have bulbous squamosals found in Struthio and the NatGeo embryo. Not to scale.

The post-crania has not been considered here because

  1. embryo birds have different proportions than adults
  2. the NatGeo embryo long bones do not have ossified articular surfaces

This is not the first time a giant reptile
(birds are still reptiles!) became known first from its embryo. The IVPP embryo anurognathid pterosaur is the size of contemporary adult anurognathids and this taxon is also known, so far, only from its embryo. More info here.

References
Andrews CW 1896. On the skull, sternum, and shoulder-girdle of Aepyornis. Ibis, Seventh Series, 2:376-389.
Balanoff AM 2003.
Osteological description of an embryonic elephant bird (Ratitae: Aepyornis) using    high-resolution X-ray computed tomography, with a discussion of growth in Aepyornis. M.S. thesis, The University of Texas, Austin, Texas, 175 pp.
Balanoff AM and Rowe T 2007. Osteological description of an embryonic skeleton of the extinct elephant bird, Aepyornis (Palaeognathae: Ratitae). Journal of Vertebrate Paleontology 27(sp9):1–53.
Gefen E and Ar A 2001. Morphological description of the developing ostrich embryo: a tool for embryonic age estimation. Israel Journal of Zoology 47:87-97.

the-surprising-closest-relative-of-the-huge-elephant-birds/

The origin of giant birds: Phorusrhacos, the giant secretary bird

Figure 1. Phorushacids to scale. The extant Sagittarius is in color at lower right.

Figure 1. Phorushacids to scale. The extant Sagittarius is in color at lower right. Considering how closely Sagittarius looks like these taxa, one might be surprised to hear that Cariama (Fig. 4) is widely considered the extant relative. Cariama is not the sister in the LRT.

Traditionally
the seriema (genus: Cariama; Fig. 4) has been allied to the ‘terror’ birds, the phorusrhacids (Fig. 1), but it does not have the elevated external naris and deep beak found in the secretary bird (genus: Sagittarius, Figs. 1, 3). Sagittarius also has a more robust set of cervicals. Heretically, in the large reptile tree (LRT, 1120 taxa), the secretary bird of Africa is closer to phorusrhacids of South America.

Figure 3. Skull of Phorusrhacos, a giant terror bird.

Figure 3. Skull of Phorusrhacos, a giant terror bird in three views.

The terror-bird clade is represented in the fossil record
all the way back to the mid-Paleocene (Paleopsilopterus, no skull material known).

Figure 2. Sagittarius (secretary bird) and Cariama (seriema). While clearly related, these two nest at the base of two different major bird clades.

Figure 4. Sagittarius (secretary bird) and Cariama (seriema). While clearly related, these two nest at the base of two different major bird clades. Sagittarius is allied with terror birds. Cariama is allied with flamingo.

Sagittarius serpentarius (Miller 1779) The extant secretary bird is a chiefly terrestrial bird with long legs capable of short flights. It is a sister to Llallawavis, an ancient ‘terror bird.’

Figure x. Bird giants in the bird subset of the LRT.

Figure 5. Bird giants in the bird subset of the LRT.

References
Alvarenga, HMF and Höfling E 2003. Systematic revision of the Phorusrhacidae (Aves: Ralliformes). Papéis Avulsos de Zoologia 43(4): 55-91.
Statius Müller PL 1776. Des Ritters Carl von Linné Königlich Schwedischen Leibarztes &c. &c. vollständigen Natursystems Supplements- und Register-Band über alle sechs Theile oder Classen des Thierreichs. Mit einer ausführlichen Erklärung. Nebst drey Kupfertafeln.Nürnberg. (Raspe).

wiki/Phorusrhacos
wiki/Sagittarius