The rest of Lonchodraco probably looks like this large unnamed ornithocheird

Only the deep toothy jaw tips,
of the pterosaur Lonchodraco giganteus (Hooley 1914; Rodrigues & Kellner 2013; NHMUK PV 39412; originally Pterodactylus giganteus Bowerbank 1846; Fig. 1) are known. Ever wonder what the rest of this pterosaur looked like?

Well,
the 174-year wait is over.

Figure 1. Lonchodraco jaw tips. Colors added here.

Figure 1. Lonchodraco jaw tips. Colors added here. For the rest of this genus, see figure 2. The nasal (pink) is laminated between the premaxilla (yellow) and maxilla (green). The jugal (blue) also makes an appearance.

What little is known of Lonchodectes turns out to look like
the (so far) unnamed large ornithocheirid, SMNK PAL 1136 (Fig. 2) one of the largest of all flying pterosaurs. The very few parts they have in common are virtually identical, except for size (note the scale bars provided).

Figure 2. The unnamed giant ornithocheirid, SMNK PAL 1136 has a rostrum quite similar to that of Lonchodectes.

Figure 2. The unnamed giant ornithocheirid, SMNK PAL 1136 has a rostrum quite similar to that of Lonchodectes. With such giant wings, soaring over wave tops would have been ideal, dipping occasionally to feed without getting wet.


As one of the largest flying pterosaurs,

SMNK PAL 1136 (Figs. 2, 3) presents no vestigial terminal wing phalanges. No hyper-elongated neck cervicals are present. This pterosaur was built to soar like a big pelican.

Sorry, giant azhdarchids lovers 
(Fig. 3). Those were not volant, as we learned earlier here. They grew to be so big AFTER they became flightless, like flightless birds do. Giant azhdarchids DO have vestigial wing phalanges and a hyper-elongated neck.

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

Figure 3. Click to enlarge. The largest flying and non-flying birds and pterosaurs to scale.

Earlier workers 
did not match Lonchodraco to the SMNK PAL 1136 specimen. Earlier workers did not name the SMNK specimen. Perhaps someone is working on that specimen at present and other workers are giving him/her the honor/duty of naming it.

Wonder if
the Lonchodraco name will stick to the SMNK specimen?

Recently, Martill et al. 2020 took a close look
at the foramina in the jaw tips of Lonchodraco and thought they indicated enhanced sensitivity of the rostrum tip, which implied tactile feeding. With such giant wings, soaring over wave tops would have been likely, dipping occasionally to feed without getting the wings wet.

Odd that the top workers at the top universities
have decided to spend their time examining tiny pits on a broken 174-year-old pterosaur snout while ignoring the origin of pterosaurs… while ignoring many dozen complete pterosaurs that should be in phylogenetic analysis… while ignoring the lepidosaurs that gave rise to the ancestors of pterosaurs. Unfortunately, that’s the world academics live in today. They keep trying to not upset the lectures and textbooks from which they make their living. Apparently if academics focus on the details they won’t have to worry about the big picture. No one will ever know the difference if no one points out the elephant in the room.


References
Averianov AO 2020. Taxonomy of the Lonchodectidae (Pterosauria, Pterodactyloidea). Proceedings of the Zoological Institute RAS. 324 (1): 41–55. doi:10.31610/trudyzin/2020.324.1.41
Bowerbank JS 1846. On a new species of pterodactyl found in the Upper Chalk of Kent (Pterodactylus giganteus). Quarterly Journal of the Geological Society of London. 2: 7–9.
Bowerbank JS 1848. Microscopical observations on the structure of the bones of Pterodactylus giganteus and other fossil animals”. Quarterly Journal of the Geological Society. 4: 2–10.
Martill DM, Smith RE, Longrich N and Brown J 2020. Evidence for tactile feeding in pterosaurs: a sensitive tip to the beak of Lonchodraco giganteus (Pterosauria, Lonchodectidae) from the Upper Cretaceous of southern England. Cretaceous Research
Available online 3 September 2020, 104637 Cretaceous Research https://doi.org/10.1016/j.cretres.2020.104637
Rodrigues T and Kellner A 2013. Taxonomic review of the Ornithocheirus complex (Pterosauria) from the Cretaceous of England. ZooKeys. 308: 1–112. doi:10.3897/zookeys.308.5559

wiki/Lonchodraco

Can the LPT identify a pterosaur known only by its palate (and a few cervicals)?

Summary for those in a hurry:
Once the phylogeny of this specimen was determined (after considering all options in the LPT), the stratigraphic age of this specimen turned out to be the real surprise.

Wang et al. 2008
described a 22cm pterosaur skull exposed in palatal view (Fig. 1) from the Early Cretaceous Jiufotang Formation of Liaoning, China. Hongshanopterus lacustris (IVPP V14582) was considered a subadult individual. The robust, triangular teeth were flattened inside and out like those of other istiodactylids, but unlike other istiodactylids, the tooth row extended beyond the first third of the skull and in having some premaxillary teeth curved like sharp hooks.

Figure 1. Hongshanopterus in situ compared to Darwinopterus and Wukongopterus.

Figure 1. Hongshanopterus in situ compared to Darwinopterus and Wukongopterus. Not an istiodactylid, but a wukongipterid. Here all are shown about half life size.

Witton 2012
nested Hongshanopterus in an unresolved clade with Pteranodon, Coloborhynchus and Haopterus.

Kellner et al. 2019 again
nested Hongshanopterus basal to the clade Istiodactylidae.

By contrast
the large pterosaur tree (LPT, 251 taxa) nested Hongshanopterus between the wukongopterids, Wukongopterus and Kupengopterus, far from any istiodactylids. It takes 5 extra steps to force fit Hongshanopterus in the base of the Istiodactylidae (and that’s using just the few characters visible in Hongshanopterus).

That makes Hongshanopterus the largest and latest surviving
wukongopterid (Fig. 2), a clade otherwise restricted to the Middle to Late Jurassic and a clade famous for having a ‘pterodactyloid’-grade skull with a more primitive long-trailed post-crania.

Figure 1. Click to enlarge. The five specimens of Darwinopterus to scale and in phylogenetic order preceded by six more primitive taxa. The ZMNH 8802 specimen is a female associated with an egg. The others genders shown are guesses by Lü et al. 2011a. Note the skull did not elongate, it actually shrank in the vertical dimension, probably reducing its weight. The female is crestless because it is the most primitive of the five known Darwinopterus specimens. The odds that the remaining four specimens are all males is relatively small.

Figure 2. The five specimens of Darwinopterus to scale and in phylogenetic order preceded by six more primitive taxa. The ZMNH 8802 specimen is a female associated with an egg. The others genders shown are guesses by Lü et al. 2011a. Note the skull did not elongate, it actually shrank in the vertical dimension, probably reducing its weight. The female is crestless because it is the most primitive of the five known Darwinopterus specimens. The odds that the remaining four specimens are all males is relatively small.

A clade member,
Darwinopterus, was considered a transitional taxon leading to pterodactyloid-grade pterosaurs. Adding more taxa, as in the LPT, does not support that hypothesis. At present Darwinopterus is a terminal taxon leaving no descendants. Hongshanopterus is the only wukongopterid (so far) to make it into the Early Cretaceous… and it has the largest skull.

Figure 2. Click to enlarge. Anurognathids to scale. The adult of the IVPP embryo is 8x the size of the embryo, as in all other tested adult/embryo pairings.

Figure 3. Click to enlarge. Anurognathids to scale. The adult of the IVPP embryo is 8x the size of the embryo, as in all other tested adult/embryo pairings.

Only a few basal pterosaurs survived into the Cretaceous.
The giant anurognathid embryo, IVPP V13758  (Fig. 3) is the only other basal pterosaur known at present to survive into the Cretaceous.


References
Kellner AWA et al. (6 co-authors) 2019. First complete pterosaur from the Afro-Arabian continent: insight into pterodactyloid diversity. Nature.com/ScientificReports 9:17875. PDF
Wang X, de Almeida Campos D, Zhou Z and Kellner AWA 2008. A primitive istiodactylid pterosaur (Pterodactyloidea) from the Jiufotang Formation (Early Cretaceous), northeast China. Zootaxa. 1813: 1–18.
Witton MP 2012. “New Insights into the Skull of Istiodactylus latidens (Ornithocheiroidea, Pterodactyloidea)”. PLoS ONE. 7 (3): e33170.

wiki/Hongshanopterus
wiki/Wukongopteridae

Luchibang xingzhe enters the LPT… again… still not an istiodactlyid

Luchibang (Hone, Fitch, Ma and Xu 2020) is a new pterosaur from China
(Figs, 1–3) which we first learned about from a Flugsaurier 2018 abstract with photo (Hone and Xu 2018) and more recently from a pair of ‘Archosaur musings’ blogposts (links below).

Critically, Dr. Hone wrote in his blogpost:
“I didn’t include a phylogenetic analysis for a number of reasons, but notably as the specimen was so clearly an istiodactylid and their own relationships were rather unresolved, adding what was obviously a juvenile into the mix would have been a fair bit of work to not actually add any real information.” The paper includes a cladogram now, but it is heavily biased toward ornithocheirids and excludes important taxa discussed here in 2018.

Both then (233 taxa) and now (242 taxa)
with more highly resolved data the large pterosaur tree (LPT) nests Dr. Hone’s ‘young istiodactylid’ with the largest pterodactylids (Fig. 2), not istiodactylids or ornithochierids. We’ve known this for two years, so it is surprising to see this mistake perpetuated in a recent paper. Dr. Hone acknowledges the many ways in which Luchibang was ‘odd’ for an  istiodactylid: long legs, large feet, long metacarpals, short wings and a long neck.

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 istiodactylidae nests in the LPT with the large derived pterodactylids.

It should be noted
that the skulls of the largest pterodactylids (Fig. 2) mimic those of istiodactylids to a remarkable degree. However, the rest of the body is distinctively different.

Figure 2. The Erlianhaote specimen nests with these pterodactylids in the LPT, not with Istiodactylus (Fig. 3). Compare to valid istiodactylids in figures 4–6/

Figure 2. The Erlianhaote specimen nests with these pterodactylids in the LPT, not with Istiodactylus (Fig. 3). Compare to valid istiodactylids in figures 4–6/

The new data from Hone et al. 2020
(Fig. 3) is more highly resolved, but the phylogenetic results are the same. Luchibang does not have the proportions of an istiodactylid, nor an ornithocheirid. Taxon exclusion might be to blame here. That, and an over reliant confidence on an earlier hunch by Dr. Hone (see quote above), a young professor known to toss out and ignore data on several previous occasions. Links can be found here, but most infamously here.

In the old days
papers would be submitted then reviewed by readers and colleagues. Nowadays, papers are reviewed prior to publication. Thereafter they may be cited, but are rarely reviewed. Dr. Hone notes that his team’s manuscript was rejected by another publication, not on the basis of its phylogenetic shortcomings, but on the suspicion that the odd proportions (for an istiodactylid) of the specimen resulted from a chimaera of unrelated pterosaur parts glued together to form a single complete specimen. That does not appear to be the case. All left and right parts are identical.

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

Oddly,
none of the referees mentioned in the blog posts by Dr. Hone (below) noted that Luchibang was a pterodactylid, not an istiodactylid. Unfortunately, that is the level of expertise we are dealing with out there in this topsy-turvy world, where the PhDs have no idea and thus leave it to the amateurs to do the “fair bit of work” as Dr. Hone put it (see quote above).

Also oddly,
Pterodactylus antiquus (Fig. 2) was included in the Hone et al. analysis, but did not attract Luchibang as it did in the LPT. I have not checked the scores published by Hone et al., but Hone’s own words (see above) demonstrate an initial and continuing bias toward making Luchibang an istiodactylid, despite the many traits he considered odd.

Figure 3. New tracings from Hone et al. 2020 of Luchibang (spelled Luichibang in the caption). Valid istiodactylids (see below) have much larger wings, much shorter metacarpals, much shorter necks and much smaller feet.

Figure 3. New tracings from Hone et al. 2020 of Luchibang (spelled Luichibang in the caption). Valid istiodactylids (see below) have much larger wings, much shorter metacarpals, much shorter necks and much smaller feet.

The danger from the Hone et al. paper lies in the
supposition of Hone’s team that this ‘young istiodactylid’ would grow allometrically to someday match the proportions of a full-grown istiodactylid. The Hone team does not yet realize that as tritosaur lepidosaurs, pterosaurs grow isometrically, with hatchlings having identical proportions to adults, as demonstrated by the JZMP embryo ornithocheirid.

The largest ornithocheirid

Figure 6. The unnamed largest ornithocheirid, SMNK PAL 1136

As you can see 
valid istiodactylids have much larger wings, much shorter metacarpals, much shorter necks and much smaller feet.

Figure 7. Luchibang skull in situ and reconstructed. Contra Hone et al. 2020, the cranial portion of the skull is visible and can be reconstructed.

Figure 7. Luchibang skull in situ and reconstructed. Contra Hone et al. 2020, the cranial portion of the skull is visible and can be reconstructed. The skull does resemble that of istiodactlyids by convergence, but details overlooked by the authors indicate otherwise.

Hone reported,
“apart from the back of the skull, the tail and few tiny bits, everything is there.” Using DGS methods, here (Fig. 7)  the scattered parts making up the face and back of the skull were identified, colored and reconstructed. Below (Fig. 8) the complete tiny tail is identified along with a reconstruction of the pelvis and a possible egg shell.

Figure 8. Pelvic area of Luchibang from Hone et al. 2020 with elements, including the overlooked tiny tail (green in ghosted oval) colorized. A possible egg is indicated here (blue).

Figure 8. Pelvic area of Luchibang from Hone et al. 2020 with elements, including the overlooked tiny tail (green in ghosted oval) colorized. A possible egg is indicated here (blue).

Fellow pterosaur workers…
the LPT is an open access cladogram that helps one avoid the sort of mistakes encountered by the Hone team. Coloring the bones (DGS) using layers in Photoshop is a better way to identify crushed bones. Reconstructions are essential.


References
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.
Hone, DWE, Fitch AJ, Ma F, and Xu X 2020. An unusual new genus of istiodactylid pterosaur from China based on a near complete specimen. Palaeontologica Electronica 23(1):a09 Online link to PDF

https://archosaurmusings.wordpress.com/2020/03/09/a-long-overdue-welcome-to-luchibang/

https://archosaurmusings.wordpress.com/2020/03/10/ten-years-in-the-making-of-luchibang/#comment-105683

https://pterosaurheresies.wordpress.com/2018/08/11/flugsaurier-2018-young-istiodactylid-nests-with-tall-pterodactylids-in-the-lpt/

Looking for the sternal complex in a tiny pterosaur

All pterosaurs have a sternal complex
(sternum + interclavicle + wrap-around clavicles), even the flightless ones. This tiny specimen (Fig. 1) probably had a sternal complex, but where is it? As everyone knows, it should be between the elbows, but it’s not there.

Figure 1. Tiny pterosaur mistakenly named Pterodactylus? pulchellus. I cannot find the sternal complex here. It should be between the elbows. That tiny red triangle under the mid-humerus is the ventral coracoid.

Figure 1. Tiny pterosaur mistakenly named Pterodactylus? pulchellus. I cannot find the sternal complex here. It should be between the elbows. That tiny red triangle under the mid-humerus is the ventral coracoid.

Pterodactylus? pulchellus BM NHM 42735 is the same size as the closely related Gmu-10157 specimen, but has a longer rostrum. The BM NHM specimen is one node closer to the common ancestor of cycnorhamphids + ornithocheirids in the large pterosaur tree (LPT, 242 taxa). The sternal complex appears to be missing or displaced in this otherwise undisturbed tiny specimen. Soft tissue confirms the narrow chord wing membrane and dual uropatagia. Pedal digit 5 remained long.

Figure 2. The GMU 10157 specimen and the P? pulchellus BM NHM 42735 specimens to scale and full size.

Figure 2. The GMU 10157 specimen and the P? pulchellus BM NHM 42735 specimens to scale and full size.

These tiny adults,
(Fig. 2) derived from slightly larger scaphognathids (Fig. 3) are transitional taxa undergoing phylogenetic miniaturization at the genesis of Cycnorhamphidae + Ornithocheiridae. They have not been given novel generic names by established workers because the traditionalists among them consider these to be babies/juveniles of larger, undiscovered taxa. Thus they have remained relatively ignored, despite their pristine preservation and sometimes gravid condition.

Figure 3. Click to enlarge. Taxa in the lineage of Cycnorhamphidae + Ornithocheiridae in the LPT.

Figure 3. Click to enlarge. Taxa in the lineage of Cycnorhamphidae + Ornithocheiridae in the LPT.

The key to finding the missing sternal complex
on this relatively undisturbed specimen is to look to the only area of the skeleton that is slightly disturbed (Fig. 4). The gastralia basket is expanded beyond its natural contours in the BM NHM specimen and that’s where I find (thanks to DGS) a displaced sternal complex, separated from the coracoids and jammed back into the stomach, surrounded by gastralia, almost hidden from view.

Figure 4. Here the sternal complex of the BM NHM 42735 specimen is colored indigo.

Figure 4. Here the sternal complex of the BM NHM 42735 specimen is colored indigo.

Not sure how that happened during taphonomy,
but there you go: mystery solved!

Shenzhoupterus skull in situ with sternum in blue.

Figure 5. Shenzhoupterus skull in situ with sternum in blue.

Earlier a sternal complex was found beneath the skull
of Shenzhoupterus (Figs. 5, 6) using the same techniques, contra traditional reconstructions (Lü, Unwin, Xu and Zhang 2008; see skull diagram insert matching no other pterosaur skull morphology in Fig. 6). Despite its derived state, the newly reconstructed Shenzhoupterus skull (Fig. 6 standing skeleton) bears all the hallmarks of sister taxa.

Shenzhoupterus reconstructed alongside original interpretation of skull.

Figure 6. Shenzhoupterus reconstructed alongside original interpretation of skull.

While we’re on this subject,
Shenzhoupterus does not nest with azhdarchoids, as originally hypothesized, but with tiny Nemicolopterus, between dsungaripterids and tapejarids in the LPT—and neither of these clades are related to azhdarchids in the LPT, contra traditional thinking that excludes tiny taxa and large swathes of congeneric taxa.


References
both of the tiny taxa listed above await description and publication other than in:
Wellnhofer P 1970. Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlungen der Bayerischen Akademie der Wissenschaften, N.F., Munich 141: 1-133.

Shenzhoupterus was first described in:
Lü J, Unwin DM, Xu L and Zhang X 2008. A new azhdarchoid pterosaur from the Lower Cretaceous of China and its implications for pterosaur phylogeny and evolution. Naturwissenschaften 95 (9): online (preprint). doi:10.1007/s00114-008-0397-5. PMID 18509616.

Meet Mimodactylus, a small ornithocheirid from Lebanon

Figure 1. Mimodactylus in situ from Kellner et al. 2019.

Figure 1. Mimodactylus in situ from Kellner et al. 2019.

Mimodactylus libanensis (Kellner et al. 2019; Late Cretaceous, 95mya; MIM (no number), Lebanon) is known from a virtually complete specimen (Figs. 1, 2), with the top of the skull still buried in the sediment (Fig. 3). Originally it was considered closest to Haopterus, together comprising the Mimodactylidae. This is a pterosaur I was introduced to over ten years ago. Back then Roy Nohra, one of the co-authors, sent me photos of the unprepared slabs from which I created this bipedal reconstruction (Fig. 2) prior to the publication of Kellner et al.

Figure 1. a basal ornithocheirid, undescribed, from Lebanon.

Figure 2. Mimodactylus reconstruction created several years ago, prior to fossil preparation and publication.

Here,
in the large pterosaur tree (LPT, 242 taxa), Mimodactylus nests between Yixianopterus and Haopterus — closer to Yixianopterus. So the LRT does not support the newly erected clade Mimodactylidae. Yixianopterus was omitted from the cladogram of Kellner et al. Once again, taxon exclusion is the number one problem.

Figure 1. Mimodactylus skull in situ and reconstructed. Kellner et al. misidentified the maxillary palate as the palatine. This is repaired in the reconstruction below.

Figure 3. Mimodactylus skull in situ and reconstructed. Kellner et al. misidentified the maxillary palate as the palatine (PL), apparently unaware that this was correctly identified by several authors years ago. This is repaired in the reconstruction below.

Apparently seven co-authors were not enough
to edit out the seven mistakes in the basic understanding of pterosaurs found in this long-awaited paper.

  1. The broad maxillary palate was misidentified as the palatine. This correction was made by Peters 2000 and later by Osi et al. 2010 and Pinheiro and Schultz 2012. The actual tiny pterygoids and ectopalatine (ectopterygoid + palatine) were not identified.
  2. The manual digits are aligned 1–4 palmar side down in flight in pterosaurs, not palm side anterior in flight with #3 on the top as shown in Kellner et al.
  3. All pterosaurs have 8 cervical vertebrae, not 6
  4. The brachiopatagium stretches between the wingtip and elbow, not the tail tip
  5. The feet of ornithocheirid pterosaurs, and Mimodactylus, too, are half the size pictured.
  6. The Kellner et al. cladogram (Supp Data) mistakenly includes the archosauriforms Ornithosuchus, Herrerasaurus and Scleromochlus as outgroup taxa, none of which are related to pterosaurs. Pterosaurs nest within Lepidosauria in the large reptile tree (LRT, 1611+ taxa). Also see Peters 2000, 2007.
  7. Kellner et al. wrote, “dorsal vertebrae not fused into a notarium, it is likely that it was a very young animal at the time of death, having reached an ontogenetic stage between 2 and 32.” No phylogenetic sisters in the LPT have a notarium. Kellner et al. are unaware that as lepidosaurs pterosaurs have a distinctly different ontogenetic pattern of ossification. Their cladogram suffers from massive taxon exclusion.
Figure 1. Original from Kellner et al. 2019 showing the several basic morphology mistakes made by their artist.

Figure 4. Original Mimodactylus illustration from Kellner et al. 2019 showing the several basic morphology mistakes made by their artist.

The cladogram of Kellner et al.
(Fig. 5) continues several myths based on taxon exclusion of the tiny Solnhofen pterosaurs, all of which were outgroups to all known Cretaceous pterosaurs. I have colorized clades that appear in the LPT because they type size they used was way too small to read. Yixianopterus is not present here and Mimodactylus is not closely related to the istiodactylids in the LRT, contra Kellner et al. 2019. These authors simply have no idea what the tree topology of the pterosaur looks like when small taxa are included. Nor do they understand that pterosaurs arose from tritosaur lepidsosaurs, not a scattershot of unrelated and dissimilar archosauriforms.

Figure 3. Cladogram from Kellner et al. 2019. Color overlays show clades recovered in the LPT.

Figure 5. Cladogram from Kellner et al. 2019. Color overlays show clades recovered in the LPT. If you find this difficult to read, you’re in the majority. This cladogram does not include taxa listed in the SuppData in which Anurognathus nests as the basalmost pterosaur.

A subset of the LPT
(Fig. 6) includes several pertinent taxa omitted by Kellner et al. 2019. Even so, Haopterus nests close by, but Pteranodon and kin do not. Not sure if you ask yourself this question, but I do: What does it mean when scientists refuse to test competing hypotheses for twenty years? … and continue traditions they know don’t make sense?

Figure 1. Subset of the LPT with the addition of Mimodactylus within the clade Scaphognathia.

Figure 6. Subset of the LPT with the addition of Mimodactylus within the clade Scaphognathia.

Here’s Haopterus
(Fig. 7) a taxon closely related to Mimodactylus in both cladograms. Note the tiny feet, skull shape, robust tail, and palate morphology, all instructive with regard to Mimodactylus.

Figure 6. Haopterus is close to Mimodactylus and provides a bauplan for a bipedal stance. Note the tiny feet and palate morphology.

Figure 7. Haopterus is close to Mimodactylus and provides a bauplan for a bipedal stance. Note the tiny feet, pelvis, skull and palate morphology.

And here’s Yixianopterus
the basalmost ornithocheirid in the LPT. Mimodactylus is more closely related to this taxon than to Haopterus. Kellner et al. 2019 omitted Yixianopterus from their analysis.

Figure 2. Reconstruction of Yixianopterus. Roadkill fossils really need at least this much reconstruction to make then intelligible. And don't ignore them in phylogenetic studies. Nothing spectacular here, which means it is more likely to be phylogenetically important.

Figure 8. Reconstruction of Yixianopterus. This is the basalmost ornithocheirid in the LPT.

Believe it or not,
Peters 2009 was actually cited in this paper based on the evidence of a ‘clear articulation’ of the pteroid with the radiale and medial orientation of the free end, contra prior studies on pteroid orientation. That shouldn’t be a citation. It’s just the way it has always been.

Figure 8. Artwork in Kellner et al. of Mimodactylus by Julius Csotonyi. Second frame shows repairs to morphology needed to bring this illustration up to date. Figure 8. Artwork in Kellner et al. of Mimodactylus by Julius Csotonyi. Second frame shows repairs to morphology needed to bring this illustration up to date.

Figure 9. Artwork in Kellner et al. of Mimodactylus by Julius Csotonyi. Second frame shows gross repairs to morphology needed to bring this illustration up to date. 

 

References
Kellner AWA et al. (6 co-authors) 2019. First complete pterosaur from the Afro-Arabian continent: insight into pterodactyloid diversity. Nature.com/ScientificReports 9:17875. PDF
Ösi A, Prondvai E, Frey E and Pohl B 2010. New interpretation of the palate of pterosaurs. The Anat Rec 293: 243–258. doi: 10.1002/ar.21053.
Peters D 2000b.
 A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.
Pinheiro FL and Schultz CL 2012. An Unusual Pterosaur Specimen (Pterodactyloidea, ?Azhdarchoidea) from the Early Cretaceous Romualdo Formation of Brazil, and the Evolution of the Pterodactyloid Palate. PLoS ONE 7(11): e50088. doi:10.1371/journal.pone.0050088

wiki/Mimodactylus

Ferrodraco, a new Aussie ornithocheirid with gracile wings

Most ornithocheird pterosaurs have robust wings
(Figs. 1–3). This new one from Australia (Pentland et al. 2019) has gracile cervicals and wing bits relative to the normally proportioned crested rostrum, a fact overlooked by the authors. Ferrodraco (Early Cretaceous) has small and gracile cervicals and wing elements relative to other ornithocheirids.

FIgure 1. Apparently overlooked by all eight authors, Ferrodraco has a gracile post-crania compared to its rostrum.

FIgure 1. Apparently overlooked by all eight authors, Ferrodraco has a gracile post-crania compared to its rostrum and relative to related pterosaurs. It is possible that this taxon was another flightless pterosaur, but the distal wing phalanges remain unknown.

It was skinny, but was it flightless?
We don’t have the distal wing phalanges. So whether Ferrodraco was flightless or not cannot be definitively answered. This specimen is extremely gracile compared to sister taxa (Figs. 1-3). Only one other pterosaur, Raeticodactylus (Late Triassic) had such gracile wing elements, but the distal elements were normally proportioned.

The holotype described in situ:
“Several elements, including the skull and mandible and many of the appendicular elements (based on key-fits between adherent matrix on anatomically adjacent elements) were clearly articulated post-fossilisation; however, erosion and soil rotation led to fragmentation of the specimen prior to its excavation.”

Figure 2. Ferrodraco scaled to Arthurdactylus. Note the robust antebrachium in Arthurdactylus vs. the gracile antebrachium in Ferrodraco.

Figure 2. Ferrodraco scaled to Arthurdactylus. Note the robust antebrachium in Arthurdactylus vs. the gracile antebrachium in Ferrodraco.

The new ornithocheirid has been nicknamed ‘Butch’
(AODF 876, Australian Age of Dinosaurs Fossil, Winton, Queensland, Australia).

FIgure 3. Ferrodracto compared to Coloborhynchus to the same scale.

FIgure 3. Ferrodracto compared to Coloborhynchus to the same scale. Note the difference in cervical size.

Every new pterosaur specimen
continues to be amazing in its own way. Fortunately ReptileEvolution.com provides a ready reference for easy comparison within hours of publication for new specimens.

Figure 5. Added late. The cervicals restored and to scale creating a neck of appropriate length.

Figure 4. Added late. The cervicals restored and to scale creating a neck of appropriate length.

Added later the same day:
Here (Fig. 4) are the cervicals restored to scale and 5x larger for detail.


References
Pentland AH et al. (seven co-authors) 2019.
Ferrodraco lentoni gen. et sp. nov., a new ornithocheirid pterosaur from the Winton Formation (Cenomanian–lower Turonian) of Queensland, Australia. Nature.com/scientificreports 9:13454 https://doi.org/10.1038/s41598-019-49789-4

New pterosaur skull from China: Nurhachius luei

Riley Black (formerly Brian Switek) wrote:
in the subhead of her Scientific American blogpost, “New pterosaur was fossilized with a ridiculous grin.”

Well… maybe,
but in situ (Fig. 1) it’s not the first or only one. And when reconstructed (Fig. 2) the grin is gone.

On the plus side,
the Aptian (Early Cretaceous) skull attributed to Nurhachius is complete, which is always wonderful, especially for such fragile skulls.

Figure 1. New Nurhachius skull in situ. Bone colors added using DGS methods. BPMC-0204

Figure 1. New Nurhachius skull in situ. Bone colors added using DGS methods. BPMC-0204. The little curved pink ridge ventral to the jugal is the displaced descending nasal process found in sister taxa. Tiny cervical ribs are present, but overlooked.

Then Black’s subhead reports, 
“A skull found in China reveals a previously unknown flying reptile.” Well, if you read the text, not really. The authors consider the new specimen congeneric with the holotype Nurhachius (Fig. 3).

FIgure 2. New Nurhachius reconstruction. Sorry,Riley, no grin. The tiny, slit-like nostril and anterior extensions of the nasal and jugal following it are shown here.

FIgure 2. New Nurhachius reconstruction. Sorry,Riley, no grin. The tiny, slit-like nostril and anterior extensions of the nasal and jugal following it are shown here.

The teeth are like those of other istiodactylids in shape and distribution,
but when you put the two Nurhachius skulls together (Fig. 3), the two are not congeneric, so far as can be determined from available data. The mandible is not as robust in the new specimen, the rostrum is not as long. There in indication of the broader rostral tip found in Istiodactylus and other istiodactylids, nor is the orbit subdivided by circumorbital processes. The referred specimen preserves post orbital and cranial bones unknown in the holotype.

Figure 3. Nurhachius ignaciobritol reconstructed to scale alongside N. luei skull. These two do not look congeneric. The authors should have shown the two together like this.

Figure 3. Nurhachius ignaciobritol reconstructed to scale alongside N. luei skull. These two do not look congeneric. The authors should have shown the two together like this.

 

The genus holotype is
Nurhachius ignaciobritoi 
(Wang, Kellner, Zhou & Campos 2005; Fig. 3) IVPP V-13288, Early Cretaceous, skull length ~30 cm, ~2.5 m wingspan). The wings are long. The free fingers and toes are tiny. The sternum portion of the sternal complex is deep.

From the abstract:
“A revised diagnosis of the genus Nurhachius is provided, being this taxon characterized by the presence of a slight dorsal deflection of the palatal anterior tip, which is homoplastic with the Anhangueria and Cimoliopterus. N. luei sp. nov. shows an unusual pattern of tooth replacement, with respect to other pterodactyloid species.”

Istiodactylus model by David Peters

Figure 4. Istiodactylus model

The phylogenetic analysis presented by Zhou et al. 2019
is not worth showing or discussing due to the inclusion of Scleromochlus (a basal bipedal croc) and the exclusion of dozens of relevant pterosaur and fenestrasaur taxa. The new Nurhachius nests in the large pterosaur tree (LPT, 240 taxa), basal to other istiodactylids, next to, but not with Nurhachius. Proximal outgroup taxa include Coloborhynchus and Criorhynchus.


References
Zhou X, Pegas RV, Leal MEC and Bonde N 2019. Nurhachius luei, a new istiodactylid pterosaur (Pterosauria, Pterodactyloidea) from the Early Cretaceous Jiufotang Formation of Chaoyang City, Liaoning Province (China) and comments on the Istiodactylidae. PeerJ 7:e7688 DOI 10.7717/peerj.7688

https://peerj.com/articles/7688/

scientificamerican.com/laelaps/new-pterosaur-was-fossilized-with-a-ridiculous-grin

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). Compare to valid istiodactylids in figures 4–6/

Figure 2. The Erlianhaote specimen nests with these pterodactylids in the LPT, not with Istiodactylus (Fig. 3). Compare to valid istiodactylids in figures 4–6/

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

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.

Hamipterus – a closer look at gender and ontogeny

Wang et al. 2014 introduced us
two years ago to a new collection of pterosaur parts from a monotypic population that was swept together and disarticulated by a flood event. As you may recall, five well-preserved three-dimensional eggs were recovered from the Early Cretaceous site in northwestern China. Sexual dimorphism was identified for the first time in pterosaurs with two different types of crests appeared on a variety of sizes of skulls (Figs. 1, 2). They named the new specimen, Hamipterus tianshanensis and the holotype was described as, One complete presumed female skull (IVPP V18931.1)”.

Figure 1. The female holotype and male paratype from the Hamipterus population assemblage fossil. The second tracing enlarges the male skull to the same length as the female skull. The color bar overprints indicate parts that differ in length from one skull to the other and a second overlay traces tooth position shifts from one to another.

Figure 1. The female holotype and male paratype from the Hamipterus population assemblage fossil. The second tracing enlarges the male skull to the same length as the female skull. The color bar overprints indicate parts that differ in length from one skull to the other and a second overlay traces tooth position shifts from one to another. The vestigial naris appears between the nasal and jugal beneath the crest. Direct comparisons like this help reveal subtle differences that otherwise might be overlooked.

Such a sweeping together of so many individuals
provides an unprecedented insight into several areas of pterosaur biology, but the data need to be rigorously examined so as not to jump to any conclusions.

Visible differences in the two skulls

  1. Crest shape
  2. Tooth placement
  3. Ventral maxilla shape
  4. Lateral extent of the premaxilla
  5. Depth of the skull anterior to the antorbital fenestra
  6. Concave vs. straight rostral margin (sans crest)
  7. Length of the upper temporal fenestra
  8. Placement of the vestigial naris
  9. Suborbital depth of the jugal

Gender
Wang et al. report, “About 40 male and female individuals in total were recovered, but the actual number associated might be in the hundreds. All of the discovered skulls have crests, which exhibit two different morphologies in size, shape, and robustness. Although morphological variation could be interpreted as individual variation, these marked differences suggest that the skulls belong to different genders. Hamipterus tianshanensis contradicts this hypothesis, because this species indicates that morphology of the crest, rather than its presence.”

Consider what we know about gender differences in birds and lizards,
It may be too soon to generalize over gender differences in pterosaurs. While each gender could have its own signature crest, size, etc., likewise each species likely had its own signature identity/crest/color/call, plumage, etc. At present, no other pterosaurs show verifiable gender differences. That’s why the Wang et al. paper was so important. Gender differences described for both Darwinopterus and Pteranodon were shown to be phylogenetic. Darwinopterus does present a mother with an aborted egg, but the father of the egg has not been identified. Hamipterus offers the best opportunity, so far, to bring some data to the table on this topic. And what Wang et al. indicate may indeed be true.

However, not enough care, IMHO, was administered to the non-crest differences in the skull material was made. Considering just the arrangement of teeth in the jaws (Fig. 1), is it possible that two very closely related species lived near one another? Or did individual variation cover a wider gamut than we now think is reasonable? Remember, among all the Pteranodon specimens now known (to me, at least), no two are identical. The same can be said for the Rhamphorhynchus and Pterodactylus specimens. And when you give Hamipterus a rigorous study, several subtle variations arise. Some of these arise from crushing. Others do not. With given data, one wonders if these could be two Hamipterus variations could be very closely related and.or very closely nesting sister taxa. OR… with present data, gender differences could extend beyond just the crest.

It is also possible
that male pterosaurs were rare rogues and this was a colony of females only with lots of individual variation. Do male lizards help raise their young? Do females? No. But pterosaurs might have been different. Wang et al. report on 40 individuals, but not on the male/female ratio or how many skulls are known. There were three in the holotype block. I’m guessing their specimen count was based on 40 skulls.

Figure 2. Finishing up the large skull with the large crest with two smaller candidates reveals that the slightly better fit is with the female skull.

Figure 2. Finishing up the large skull with the large crest with two smaller candidates reveals that the slightly better fit is with the female skull.

Ontogeny
Wang et al. report, “Ontogenetic variation is reflected mainly in the [lateral] expansion of the [spoon-shaped in dorsal view] rostrum.” Wang et al. reinforce what we know from other pterosaurs that they developed isometrically. Note the similarity between the crests of the smaller and larger ‘male’ specimens (Fig. 2). We’ve seen that before with Tupuxuara juveniles (Fig. 3).

Figure 1. Ontogenetic skull and crest development in Tupuxuara. Note the eyes are small and the rostrum is long in juveniles. Only the crest expands and only posteriorly.

Figure 3. Presumed ontogenetic skull and crest development in Tupuxuara. Note the eyes are small and the rostrum is long in juveniles. Only the crest expands and only posteriorly. Are are these two different sized but otherwise related species? With that longer rostrum, the smaller specimen may be distinct phylogenetically. No small crest Tupuxuara specimens are known.

Sedimentology
Wang et al. report, “Tempestite interlayers where nearly all of the pterosaur fossils are found suggest that large storms caused the mass mortality, event deposits, and lagersta¨ tte of the pterosaur population.”

Phylogenetically
Wang et al. discussed what Hamipterus is not. Their analysis nested it at the base of the Ornithocheiridae with complete lack of resolution. The large pterosaur tree nests Hamipterus with complete resolution between Boreopterus and Zhenyuanopterus.

Eggs
Wang et al. report, “A total of five eggs were recovered from the same site. The outer surface is smooth and exhibits no ‘papilla-like ornamentation,’ as was reported of the first pterosaur egg found in China.” Well that was a giant anurognathid egg, for which finding the parent will be big news. I’d be more interested to see comparisons to the second pterosaur egg found in China, the JZMP egg/embryo, which belonged to a rather closely related [to Hamipterus] ornithocheirid.

Wang et al. report, “Due to the close proximity to Hamipterus tianshanensis, the sole taxon found at the site, all of the eggs are referred to this species. Compared with other reptiles, the Hamipterus eggs show more similarities with some squamates,” I love it when every bit of data supports the theory that pterosaurs are lepidosaurs.

Wang et al. report, a 60µm calcareous eggshell followed by a thin 11µm inner membrane. They compared that to a snake egg of similar dimensions with a 60µm calcareous membrane followed by a much thicker 200µm inner membrane. Then they speculate wildly with this imaginative statement, “It is possible that Hamipterus also had a much thicker membrane, which was not completely preserved. We propose that such an eggshell structure, similar to that of some snakes, may well explain the preservation of the outer surface observed in pterosaur eggs.” IMHO, paleontologists go too far when they try to explain away data, rather than dealing with it directly. Elgin, Hone and Frey (2011) did this with their infamous wing membranes which they speculated suffered from imagined “shrinkage” in order to protect their verifiably false deep chord wing membrane hypothesis.

Wang et al report, “The [egg] size differences might also reflect different stages of development, since mass and dimensions differ between recently laid eggs and more developed ones.” There’s another possibility. Since we know that half-sized female pterosaurs were of breeding age (Chinsamy et al. 2008) they could have laid smaller eggs, producing smaller young, one source of rapid phylogenetic miniaturization.

Wang et al. report, “The combination of many pterosaurs and eggs indicates the presence of a nesting site nearby and suggests that this species developed gregarious behavior. Hamipterus likely made its nesting grounds on the shores of freshwater lakes or rivers and buried its eggs in sand along the shore, preventing them from being desiccated.” There’s another possibility. Since pterosaurs are lepidosaurs, they could have retained the eggs in utero until the young were ready to hatch. That also prevents them from desiccation. Since the flood tore the bones apart, any in utero eggs would have been torn away from the mother as well.

Notable by its absence
is any report of embryo bones inside the eggshells. I presume none were found or they would have been reported. That’s a shame, too, because eggs are nice little containers for complete skeletons, something lacking at the Hamipterus site. Some of the eggs appear to be evacuated, as if they were empty when buried. Or maybe all the juices were squeezed out during the rush and tumble of flood waters. If there was an embryo inside one of the Hamipterus eggs, and that is likely as the egg shell is applied just before egg laying, the embryo might have looked something like this (Fig. 3) based on the other pterosaur embryos inside their own two-dimensional eggs and the appearance of more complete sister taxa. During taphonomy the embryo inside would have been shaken AND stirred (but note some skulls are preserved complete without destruction!). The three dimensional egg contents would not accumulate on the randomly chosen longitudinal saw cut.

Figure 3. Wang et al. sliced one of the eggs lengthwise (yellow). if there is an embryo inside, it might have looked something like this. Since the egg has not been crushed to two dimensions, all the bones would not be now located in the plane of the slice, which was a random cut, not recognizing any embryo inside.

Figure 3. Wang et al. sliced one of the eggs lengthwise (yellow). if there is an embryo inside, it might have looked something like this. Since the egg has not been crushed to two dimensions, all the bones would not be now located in the plane of the slice, which was a random cut, not recognizing any embryo inside. Other embryos are typically in this pose.

Pterosaur hatchlings
of this size were precocial, able to fly shortly after hatching and large enough not to suffer from desiccation caused by so much surface area compared to volume.

References
Chinsamy A, Codorniú L and Chiappe LM 2008. Developmental growth patterns of the filter-feeder pterosaur, Pterodaustro guinazui. Biology Letters, 4: 282-285.
Elgin RA, Hone DWE, and Frey E. 2011.
The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56 (1), 2011: 99-111 doi:10.4202/app.2009.0145 online pdf
Wang X et al.*, 2014.
 Sexually Dimorphic Tridimensionally Preserved Pterosaurs and Their Eggs from China, Current Biology. http://dx.doi.org/10.1016/j.cub.2014.04.054