Labidolemur enters the LRT as a ‘freakish dead-end’ taxon

Labidolemur kayi
(Matthew and Granger 1921; Eocene, 55mya; Fig. 1) was re-described by Silcox et al. 2010 with µCT scans that provided cranial cavity and other never-before-seen details. The several skeletons analyzed in the publication were recovered from freshwater limestone in the Bighorn Basin by co-author Peter Houde of New Mexico State University.

Figure 1. Co-author Jonathan Block holding up the rather complete and articulated skeleton of Labidolemur still encased in a bit of reddish matrix.

Figure 1. Co-author Jonathan Block holding up the rather complete and articulated skeleton of Labidolemur still encased in a bit of reddish matrix.

According to a publicity release
(link below) “Researchers said the new information will aide future studies to better understand the origin of primates. Scientists have disputed the relationships of Apatemyidae, the family that includes L. kayi, for more than a century because of their unusual physical characteristics. With can opener-shaped upper front teeth and two unusually long fingers, apatemyids have been compared to a variety of animals, from opossums to woodpeckers.”

When added to
the large reptile tree (LRT, 1698+ taxa) Labidolemur unsurprisingly nests with Apatemys, within Glires (gnawing placentals). Labidolemur and Apatemys are virtually identical according to the LRT scores, but proportional differences can still be discerned when the two skulls are side-by-side.

So Labidolemur will not help us,
“better understand the origin of primates.”

Silcox et al. 2010 wrote:
“To test all of the hypotheses that have been suggested, it is necessary to include a very broad range of eutherians, including other apatemyids, eulipotyphlans, ‘proteutherians’ (leptictids and palaeoryctids), primates and other euarchontans, and any other groups that might be relevant for accurately reconstructing basal states for larger clades that include those taxa (e.g. carnivorans and gliroids). To this end we have assembled a matrix of 33 in-group taxa and one out-group (Ukhaatherium nessovi) that were assessed for 240 morphological characters (68 postcranial, 45 cranial, and 127 dental.”

Figure 2. Cladoram from and Bloch 2020 lacking many pertinent taxa.

Figure 2. Cladoram from Silcox et sl. 2020 lacking many pertinent taxa. See text for list.

A broad range, indeed, but not broad enough
according to the LRT. Missing taxa include:

  1. All three shrew opossums, which surround Microsyops and Trogosus. Labidolemur correctly nests with Apatemys.
  2. Any metatherians (marsupials), including Caluromys, the proximal outgroup to the Eutheria (placentals) of which Carnivora is the basalmost clade.
  3. Leptictidae are not basalmost placentals, but basal to tenrecs + odontocetes when more taxa are added
  4. Vulpavus and other arboreal, wooly opossum-like Carnivora nest at the base of the Eutheria apart from Erinaceus (hedgehog) and Sorex (shrew) both members of Glires. Missing basal shrew: Uropsilus.
  5. Tupaia is basal to Glires in the LRT. Missing relatives include Macroscelides, Chrysochloris and Necrolestes.
  6. All the rodents and multituberculates are missing. They attract carpolestids and plesiadiformes away from Primates in the LRT.
  7. Altanius requires study, but is represented by teeth and jaw fragments described as plesiadapiform-like.
Figure 2. Apatemys nests as a proximal sister to bats in the Halliday et al. tree. But it shares very few traits with bats. Note the very odd dentition.

Figure 2. Apatemys nests as a proximal sister to bats in the Halliday et al. tree. But it shares very few traits with bats. Note the very odd dentition, largely matched to Labidolemur.

John Wible, is curator of mammals
at the Carnegie Museum of Natural History. After reviewing the Silcox et al. 2010b study, he reported, “It is now clear that any assessment of the origins of primates in the future will have to include apatemyids. Apatemyids are not some freakish dead-end, but significant members of our own history.”

Figure 1. Subset of the LRT focusing on Glires and subclades within.

Figure 3. Subset of the LRT focusing on Glires and subclades within. Slightly out of date, Ptilocercus now nests basal to colugos, but the nesting of Apatemys has not changed.

The LRT invalidates Wible’s statement.
Instead, apatemyids are indeed ‘some freakish-dead taxa’, nesting in Glires, far from Primates. The myth of a plesiadapid-primate interrelationship (that includes the aye-aye, Daubentonia) is not supported when more taxa are added. In the LRT plesiadapiformes, like Daubentonia, are primate-mimics nesting within Glires close to multituberculates and carpolestids. Simply adding taxa recovers this topology. That’s all it takes.


References
Matthew WD and Granger W 1921. New genera of Paleocene mammals. American Museum Novitates 13:1-7
Silcox MT, Bloch JI, Boyer DM and Houde P 2010. Cranial anatomy of Paleocene and Eocene Labidolemur kayi (Mammalia: Apatotheria), and the relationships of the Apatemyidae to other mammals. Zoological Journal of the Linnean Society160: 773–825.

https://www.floridamuseum.ufl.edu/science/labidolemur-kayi-bizarre-extinct-mammal/https://www.eurekalert.org/pub_releases/2010-10/w-uof101110.php

Was the first dinosaur egg soft?

Norell et al. (8 co-authors) 2020
used phylogenetic bracketing to determine that the first dinosaur egg (still unknown) was soft. They made one mistake that invalidates their phylogenetic bracket (Fig. 1).

Figure 1. From Norell et al. 2020 misleading readers by placing pterosaurs, Lagerpeton and Silesaurus in the lineage of dinosaurs after crocodylomorphs.

Figure 1. From Norell et al. 2020 misleading readers by placing pterosaurs, Lagerpeton and Silesaurus in the lineage of dinosaurs after crocodylomorphs.

From the Norell et al. abstract:
“However, pterosaurs—the sister group to dinosauromorphs—laid soft eggs.”

Simply adding taxa reveals this is wrong.
In the large reptile tree (LRT, 1698+ taxa) pterosaurs nest within Lepidosauria. The pterosaur – dinosaur myth was invalidated by Peters 2000, 2007. So we have to toss out pterosaurs as an invalid nesting. What are we left with?

According to Norell et al.
Crocodylia create rigid calcite eggs. So do members of the Theropoda (including birds). So do members of the phytodinosaur clades, Ornithopoda and Macronaria. Exceptions occur among the highly derived Ceratopsia, which lay soft eggs. Two more exceptions include the primitive sauropodomorphs, Massospondylus and Mussaurus. More importantly, egg shellls remain unknown for basal poposaurs, basal crocodylomorphs, basal theropods and basal phytodinosaurs.

When we use phylogenetic bracketing to make a statement like this
we need to be sure that we have the proper phylogeny. Norell et al. relied on tradition and myth rather than testing. They were wrong. In their claodgram, Norell et al. are hopeful that pterosaurs arose between crocodylomorphs and Lagerpeton (a bipedal proterochampsid also not related to dinosaurs). The Norell et al. cladogram was invalidated by Peters 2000 using four prior phylogenetic analyses. Those citations do not appear in Norell et al. (fufilling Bennett’s curse). In the LRT Silesaurus is a poposaur and thus a dinosaur-mimic, less related to dinosaurs than crocodylomorphs.

When we find eggs for Herrerasaurus and Eoraptor
then we can send a manuscript to Nature. Norell et al. were premature at best, misleading and myth perpetuating at worst. That the referees considered this manuscript okay to publish shows the dinosaur – pterosaur myth is still widespread and deeply entrenched, as discussed earlier here.


References
Norell et al. 2020. The first dinosaur egg was soft. Nature https://doi.org/10.1038/s41586-020-2412-8
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 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.

https://www.cnn.com/2020/06/17/world/soft-dinosaur-eggs-scn/index.html
https://www.cnet.com/news/soft-shelled-dinosaur-eggs-crack-the-mystery-of-missing-fossils/

Enigmatic 29cm Antarctic Late Cretaceous soft-shell egg

Legendre et al. (6 co-authors) 2020
report on an enigmatic egg they cannot identify. They nicknamed it “The Thing”. Without knowing anything else about it, my first guess, based on “giant” and “leathery or soft” is a giant azhdarchid (Fig. 1; first imagined in 2012). Let’s see if any clues guide us toward or away from that initial guess.

Quetzalcoatlus embryo and egg.

Figure 1. Hypothetical Quetzalcoatlus embryo and egg imagined in 2012. Compare to figure 2. The elongated shape and soft, thin shell were needed to encompass the elongated beak, neck and metacarpals. The long axis is ~35cm. See figure 4 for images of the mother.

Excerpts from the abstract
“Here we report a new type of egg discovered in nearshore marine deposits from the Late Cretaceous period (roughly 68 million years ago) of Antarctica. It exceeds all nonavian dinosaur eggs in volume and differs from them in structure.”

As in the azhdarchid hypothesis (Fig. 1).

“the new fossil, visibly collapsed and folded, presents a thin eggshell with a layered structure that lacks a prismatic layer and distinct pores, and is similar to that of most extant lizards and snakes (Lepidosauria).

As in the azhdarchid hypothesis (Fig. 1; Peters 2007).

“The identity of the animal that laid the egg is unknown, but these preserved morphologies are consistent with the skeletal remains of mosasaurs (large marine lepidosaurs) found nearby. They are not consistent with described morphologies of dinosaur eggs of a similar size class.”

Is taxon exclusion a factor here?

“Phylogenetic analyses of traits for 259 lepidosaur species plus outgroups suggest that the egg belonged to an individual that was at least 7 metres long, hypothesized to be a giant marine reptile, all clades of which have previously been proposed to show live birth.”

Perhaps taxon exclusion is a factor here. I will need to see the list of 259 lepidosaur species to see if it includes any pterosaurs.

“Such a large egg with a relatively thin eggshell may reflect derived constraints associated with body shape, reproductive investment linked with gigantism, and lepidosaurian viviparity, in which a ‘vestigial’ egg is laid and hatches immediately.”

As in the azhdarchid hypothesis (Fig. 1).

Now let’s look at the supplemental data
(writing this in real time as I do the research).

Specimen name: Antarcticoolithus bradyi.
The long axis is 29cm (Fig. 2). The short axis is estimated at 15cm. Compare that to the imagined 2012 azhdarchid egg (Fig. 1) with a long axis of 35cm. Just curl the embryo a bit and the guess = the discovery. The wider, but shorter Antarcticoolithus egg gives the developing azhdarchid? embryo a bit more room to move about. By the look of the egg, it appears to have a slit in it, as if it hatched already.

Figure 2. Antarcticoolithus bradyi from Legendre et al 2020.

Figure 2. Antarcticoolithus bradyi from Legendre et al 2020.

Figure 2b. Is that a slit in the egg shell? I am still awaiting the text of the study.

Figure 2b. Antarcticoolithus bradyi from Legendre et al 2020. Side two. Is that a slit in the egg shell from arrow to arrow? I am still awaiting the text of the study. (turns out to be a crack in the rock)

From the Supplemental Data:
“The first known remains of Late Cretaceous Antarctic pterosaurs were recently described (Kellner et al. 2019) however, the largest known pterosaur eggs with known taxonomic affinities (Pterodaustro guiñazui, egg length: ~60 mm; Fig. 3) belonged to a species with a ~2.5 m adult wingspan102. Hence, if the 290 mm-long Antarcticoolithus was a pterosaur egg, it would have been laid by a species with a wingspan of over 12 m, which is much larger than the maximum wingspan of 4–5 m described in known Antarctic pterosaurs.”

The known Antarctic pterosaurs include bits from one or two specimens (Fig. 6).

Figure 2. Original interpretations (2 frames black/white) vs. new interpretations (color).

Figure 3. Original interpretations (2 frames black/white) vs. new interpretations (color).

Now let’s check out the mother’s pelvis
(Fig. 4). Looks like 10cm in the short axis was about the maximum, unless the ischia were free to expand during egg-laying. It is also possible that the pliability of the egg itself might have enabled Antarcticoolithus to pass through a hypothetical pelvis of a giant Q. northropi, if similar in proportion to the small Q. species, which is no sure thing in these flightless giants., wingspan ~11m.

Quetzalcoatlus eggs

Figure 4. Quetzalcoatlus northropi (left) nd Q. sp. (right) to the same scale alongside hypothetical eggs and hatchlings. The egg-layer of Antarcticoolithus, if azhdarchid pterosaurian, might have had a larger cloacal opening than shown here.

Finally, let’s consider those Antarctic pterosaurs. What were they?
Hard to say because they are such small parts of the pterosaur wing (Fig. 5).

Figure 6. Antarctic pterosaur bones from Kellner et al. 2019. The elements appear to be too gracile to fit the hypothetical outline provided.

Figure 6. Antarctic pterosaur bones from Kellner et al. 2019. The elements appear to be too gracile to fit the hypothetical outline provided.

Conclusion:
Don’t overlook the possibility of a giant azhdarchid egg layer for Antarcticoolithus.

Legendre et al. report,
“Interestingly, the two specimens of pterosaurs in our sample fall within the range of soft-shelled lepidosaur eggs, despite one of them showing a prismatic calcareous layer.”

We’ve known since Peters 2007 that pterosaurs are lepidosaurs.

“Pterosaur eggs have been repeatedly described as soft-shelled due to the thin and pliable aspect of their eggshell. The first detailed description of a pterosaur egg microstructure, however, showed a conspicuous prismatic layer. Another specimen was reported to lack a calcareous layer, and be most similar in structure to a lepidosaur eggshell, but no description of its microstructure using microscopy techniques was provided, preventing a clear identification of a soft-shelled structure. Since these first descriptions, more specimens of exceptionally preserved eggs have been described for a handful of pterosaur species – some hard-shelled (Grellet-Tinner et al. 2014) some soft-shelled.”

Pterodaustro eggs (Fig. 3) can hardly be called ‘hard-shelled’ contra Grellet-Tinner et al. 2014. Eggs with deep infolds, like those of Antarcticoolithus are not filled to bursting with full-term embryos, as is formerly empty, sediment-filled egg shown in figure 2.

“There is currently no consensus on whether such a soft eggshell was widespread among pterosaurs, nor on the relationship of the structure of that soft eggshell to that of lepidosaur eggshells.”

No consensus, for reasons listed earlier, but Peters 2007 was the first worker to nest pterosaurs within lepidosauria simply by adding taxa.

“More studies on pterosaur eggshells are thus necessary to assess their potential microstructural similarity with extant soft-shelled eggs. While the possibility of Antarcticoolithus being a fossilized pterosaur egg cannot definitely be ruled out, it should be noted that no remains of giant pterosaurs likely to have laid such a large egg are known from Antarctic deposits, contrary to giant marine reptiles.”

Leave the options open. Always a good idea. This egg may belong to something else entirely, like a mosasaur (see NPR online below). As more information arrives, I will add data to this blogpost.


References
Grellet-Tinner, G. et al. 2014. The first pterosaur 3-D egg: Implications for Pterodaustro guinazui nesting strategies, an Albian filter feeder pterosaur from central Argentina. Geoscience Frontiers 5, 759–765.
Kellner AWA et al. 2019. Pterodactyloid pterosaur bones from Cretaceous deposits of the Antarctic Peninsula. Anais da Academia Brasileira de Ciências91,e20191300.
Legendre LJ, et al. (6 co-authors) 2020.
A giant soft-shelled egg from the Late Cretaceous of Antarctica. Nature Jun 17 https://doi.org/10.1038/s41586-020-2377-7
Peters D 2007.
The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.

At ResearchGate.net:
A_new_lepidosaur_clade_the_Tritosauria

From NPR with mosasaur baby illustration
https://www.npr.org/2020/06/17/877679868/scientists-find-the-biggest-soft-shelled-egg-ever-nicknamed-the-thing

https://static-content.springer.com/esm/art%3A10.1038%2Fs41586-020-2377-7/MediaObjects/41586_2020_2377_MOESM3_ESM.mov

https://pterosaurheresies.wordpress.com/2012/02/21/an-egg-for-quetzalcoatlus/

Oculudentavis reply: bird? lizard? or option #3?

O’Connor et al. 2020 are not giving up without a fight. 
Now they are arguing against a published objection (Li et al. 2020) to their interpretation of Oculudentavis as a strange tiny bird encased in Early Cretaceous Burmese amber. Citation and excerpts are below. You have to admire their courtesy while defending their hypothesis with every weapon they have… except the correct one.

From the O’Connor et al. abstract:
“We welcome any new interpretation or alternative hypothesis regarding the taxonomic affinity of the enigmatic Oculudentavis khaungraae. However, here we demonstrate that Li et al. have failed to provide conclusive evidence for the reidentification of HPG-15-3 as a squamate. We analyse this specimen in a matrix that includes a broad sample of diapsid reptiles and resolve support for this identification only when no avian taxa are included. Regardless of whether this peculiar skull belongs to a tiny bird or to a bizarre new group of lizards, the holotype of Oculudentavis khaungraae is a very interesting and unusual specimen, the discovery of which represents an important contribution to palaeontology.”

‘Regardless’ indeed, as a scientist it’s your job to figure this out. This time it’s not either this or that… it’s something else, a third alternative nobody wants to talk about.

FIgure 1. CT scan model from Li et al. 2020, who denied the presence of a quadratojugal and an antorbital fenestra, both of which are present. Colors applied here.

FIgure 1. CT scan model from Li et al. 2020, who denied the presence of a quadratojugal and an antorbital fenestra, both of which are present. Arrow points to antorbital fenestra Colors applied here. In the LRT Oculudentavis nests with Cosesaurus, a pterosaur precursor. See figure 2.

Interesting that O’Connor et al. bring up taxon exclusion,
yet keep excluding the taxa that would resolve this stand-off, members of the Fenestrasauria (Peters 2000). The O’Connor et al. taxon list was ‘broad’, but not broad enough.

Figure 1. Cosesaurus flapping - fast. There should be a difference in the two speeds. If not, apologies. Also, there should be some bounce in the tail and neck, but that would involve more effort and physics.

Figure 2. Cosesaurus flapping animation. This sister to Oculudentavis in the LRT was a flapping lizard and a pterosaur precursor provided with locked down coracoids, a aternum, strap-like scapulae, an antorbital fenestra a large orbit and bulbous cranium.

From the O’Connor et al 2020 introduction.
“We welcome any new interpretation or alternative hypothesis regarding the taxonomic affinity of the enigmatic Oculudentavis khaungraae.”

No they don’t! They were sent an alternative hypothesis the day after publication. (Not whining. Just stating fact in the face of all their righteous signaling).

“Several of the squamate morphologies described by Li et al. were noted by ourselves in the original manuscript (e.g., pleurodont dentition, morphology of the eye)1. However, we will argue that other features which Li et al. describe as unusual for archosaurs are not incompatible with our original interpretation.”

The solution continues to be the third choice, which both sides continue to overlook (= taxon exclusion).

From the O’Connor et al. text,
“Li et al. criticize our phylogenetic analysis yet provide none themselves.”

Good point! A phylogenetic solution is paramount. Otherwise you’re “Pulling a Larry Martin” trying to make your argument with possibly convergent traits, not last common ancestry, which, when done right, is irrefutable.

The O’Connor et al. text continues,
“However, this does highlight a weakness of a majority of phylogenetic analyses utilized to describe new taxa. If a new specimen is identified as a bird it is analysed in a matrix targeted at birds; if the specimen is identified as a lizard, it is analysed in a matrix targeted at lizards. Descriptions of new taxa rarely include phylogenetic datasets targeted at higher level relationships such as all of Reptilia or Amniota that would be capable of testing alternative placements.”

Another excellent point! That’s why the large reptile tree (LRT, 1697+ taxa) is online and available for anyone to use, precisely for problem taxa, like Oculudentavis.

O’Connor et al. report,
“However, removal of all avian taxa results in Oculudentavis being resolved among squamates.”

That’s interesting! (and supports Peters 2007). By the way, such a phylogenetic leap rarely happens in the LRT. Removing large proximal clades usually results in the next closest clade nesting the enigma taxon.

O’Connor et al. conclude:
“Oculudentavis may represent an outstanding case of convergent evolution between squamates and birds, the likes of which biologists have rarely seen before.”

Well, yes, if you’re referring to flapping, flying lizards (aka ‘pterosaurs’; Peters 2007). This citation is rare due to academic suppression.

Unfortunately, O’Connor et al. are still missing the headline of this story: Oculudentavis is a late-surviving member of the Middle Triassic radiation that produced pterosaurs. The arose from an overlooked third clade of Lepidosaurs, some on which became protorosaur mimics. Others became archosaur mimics.

“However, regardless of whether this peculiar skull belongs to a tiny bird or to a bizarre new group of lizards, the holotype of Oculudentavis khaungraae is a very interesting and unusual specimen, the discovery of which represents an important contribution to palaeontology.”

It won’t be ‘bizarre’ once you understand what Oculudentavis is: a sister to the lepidosaur tritosaur fenestrasaur Cosesaurus. Just expand that taxon list and come to an agreement.

Again, when someone uses the word “bizarre” they have not included all the pertinent taxa. It’s sign they are giving up. Nothing is bizarre in the LRT. All enigmas are nested. No taxon stands alone.

This is what citation avoidance and suppression results in. Neither party understands what they have here. We looked at this exact problem yesterday.

We looked at the Oculudentavis controversy
earlier here, here, here, here and here. And the story has yet to reach a conclusion.

Figure 3. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx.

Figure 3. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx.

Postscript:
The post-crania of Oculudentavis remains unknown. It could resemble anything from Cosesaurus (Fig. 3) through pterosaurs, given its Early Cretaceous age and the variety we already find in the clade Fenestrasauria, from which it arose.


References
Li Z, Wang W, Hu H, Wang M, Y H and Lu J 2020. Is Oculudentavis a bird or even archosaur? bioRxiv (preprint) doi: https://doi.org/10.1101/2020.03.16.993949 (Not cited in O’Connor et al. 2020)
O’Connor J Xing, Chiappe L, Schmitz L, McKellar R,  Li G and Yi Q 2020. Reply to Li et al. “Is Oculudentavis a bird or even archosaur?” bioRxiv 2020.06.12.147041 (preprint)
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Xing L, O’Connor JK,; Schmitz L, Chiappe LM, McKellar RC, Yi Q and Li G 2020. Hummingbird-sized dinosaur from the Cretaceous period of Myanmar. Nature. 579 (7798): 245–249.

https://pterosaurheresies.wordpress.com/2020/03/22/oculudentavis-in-more-incredible-detail-thanks-to-li-et-al-2020/

Where do we stand on the origin of pterosaurs today?

For most of the last 200 years,
all hypotheses of tetrapod interrelationships had to await novel and random discoveries as the number of known fossil taxa slowly accumulated over time. Expertise, persistence, access to the literature, access to fossil-bearing localities, teamwork and luck all played equal parts in helping this list to grow.

Nowadays in 2020,
we’re sitting on top of two centuries of discoveries preserved in museums, private collections and the literature. So figuring out the ancestors and sisters of any genus no longer depends on access to fossil-bearing localities, luck or teamwork. With persistence and access to the literature anyone can assemble a large taxon list, couple it with a large trait list, and recover a cladogram of tetrapod interrelationships using available software. Larger taxon lists are better because that minimize taxon exclusion, the number one problem with smaller studies.

Figure 3. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx.

Figure 1. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx.

Back in 2011
PterosaurHeresies started with a 3-part review of pterosaur origins here, here and culminating here.  Peters 2000a, 2000b, 2002, 2007, 2009 and 2011 (plus a suppressed manuscript correcting earlier errors at ResearchGate.net), solved the problem of pterosaur origins and wing genesis. No new discoveries were required. Taxon inclusion neatly resolved the problem. That’s all it took… adding previously omitted taxa.

Unfortunately,
even in the present era of phylogenetic analysis by software (~1990 to the present), many pterosaur ‘experts’ continue to shrug their shoulders when the subject of pterosaur origins comes up (examples below). And they don’t really care about the genesis of pterosaurs either. If they did care, they would be running analyses that recover last common ancestors.

Ignoring the literature,
the PhDs are all still waiting for the discovery of an imaginary archosaur with a long fourth finger and a long fifth toe. For reasons unknown, the experts are overlooking the fact that archosaurs don’t have a long fourth finger or a long fifth toe. Even so, this ‘waiting for specimens’ tradition continues unabated in professional circles. Instead they should be looking for the last common ancestor of pterosaurs and its relatives among known fossil and extant taxa. Look here for an example cladogram that covers such a wide gamut of taxa that taxon exclusion is minimized: the large reptile tree (LRT, 1697+ taxa).

The imaginary dinosaur-pterosaur connection
is taught at all paleo universities. It is found in all college textbooks and popular books written by PhDs. It is repeated over and over in YouTube videos (see below). If you’re a paleo student and you want a passing grade, you have to give that answer to the professor, class after class, decade after decade, perpetuating the myth.

Given that the solution to pterosaur origins
has been in the peer-reviewed literature for the last 20 years, it’s almost comical how pterosaur workers dance around the question, “Where do pterosaurs come from?”.

“We don’t know,” is the most common answer.
The 20-year-old published hypothesis of pterosaur origins (Fig. 1, Peters 2000) continues to be ignored. That hypothesis was first labeled, “heterodox“(= different). Other PhDs (e.g. Mark Witton) labeled the author a crank. Still other PhDs (e.g. Darren Naish) attempted to divert the world away from solutions published online.

The more interesting quandary, however,
is the continuing predicament the PhDs have gotten themselves into and how it will continue indefinitely. Apparently there is just no way pterosaur workers are ever going to admit that an outsider solved the problem of pterosaur origins using the most common tool of the trade, phylogenetic analysis.

Apparently there is just no way any PhD or grad student is going to observe the specimens and repeat every aspect of the experiment that resulted in the 2000 solution to pterosaur origins. No one wants to be the second person to discover something, especially after it has been attacked from all sides or ignored for the last twenty years. Any move PhDs make now will make them all look bad. Not making any move also makes them look bad. They have a job to do. They should do it.

Pterosaur workers continue to ignore the pertinent taxa and omit the pertinent citations in favor of a myth (that pteros are dino cousins), even though they also loudly confess they have no evidence for support of that hypothesis. Often phytosaurs show up just outside the Pterosauria when fenestrasaurs are omitted or poorly scored.

In the following short video from 2009
watch German pterosaur experts Gunther Viohl and Peter Wellnhofer undercut previously published studies on pterosaur origins by remarking, the ancestors are not known” and “in fact, it is a mystery which group of reptiles prior to the Triassic, might have given rise to the pterosaurs. So we don’t actually have the ancestor to the pterosaurs in the fossil record.”

The delighted Creationist narrator is then free to claim,
“No transitional forms have been found showing a ground lizard slowly changing into a flying reptile. There are no fossils of a ground reptile with partially developed wings. All of the known pterosaur fossils are perfectly developed.”

Actually
we do know of several ground lizards slowly changing into a flying reptile (Figs. 1, 2). They were re-described by Peters 2000 (see ResearchGate.net for additions and corrections).

Figure 1. Click to enlarge. The origin of the pterosaur wing and the migration of the pteroid and preaxial carpal. A. Sphenodon. B. Huehuecuetzpalli. C. Cosesaurus. D. Sharovipteryx. E. Longisquama. F-H. The Milan specimen MPUM 6009, a basal pterosaur.

Figure 2. Click to enlarge. The origin of the pterosaur wing and the migration of the pteroid and preaxial carpal. A. Sphenodon. B. Huehuecuetzpalli. C. Cosesaurus. D. Sharovipteryx. E. Longisquama. F-H. Bergamodactylus, MPUM 6009, a basal pterosaur.

Hone and Benton 2007, 2008 had high hopes
when they decided to test the results of Peters 2000 (Cosesaurus and kin as pterosaur ancestors) against the results of Bennett 1996 (Scleromochlus as a pterosaur ancestor). In their two-part paper Hone and Benton used the Supertree Method. It joins previously published cladograms, trusting their accuracy without observing specimens firsthand. Dr. Benton may have been waiting for a student interested in pterosaurs for several years because Benton 1999 agreed with Bennett 1996 in suggesting Scleromochlus was a pterosaur ancestor. Both ignored the fact that Scleromochlus had vestiges for finger 4 and toe 5, among dozens of other invalidating traits. Peters 2000 introduced better candidates and showed both PhDs were wrong by testing more taxa in four separate phylogenetic analyses based on prior studies, including Benton 1999 and Bennnett 1996.

Problems arose for Hone and Benton when their supertree results recovered Cosesaurus and kin as pterosaur ancestors. Rejecting this result, Hone and Benton dropped all data and reference to Peters 2000 and gave Bennett 1996 credit for coming up with both competing views. They had the bullocks to ignore the premise of their experiment, perhaps thinking their status as PhDs would save them. So far it has. Most of the rest of the paleo community has silently witnessed this odd turn of events without raising an objection or pointing a finger. Only Bennett 2012, 2013 reported the mistakes reported by Hone and Benton were of their own doing. Even so, Bennett 2012, 2013 continued to ignore taxa proposed by Peters 2000. Strange. Why put blinders on?

David Hone at his blogsite
ArchosaurMusings reports, “To cut a long story short, pterosaurs are damned difficult to place in the reptile tree. The truth of the matter is that currently the best supported hypothesis is that pterosaurs derived from the dinosauromorphs and thus are very close relatives of the dinosaurs.” Actually it’s not ‘damn difficult’. It simply takes more taxa. By the way, ‘the best supported hypothesis’ is not the best supported hypothesis. Rather it’s the one they teach at university, the one that omits Peters 2000.

The American Museum of Natural History
is likewise culpable. In the following video watch pterosaur expert, Alex Kellner, and Museum Director, Mark Norell, tell you pterosaurs are dinosaur relatives. But you’ll never see evidence of that because they don’t have it. It’s a traditional myth they cling to due to peer group pressure, not science.

Venerable PBS
became a frenemy of pterosaurs with the following video that omits the actual evolution of wings in favor of the traditional myth. Sadly, the promise of the headline is not fulfilled in the video.

Likewise, in the ‘It’s Okay to Be Smart’ video
Mike Habib perpetuates the archosaur origin myth. He also promotes an invalid, impossible and dangerous quad-catapult take-off technique (Fig. 3) rather than leaping and flapping at the same time for maximum thrust from the first nanosecond (Fig. 4) as birds do. He also promotes the invalid hypothesis of giant pterosaur flight.

Unsuccessul Pteranodon wing launch based on Habib (2008).

Figure 3. Unsuccessful Pteranodon wing launch based on Habib (2008) in which the initial propulsion was not enough to permit wing unfolding and the first downstroke.

Successful heretical bird-style Pteranodon wing launch

Figure 4. Successful bird-style Pteranodon wing launch in which the already upraised wing provides the necessary thrust for takeoff from moment one. This assumes a standing start and not a running start in the manner of lizards and some birds. Note three wing beats take place in the same space and time that only one wing beat takes place in the hazardous Habib model (Fig. 3).

Good scientists observe and report.
Then other good scientists repeat the experiment again and again to make sure the hypothesis is correct, rectifying errors as they appear. Sadly, that’s not what we observe among pterosaur workers.

Taxon exclusion is a powerful tool.
Some of you might remember when I was able to nest pterosaurs with turtles by taxon exclusion and again retested when more taxa were present. False positives are possible when using small taxon lists.

I never imagined
pterosaur workers would end up avoiding and suppressing a valid hypothesis in favor of a myth they admit they cannot support with evidence. Twenty years later there are still no competing papers on pterosaur origins that include accurate scoring for taxa in the Fenestrasauria and Tritosauria. This could still be a hot topic, but, no one is interested in finding out how pterosaurs got their wings anymore. Their preferred answer continues to be, “We don’t know.” The unspoken takeaway is,”and we’re not even going to try to find out because the status quo has been working for us.


References
Bennett SC 2008. Morphological evolution of the forelimb of pterosaurs: myology and function. Pp. 127–141 in E Buffetaut and DWE Hone eds., Flugsaurier: pterosaur papers in honour of Peter Wellnhofer. Zitteliana, B28.
Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoolological Journal of the Linnean Society 118: 261–308.
Benton MJ 1999. Scleromochlus taylori and the origin of the pterosaurs. Philosophical Transactions of the Royal Society London, Series B 354 1423-1446. Online pdf
Bennett SC 2012. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined. Historical Biology. iFirst article, 2012, 1–19.
Bennett SC 2013. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined. Historical Biology 25(5-6): 545-563.
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
Habib M 2008. Comparative evidence for quadrupedal launch in pterosaurs. Pp. 161-168 in Buffetaut E, and DWE Hone, eds. Wellnhofer Pterosaur Meeting: Zitteliana B28
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008. Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Mazin J-M, Billon-Bruyat J-P and Padian K 2009. First record of a pterosaur landing trackway. Proceedings of the Royal Society B doi: 10.1098/rspb.2009.1161 online paper
Padian K. 1984. The Origin of Pterosaurs. Proceedings, Third Symposium on Mesozoic Terrestrial Ecosystems, Tubingen 1984. Online pdf
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
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 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. Hist Bio 15: 277–301.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D 2009.
A reinterpretation of pteroid articulation in pterosaurs.
Journal of Vertebrate Paleontology 29: 1327-1330
Prondvai E and Hone DWE 2009. New models for the wing extension in pterosaurs. Historical Biology DOI: 10.1080/08912960902859334
Senter P 2003. Taxon Sampling Artifacts and the Phylogenetic Position of Aves. PhD dissertation. Northern Illinois University, 1-279.
Sereno PC 1991. Basal archosaurs: phylogenetic relationships and functional implications. Journal of Vertebrate Paleontology 11 (Supplement) Memoire 2: 1–53.
Sharov AG 1971. New flying reptiles fro the Mesozoic of Kazakhstan and Kirghizia. Trudy of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.
Woodward AS 1907. On a new dinosaurian reptile (Scleromochlus taylori, gen. et sp. nov.) from the Trias of Lossiemouth, Elgin. Quarterly Journal of the Geological Society 1907 63:140-144.

https://pterosaurheresies.wordpress.com/2017/11/26/why-do-pterosaur-workers-ignore-the-most-basic-data/

Microsyops enters the LRT between three overlooked shrew opossums

Silcox, Gunnell and Bloch 2020
described the cranium of Microsyops annectens (Leidy 1872, Marsh 1872, Fig. 1), but were not able to nest it phylogenetically due to taxon exclusion. The authors mistakenly kept calling it a plesidapiform and mistakenly considered plesiadapiforms ‘plausible stem primates.’

More taxa
solve this problem.

Figure 1. Micrsyops skull from Silcox et al. 2020. The third tooth is the canine.

Figure 1. Micrsyops skull from Silcox et al. 2020. The third tooth is the canine.

From their abstract:
“While results from phylogenetic analyses support euarchontan affinities, specific relationships of microsyopids to other plesiadapiforms (plausible stem primates), Euprimates (crown primates), Scandentia (treeshrews), and Dermoptera (colugos) are unresolved.”

From the discussion and conclusions:
“The basicranial anatomy of microsyopids does not provide evidence in support of a clear link to any of the extant euarchontans, and suggests that the primitive morphology of this region in Euarchonta was little differentiated from that observed in the primitive placental mammals.”

Figure 1. Not a marsupial, and not a shrew opossum, Palaeothentes nests in the LRT at the base of the Apatemys + Trogosus clade nest to the clade of living shrew opossums within Glires.

Figure 2. Not a marsupial, and not a shrew opossum, Palaeothentes nests in the LRT at the base of the Apatemys + Trogosus clade nest to the clade of living shrew opossums within Glires.

By contrast
in the large reptile tree (LRT, 1698+ taxa) using fewer traits and more taxa, Microsyops nests as a near basal member of Glires (gnawing mammals) between three traditional pouchless ‘marsupials’, the two extant shrew ‘opossums’, Rhyncholestes (Fig. 3) + Caenolestes and Palaeothentes (Miocene. Fig. 2). These nest at the base of Trogosus (Eocene) + the Apatemyidae (Eocene). None of these taxa, other than Apatemys, were included in the Silcox et al. cladograms.

Figure 1. Skull of Rhyncholestes along with in vivo photo.

Figure 3. Skull of Rhyncholestes along with in vivo photo.

Ironcally, ten years earlier,
Silcox, Bloch, Boyer and Houde (2010) wrote: “Microsyopids are the most similar to apatemyids in the basic form of the basicranium of any ‘plesiadapiform’.

Again, adding taxa
(more rodents, rabbits and shrew opossums ) solves this problem. Don’t assume pouchless shrew opossums are marsupials. In the LRT they are gnawing placentals, derived from tree shrews, as we learned earlier here. Call them marsupial-mimics.


References
Leidy J 1872.
Remarks on fossils from Wyoming: Proceedings of the Academy of Natural Sciences, Philadelphia 1872: 19–21.
Marsh OC 1872. Preliminary description of new Tertiary Mammals. Parts I– IV: American Journal of Science 4: 122–128, 202–224.
Silcox MT, Bloch JI, Boyer DM and Houde P 2010. Cranial anatomy of Paleocene and Eocene Labidolemur kayi (Mammalia: Apatotheria), and the relationships of the Apatemyidae to other mammals. Zoological Journal of the Linnean Society160: 773–825.
Silcox MT, Gunnelll GF and Bloch JI 2020. Cranial anatomy of Microsyops annectens (Microsyopidae, Euarchonta, Mammalia) from the middle Eocene of Northwestern Wyoming. Journal of Paleontology, 28pp. 0022-3360/20/1937-2337
doi: 10.1017/jpa.2020.24

wiki/Microsyops

Two papers in one: Haramiyidans and Juramaia

Part 1: King and Beck 2020
bring us their views (again), on ‘early mammal relationships‘. Let’s see how they stack up (again) against the validated (thanks to taxon inclusion) results of the large reptile tree (LRT, 1697+ taxa).

From their abstract:
“Many phylogenetic analyses have placed haramiyidans in a clade with multituberculates within crown Mammalia, thus extending the minimum divergence date for the crown group deep into the Triassic. Here, we apply Bayesian tip-dated phylogenetic methods [definition below] to investigate these issues. Tip dating firmly rejects a monophyletic Allotheria (multituberculates and haramiyidans), which are split into three separate clades, a result not found in any previous analysis. Most notably, the Late Triassic Haramiyavia and Thomasia are separate from the Middle Jurassic euharamiyidans.”

Bayesian tip-dated phylogenetic methods = online definition here.

You heard it here first
Earlier (2016) the LRT rejected a monophyletic Allotheria (separating Haramiavia (Fig. 1) and Thomasia), from Megaconus and all the multituberculates (Fig. 2). Haramiavia and Thomasia nest as pre-mammal synapsids (tritylodontids), not far from Pachygenelus. Several dozen nodes away, Megaconus and the multis nest within the placental clade Glires, at a node more highly derived than tree shrews, rodents and rabbits. So far that hypothesis of relationships has not been tested by other workers, despite several invitations to expand their taxon lists.

Figure 4. Haramiyava dentary showing what a more typical stem mammal dentary and teeth look like. Earlier studies linked this clade to multituberculates, but this dentary was cause to reject that association.

Figure 1. Haramiyava dentary showing what a more typical stem mammal dentary and teeth look like. Earlier studies linked this clade to multituberculates, but this dentary was cause to reject that association.

According to King and Beck 2020,
“Our analysis places Haramiyavia and Thomasia in a clade with tritylodontids, a result that may be the result of insufficient sampling of non-mammaliaform cynodont characters and taxa, and which we consider in need of further testing (see detailed discussion in the electronic supplementary material).” This confirms relationships first recovered by the LRT.

Figure 1. LRT taxa in the lineage of multituberculates arising from Carpolestes and Paulchoffatia.

Figure 2. LRT taxa in the lineage of multituberculates arising from Carpolestes and Paulchoffatia.

The authors continue,
“Our focal dataset was taken from Huttenlocker et al. 2018, which comprises 538 morphological characters scored for 125 mammaliaforms and non-mammaliaform cynodonts.

Unfortunately,
as I mentioned earlier, King and Beck still need to include extant mammals, like montoremes, marsupials, rodents and Daubentonia, rather than rely on fossil taxa exclusively. (See below).

Figure 1. Subset of the LRT focusing on Glires and subclades within.

Figure 3. Subset of the LRT focusing on Glires and subclades within.

Part 2: King and Beck 2020 report:
“A second taxon of interest is the eutherian Juramaia (Fig. 4) from the Middle–Late Jurassic Yanliao Biota, which is morphologically very similar to eutherians from the Early Cretaceous Jehol Biota and implies a very early origin for therian mammals. We also test whether the Middle– Late Jurassic age of Juramaia is ‘expected’ given its known morphology by assigning an age prior without hard bounds. Strikingly, this analysis supports an Early Cretaceous age for Juramaia, but similar analyses on 12 other mammaliaforms from the Yanliao Biota return the correct, Jurassic age.”

Figure 2. Juramaia (Late Jurassic, 160 mya) is more completely known and nests between monotremes and therians (marsupials + placentals).

Figure 4. Juramaia (Late Jurassic, 160 mya) is more completely known and nests between monotremes and therians (marsupials + placentals).

By contrast In the LRT,
Juramaia is a basal protorothere, nesting between Megazostrodon + Sinodelphys and Chaoyangodens, all basal to the extant platypus and echidna in the LRT. Beck and King omit so many key taxa that they do not recover Prototheria, Metatheria and Eutheria.

The same authors publishing on a similar topic in 2019
were reviewed here. The following is one paragraph from that review: King and Beck 2019 bring us a new phylogenetic analysis restricted to Mesozoic mammals. This represents a massive case of taxon exclusion of basal mammals as demonstrated earlier here, because so many basal mammals are still alive! Think of all the tree shrews, arboreal didelphids, and nearly every little creeping taxon in Glires that nest basal to known Mesozoic mammals. You cannot restrict the taxon list to just those extremely rare Mesozoic mammals.

Colleagues: Please use extant mammals in your analyses!
They are guaranteed complete and articulated with soft tissues and gut contents. Figure out your cladogram with as many of these complete specimens as possible. Then… start adding crushed, incomplete and disarticulated fossil taxa. In other words, give yourself a basic education first. Establish a valid tree topology first. Don’t muddle through your studies with questionable traits based on fractured mandibles missing several teeth. As longtime readers know, a valid phylogenetic context is paramount for all further studies.


References
Huttenlocker AK, Grossnickle DM, Kirkland JI, Schultz JA and Luo Z-X 2018. Late-surviving stem mammal links the lowermost Cretaceous of North America and Gondwana. Nature 558, 108–112. 8. (doi:10.1038/s41586-018-0126-y);
King B and Beck R 2019. Bayesian Tip-dated Phylogenetics: Topological Effects, Stratigraphic Fit and the Early Evolution of Mammals. PeerJ
doi: http://dx.doi.org/10.1101/533885.
King B and Beck RMD 2020.
Tip dating supports novel resolutions of controversial relationships among early mammals. Proceedings of the Royal Society B 287: 20200943. http://dx.doi.org/10.1098/rspb.2020.0943

https://pterosaurheresies.wordpress.com/2019/02/07/taxon-exclusion-mars-mesozoic-mammal-study/

Bipedal crocodylomorph (or giant pterosaur tracks?) from Korea

Kim et al. 2020 describe
sets of 18-24cm narrow-gauge tetradactyl (four-toed) bipedal tracks from the Early Cretaceous (Aptian?) coast of South Korea they name Batrachopus grandis (Figs. 1, 2) a new ichnospecies. The authors attribute the tracks to a large (3m) crocodylomorph. They also note: “Surprisingly, the trackways appear to represent bipedal progression which is atypical of all known smaller batrachopodid trackways.”

You might find their logic train interesting. (See below.)

By the way, such narrow-gauge tracks (Fig. 2) are also atypical for Cretaceous crocs and azhdarchid pterosaurs, like the Late Cretaceous trackmaker of the ichnospecies, Haenamichnus (Figs. 2, 3).

On the other hand, basalmost Triassic crocs were all narrow-gauge bipeds. None of these were large (but that can change), plantigrade (but that can change) or left tracks (that we know of).

Such narrow-gauge tracks were also typical for strictly bipedal pterosaurs, like the coeval (Early Cretaceous) Shenzhoupterus (Figs. 5–7), a taxon overlooked by Kim et al. 2018, 2020.

Figure 1. Batrachopodus grandis tracks from Kim et al. 2020. Note the digits are shorter than the metatarsals and the heel is half the maximum width of the foot, matching both Early Jurassic Protosuchus and coeval (Early Cretaceous) Shenzhoupterus.

Figure 2. Batrachopus tracks (2nd from left) compared to other croc tracks.

Figure 2. Batrachopodus tracks (2nd from left) compared to other croc tracks. Haenamichnus uhangriensis, azhdarchid quadrupedal pterosaur tracks shown at far right, with three fingered manus track, outside and slightly behind the oval (here at this scale) pedal track.

From the Kim et al. abstract:
“This interpretation helps solve previous confusion over interpretation of enigmatic tracks of bipeds from younger (? Albian) Haman formation sites by showing they are not pterosaurian as previously inferred. Rather, they support the strong consensus that pterosaurs were obligate quadrupeds, not bipeds.”

Consensus = current opinion. What you really want  and deserve is evidence! (…and not to overlook evidence that is already out there). Peters 2000, 2011 showed that many pterosaurs were bipedal. Specific beachcombing clades were quadrupedal secondarily.

Figure 2. The large azhdarchid pterosaur, Zhejiangppterus. is shown walking over large pterosaur tracks matched to its feet from Korea (CNUPH.p9. Haenamichnus. (Hwang et al. 2002.)

Figure 3. The large azhdarchid pterosaur, Zhejiangppterus. is shown walking over large pterosaur tracks matched to its feet from Korea (CNUPH.p9. Haenamichnus. (Hwang et al. 2002.)

Unfortunately,
basal crocodylomorph feet are almost entirely absent from the fossil record in tested taxa in the large reptile tree (LRT, 1697+ taxa). The only exception is bipedal and likely digitigrade, Terrestrisuchus (Fig. 4). We don’t get another complete set of toes for testing until quadrupedal and plantigrade Protosuchus (Fig. 4), a not so basal crocodylomorph, that had the slightly more gracile digit 4 common to all extant crocs. Digit 4 does not appear to be any more gracile than the other toes in the new South Korean tracks, but let’s overlook that trifle for the moment.

Figure 2. Same feet, reordered according to the large reptile tree. Only Terrestrisuchus and Protosuchus are croc-like archosaurs here. Poposaurs are basal dinosaurs.

Figure 4. Same feet, reordered according to the large reptile tree. Only Terrestrisuchus and Protosuchus are croc-like archosaurs here.

Perhaps that is why Kim et al. write:
“Lower Jurassic Batrachopus with foot lengths (FL) in the 2–8 cm range, and Cretaceous Crocodylopodus (FL up to ~9.0 cm) (Fig. 2) known only from Korea and Spain registered narrow gauge trackways indicating semi-terrestrial/terrestrial quadrupedal gaits. Both ichnogenera, from ichnofamily Batrachopodidae, have been attributed to Protosuchus-like semi-terrestrial crocodylomorphs.”

… with a wider-gauge quadrupedal track.

On that note: The type species for Batrachopus is much smaller, fleshy, quadrupedal, narrow-gauge, with pedal impressions just behind the much smaller manus impressions.

By the start of the Cretaceous all the earlier bipedal crocodylomorphs were extinct, according to the current fossil record. Shenzhoupterus, from China, was a nearby contemporary of the South Korean trackmaker with nearly identical feet and gait. Did I hear someone say, “Occam’s Razor“? Did someone mention, “taxon exclusion”?

Earlier Kim et al. 2012 described similar tracks
as pterosaurian. Back then they were matched here to a giant Shenzhoupterus (Figs. 5–7), a coeval (Aptian, Early Cretaceous) dsungaripterid relative found in nearby China, with forelimbs less likely to reach the ground. Later a partial skeleton of a giant Late Cretaceous pterosaur from France, Mistralazhdarcho (Vullo et al. 2018), was reidentified here as a giant shenzhoupterid, rather than an azhdarchid. So shenzhoupterids were not restricted in size.

Kim et al report on, “Distinguishing crocodilian from pterosaurian trackways.”
“An unexpected result of the discovery of B. grandis trackway has been to shed light on a the controversial issue of pterosaur locomotion debated since the 1980 and 1990s: were pterosaurs bipedal or quadrupedal?

The answer is some were bipedal. Others were quadrupedal (Peters 2000, 2011, not cited by Kim et al.). It all depends on the clade and their niche.

Kim et al continue:
“These debates, mainly concerning relatively small pterosaurian tracks, have largely been resolved in favor of quadrupedalism.

Largely? Does that mean Kim et al. recognize exceptions? If so, they were not cited. More importantly, look for any other distinguishing traits in what follows from the Kim et al. text.

Kim et al continue:
“However, some uncertainty remained regarding tracks of purported ‘giant’ pterosaurians that were described as ‘enigmatic’ and inferred to have progressed bipedally (Kim et al. 2012). These trackways from the Lower Cretaceous, Haman Formation, at the Gain-ri tracksite, Korea were named Haenamichnus gainensis and inferred to represent, large, plantigrade pterodactyloid pterosaurs that might have walked bipedally so that the long wings did not become mired in the substrate. It was further inferred they may have been wading in shallow water.”

amples from the Lower Cretaceous, Gain, Korea trackway

Figure 5. Samples from the Lower Cretaceous, Gain, Korea trackway (left) along with original tracings of photos, new color tracings of photos with hypothetical digits added in red, then candidate trackmakers from the monophyletic Shenzhoupterus/Tapejarid clade.

Estimating Gain pterosaur trackmakers from track sizes and matching taxa.

Figure 6. Estimating Gain pterosaur trackmakers from track sizes and matching taxa. Note the Shenzhoupterus manus is a wee bit too short to touch the substrate as in Tupuxuara and many other derived pterosaurs.

Figure 1. Mistralazhdarcho compared to reconstructions of Shenzhoupterus and Nemicolopterus.

Figure 7. Mistralazhdarcho compared to reconstructions of Shenzhoupterus and Nemicolopterus.

Kim et al continue:
“We can now confirm confidently, that these tracks from the Gain-ri tracksite and others from Adu Island: are identical to poorly preserved large Batrachopus trackways. Thus, they should be removed from Haenamichnus and regarded as large poorly preserved batrachopodid tracks. The type specimen then tech- nically becomes Batrachopus gainensis (comb nov.). Thus, H. gainensis becomes a footnote to ichnotaxonomic history, shown to be an extramorphological expressions large of Batrachopus, only recognizable retrospectively after comparison with B. grandis. Therefore ichnologists may retrospectively choose to regard H. gainensis as a nomen dubium, and find little value in the trival name (gainensis). Alternatively they may simply refer to the Haman Formation tracks as Batrachopus cf. grandis.

Taken on its face, this is a rare instance of a paleontologist admitting a mistake. The other option is: both tracks are pterosaurian. So far, as you’ll note, the authors have not pointed to any factors, other than ‘bipedalism’, that would dissuade a pterosaurian trackmaker interpretation. I will admit and you can see (Figs. 4–5) that the pedes of Protosuchus and Shenzoupterus are rather close matches when covered with pads.

Kim et al continue:
“Note that the Gain-ri and Adu island trackways are from the Haman Formation and so these occurrences indicate a widespread distribution in space (three sites) and time (two formations) of this distinctive apparently bipedal morphotype. The pes tracks from the two Haman Formation sites are also larger (27.5–39.0 cm long), but with trackway proportions (step, stride, pace angulation etc.,) quite similar to those from the Jinju Formation.”

“The identification of the Haman Formation trackways as poorly preserved large batrachopodid tracks apparently suggests that the trackmakers habitually progressed bipedally. Alternatively the same speculative arguments for apparent rather than real bipedalism would have to be invoked as was the case with the Jinju material. Moreover, in almost all cases the trackways are very narrow gauge with a narrower straddle than seen in modern crocodylians. It is also of interest that least five subparallel more or less equally spaced trackways were registered on the level 4 surface. This suggests either that the trackmakers may have been gregarious, or that they were following a physically controlled route, such as a shoreline, defined by the paleoenvironment.”

Still no distinguishing traits, other than bipedalism, according to the authors. And note, they never considered the coeval and neighboring pterosaur, Shenzhoupterus, which is also a close match for the new tracks. They chose to invent a croc trackmaker rather than consider a pterosaurian trackmaker, evidently bowing to the consensus (their word, not mine, see above) and to follow Dr. Bennett’s curse and keep their blinders on. I wish they had dived deeper into the literature and evidence instead of following the crowd.


References
Hwang KG, Huh M, Lockley MG, Unwin DM and Wright JL 2002. New pterosaur tracks (Pteraichnidae) from the Late Cretaceous Uhangri Formation, southwestern Korea. Geology Magazine 139(4): 421-435.
Kim, JY et al. 2012. Enigmatic giant pterosaur tracks, and associated ichnofauna from the Cretaceous of Korea: implications for bipedal locomotion of pterosaurs. Ichnos 19, 50–65 (2012).
Kim KS, Lockley MG, Lim JD, Bae SM and Romilio A 2020. Trackway evidence for large bipedal crocodylomorphs from the Cretaceous of Korea. Nature Scientific Reports 10:8680 | https://doi.org/10.1038/s41598-020-66008-7
Lockley, MG et al. 2020. First reports of Crocodylopodus from Asia: implications for the paleoecology of the Lower Cretaceous.Cretaceous Research (2020) (online, March 2020).
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods. Ichnos, 7: 11-41
Peters D 2011.
A Catalog of Pterosaur Pedes for Trackmaker Identification Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605
Vullo R, Garcia G, Godefroit P, Cincotta A, and Valentin X 2018.
 Mistralazhdarcho maggii, gen. et sp. nov., a new azhdarchid pterosaur from the Upper Cretaceous of southeastern France. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2018.1502670.

https://pterosaurheresies.wordpress.com/2012/03/25/giant-bipedal-pterosaur-tracks-from-korea/

https://pterosaurheresies.wordpress.com/2018/10/19/mistralazhdarcho-a-new-pterosaur-but-not-an-azhdarchid/

New tiny ‘Ctenochasma’ at the Field: Lauer Foundation Collection

The Lauer Foundation for Paleontology provided
this tiny crushed Ctenochasma? elegans? Fig. 1) to the Field Museum, Chicago, USA. The foundation number is: #LF 2296. It enters the large pterosaur tree (LPT, 250 taxa; Fig. 2) distinct from all other tested pterosaurs.

Figure 1. A tiny Ctenochasama micronyx undergoes DGS here. Every bone is present, but no soft tissue this time. Note the tiny claws on all digits along with the slightly spoon-shaped rostrum and needle-like teeth.

Figure 1. A tiny Ctenochasama micronyx undergoes DGS here. Every bone is present, but no soft tissue this time. Note the tiny claws on all digits along with the slightly spoon-shaped rostrum and needle-like teeth.

Tiny, yes, but not a juvenile.
As we learned earlier, pterosaur hatchlings have adult proportions. Pterodaustro presents the phylogenetically closest example, in this case. Phylogenetic miniaturization is how we get tiny pterosaurs. And tiny pterosaurs are transitional taxa. That’s how we get derived pterosaurs. Note the tiny Ctenochasma? elegans specimens all nest together (Fig. 2). These tiny pterosaurs are adults that would have produced 8x smaller hatchlings, often about the size of house flies. and therefore unable to fly without risking desiccation due to a high surface-to-volume ratio. In other words, hatchlings of tiny pterosaurs could have flown, but needed to keep their wings folded. So they walked, picking up small prey in damp leaf litter. And that’s why so many pterosaur tracks are from pterodactyloid-grade pterosaurs, many of which continued to feet quadrupedally as they grew into phylogenetically larger genera.

Figure 3. Subset of the LRT focusing on ctenochasmatids and kin.

Figure 2. Subset of the LRT focusing on ctenochasmatids and kin.

Earlier we looked at the Fossilienatlas.de specimen
assigned to Ctenochasma elegans #204 (Fig. 4), which provides a similar morphology in reconstruction. No scale bars were provided with the Lauer Collection specimen, but the size can’t be too far off from this.

Figure 3. Click to enlarge. Private pterosaur #2042 together with St/Ei1, which nests at the base of the ctenochasmatidade, close to Angustinaripterus.

Figure 3. Click to enlarge. Private pterosaur #2042 together with St/Ei1, which nests at the base of the ctenochasmatidade, close to Angustinaripterus.

References
https://www.fieldmuseum.org/blog/meet-pterosaur-flock
https://www.lauerfoundationpse.org/about

New Rhamphorhynchus at the Field: Lauer Foundation Collection

The Lauer Foundation for Paleontology provided
this deep cut Rhamphorhynchus (Fig. 1) to the Field Museum, Chicago, USA. The foundation number is: #LF 1182. Photoshop helps get rid of the surface and deep cuts to see the bones without those distractions.

Figure 1. Another deep cut Solnhofen fossil from the Lauer Collection at the Field Museum, Rhamphorhynchus.

Figure 1. Another deep cut Solnhofen fossil from the Lauer Collection at the Field Museum, Rhamphorhynchus.

Due to its generic look,
the Lauer Foundation specimen enters the large pterosaur tree (LPT, 250 taxa) somewhere in the middle of this genus, distinct from all others, between the ROM specimen (first row, far right, Fig. 2) and the Imhof specimen (second row, far left, Fig. 2).

Figure 2. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row.

Figure 2. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row. Click to enlarge.

This wonderful and complete specimen
nests in the middle of the tested Rhamphorhynchus (Fig. 2) specimens (Fig. 3), outside the clade of the largest specimens (including the large and only juvenile, the Vienna specimen row 2, second from right)..

Figure 4. Subset of the LRT focusing on Rhamphorhynchus.

Figure 3. Subset of the LPT focusing on Rhamphorhynchus.

References
https://www.fieldmuseum.org/blog/meet-pterosaur-flock
https://www.lauerfoundationpse.org/about