New pterosaur wingtip paper: Hone et al. 2015

We looked at this subject earlier 
here and here as this idea was first presented in an abstract.

A new paper on pterosaur wingtips
(Hone et al. 2015) insists that among all pterosaurs Bellubrunnus > alone < had an inverted curve on its wingtip phalanx, m4.4 (Fig. 1).

The wing tip of Bellubrunnus.

Figure 1. The wing tip of Bellubrunnus. Ghosted image: the in situ fossil. At left, reconstructed wing elements according to Hone et al. (2015) with an anteriorly concave m4.4. This produces an atypical wingtip and a pointed one at that. At right, rotating m4.3+m4.4 to produce a more typical configuration. Note the largest part of the knuckle is typically oriented posteriorly, but not always. The knuckles on m4.3 appear to be oriented anteriorly in situ. Rotating them posteriorly would bring about a more typical orientation of m4.4 despite the appearance of the knuckle of m4.4. This knuckle varies among taxa and varies within this specimen, as the right wing does not have this knuckle.

From the abstract
“Here we examine the evidence for curved wingtips in pterosaurs and evaluate the possible aerodynamic and aeronautical effects. The recently described genus Bellubrunnus provides new anatomical novelty for pterosaurs having anteriorly directed wingtips and thus likely had a different flight profile to all previously known pterosaurs.”

This singular oddity is rather easily explained 
by axial rotation of m4.3 and m4.4 as a unit to match all other pterosaurs (Fig. 1). Phalanx rotation happens often enough in pterosaurs during taphonomy that this isn;t invoking a special dispensation. Not sure why the Hone team did not pick up on this. Autapomorphies (singleton exceptions = novelty) are usually red flags that the interpretation is wrong, as it is here.

I’d like to see the paper if anyone has a pdf of it.

Hone and his followers have come up with some very unusual and falsifiable ideas, as readers are well aware. Not sure how they keep publishing this stuff, and which referees are letting this through, but it keeps me active, this time raiding the archives. On the same note, with these guys refereeing manuscript submissions, you’ll never see the good stuff published.

References
Hone DWE, Van Rooijen and Habib MB 2015. The wingtips of the pterosaurs: Anatomy, aeronautical function and ecological implications. Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication) doi:10.1016/j.palaeo.2015.08.046

The origin of Limnoscelis

Limnoscelis, according to Wikipedia, “is a genus of large (1.5 m in total length), very reptile-like diadectomorph (a type of reptile-like amphibian) from the Early Permian of North America. Contrary to other diadectomorphans, Limnoscelis appear to have been a carnivore. Though the post cranial skeleton is very similar to the early large bodied reptiles like pelycosaurs and pareiasaurs, the digits lacked claws, and the bones of the ankle bones were fused like in other reptile-like amphibians. This would not allow them to use their feet actively in traction, but rather as holdfasts, indicating Limnoscelis primarily hunted slow moving prey.”

Figure 1. Limnoscelis and two suitable ancestral taxa, Orobates and Milleretta, all shown to scale (below) and to fit (above).

Figure 1. Limnoscelis and two suitable ancestral taxa, Orobates and Milleretta, all shown to scale (below) and to fit (above).

The large reptile tree nested Limnoscelis well within the Lepidosauromorpha branch of the Reptilia/Amniota along with the smaller Orobates and not far from tiny Milleretta (Fig. 1). The latter two are the most suitable ancestral morphologies yet found on the large reptile tree.

Limnoscelis and Orobates do not nest with Diadectes and other diadectomorphs, but also, not too far away from that clade. The Limnoscelis clade still nests with Tseajiaia and Tetraceratops.

Are those carnivorous teeth in Limnoscelis?
Most sister taxa in surrounding clades are likely herbivores. Some related taxa had canines, but not Limnoscelis.

Figure 4. Tetraceratops and LRT relatives including Saurorictus, Limnoscelis, Orobates and Milleretta.

Figure x. Tetraceratops and LRT relatives including Saurorictus, Limnoscelis, Orobates and Milleretta.

When are we going find consensus
on the nesting of Limnoscelis? We need a competing large gamut phylogenetic analysis to confirm or refute the topology recovered by the large reptile tree. Either that, or let the results of the large reptile tree get published.

Added Janurary 10, 2019
Saurorictus (Fig. 2; Late Permian; Modesto and Smith 2001; SAM PK-8666), nesting at the base of the captorhinids and their sisters, is the proximal outgroup taxon in the LRT now. Except for size, the resemblance is striking.

Figure 1. Limnoscelis and its outgroup sister, Saurorictus.

Figure 2. Limnoscelis and its outgroup sister, Saurorictus.

References
Berman DS, Reisz RR and Scott D 2010. Redescription of the skull of Limnoscelis paludis Williston (Diadectomorpha: Limnoscelidae) from the Pennsylvanian of Canon del Cobre, northern New Mexico: In: Carboniferous-Permian Transition in Canon del Cobre, Northern New Mexico, edited by Lucas, S. G., Schneider, J. W., and Spielmann, New Mexico Museum of Natural History & Science, Bulletin 49, p. 185-210.
Modesto SP and Smith RMH 2001. A new Late Permian captorhinid reptile: a first record from the South African Karoo. Journal of Vertebrate Paleontology 21(3): 405–409.
Romer AS 1946. The primitive reptile Limnoscelis restudied American Journal of Science, Vol. 244:149-188
Williston SW 1911. A new family of reptiles from the Permian of New Mexico: American Journal of Science, Series 4, 31:378-398.

wiki/Saurorictus
wiki/Limnoscelis

 

News on the Origin of Turtles Video on YouTube

There’s a new YouTube video on turtle origins.

Figure 1. A new YouTube video on the origin of turtles has just been launched. Click to view

Figure 1. A new YouTube video on the origin of turtles has just been launched. Click to view

Paleontologists
have been arguing for decades about the origin of turtles. Unfortunately, they have been promoting unrelated taxa (Eunotosaurus and Pappochelys) while avoiding the verified sisters. Meiolania is a basal turtle with horns. Apparently it is more primitive than Proganochelys and Odontochelys despite its late appearance in the fossil record. Elginia is known only from a toothed and horned skull. We don’t know if it had a plastron and carapace. It was not a turtle unless it had a shell. Currently Elginia nests just outside of the turtle clade in the large reptile tree at http://www.reptileevolution.com. Sclerosaurus, Arganaceras and a few pareiasaurs, all without shells or broad ribs, are successively more distant relatives.

Adding to the problems of turtle origins, |
several temporal bones in turtles have been traditionally mislabeled. Here those misidentifications are corrected. Turtles now nest in a large gamut cladogram (572 taxa) with sisters and more distant relatives that document a gradual accumulation of turtle traits.

Other turtle sister candidates
are also examined, including Eunotosaurus and Pappochelys. The former converged with turtles as it had only a few very broad, turtle-like dorsal ribs. The latter was a basal placodont, not far from other placodonts that also developed a protective shell.

DNA
aligns turtles with archosaurs in some molecule studies, but no morphological studies do the same. That’s a problem still awaiting a solution.

The skull of Eunotosaurus CT scanned – still not a turtle ancestor!

Fiigure 1. The turtle mimic Eunotosaurus from the Middle Permian was actually closer to Acleistorhinus.

Fiigure 1. The turtle mimic Eunotosaurus from the Middle Permian was actually closer to Acleistorhinus.

Before yesterday,
the best images of the skull of Eunotosaurus were simple drawings (Fig. 1). Now, thanks to Bever et al. (2015) we have CT scans of several skulls in several views (Fig. 2). For those we are all most grateful!

Figure 1. Click to enlarge. Eunotosaurus from CT scans. Left column, DGS tracings with restoration to in vivo positions. Middle column, CT scans from Bever et al. Right column, top, reconstructions by Bever et al. Bottom, juvenile skull with incorrect scale bar and correct scale bar.

Figure 2. Click to enlarge. Eunotosaurus from CT scans. Left column, DGS tracings with restoration to in vivo positions. Middle column, CT scans from Bever et al. Right column, top, reconstructions by Bever et al. Bottom, juvenile skull with incorrect scale bar and correct scale bar.

Bever et al. reports, “If turtles are closely related to the other living reptiles then we would expect the fossil record to produce early turtle relatives with diapsid skulls. That expectation remained unfulfilled for a long time, but we can now draw the well-supported and satisfying conclusion that Eunotosaurus is the diapsid turtle. The skull of Eunotosaurus grows in such a way that its diapsid nature is obvious in juveniles but almost completely obscured in adults.”

The important word
in that paragraph is “IF.” Turtles are related to other living reptiles, but they are not either kind of diapsid (lepidosaur or archosaur). And, as you’ll see, the skull of Eunotosaurus does not grow in such a way that its diapsid nature is obvious. Bever et al. made several mistakes in their observations and analyses, as will be shown.

Bever et al. note thatEunotosaurus africanus, a 260-million-year-old fossil reptile from the Karoo Basin of South Africa, whose distinctive postcranial skeleton shares many unique features with the shelled body plan of turtles.

What Bever et al. fail to note
is that such an armored postcrania has evolved several times independently within the Reptilia. In addition to Eunotosaurus and turtles there are Sinosaurosphargis, Henodus and Cyamodus,  not to mention ankylosaurs, aetosaurs, armadillos and pangolins.
Bever et al. note: “Scepticism regarding the status of Eunotosaurus as the earliest stem turtle arises from the possibility that these shell-related features are the products of evolutionary convergence.”
True.
The large reptile tree indicates these shell-related features are convergent in the above-named taxa.
Figure 3. Sister taxa according to Bever et al. Eunotosaurus purportedly nests between Ascerosodontosaurus and the turtles. The large reptile tree, on the other hand, finds that only the turtles are related to each other.

Figure 3. Sister taxa according to Bever et al. Eunotosaurus purportedly nests between the diapsid, Ascerosodontosaurus, and the turtles. The large reptile tree, on the other hand, finds that only the turtles are related to each other. Click to enlarge.

Bever et al. note: “Our phylogenetic analyses indicate strong cranial support for Eunotosaurus as a critical transitional form in turtle evolution. Furthermore, we find unexpected evidence that Eunotosaurus is a diapsid reptile in the process of becoming secondarily anapsid.”
That’s big news.
Worthy of a Nature paper, if valid. At it happens, secondary anapsids do occur in mesosaurs and ankylosaurs, but not turtles. The large reptile tree indicates turtle ancestors were always anapsids. And that Eunotosaurus and kin were all synapsid in skull morphology, but were not related to the real synapsids: pelycosaurs + therpasids + mammals (pan-mammals). Bever et al. did not test enough taxa or pertinent taxa. Most importantly, even if Eunotosaurus juveniles did have an upper temporal fenestra (Figs. 4, 5), they did so alone. All their closest sisters did not and adult Eunotosaurus did not have the upper temporal fenestra, but instead had a bone in that area.
Figure 4. Juvenile Eunotosaurus showing purported left upper temporal fenestra left by an absent supratemporal.

Figure 4. Juvenile Eunotosaurus showing purported left upper temporal fenestra left by an absent supratemporal.

Bever et al. note: “This is important because categorizing the skull based on the number of openings in the complex of dermal bone covering the adductor chamber has long held sway in amniote systematics, and still represents a common organizational scheme for teaching the evolutionary history of the group.”
Held sway?? What Bever et al. fail to note
is that several of these skull morphologies arose more than once by convergence. This fact is not commonly known, but recovered in the large reptile tree. Remind yourself not to follow anyone who holds “held sway” up as evidence.
Figure 5. Eunotosaurus juvenile right side showing purported absent supratemporal. At right a possible displaced supratemporal is identified as bump on the otherwise humpless parietal that pretty well fits the opening left by its taphonomic shift.

Figure 5. Eunotosaurus juvenile right side showing purported absent supratemporal. At right a possible displaced supratemporal is identified as bump on the otherwise humpless parietal that pretty well fits the opening left by its taphonomic shift.

Bever et al. note: “Our results suggest that Eunotosaurus represents a crucially important link in a chain that will eventually lead to consilience in reptile systematics, paving the way for synthetic studies of amniote evolution and development.”

Actually
Eunotosaurus currently represents a dead end in the large reptile tree.
The Bever et al figure 1 
misidentifies several bones on the skull of Proganochelys. They mistakenly follow the original bone identifications, where were changed here.
  1. The postorbital + postfrontal was mistakenly labeled ‘postorbital.’
  2. The tabular was mislabeled ‘supratemporal.’
  3. The supratemporal was mislabeled ‘squamosal.’
  4. The squamosal was mislabeled ‘quadratojugal.’
  5. The quadratojugal was not separated from the jugal.
In support of this,
the long Eunotosaurus supratemporal is actually homologous to the mislabeled ‘squamosal’ (actually the supratemporal) of Proganochelys (same shape, same placement), despite their separation on the large reptile tree. Noting that would have added evidence to the Bever et al claims, but they let that one pass and stuck to the old paradigm. Basal turtles, like Elginia and Meiolania, and pre-tuirtles like Sclerosaurus and Arganacerashad supratemporal horns, not squamosal horns.
The Bever et al cladogram (their figure 1) has several errors.
  1. Eothyris is not a member of the Pan-mammals (Synapsida), but is in the Milleretta and Casea clade.
  2. The term ‘Parareptilia’ does not represent a monophyletic clade.
  3. Youngina does not belong on this cladogram of several Lepidosauromorpha, but belongs on another branch, the Archosauromorpha.
  4. Elginia is a more basal and earlier stem turtle than Proganochelys, but is omitted in the cladogram.
  5. Some of the drawings used are inaccurate, but that may matter only a wee bit.
Bever et al. report, “The skull of Eunotosaurus is relatively short and wide. Its compact snout bears approximately 23 robust, subthecodont marginal teeth and nasals that are longer than the frontals.” Actually the nasals are subequal to the frontals. You can measure them yourself.
Bever et al. report a “moderately sized suborbital fenestra,” but I did not see any space between the ectopteryoid and palatine, only between the palatine and anterior pterygoid. In any case, the palate of Eunotosaurus does not resemble the palate of basal turtles.
Bever et al. report, “A lower temporal arcade is not present, leaving the cheek open ventrally.” Actually the adult jugal has a very tiny quadratojugal process. In the juvenile (Figs. 4, 5) the jugal has a large process that invades the lateral temporal fenestra, as in Acleistorhinus and Deloryhnchus, the verified sisters of Eunotosaurus. We just looked at that new process here.
Bever et al report, “The roof of the adductor chamber in a juvenile skull is marked by a distinct upper temporal fenestra (on both sides.” 
Actually there are several new fenestra in the juvenile skull (Fig. 4). And where is the supratemporal? On the left, the supratemporal appears to be crushed down into, rather than arching over the other temporal bones. On the right (Fig. 5) the supratemporal appears to have shifted medially. Now it looks like an unintended bump. So these purported ‘upper temporal fenestra’ were not really present in vivo. Furthermore, there are no genuine diapsids that nest close to Eunotosaurus in the large reptile  tree.

In the Bever et al. phylogenetic studies 
(Fig. 3) Eunotosaurus nests between basal Sauropterygia + Acerosodontosaurus and the turtles, Proganochelys + Odontochelys. Many suprageneric taxa were used, so there were many opportunites to cherry pick traits to fit a preconceived idea. That does not happen in the large reptile tree where every taxon is represented by a specimen or species. The large reptile tree is still fully resolved, and breaks down into fully resolved subsets.

Bever et al. report, “The adductor chamber (in Eunotosaurus)  is closed posteriorly by what appears to be an expanded tabular, though this bony plate may represent a posterolateral flange of the parietal. The putative tabular fills a space corresponding to what would otherwise be a moderately sized post-temporal fenestra.” That is a tabular.
Bever et al write, “The presence of a lower temporal fenestra in Eunotosaurus supports the hypothesis that the characteristically closed cheek of modern turtles is a secondary condition that evolved through expansion of the jugal, quadratojugal, and squamosal.”
 
Actually
the lower (lateral) temporal fenestra in Eunotosaurus is homologous with that of Acleistorhinus and kin. Turtle ancestors never had a lateral temporal fenestra according to the large reptile tree, but came closest with bolosaurs.
Eunotosaurus is not a good turtle ancestor.
Better ones are to be found. Unfortunately, the best turtle ancestors, Stephanospondylus, Arganaceras, Sclerosaurus, Meiolania and Elginia are not represented in the Bever et al. taxon list. Once again, taxon exclusion raises its ugly head.
Removal
of Acleistorhinus and Delorhynchus from the large reptile tree nests Eunotosaurus with its other sisters, Feeserpeton and Australothyris. One look, or deep study, and you’ll see why. Removal of those taxa nests Eunotosaurus between cousins Milleretta and the casesauria. Removal of those taxa nests Eunotosaurus with second cousins, Limnoscelis, Orobates and kin. Still no change in tree topology. Removal of these taxa finally nests Eunotosaurus between Stephanospondylus and Bashkyroleter, each at the base of their own clades with a slight change in tree topology. Still Eunotosaurus does not nest with turtles, Ascerosodontosaurus or basal sauropterygians.
At least some of the problem
with the Bever et al. report rests with their use of prior phylogenetic analyses, and/or accepting the results of those analyses without their own critical analysis of recovered sister taxa. For instance, the swimming  Claudiosaurus and they gliding Kuehneosauridae appear as sister taxa, while Claudiosaurus and another similar swimmer, Hovasaurus, do not. Those are problems. Nesting Diadectomorpha outside the Amniota is a problem.. Nesting bulky Rhynchosaurs as relatives of gliding Kuehneosaurs is also a problem. None of these problems exist in the large reptile tree, where all sister taxa look alike and display gradual accumulations of derived traits. Perhaps Bever et al. should have created their own matrix from scratch, as in the large reptile tree.
Bever et al. write: “Although it is the case that neither our parsimony nor Bayesian analyses recover the dominant molecular solution of a unique turtle–archosaur relationship, both approaches do agree that turtles arose somewhere within the greater diapsid radiation.”
No one knows
why turtle DNA is close to archosaur DNA. It is not supported by morphology.
Bever et al. write: “Singular expression of a lower temporal fenestra once unambiguously diagnosed mammals and their stem lineage, but is now recognized in a number of phylogenetically disparate ‘anapsid’ parareptiles, and may represent the ancestral
condition for the amniote crown. That is a false statement. The ancestral condition in basal amniotes was anapsid. Such a statement by Bever et al. is one based on hope, not observation.
Bever et al. write: “This observed pattern of concentrated homoplasy near the evolutionary origin of a character state is congruent with the concept of a protracted zone of variability that may commonly confound attempts to resolve the early history of clades and character systems” \This is observed only in bad cladograms. There is no such thing as a “protracted zone of variability.” At least I haven’t seen one. How would you measure it?
Bever et al. write, “The amniote upper temporal fenestra has enjoyed a famously uncomplicated history, being a nearly consistent fixture of the diapsid body plan since its first appearance in the Carboniferous.”  This is another false statement, according to the large reptile tree. The so-called Diapsida had two origins. Bever et al are working with outmoded data and small taxon sets.
Bever et al. write, “The combined morphologies expressed in the juvenile and adult specimens of Eunotosaurus provide not only the earliest direct evidence of an upper
temporal fenestra in a putative stem turtle, but the first evidence for how that fenestra may have closed before the origin of the turtle crown clade.” Except the juvenile does not have an upper temporal fenestra (careful examination reveals otherwise) and so it cannot close at this point. Bever et al did not examine the specimen carefully enough to find the taphonomically displaced supratemporals. Turtle embryos do not recapitulate this change during ontogeny. No sister taxa have an upper temporal fenestra. This is just a unique fossil that has successfully tempted a set of paleontologists into accepting its illusion, just like the pterosaur, Sordes and the thalattosaur, Vancleavea
Bever et al write: “The role of the supratemporal is an aspect of the Eunotosaurus model of temporal closure that would not have been predicted based on earlier studies.” No shit, Sherlock. “An anteriorly expanded supratemporal that develops late in postnatal development to cover the upper temporal fenestra must currently be considered an autapomorphy of Eunotosaurus.” Be wary of autapomorphies. Evolution does not create many of those.
Morevover, what is wrong with the logic here?
According to Bever et al. the giant supratemporal closed off the upper temporal fenestra in Eunotosaurus, but the supratemporal is a tiny bone at the back of the skull in Proganochelys. The several misidentifications in Proganochelys are noted above.
Bever et al. answer this logic conundrum with,
“but it is important to stress that an expanded supratemporal is not a necessary component of an evolutionary model of fenestral closure in turtles that has Eunotosaurus as a central figure. For example, an analogous secondary expansion of the supratemporal partially or completely covers the upper temporal fenestra of the marine thalattosaurs.” This is false. The upper temporal fenestra in thalattosaurs is not reduced by expansion of the supratemporal, which remains small and not involved. Rather the upper temporal fenestra in thalattosaurs is reduced to a slit or less by the straightening (loss of curvature) of the parietal and postorbital rims.
Bever et al. further speculate, “Moreover, the construction of the modern turtle skull played out over a time span of tens of millions of years, and it is well attested that dermal bones in
major vertebrate lineages can shift back and forth considerably relative to the underlying tissues on these timescales.” As you have seen so far, Bever et al. have no idea how the turtle skull evolved, based on evidence from the large reptile tree. They have not included the correct ancestral taxa, but have pulled similar taxa from other clades. They are working in a hopeful vacuum of outmoded analyses, small taxon lists and incorrect bone identities.
Bever et al. conclude, “It is thus evident that the turtle skull, like the turtle postcranium,
underwent profound modifications during its history that similarly obscured anatomical evidence for phylogenetic affinities by the time the crown-group condition was reached.” This is, as you know by now, a conclusion based on mistake after mistake.
Finally,
let us remind ourselves that turtles developed their own method for creating space for larger temporal adductors. It seems illogical that they would first lose this space by early closure of the upper temporal fenestra only to reacquire additional space by anterior expansion of the posttemporal fenestra and subsequent skull emargination.
But logic is not a factor here.
This is evolution. Phylogenetic analysis, as recovered in the large reptile tree, provides the story of how the turtle got its skull… and shell… and all of its other accessories.
And if the juvenile Eunotosaurus did have missing supratemporals creating quasi and temporary upper temporal fenestrae, like the fontanelle in the baby human skull, then the diapsid status of turtles is still not verified. Turtles have no diapsid relatives when enough pertinent taxa are included in analysis.

References
Bever GS, Lyson TR, Field DJ and Bhular B-A S 2015. Evolutionary origin of the turtle skull. Nature published online Sept 02. 2015.

News on the Origin of Pterosaurs on YouTube

I just uploaded a pterosaur origins video on YouTube. Click here to view it.

Click to view this "Origin of Pterosaurs" video on YouTube.

Click to view this “Origin of Pterosaurs” video on YouTube. 17 minutes long. 

A new view of the first archosauriform antorbital fenestra

Earlier we looked at the FMNH UC 1528 specimen of Youngoides romeri. Today we’ll see another view of the same specimen in a GIF movie (Fig. 1). The antorbital fenestra identified here has been overlooked for several decades.

Figure 1. GIF movie tracing the antorbital fenestra with fossa and surround bones of the FMNH UC 1528 specimen of Youngoides romeri. This is one of the earliest and most primitive appearances of the archosauriform antorbital fenestra, previously overlooked.

Figure 1. GIF movie tracing the antorbital fenestra with fossa and surround bones of the FMNH UC 1528 specimen of Youngoides romeri. This is one of the earliest and most primitive appearances of the archosauriform antorbital fenestra, previously overlooked.

Youngoides romeri FMNH UC1528 (Olson and Broom 1937) Late Permian, Wuchiapingian, ~255 mya was derived from a sister to Youngina AMNH 5561 and preceded Proterosuchus at the base of the Eurchosauriformes.

This nesting of Youngina and Youngoides at the base of the Protorosauria and Archosauriformes is recovered in the large reptile tree. Prior studies tended to include squamates close to this node, but the large reptile tree found squamates nesting on a completely separate branch with a last common ancestor at the origin of the Amniota/Reptilia.

References
Olson EC and Broom R 1937. New genera and species of tetrapods from the Karroo Beds of South Africa. Journal of Paleontology 11(7):613-619

wiki/Youngina