Turtles and pterosaurs tested again, nine years later with 1300 more taxa

In 2011,
back when the large reptile tree (LRT, 1786+ taxa) was much smaller (only about 400 taxa) I attempted a rather odd test. I wondered if turtles and pterosaurs (both Lepidosauromorpha in the LRT) would nest together while playing taxon deletion games. Here’s the 2011 link:

https://pterosaurheresies.wordpress.com/2011/07/25/pterosaurs-and-turtles-say-it-aint-so/

Click here to see those 2011 turtle-pterosaur results, still posted online.

Other workers interested in pterosaurs
(most recently Ezcurra et al. 2020) also like to play taxon deletion games as they attempt to cherry-pick preferred sisters close to dinosaurs while omitting tested and validate sisters far from dinosaurs.

The backstory
Peters 2000 added four tritosaur tanystropheid, fenestrasaur pterosaur precursors, Langobardisaurus, Cosesaurus, Sharovipteryx, and Longisquama (Fig. 1) to four previously published analyses and in every case these four nested closer to pterosaurs than any archosaur, archosauriform or archosauromorph. Unfortunately those taxa were omitted from more recent analysis, like those of Kellner 2003, Unwin 2003, Hone and Benton 2007, 2008, Bennett 2012 and Ezcurra et al. 2020.

A few years later, but still 14 years ago,
Peters 2007 added the lepidosaur, Huehuecuertzpalli and it attracted the four fenestrasaurs + pterosaurs. The LRT nested turtles within the Lepidosauromorpha here in 2011, updated here in 2014.

Now that many more taxa are present in the LRT,
let’s rerun that test and its various deletion subunits.

Today, in 2020, repeating the experiment with more taxa
deleting all lepidosauromorphs, other than turtles (and their ancestors back to Stephanospondylus) and pterosaurs, and keeping all archosauromorphs and enaliosaurs. Outgroups retained = Gephyrostegus and Silvanerpeton.

Results: Pterosaurs nest with turtles and basal sea reptiles rather than archosaurs and archosauromorphs.

Adding back all basal diapsids and protosaurs

Results: Basal diapsids as the first large clade, followed by protorosaurs with tritosaurs based on the convergence found there.

Adding back all tritosaurs
(= Macrocnemus as the last common ancestor) nests turtles and pareiasaurs as the first large clade, tritosaurs (including pterosaurs) as the next large clade, followed by archosauromorophs (including Lagerpeton and Scleromochlus).

Click to enlarge. Squamates, tritosaurs and fenestrasaurs in the phylogenetic lineage preceding the origin of the Pterosauria.

Figure 1. Squamates, tritosaurs and fenestrasaurs in the phylogenetic lineage preceding the origin of the Pterosauria.

Deleting all non-fenestrasaur tritosaurs
(= Cosesaurus as the last common ancestor)

Results: Fenestrasaurs nest with basal diapsids. Orovenator is the proximal outgroup.

Deleting all non-pterosaur fenestrasaurs
(Bergamodactylus as the last common ancestor).

Results: Pterosaurs nest between turtles and choristoderes.

Figure 1. Basal diasids and proto-diapsids. Largely ignored these putative synapsids actually split from other synapsids while retaining the temporal fenestra trait that serves as the basis for the addition of upper temporal fenestra in diapsids. Included here are Protorothyris, Archaeovenator, Mycterosaurus, Heleosaurus, Mesenosaurus, Broomia, Milleropsis, Eudibamus, Petrolacosaurus, Spinoaequalis, and Tangasaurus.

Figure 2. Basal diasids and proto-diapsids. Largely ignored these putative synapsids actually split from other synapsids while retaining the temporal fenestra trait that serves as the basis for the addition of upper temporal fenestra in diapsids. Included here are Protorothyris, Archaeovenator, Mycterosaurus, Heleosaurus, Mesenosaurus, Broomia, Milleropsis, Eudibamus, Petrolacosaurus, Spinoaequalis, and Tangasaurus.

Deleting all basal diapsids
(only turtles, pterosaurs and archosauromorphs are ingroup taxa).

Results: Pterosaurs nest between turtles and choristoderes, far from Scleromochlus, dinosaurs and Lagerpeton.

Deleting all turtle ancestors 
(= deleting Stephanospondylus through pareiasaurs)

Results: Pterosaurs nest between turtles and choristoderes, far from Scleromochlus, dinosaurs and Lagerpeton.

Faxinalipterus matched to Scleromochlus. The former is more primitive, like Gracilisuchus, in having shorter hind limbs and more robust fore limbs. The maxilla with fenestra and fossa, plus the teeth, are a good match.

Figure 3. Faxinalipterus matched to Scleromochlus. The former is more primitive, like Gracilisuchus, in having shorter hind limbs and more robust fore limbs. The maxilla with fenestra and fossa, plus the teeth, are a good match.

Re-inserting terrestrial younginiforms and protorosaurs
to this last taxon list.

Results: Two large clades follow the turtle clade. Pterosaurs nest between three basal Youngina specimens and the clade Protorosauria, apart from the terrestrial younginiformes (other Youngina specimens + Pararchosauriformes (= Proterosuchus as the last common ancestor and choristoderes) and Euarchosauriformes (= Euparkeria as the last common ancestor and Lagerpeton and Scleromochlus).

Figure 3. The closest kin of Tropidosuchus are the much larger Chanaresuchus (matching Nesbitt 2011) and the smaller Lagerpeton.

Figure 4. The closest kin of Tropidosuchus are the much larger Chanaresuchus (matching Nesbitt 2011) and the smaller Lagerpeton.

Bottom line:
With or without tritosaurs and fenestrasaurs, pterosaurs prefer to nest with terrestrial younginiforms, choristoderes or turtles rather than lagerpetids, dinosaurs or Scleromochlus. Taxon exclusion remains the problem in traditional cladograms (like the recent Ezcurra et al. 2020).

Please send this post to anyone who still believes or protects
the outmoded clades ‘Ornithodira’ or ‘Avemetatarsalia’. Too many professors and their students are clinging to invalidated myths based on taxon exclusion — which is not what real scientists do. Real scientists test all competing candidates without cherry-picking or omitting taxa to suit their personal whims and traditions, in fear of their professors or colleagues.

If you would like to play taxon deletion games with the LRT,
click here, then click on the yellow CLICK HERE for LRT MacClade.nex file box with your request.


References
Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoological Journal of the Linnean Society 118:261-308.
Bennett SC 2012. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined. Historical Biology. iFirst article, 2012, 1–19.
Benton MJ 1983. The Triassic reptile Hyperodapedon from Elgin, functional morphology and relationships. Philosophical Transactions of the Royal Society of London, Series B, 302, 605-717.
Brusatte SL , Benton MJ , Desojo JB and Langer MC 2010. The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida), Journal of Systematic Palaeontology, 8:1, 3-47.
Evans SE 1988. The early history and relationships of the Diapsida. In: M. J. BENTON (Ed.), The Phylogeny and Classificationof the Tetrapoda. 1. Amphibians, Reptiles, Birds. Systematics Symposium Association Special Volume; Oxford (Clarendon Press), 221–260.
Ezcurra MD et al. (17 co-authors) 2020. Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria. Nature (2020). https://doi.org/10.1038/s41586-020-3011-4
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.
Jalil N-E 1997. A new prolacertiform diapsid from the Triassic of North Africa and the interrelationships of the Prolacertiformes. Journal of Vertebrate Paleontology 17(3), 506-525.
Kellner AWA 2003. Pterosaur phylogeny and comments on the evolutionary history of the group. Geological Society Special Publications 217: 105-137.
Nesbitt SJ 2011. The early evolution of archosaurs: relationships and the origin of major clades. Bulletin of the American Museum of Natural History 352: 292 pp.
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 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.
Sereno PC 1991. Basal archosaurs: phylogenetic relationships and functional implications. Journal of Vertebrate Paleontology 11 (Supplement) Memoire 2: 1–53.
Unwin DM 2003. On the phylogeny and evolutionary history of pterosaurs. Pp. 139-190. in Buffetaut, E. & Mazin, J.-M., (eds.) (2003). Evolution and Palaeobiology of Pterosaurs. Geological Society of London, Special Publications 217, London, 1-347.

https://pterosaurheresies.wordpress.com/2012/09/27/bennett-2012-still-barking-up-the-wrong-pterosaur-tree/

https://pterosaurheresies.wordpress.com/2020/12/10/new-pterosaur-precursor-study-excludes-all-pterosaur-precursors/

https://pterosaurheresies.wordpress.com/2012/04/13/a-supertree-of-pterosaur-origins-hone-and-benton-2007-2009/

The base of the new Lepidosauriformes illustrated to scale

Short one today, 
told mostly in pictures (Figs. 1, 2). Click here or see below for more data and taxon links.

These are the taxa from which all later lepidosaurs
arose and diversified. Thus, these are the ancestors of snakes, pterosaurs, ‘rib’ gliders and rhynchosaurs at their genesis and basal diversification.

Proximal outgroups
in the large reptile tree (subset Fig. 2) include Owenetta, Barasaurus and other small, low, wide owenettid lepidosauromorphs lacking an upper temporal fenestra.

Figure 1. Taxa at the base of the Lepidosauria include Paliguana, Tridentinosaurus, Lanthanolania, Lacertulus, Gephyrosaurus, Megachirella, Lacertulus and Palaegama.

Figure 1. Taxa at the base of the Lepidosauria include Paliguana, Tridentinosaurus, Lanthanolania, Lacertulus, Gephyrosaurus, Megachirella, Lacertulus and Palaegama. See figure 2 for a subset of the LRT.

Basal lepidosauriformes are rare.
For tens of millions of years, between the the first and last days of the Triassic, these are just about all we have in the sparse fossil record at the genesis of new Lepidosauriformes (= Paliguana + Sophineta, their last common ancestor and all descendants). Paliguana is a late survivor of that earlier genesis.

Figure 2. Subset of the LRT focusing on basal Lepidosauria. Taxa in colored blocks are shown to scale in figure 1.

Figure 2. Subset of the LRT focusing on basal Lepidosauria. Taxa in colored blocks are shown to scale in figure 1. Note: the chronology is not reflected in the phylogeny due to the rarity of fossil specimens.

Chronology does not always mirror phylogeny.
And that’s okay.

For instance:
It’s okay that Archaeopteryx was found in Late Jurassic strata and one of its its putative ancestor, Velociraptor, was found in Late Cretaceous strata. You might remember when a bunch of paleontologists waved their hands over that matter, then later blushed and said, “Never mind.” In like manner, it’s okay that Paliguana was found in younger strata than its phylogenetic descendants.


References
http://reptileevolution.com/owenetta.htm
http://reptileevolution.com/paliguana.htm
http://reptileevolution.com/lacertulus.htm

SVP abstracts 22: Weigeltisaurus reexamined

Pritchard, Sues, Reisz and Scott 2020
promise to bring us a look at the ‘osteology and phylogenetic affinities of the early gliding reptile Weigeltisaurus jaekeli” (Fig. 1).

Unfortunately,
no phylogenetic analysis, or any hint thereof, is to be found in the abstract.

We looked at Weigeltisaurus earlier
here when the skull (Fig. 1) was described by Bulanov and Sennikov 2015.

Figure 1. Weigeltisaurus skull reconstructed by Bulanov and Sennikov (gray scale), and using DGS techniques (color). They did not attempt to trace the occiput, nor did they understand that the posterior crest is the supratemporal, displaced in situ and that the main portion is a very large squamosal that sweeps up. This skull is nearly identical to that of sister taxa, with the exception of the extended posterior elements, probably for secondary sexual selection. The same cannot be said of the Bulanov and Sennikov reconstruction which is, unfortunately, unique as is.

Figure 1. Weigeltisaurus skull reconstructed by Bulanov and Sennikov (gray scale), and using DGS techniques (color). They did not attempt to trace the occiput, nor did they understand that the posterior crest is the supratemporal, displaced in situ and that the main portion is a very large squamosal that sweeps up. This skull is nearly identical to that of sister taxa, with the exception of the extended posterior elements, probably for secondary sexual selection. The same cannot be said of the Bulanov and Sennikov reconstruction which is, unfortunately, unique as is.

Weigeltisaurus is a relative of Coelurosauravus 
(Fig. 2) and other pseudo-rib gliders. The ribs are dermal in nature, extending from the tips of the dorsal and lumbar ribs, whether few or many.

The Triassic kuehneosaur gliders and their non-gliding precursors.

Figure 2. Click to enlarge. The Triassic kuehneosaur gliders and their non-gliding precursors. Note the icarosaurs are not rib gliders. Their actual ribs are fused to mimic transverse processes as demonstrated around the neck and anterior torso.

From the Pritchard et al. 2020 abstract:
“Weigeltisauridae is a clade of small-bodied Permian diapsids that represent the oldest known vertebrates with skeletal features for gliding. It is characterized by a cranium with a posterior bony casque, prominent horns on the temporal arches, and a series of elongate bony spars projecting from the ventrolateral surface on both sides of the trunk. Definitive specimens are known from upper Permian of Germany, Russia, and Madagascar, but the quality of their preservation previously limited understanding of the skeletal structure and phylogenetic affinities of these reptiles.”

All you have to do is add taxa (= minimize taxon exclusion) and let the software determine where these Permian pseudo-rib gliding lepidosauriforms nest. In the large reptile tree (LRT, 1752+ taxa; subset Fig. 3) these arboreal gliders nest at the base of the lepidosauriformes. (The Diapsida is now limited to just archosauromorphs with a diapsid-skull morphology, by convergence with lepidosauriformes). Only here, in the LRT, among all prior pertinent cladograms, is the clade of pseudo-rib gliders surrounded by arboreal taxa with weigeltosaurs nesting with kuehneosaurs. Usually they nest apart and too often close to marine taxa.

Figure 2. Derived lepidosauriformes. The clade Pseudoribia includes the pseudo-rib gliders

Figure 2. Derived lepidosauriformes. The clade Pseudoribia includes the pseudo-rib gliders

The Pritchard, Sues, Reisz and Scott abstract continues:
“Here, we present a revised account based on a nearly complete skeleton of Weigeltisaurus jaekeli from the Kupferschiefer of central Germany and a revised phylogenetic analysis of early Diapsida and early Sauria.”

That analysis must have been part of the oral presentation. There is no hint of it here. Sauria is an invalid clade. Diaspsida is restricted to the Archosauromorpha in the LRT.

“The specimen preserves all elements of the skeleton, save for the braincase, palate, some dorsal vertebrae, the carpus, and the tarsus. The well-preserved teeth in the maxilla are not conical but leaf-shaped, resembling those in the middle portion of the maxillae of the Russian weigeltisaurid Rautiania. The parietals bear rows of dorsolaterally oriented horns similar to those on the squamosals. The quadrate is a dorsoventrally short element with a tapering dorsal margin that lacks a cephalic condyle. The squamosal appears to cover the quadrate both laterally and posterodorsally. The manual and pedal phalanges are elongate and slender, similar to those of extant arboreal squamates. The unguals have very prominent flexor tubercles. A patagium was supported by elongate, slender bony rods. They are situated superficial to the preserved dorsal ribs and gastralia, corroborating the hypothesis that these structures represent dermal ossifications independent of and greater in number than the bones of the dorsal axial skeleton.”

Excellent description. But that was provided earlier (Bulanov and Sennikov 2015).

Phylogenetic conclusions? 
I guess we’ll have to wait for the paper.


References
Bulanov VV and Sennikov AG 2015. Substantiation of validity of the Late Permian genus Weigeltisaurus Kuhn, 1939 (Reptilia, Weigeltisauridae) Paleontological Journal 49 (10):1101–1111.
Pritchard A, Sues HD, Reisz R and Scott D 2020. Osteology and phylogenetic affinities of the early gliding reptile Weigeltisaurus jaekeli. SVP abstracts.

https://pterosaurheresies.wordpress.com/2011/09/26/icarosaurus-kuehneosaurus-and-the-so-called-rib-gliders/

https://pterosaurheresies.wordpress.com/2015/12/17/weigeltisaurus-skull-reconstructions/

Prior citations
Colbert, Edwin H. (1966). A gliding reptile from the Triassic of New Jersey. American Museum Novitates 2246: 1–23. online pdf
Evans SE 1982. Gliding reptiles of the Late Permian. Zoological Journal of the Linnean Society, 76:97–123.
Evans SE and Haubold H 1987. 
A review of the Upper Permian genera  CoelurosauravusWeigeltisaurus and Gracilisaurus (Reptilia: Diapsida). Zool J Linn Soc, 90:275–303.
Fraser NC, Olsen PE, Dooley AC Jr and Ryan TR 2007. 
A new gliding tetrapod (Diapsida: ?Archosauromorpha) from the Upper Triassic (Carnian) of Virginia. Journal of Vertebrate Paleontology 27 (2): 261–265. doi:10.1671/0272-4634(2007)27[261:ANGTDA]2.0.CO;2.
Frey E, Sues H-D and Munk W 1997. 
Gliding Mechanism in the Late Permian Reptile Coelurosauravus. Science Vol. 275. no. 5305, pp. 1450 – 1452
DOI: 10.1126/science.275.5305.1450
Li P-P, Gao K-Q, Hou L-H and Xu X. 2007. A gliding lizard from the Early Cretaceous of China. PNAS 104(13): 5507-5509. doi: 10.1073/pnas.0609552104 online pdf
Modesto SP and Reisz RR 2003. An enigmatic new diapsid reptile from the Upper Permian of Eastern Europe. Journal of Vertebrate Paleontology 22 (4): 851-855.
Modesto SP and Reisz RR 2011. The neodiapsid Lanthanolania ivakhnenkoi from the Middle Permian of Russia, and the initial diversification of diapsid reptiles. SVPCA abstract.
Robinson PL 1962. Gliding lizards from the Upper Keuper of Great Britain. Proceedings of the Geological Society London 1601:137–146.
Stein K, Palmer C, Gill PG and Benton MJ 2008. The aerodynamics of the British Late Triassic Kuehneosauridae. Palaeontology, 51(4): 967-981. DOI: 10.1111/j.1475-4983.2008.00783.x
Piveteau J 1926. Paleontologie de Madagascar, XIII. Amphibiens et reptiles permiens: Annales de Paleontologie, v. 15, p. 53-128.

Megaevolutionary dynamics in reptiles: Simoes et al. 2020

Simoes et al 2020 discuss
“rates of phenotypic evolution and disparity across broad scales of time to understand the evolutionary dynamics behind the origin of major clades, or how they relate to rates of molecular evolution.”

“Here, we provide a total evidence approach to this problem using the largest available data set on diapsid reptiles.”

Unfortunately not large enough to understand that traditional ‘diapsid’ reptiles are diphyletic, splitting in the Viséan and convergently developing two

“We find a strong decoupling between phenotypic and molecular rates of evolution,”

Yet another case of gene-trait mismatch in analysis.

“and that the origin of snakes is marked by exceptionally high evolutionary rates.”

Taxon exclusion is the reason for this exclusion.

Figure 1. Cladogram from Simoes et al. 2020. Gray tones added to show Lepidosauromorpha in the LRT.

Figure 1. Cladogram from Simoes et al. 2020. Gray tones added to show Lepidosauromorpha in the LRT.

“Here, we explore megaevolutionary dynamics on phenotypic and molecular evolution during two fundamental periods of reptile evolution: i) the origin and early diversification of the major lineages of diapsid reptiles (lizards, snakes, tuataras, turtles, archosaurs, marine reptiles, among others) during the Permian and Triassic periods,”

In the LRT the new archosauromorphs split from new lepidosauromorphs in the Viséan (Early Carboniferous).

“as the origin and evolution of lepidosaurs (lizards, snakes and tuataras) from the Jurassic to the present.”

In the LRT lepidosaurs had their origin in the Permian and the Simoes team ignores the Triassic radiation of lepidosaurs leading to tanystropheids and pterosaurs.

So without a proper and valid phylogenetic context,
why continue? How can they possibly discuss ‘rates of change’ if they do not include basal taxa from earlier period?

“Our results indicating exceptionally high phenotypic evolutionary rates at the origin of snakes further suggest that snakes not only possess a distinctive morphology within reptiles,  but also that the first steps towards the acquisition of the snake body plan was extremely fast.”

In the LRT many taxa are included in the origin of snakes from basal geckos. These are missing from Simoes list of snake ancestor.

Figure 1.  Subset of the LRT focusing on lepidosaurs and snakes are among the squamates.

Figure 1.  Subset of the LRT focusing on lepidosaurs and snakes are among the squamates.

In the LRT all sister taxa resemble one another
and document a gradual accumulation of derived traits.

If you have any particular evolutionary questions,
they were probably answered earlier in previous posts. Use the keyword box at upper right to seek your answer.

 

Early Triassic Elessaurus: another overlooked Cosesaurus sister!

Cosesaurs (basal fenestrasaurs)
(Figs. 1–3) are popping up everywhere lately!

Current interpretation of Cosesaurus.

Figure 1. MIddle Triassic Cosesaurus. Double its size and it would be close to Early Triassic Elessaurus. See figure 6.

Earlier we looked at a tiny Early Cretaceous cosesaur skull in amber
originally mistaken for a bird/dinosaur: Oculudentavis.

Figure 2. Elessaurus hind limb elements gathered together to scale. Some original scale bars were off by 2x.

Figure 2. Elessaurus hind limb elements gathered together to scale. Some original scale bars were off by 2x.

Today De-Oliveira et al. 2020 bring us
a new Early Triassic cosesaur, Elessaurus gondwanoccidens (UFSM 11471, Figs. 2, 3) known from a hind limb, pelvis, partial sacrum and proximal caudal vertebrae. Cosesaurus was a derived tanystropheid, close to Langobardisaurus, but was not included in the De-Oliveira taxon list.

Figure 1. Elessarus pes compared to Cosesaurus to scale and x2. Note differences between original tracing and DGS tracing.

Figure 3. Elessarus pes compared to Cosesaurus to scale and x2. Note differences between original tracing and DGS tracing. Digit 5 was not lost. It is tucked beneath the metatarsals and was not scored in the LRT.

In the De-Oliveira et al. published cladogram
(Fig. 4) Elessaurus nests basal to the Tanystropheidae (= Macrocnemus, Amotosaurus, Tanystropheus, Tanytrachelos and Langobardisaurus) a clade they derive from Protorosaurus and Trilophosaurus. in one cladogram (Fig. 4), but not in the other (Fig. 5). The authors reported, “In addition, the new specimen presents some features only found in more specialized representatives within Tanystropheidae, such as the presence of a well-developed calcaneal tuber with a rough lateral margin.” 

Figure 3. Published cladogram by De-Oliveira et al. 2020. Note difference with their SuppData cladogram.

Figure 4. Published cladogram by De-Oliveira et al. 2020. Note different nesting than their SuppData cladogram in figure 5.

By contrast, in the De-Olveira et al. SuppData cladogram
Elessaurus nests without resolution within the Rhynchosauria (Fig. 5). Distinct from the first analysis (Fig. 4), this (Fig. 5) included the drepanosaur ancestor, Jesairosaurus, and the derived macrocnemid, Dinocephalosaurus. The authors reported, “In this second analysis, Elessaurus adopts different positions among the MPTs, it is recovered, e.g. within Archosauriformes, as a sister-taxa of Allokotosauria+Archosauriformes and an early rhynchosaur.” This is a red flag indicating major problems in scoring and taxon exclusion.

Figure 3. Cladogram from DeOliveira et al. 2020 with colors added to show distribution and mixing of Lepidosauromorpha and Archosauromorpha clades in the LRT. Many of these purported sister taxa do not look alike! Here Elessaurus nests with rhynchosaurs, not tanystropheids. 

Figure 5. Cladogram from DeOliveira et al. 2020 with colors added to show distribution and mixing of Lepidosauromorpha and Archosauromorpha clades in the LRT. Many of these purported sister taxa do not look alike! Strangely, here Elessaurus nests with rhynchosaurs, not tanystropheids (Fig. 2). The taxon in pink had to be looked up and revised here.

By contrast, 
in the large reptile tree (LRT, 1661+ taxa), Elessaurus nests as a derived tanystropheid, alongside Cosesaurus (Fig. 1). a smaller Middle Triassic taxon omitted from the original study. The authors mistakenly considered tanystropheids to be archosauromorphs, again due to taxon exclusion. Despite the many traits that converged with archosauromorph protorosaurs, tanystropheids are tritosaur lepidosaurs, derived from Huehuecuetzpalli (Fig. 7) and Tijubina. In the LRT, adding taxa does not create chaos. New taxa neatly take their place within the current tree topology. By omitting Cosesaurus, the authors omitted the most similar taxon to Elessaurus and all the added information included herein.

The cladogram by De-Oliveira et al. shuffles lepidosauromorphs
with archosauromorphs without an understanding of their Viséan split. As a result, several purported ‘sisters’ in figure 5 do not look alike, but apparently nested together by default. Based on these ‘odd bedfellows’ I suspect the authors borrowed another worker’s cladogram without checking scores or examining results.

From the abstract:
“The origin and early radiation of Tanystropheidae, however, remains elusive.”

This is false. We know the origin of Tanystropheidae back to Cambrian chordates. Taxon exclusion by the authors prevents them from recovering both distant and proximal sister taxa.

“Here, a new Early Triassic archosauromorph is described and phylogenetically recovered as the sister-taxon of Tanystropheidae.”

By contrast, in the LRT Elessaurus is a derived fenestrasaur close to Cosesaurus, a taxon excluded by the authors. We know cosesaur tracks (= Rotodactylus, Fig. 6) go back to the Early Triassic and some were much larger than Cosesaurus.

Figure 1. Scaling a quadrupedal Cosesaurus to the larger Rotodactylus tracks from Haubold 1983. Quadrant represents center of balance in the closeup foot. Graphic representation of a butt joint is nearby.

Figure 6. Click to enlarge. Scaling a quadrupedal Cosesaurus to the larger Rotodactylus tracks from Haubold 1983. Quadrant represents center of balance in the closeup foot. Graphic representation of a butt joint is nearby.

More from the abstract:
“The new specimen, considered a new genus and species, comprises a complete posterior limb articulated with pelvic elements. It was recovered from the Sanga do Cabral Formation (Sanga do Cabral Supersequence, Lower Triassic of the Parana Basin, Southern Brazil), which has already yielded a typical Early Triassic vertebrate assemblage of temnospondyls, procolophonoids, and scarce archosauromorph remains. This new taxon provides insights on the early diversification of tanystropheids and represents further evidence for a premature wide geographical distribution of this clade. The morphology of the new specimen is consistent with a terrestrial lifestyle, suggesting that this condition was plesiomorphic for Tanystropheidae.”

Likewise, Cosesaurus and related fenestrasaurs in the LRT are terrestrial taxa, distinct from other tanystropheids, all arising from tritosaur lepidosaurs like Tijubina and Huehuecuetzpalli.

Huehuecuetzpalli

Figure 7. The father of all pterosaurs and tanystropheids, Huehuecuetzpalli, a late survivor in the Early Cretaceous from a Late Permian radiation.

Larger quadrupedal cosesaurs, 
like Elessaurus, had two sacrals (Fig. 1). Smaller bipedal cosesaurs (Fig. 1) had four. Both had anterior processes on the ilium, not longer than the acetabulum width, distinct from non-fenestrasaur tanystropheids.

PS
Figure 2 in De-Oliveira has a scale bar problem in their figure 2 (explained here in Fig. 2).


References
De-Oliveira TM, Pinheiro FL, Da-Rosa AAS, Dias-Da-Silva S and Kerber L 2020.
A new archosauromorph from South America provides insights on the early diversification of tanystropheids. PLoS ONE 15(4): e0230890

Oculudentavis in more incredible detail! (thanks to Li et al. 2020)

Li et al. 2020 bring us
higher resolution scans of the putative tiny toothed ‘bird’ (according to Xing et al. 2020) Oculudentavis (Fig. 1). Following a trend started here a week ago, Li et al. support a generalized lepidosaur interpretation, but then tragically overlook/deny details readily observed in their own data (Fig.1).

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. Colors applied here. The previously overlooked jugal-lacrimnal suture becomes apparent at this scale and presentation.

Li et al. deny the presence of a clearly visible antorbital fenestra.
They report, “One of the most bizarre characters is the absence of an antorbital fenestra. Xing et al. argued the antorbital fenestra fused with the orbit, but they reported the lacrimal is present at the anterior margin of the orbit. This contradicts the definition of the lacrimal in birds, where the lacrimal is the bone between the orbit and antorbital, fenestra. In addition, a separate antorbital fenestra is a stable character among archosaurs including non-avian dinosaurs and birds, and all the known Cretaceous birds do have a separate antorbital fenestra.”

Contra Li et al.
a standard, ordinary antorbital fenestra is present (Fig. 1 dark arrow) and the lacrimal is between the orbit and antorbital fenestra. This is also the description of the antorbital fenestra and fenestrasaurs, like Cosesaurus (Fig. 2), Sharovipteryx and pterosaurs (Peters 2000).

Li et al. report,
“The ventral margin of the orbit is formed by the jugal.”

Contra Li et al.
the lacrimal is ventral to half the orbit (Fig. 1). The jugal is the other half. The suture becomes visible at the new magnification.

Li et al. report,
“Another unambiguous squamate synapomorphy in Oculudentavis is the loss of the lower temporal bar.” 

Contra Li et al.
the lower temporal bar is created by the quadratojugal, as in Cosesaurus, Sharovipteryx and pterosaurs. In Oculudentavis the fragile and extremely tiny quadratojugal is broken into several pieces. DGS (coloring the bones) enables the identification of those pieces (Fig. 1).

Figure 2. Cosesaurus nasal crest (in yellow).

Figure 2. Cosesaurus with colors applied. Compare to figure 1.

Li et al. conclude,
“Our new morphological discoveries suggest that lepidosaurs should be included in the phylogenetic analysis of Oculudentavis.” 

Contra Li et al.
these are all false ‘discoveries’.

Also note that Li et al. cannot discern
which sort of lepidosaurs should be tested in the next phylogenetic analysis of Oculudentavis. That’s because lepidosaur tritosaur fenestrasaurs, like Cosesaurus (Fig. 2), are not on their radar. That’s because pterosaur referees have worked to suppress the publication of new data on Cosesaurus and kin. And that’s what scientists get for not ‘playing it straight.’


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
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.

wiki/Oculudentavis

 

SVP abstracts – Drepanosaurs are not ‘highly enigmatic’

Britt et al. 2019 bring us a new look
at a 3D drepanosaur.

From the abstract:
“With a bird-like head, mole-like arms, and a “claw” at the end of the tail, derived drepanosaurs (lizard-sized neodiapsids) are highly enigmatic.” 

Not so. The large reptile tree (LRT, 1594 taxa, subset Fig. 2) documents exactly what they are. Paleontologists should stop using the word ‘enigmatic’ when what they really are saying is ‘we haven’t put in the effort.’ And that means the very little effort needed to click on www.ReptileEvolution.com where all candidates for drepanosaur ancestry are considered and tested.

“Multiple 3D skeletons of a new drepanosaur taxon from Utah provides insights into this clade, previously known from flattened skeletons and isolated 3D elements.”

Always good to have, but 2D specimens are still diagnostic, like a photo, rather than a sculpture. You don’t need as many characters as possible to make a taxonomic determination. What you need is a surfeit of taxa.

Figure 3. Drepanosaurs and their ancestor sisters, Jesairosaurus and Palaegama to scale.

Figure 1. Drepanosaurs and their ancestor sisters, Jesairosaurus and Palaegama to scale. Drepanosaurs nest at the base of the Lepidoauria. Pink bone is a sesamoid, not an ulna.

The rest of the abstract
describes the drepanosaur as a scratch-digger with an elongate naris and a hook tail capable of striking a tripod pose. They do not consider the ancestry or clade to which drepanosaurs belong, but consider them common and worldwide in distribution during the Late Triassic.

Figure 1. Subset of the LRT focusing on the Lepidosauria. Now the drepanosaur clade lumps with the rhynchocephalians in the crown group. Extant lepidosaurs are in gray.

Figure 1. Subset of the LRT focusing on the Lepidosauria. Now the drepanosaur clade lumps with the rhynchocephalians in the crown group. Extant lepidosaurs are in gray.

The title of this abstract 
may be the longest one I have ever read. See below.


References
Britt B et al. 2019. Still stranger things: MicroCT imaging of 3D drepanosaur skulls and skeletons (Saints & Sinners quarrry, Late Triassic, Eolian/Interdunal nugget formation) reveals bizarre and novel morphologies including a beak combined with transversely wide teeth, sauropod-like pneumatic dorsal vertebrae, a chevron that articulates with the pelvis and tripodal adaptations. Journal of Vertebrate Paleontology abstracts.

Excellent YouTube Video on Mosasaurs

This one features paleoartist, Brian Engh
working with the Mike Triebold’s fossil company (Triebold Paleontology, Inc).

Sadly
Triebold’s Pteranodons are leaping on their forelimbs and their Jeholopterus has giant scleral rings (eyes) in the antorbitral fenestra. Both were based on my originals, which did not have these invalid modifications. Those are market forces at work, veering away from evidence.

References
DontMessWithDinosaurs.com
TrieboldPaleontology.com

The most basal lepidosauriforms and lepidosaurs to scale

Lepidosauriform fossils are extremely rare in the Mesozoic and Paleozoic.
In the Earliest Permian we find Tridentinosaurus (Fig. 1; Dal Piaz 1931,1932; Leonardi 1959), a taxon ancestral to the pseudo-rib-gliders of the Late Permian (Coelurosauravus) through the Early Cretaceous (Xianlong) and close to the origin of all other lepidosauriforms, including living snakes, lizards and the tuatara (genus: Sphenodon).

Figure 1. Basal lepidosauriformes to scale from Tridentinosaurus (Earliest Permian) to Huehuecuetzpalli (Early Cretaceous). Subtle differences lump and split these taxa into their various clades.

Figure 1. Basal lepidosauriformes to scale from Tridentinosaurus (Earliest Permian) to Huehuecuetzpalli (Early Cretaceous). Subtle differences lump and split these taxa into their various clades.

 

Sometime during the Early Permian
the Lepidosauria split between the Sphenodontia + Drepanosauria and the Tritosauria + Protosquamata in the large reptile tree (LRT, 1381 taxa).

Short-legged
Jesairosaurus, in the Early Triassic, nests basal to the clade of slow-moving, arboreal drepanosaurs. On another branch, Megachirella (Middle Triassic) and Gephyrosaurus (Early Jurassic) are basal members of the Sphenodontia.

Long-legged
and probably arboreal Saurosternon and Palaegama, (both Late Permian) are the earliest known Lepidosauria, but they are basal to the Tritosauria + Protosquamata clades.

Figure 5. Subset of the LRT focusing on the Tritosauria. Note the separation of one specimen attributed to Macrocnemus.

Figure 5. Subset of the LRT focusing on the Tritosauria. Note the separation of one specimen attributed to Macrocnemus.

Late-surviving, long-legged basal Tritosauria
include tiny Tijubina and Huehuecuetzpalli (both Early Cretaceous). This clade gave rise to giant Tanystropheus, exotic Longisquama and volant Pteranodon.

Tiny and long-legged Late Permian
Lacertulus is the basal taxon in the previously unrecognized clade Protosquamata, the parent clade to the extant Squamata. This taxon documents the antiquity of this clade.

Going back to the Early Permian
we have a long-torso, short-legged specimen, MNC TA-1045, that nests in the LRT just outside the extant Squamata (Iguana). MNC TA-1045 was found alongside the genus Ascendonanus (MNC-TA0924), a basal archosauromorph diapsid with a shorter torso you can see here. The MNC TA-1045 specimen pushes the genesis of the lepidosaurs back to the Early Permian, nearly coeval with the basalmost lepidosauriform shown in figure 1, Tridentinosaurus.

The Lepidosauromorph-Archosauromorph dichotomy
was already present in the Viséan (Early Carboniferous, 330 mya), so the new Lepidosauromorpha had 30 million years to diverge into captorhinomorphs, diadectomorphs, millerettids and lepidosauriforms by the time Tridentinosaurus first appears in the Earliest Permian (300 mya).

Late surviving,
but basalmost lepidosauromorphs include Sophineta , Paliguana and Coletta (all Early Triassic). These taxa have an upper temporal fenestra not seen in outgroup taxa.

Proximal outgroups for the Lepidosauriforms
include the late-surviving owenettids: Barasaurus (Late Permian) and kin, Owenetta (Late Permian) and kin, and the late-surviving macroleterids (Middle Permian) and nycteroleterids (Middle Permian) before them.

At least that’s what the data says so far.
With every new taxon the tree grows stronger and more precise, so the odds of changing the tree topology with additional taxa continue to drop. Looking forward to seeing more Paleozoic arboreal lepidosauromorph discoveries as they arrive.

References
Dal Piaz Gb. 1932 (1931). Scoperta degli avanzi di un rettile (lacertide) nei tufi compresi entro i porfidi quarziferi permiani del Trentino. Atti Soc. Ital. Progr. Scienze, XX Riunione, v. 2, pp. 280-281. [The discovery of the remains of a reptile (lacertide) in tuffs including within the Permian quartz porphyry of Trentino.]
Leonardi P 1959. Tridentinosaurus antiquus Gb. Dal Piaz, rettile protorosauro permiano del Trentino orientale. Memorie di Scienze Geologiche 21: 3–15.

www.reptileevolution.com/reptile-tree.htm

 

 

 

 

Enigmatic Teraterpeton understood, at last, with better data

Finally
some photographic skull material has appeared online for Teraterpeton (Fig. 1). Not sure when these first appeared. Could have been years ago. I have not been searching until a day or two ago (see below).

First added
to the large reptile tree (LRT, 1371 taxa) on the basis of drawings by Sues 2003, the long rostrum and antorbital fenestra + the infilling of the lateral temporal fenestra of Teraterpeton  are traits that don’t go together anywhere else on anyone’s cladogram. Sues considered Teraterpeton an archosauromorph nesting with short-snouted Trilophosaurus (Figs. 1, 3).

In the LRT
Trilophosaurus is a rhynchocephalian lepidosaur nesting between derived sphenodontids, like short-snouted Sapheosaurus, and primitive rhynchosaurs, like short-snouted Mesosuchus. All related taxa have a diapsid-like temple architecture, even though the new clade Diapsida (Petrolacosaurus and kin) is restricted to members of the Archosauromorpha in the LRT. Lepidosaurs with a diapsid architecture have their own clade name: “Lepidosauriformes.” Details here and here.

The latest thinking identifies the large hole in the rostrum of Teraterpeton
that extends nearly to the orbit as a naris alone, not a combination of naris + antorbital fenestra. Here (Fig. 1) a broken strut-like bone lying atop the slender maxilla appears to have separated a naris from an antorbital fenestra in vivo. Even so, the present scoring for Teraterpeton with an antorbital fenestra without a fossa does not nest it with other taxa having an antorbital fenestra with or without a fossa.

Figure 1. Skulls of Teraterpeton and Trilophosaurus compared.

Figure 1. Skulls of Teraterpeton and Trilophosaurus compare well aft of the orbit, not so much below the orbit or in the rostrum.

This would not be the first time
an antorbital fenestra appeared in a lepidosaur. Pterosaurs and their ancestors, the fenestrasaurs, also have this trait by convergence with several other tetrapod taxa.

Comparing Trilophosaurus to Teraterpeton
(Fig. 1) is difficult until you get to the postorbital region of the skull. Then it’s a good match. Trilophosaurus has a reduced rostrum, a small naris, a robust maxilla and no hint of an antorbital fenestra. But like Teraterpeton alone, the lateral temporal fenestra found in all related taxa, is infilled with a large flange of the quadrate. Even so, the crappy character list for the LRT is able to nest these two taxa together.

Trilophosaurus and Teraterpeton nest with
the distinctively different Shringasaurus and Azendohsaurus in the LRT. The large variety in their morphologies hints at a huge variation yet to be found here. This is yet one more case where a list of traits may fail you, but a suite of several hundred traits will eliminate all other possibilities by a statistical process known as maximum parsimony. While the parsimony is minimal in this clade, it is still more than any other candidate taxa can offer from a list that has grown to over 1300.

A recent abstract on Teraterpeton
by Pritchard and Sues 2016 bears a review.

“Teraterpeton hrynewichorum, from the Upper Triassic (Carnian) Wolfville Formation of Nova Scotia, is one of the more unusual early archosauromorphs, with an elongate edentulous snout, transversely broadened and cusped teeth, and a closed lateral temporal fenestra. Initial phylogenetic analyses recovered this species as the sister taxon to Trilophosaurus spp. New material of Teraterpeton includes the first-known complete pelvic girdle and hind limbs and the proximal portion of the tail. These bones differ radically from those in Trilophosaurus, and present a striking mosaic of anatomical features for an early saurian.”

I agree completely, which makes solving this mystery so intriguing, and one perfectly suited to the wide gamut of the LRT.

The ilium has an elongate, dorsoventrally tall anterior process similar to that of hyperodapedontine rhynchosaurs

In all cladograms trilophosaurs are close to rhynchosaurs.

The pelvis has a well-developed thyroid fenestra, a feature shared by Tanystropheidae, Kuehneosauridae, and Lepidosauria. 

These taxa all nest within the Lepidosauriformes in the LRT. Mystery solved.

Figure 1. Azendohsaurus skull reconstructed with two premaxillary teeth, not four.

Figure 2. Azendohsaurus skull reconstructed with two premaxillary teeth, not four.

“The calcaneum is ventrally concave, as in Azendohsaurus”. 

Teteraterpeton and Trilophosaurus nest as sisters to Azendohsaurus (Fig. 2)  in the LRT.

The fifth metatarsal is proximodistally short, comparable to the condition in Tanystropheidae.” 

This condition is also found in lepidosaur tritosaur fenestrasaurs, including pterosaurs. Tanystropheidae nest as tritosaurs in the LRT. Mystery solved.

“Much as in the manus, the pedal unguals of Teraterpeton are transversely flattened and dorsoventrally deep.” 

The unguals of Trilophosaurus are also exceptionally deep and transversely flat.

“Phylogenetic analysis of 57 taxa of Permo-Triassic diapsids and 315 characters supports the placement of Teraterpeton as the sister-taxon of Trilophosaurus in a clade that also includes Azendohsauridae and, rather unexpectedly, Kuehneosauridae.”

Add taxa and the unexpected kuehneosaurs will drift to a more basal node.

“The mosaic condition in Teraterpeton underscores the importance of thorough taxon sampling for understanding the dynamics of character change in Triassic reptiles and the use of apomorphies in identifying fragmentary fossils.”

The term ‘mosaic’ is misleading. In the LRT there are no closer sisters to Teraterpeton than Trilophosaurus, and then, rather obviously, the similarities are immediately obvious only in the cheek region, distinct from all other taxa in the LRT.

Figure 2. Trilophosaurus has filled in the lateral temporal fenestra, reduced the orbit and increased the upper temporal fenestra, among other differences with Azendohsaurus.

Figure 3. Trilophosaurus has filled in the lateral temporal fenestra, reduced the orbit and increased the upper temporal fenestra, among other differences with Azendohsaurus.

Forcing Teraterpeton
back to long-snouted clades with an antorbital fenestra, like the Diandongosuchus clade, adds a minimum of 11 extra steps to the LRT.

Key to understanding
the lepidosaur nature of these taxa involves first understanding that the first dichotomy in the clade Reptilia separates the new Archosauromorpha from the new Lepidosauromorpha. Until someone else does this and it becomes consensus, we will continue to experience the confusion exhibited by Pritchard and Sues 2016 (above). This has been documented online for the last seven years.

References
Pritchard AC, Sues H-D 2016. Mosaic evolution of the early saurian post cranium revealed by the postcranial skeleton of Teraterpeton hrynewichorum (Archosauromorpha, Late Triassic). Abstract from the 2016 meeting of the Society of Vertebrate Paleontology.
Sues H-D 2003. An unusual new archosauromorph reptile from the Upper Triassic Wolfville Formation of Nova Scotia. Canadian. Journal of Earth Science 40(4): 635-649.

Thanks to
reader NP for bringing this taxon back to my attention.