Kongonaphon kely: a tiny ornithodiran? NO!

Kammerer et al. 2020 bring us news of a
Lagerpeton-like (Fig. 2) ‘tiny ornithodiran archosaur’ from Mid-Late Triassic of Madagascar.  What little is known of Kongonaphon (Fig. 1) might have stood 10 cm tall, according to the authors.

Figure 1. Kongonaphon bones. Very few are known. They resemble those of Lagerpeton and Tropidosuchus.

Figure 1. Kongonaphon bones. These few resemble those of Lagerpeton and Tropidosuchus (Fig. 2).

From the PNAS significance paragraph:
“Reptiles of the Mesozoic Era are known for their remarkable size: dinosaurs include the largest known land animals, and their relatives, the pterosaurs, include the largest creatures to ever fly. The origins of these groups are poorly understood, however.”

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

Figure 2 The closest kin of Tropidosuchus are the much larger Chanaresuchus (matching Nesbitt 2011) and the smaller Lagerpeton.

No. This is a traditional myth.
The origins of both groups are well known. In the large reptile tree (LRT, 1707 taxa) the origins of dinosaurs and the completely separate origins of pterosaurs are well documented back to Cambrian chordates.

Figure 3. Cladogram from Kammerer 2020 (rainbow colors). On top are clades within the LRT. So much taxon exclusion here!

Figure 3. Cladogram from Kammerer 2020 (rainbow colors). On top are clades within the LRT. So much taxon exclusion here!

From the abstract
“Early members of the dinosaur–pterosaur clade Ornithodira are very rare in the fossil record, obscuring our understanding of the origins of this important group. Small ancestral body size suggests that the extreme rarity of early ornithodirans in the fossil record owes more to taphonomic artifact than true reflection of the group’s evolutionary history.”

Fossils should be rare
because a dinosaur-pterosaur clade ‘Ornithodira” is invalid. When taxa are added dinosaurs arise from archosaurs. Pterosaurs arise from lepidosaurs. Their last common ancestor is the last common ancestor of all reptiles, Silvanerpeton, from the Early Carboniferous. That makes ‘Ornithodira’ a junior synonym of ‘Reptilia’.

From the abstract
“Kongonaphon is recovered as a member of the Triassic ornithodiran clade Lagerpetidae, expanding the range of this group into Africa and providing data on the craniodental morphology of lagerpetids.”

Funny thing is
Lagerpeton and kin are not related to dinosaurs OR pterosaurs. They are related to Tropidosuchus (Fig. 2) and the Proterochampsidae (Fig. 2). These authors, despite their PhDs, are painfully unaware of reptile systematics. All they need to do is add taxa to come to an understanding.

Figure 4. Kongonaphon kely restored. Lagerpetids have not preserved feathery soft tissue. The lack of a large finger 4 or toe 5 remove this restoration from possible pterosaur ancestry.

Figure 4. Kongonaphon kely restored. Lagerpetids have not preserved feathery soft tissue. The lack of a large finger 4 or toe 5 remove this restoration from possible pterosaur ancestry.

That miniaturization preceded the origin
of pterosaurs, dinosaurs, turtles, snakes, reptiles, mammals, birds and almost every other major clade has been well known for years.


References
Kammerer CF, Nesbitt SJ, Flynn JJ, Ranivoharimanana L and Wyss AR 2020. A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry. PNAS https://doi.org/10.1073/pnas.1916631117

Baron 2020 questions dinosaur origins

Baron 2020 discusses
the origin of dinosaurs (Fig. 1) in the Late Triassic of South America.

From the abstract
“Whilst the interrelationships between the major dinosaur clades remains to be fully resolved, the current data does seem to comprehensively answer the question of where the dinosaurs first originated.”

Actually
the dinosaur clades have been fully resolved for several years in the large reptile tree (LRT, 1707+ taxa). South America is where the last common ancestor of the dinosaurs, and all the proximal outgroups to that taxon reside (Fig. 1). We know dinosaur ancestors back to Cambrian chordates. So it is time to move on from questioning dinosaur origins. We’ve known this for several years. Academia needs to catch up.

Baron cites
(Baron et al., 2017a) as “a large scale study of early dinosaurs and their closest kin posed the first serious challenge in modern times to the traditional model of early dinosaur evolution and interrelationships.” Baron then and now omit a citation for a larger scale study first posted here in 2011 when Daemonosaurus (Sues et al. 2011) was described. Baron et al. 2017 were repositioning Chilesaurus as an early orninithischian and claiming credit for a hypothesis of interrelationships first posted here online two years earlier in 2015.

Baron was made aware of these earlier citations
via email, but chose to ignore them yet again. The earlier citation should always get the credit, no matter the circumstances. The resurrected clade ‘Ornithoscelida’ (Baron et al. 2017) is not support when more taxa are added.

After reviewing other competing hypotheses, Baron confesses,
“This lack of current overlap between datasets and taxon sampling has had a detrimental overall effect on our understanding of early dinosaur evolution and has offered very little by way of a solution to the any of issues still outstanding. The author recognises his own failing in this respect and would further seek to draw attention the fact that the original ‘challenge’ to a Southern Hemisphere point of origination was speculative, rather than robustly supported by data.”

Notably, none of these studies
included basal bipedal crocodylomorphs, which nest as the proximal outgroup taxa to the Dinosauria + Herrerasauridae in the LRT. Rather, Baron’s consensus tree includes:

  1. Silesauridae within Orinithisichia. Silesaurus is a poposaur in the LRT.
  2. Lagerpetidae as the proximal outgroup to the Dinosauria. Lagerpeton is a larger Tropidosuchus sister in the LRT.
  3. Pterosauromorpha as the proximal outgroup to Lagerpetidae + Dinosauria. Pterosaurs are lepidosaurs in the LRT. Scleromochlus is a basal bipedal crocodylomorph in the LRT.
  4. Aphanosauria includes outgroup taxa to taxa listed here (Fig. 1). Members include Teleocrater and Yarasuchus, dead end taxa nesting between rauisuchians and poposaurs in the LRT.

So taxon exclusion
remains the problem here. And face it, sometimes it takes an outsider to see problems PhDs and textbook writers surround themselves with by wearing blinders. As I discussed in Facebook recently with a famous dinosaur artist, most people follow the money and do what is popular and accepted. It’s better to follow the science. Science will catch up to popular myths sooner or later.

Figure 1. The origin of dinosaurs in the LRT to scale. Gray arrows show the direction of evolution. This image includes Decuriasuchus, Turfanosuchus, Gracilisuchus, Lewisuchus, Pseudhesperosuchus, Trialestes, Herrerasaurus, Tawa and Eoraptor.  Note the phylogenetic miniaturization at the origin of Archosauria (Crocs + Dinos).

Figure 1. The origin of dinosaurs in the LRT to scale. Gray arrows show the direction of evolution. This image includes Decuriasuchus, Turfanosuchus, Gracilisuchus, Pseudhesperosuchus, Herrerasaurus, Tawa and Eoraptor.  Note the phylogenetic miniaturization at the origin of Archosauria (Crocs + Dinos). These are the taxa studies need to include while they exclude Silesaurus and pterosaurs.

Baron 2020 offers some suggestions
“First, to try and resolve the issue relating the topology within the dinosaur lineage, the datasets produced in each of the various analyses discussed above should be combined and an effort made to consistently score all species using a standardized set of definitions for anatomical characters and character states.”

“Second, and most importantly, it is only through the full incorporation of data from newly discovered species both within and without Dinosauria, that more confidence could be placed in our understanding of the geographic setting of the common ancestor of all dinosaurs.”

Yes. Adding taxa will solve this problem. Follow the example of the LRT.

“Another substantial omission of most studies of this kind are pterosaurs. Pterosauromorpha is a clade of flying Mesozoic reptiles that are very closely related to the dinosaurs, forming with them the clade Ornithodira.” 

No. That’s a myth. Adding taxa removes pterosaurs from dinosaurs and nests them with lepidosaurs. We’ve known this since 2007, but textbooks must be sold.

“As a final point, it is worth remembering that during the Late Triassic, every continent was united into a single landmass, Pangea.”

True! Even so, you have to include more basal bipedal crocs and a raft of other taxa to figure out who is in and who is out. That’s where the LRT can be more than helpful. The debate is over when you have minimized taxon exclusion, as in the LRT.

Bottom line:
Baron and other workers choose their taxa. The LRT recovers taxa for you. Take the bias, myth and tradition out of the equation.


References
Baron MG 2020. Difficulties with the origin of dinosaurs: a comment on the current debate. Palaeovertebrata 43 (1)-e3 . doi: 10.18563/pv.43.1.e3
Baron MG, Norman DB, Barrett PM 2017. A dinosaur missing-link? Chilesaurus and the early evolution of ornithischian dinosaurs. Biology Letters 13 (8): 20170220. https://doi.org/10.1098/rsbl.2017.0220
Langer et al. (8 co-authors) 2017. Untangling the dinosaur family tree. Nature 551: doi:10.1038/nature24011
Mortimer M, Gardner N, Marjanovic D and Dececchi A 2018. Ornithoscelida, phytodinosauria, saurischia: stesting the effects of miss cores in matrices on basal dinosaur phylogeny. SVP abstracts.
Sues H-D, Nesbitt SJ, Berman DS and Henrici AC 2011. A late-surviving basal theropod dinosaur from the latest Triassic of North America. Proceedings of the Royal Society Bpublished online 

https://pterosaurheresies.wordpress.com/2017/08/16/you-heard-it-here-first-chilesaurus-is-a-basal-ornithischian-confirmed/

https://pterosaurheresies.wordpress.com/2017/11/08/you-heard-it-here-first-daemonosaurus-is-an-ornithischian/

https://pterosaurheresies.wordpress.com/2018/10/26/svp-2018-the-clade-ornithoscelida-tested/

https://pterosaurheresies.wordpress.com/2018/06/24/dr-baron-tip-toes-around-the-radiation-of-dinosaurs/

https://pterosaurheresies.wordpress.com/2017/11/03/dinosaur-family-tree-langer-et-al-responds-to-baron-et-al-2017-in-nature/

https://pterosaurheresies.wordpress.com/2017/03/23/new-radical-dinosaur-cladogram-baron-norman-and-barrett-2017/

Adelobasileus restored: NOT ‘the oldest mammal’

When Lucas and Hunt 1990
and Lucas and Luo 1993 described the cranium (all that is known) of Adelobasileus (Fig. 1) they concluded it was, ‘the oldest mammal’. 

Figure 1. Adelobasileus restored like Therioherpeton after first nesting together in the LRT.

Figure 1. Adelobasileus restored like Therioherpeton after first nesting together in the LRT. Line drawing for Adelobasileus from Lucas and Luo 1993.

By contrast
the large reptile tree (LRT, 1707+ taxa, subset Fig. x) nests Adelobasileus with the low and wide mammal-mimic cynodont, Therioherpeton (Fig. 1), despite the very few characters that could be scored here. Both also nest with Sinocodon and Haramiyavia in the LRT. Thus Adelobasileus in not the oldest mammal. It is not even a mammal.

Therioherpeton
Fig. 1) was originally described by Bonaparte and Barberena 1975 as ‘a possible mammal ancestor’.

Later
Oliveira 2006 reevaluated Therioherpeton“Therioherpetidae are distinguished from all other probainognathians by upper teeth with the imbrication angle increasing in the posterior postcanines. In addition, upper and lower postcanine teeth are labio-lingually narrow.” This author did not include Adelobasileus in his cladogram. Oliveira nested Therioherpeton with Riograndia.

Figure 1. Megazostrodon skull in several views. Drawings from Gow 1986. Colors applied here.

Figure 2. Megazostrodon skull in several views. Drawings from Gow 1986. Colors applied here. This is the last common ancestor of all mammals in the LRT.

The last common ancestor of all mammals
in the LRT (subset Fig. x) continues to be Megazostrodon (Fig. 2), from the early Jurassic. Other, more derived mammals, like Morganucodon, are found in the Late Triassic, indicating an earlier origin and radiation.

Figure x. Subset of the LRT focusing on therapsids, like Repenomamus, leading to mammals.

Figure x. Subset of the LRT focusing on therapsids leading to mammals. Adelobasileus nests with Therioherpeton in this older cladogram that does not list Adelobasileus.

The most recent paper on basal mammals
and their immediate ancestors, King and Beck 2020, shows just how different cladograms can be when taxa are excluded (Fig. 3, click to enlarge). King and Beck mix non-mammals with prototherians, metatherians and eutherians in a mish-mash as compared to the LRT (Fig. x). At least they nest Adelobasileus outside their Mammalia (which should include only Prototherians, Metatherians and all descendants of their last common ancestor, Megazostrodon, Fig. 2).

Figure 3. Click to enlarge. Stem mammal cladogram from King and Beck 2020 showing how different their topology is to the LRT (color overlays, key at left) which has a wider gamut of included taxa. Arrow points to Adelobasileus near top.

Figure 3. Click to enlarge. Stem mammal cladogram from King and Beck 2020 showing how different their topology is to the LRT (color overlays, key at left) which has a wider gamut of included taxa. Arrow points to Adelobasileus near top.

Add taxa 
and multituberculates nest with rodents, Fruitafossor nests with xenarthrans and other taxa nest appropriately with prototherians, metatherians and eutherians as shown in the LRT (subset Fig. x).

The nesting of Adeolbasileus with Therioherpeton
is not quite an original hypotheses. Google the two keywords, “Adelobasileus, Therioherpeton” and you’ll find someone tweeted these two as possible ancestor-descendant taxa, but unfortunately, still considered Adelobasilesus ‘the oldest mammal.’


References
Bonaparte JF and Barberena MC 1975. A possible mammalian ancestor from the Middle Triassic of Brazil (Therapsida–Cynodontia). Journal of Paleontology 49:931–936.
King and Beck 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
Lucas SG and Hunt 1990. The oldest mammal. New Mexico Journal of Science 30(1):41–49.
Lucas SG and Luo Z 1993. Adelobasileus from the upper Triassic of west Texas: the oldest mammal. Journal of Vertebrate Paleontology 13(3):309–334.
Oliveira EV 2006. Reevaluation of Therioherpeton cargnini Bonaparte & Barberena, 1975 (Probainognathia, Therioherpetidae) from the Upper Triassic of Brazil. Geodiversitas 28 (3): 447-465.

http://reptileevolution.com/sinoconodon.htm
wiki/Adelobasileus
wiki/Therioherpeton

Simões et al. 2020 fail to understand ‘diapsids’ due to taxon exclusion

Simões et al. 2020 brings us their study
on the rates of evolutionary change in reptiles with a diapsid skull architecture.

From the abstract:
“The origin of phenotypic diversity among higher clades is one of the most fundamental topics in evolutionary biology. However, due to methodological challenges, few studies have assessed rates of evolution and phenotypic disparity across broad scales of time to understand the evolutionary dynamics behind the origin and early evolution of new clades. Here, we provide a total-evidence dating approach to this problem in diapsid reptiles. We find major chronological gaps between periods of high evolutionary rates (phenotypic and molecular) and expansion in phenotypic disparity in reptile evolution. Importantly, many instances of accelerated phenotypic evolution are detected at the origin of major clades and body plans, but not concurrent with previously proposed periods of adaptive radiation. Furthermore, strongly heterogenic rates of evolution mark the acquisition of similarly adapted functional types, and the origin of snakes is marked by the highest rates of phenotypic evolution in diapsid history.”

This study suffers from taxon exclusion
By adding taxa the first dichotomy of the Reptilia (Amniota is a junior synonym) splits taxa closer to lepidosaurs (Lepidosauromorpha) from those closer to archosaurs (Archosauromorpha, including Synapsida). Thus members of the traditional clade ‘Diapsida’ are convergent. Other than through the last common ancestor of all Reptiles, Silvanerpeton in the Viséan, archosaurs are not related to lepidosaurs. The present paper by Simões et al. 2020 fails to recover this topology due to taxon exclusion. Without a valid phylogenetic context, the results are likewise hobbled.


References
Simões TR, Vernygora O, Caldwell MW and Pierce SE 2020. Megaevolutionary dynamics and the timing of evolutionary innovation in reptiles. Nature Communications 11: 3322.

http://reptileevolution.com/reptile-tree.htm

Ticinolepis: DGS rebuilds scattered skull parts

López-Arbarello, et al. 2016 and
López-Arbarello and Sferco 2018 brought us two closely related Middle Triassic ganoid-scaled fish. These two species of Ticinolepis (Fig. 1) are distinguished by their teeth (and other traits). The larger one has small, slender teeth (Fig. 2). It was added to the large reptile tree (LRT, 1706+ taxa, subset Fig. 3). The smaller one has large bulbous teeth.

Figure 1. Two new Ticinolepis species to scale.

Figure 1. Two new Ticinolepis species to scale from López-Arbarello 2016, Scale bar = 2 cm. The skull of the top species, T. longavea, is shown in figure 2.

Ticinolepis longaeva
(López-Arbarello and Sferco 2016; Middle Triassic; MCSN 8072) nests at the base of a clade of several ganoid fish, near the base of catfish + placoderms and not far from a clade of several spiny sharks.

Figure 2. The skull of Ticinolepis longaeva (MCSN 8072) in situ from López-Arbarello 2016, traced and reconstructed using DGS methods.

Figure 2. The skull of Ticinolepis longaeva (MCSN 8072) in situ from López-Arbarello 2016, traced and reconstructed using DGS methods. Gray part of maxilla was under the nasal. 

In the LRT
 (subset Fig. 3) Ticinolepis nests with Perleidus (Fig. 4), Tarrasius, and the living gar, Lepisosteus.

Figure 5. Subset of the LRT, focusing on fish for July 2020.

Figure 5. Subset of the LRT, focusing on fish for July 2020.

The phylogenetic ‘distance’ between any two fish taxa
is getting smaller and smaller as more taxa are added.

Figure 1. Perleidus woodwardi in situ and with skull reconstructed.

Figure 4. Perleidus woodwardi in situ and with skull reconstructed.

López-Arbarello and Sferco 2018 wrote:
“In our analysis, †Ticinolepis also joins the tree at this stem as the most basal Ginglymodi and, thus, we now find it useful to distinguish the clade (Lepisosteiformes, †Semionotiformes) as the Neoginglymodi, defined as the clade including Lepisosteus and †Semionotus, and all descendants of theirmost recent common ancestor.”

Currently in the LRT, that clade includes just those two sister taxa. Over time perhaps others will be added.

López-Arbarello and Sferco 2018 mention all LRT clade members, except Tarrasius. The authors do not attempt a reconstruction of Ticinolepis.


References
López-Arbarello A, Burgin T, Furrer H and Stockar R 2016. New holostean fishes (Actinopterygii: Neopterygii) from the Middle Triassic of the Monte San Giorgio (Canton Ticino, Switzerland). Peerj 4, 61 (doi:10.7717/peerj.2234).
López-Arbarello A and Sferco E 2018. Neopterygian phylogeny: the merger assay. Royal Society open sci. 5: 172337. http://dx.doi.org/10.1098/rsos.172337

Bavarichthys: a Late Jurassic Solnhofen anchovy

Arratia and Tischlinger 2010
bring us several fossils of Bavarichthys incognitus from the Late Jurassic Solnhofen Formation of Germany. In the large reptile tree (LRT, 1706+ taxa; subset Fig. x) it nests with Elops, the extant and much larger anchovy (Fig. 2), and for good reason. They are almost identical.

Figure 1. Bavarichthys is a big head/ short body anchovy from the Late Jurassic.

Figure 1. Bavarichthys is a big head/ short body anchovy from the Late Jurassic. Here the preorbital and cranial bones are restored.

The skull of one Bavarichthys
(Fig. 1) is largely intact, lacking a prefrontal + upper lacrimal based on phylogenetic bracketing with Elops (Fig. 2). The maxilla is slightly displaced.

Figure 2. Elops is the extant anchovy. Compare to Bavaricthys in figure 1.

Figure 2. Elops is the extant anchovy. Compare to Bavaricthys in figure 1.

Bavarichthys incognitus (Arratia and Tischlinger 2020; Late Jurassic) was originally considered a member of the “Crossognathiforms with a large head about 30% in standard length and a characteristically elongate snout, more than 25% in head length.

Figure 2. Another specimen of Pholidophorus? radians

Figure 2. Another specimen of Pholidophorus? radians

?Pholidophorus radians is a coeval Late Jurassic relative
(Fig. 3) with a more tuna-like shape.

Figure 5. Subset of the LRT, focusing on fish for July 2020.

Figure x. Subset of the LRT, focusing on fish for July 2020.

The phylogenetic ‘distance’ between any two fish taxa
is getting smaller and smaller as more taxa are added.


References
Arratia G and Tischlinger H 2010. The first record of Late Jurassic crossognathiform fishes from Europe and their phylogenetic importance for teleostean phylogeny. Mitteilungen aus dem Museum für Naturkunde in Berlin. Fossil Record; Berlin 13(2): 317–341.

wiki/Elops_saurus

New Quetzalcoatlus northropi skeletal model from Triebold Paleontology

Short one today
… focusing on a tall pterosaur skeleton model.

Figure 1. A Quetzalcoatlus northropi model from Triebold Paleontology scaled up from a Q. sp. sculpture I made and sold to Triebold.

Figure 1. A Quetzalcoatlus northropi model from Triebold Paleontology scaled up from a Q. sp. sculpture I made and sold to Triebold. Maybe it is posed trying to cool itself off, by those wing fingers can fold up against the arms for membrane protection.

First time I’ve seen this. 
Although I heard rumors that Mike Triebold (Triebold Paleontology) had scaled up the Q. sp. model I sold him a few years ago (Fig. 2) to create a 3x taller Quetzalcoatlus northropi model (Fig. 1). Giants are fascinating.

Quetzalcoatlus neck poses. Dipping, watching and displaying.

Figure 2. Quetzalcoatlus neck poses. Dipping, watching and displaying. Yes, that was my living room.

The shorter original was held together by wire
so it could be manipulated into one pose after another, or stuffed away into a small box.

As a reminder,
the brevity of the wings (vestigial distal phalanges) and the top-heavy proportions otherwise mark this as a flightless pterosaur.

Quetzalcoatlus running like a lizard prior to takeoff.

Figure 3. Quetzalcoatlus running like a lizard unable to take off due to vestigial distal wing elements and proportions that sent the center of balance anterior to the wing chord.

Even so, those wings were powerful thrusters
for speedy getaways on land (Fig. 3). I realize this is heresy, but facts are facts. Clipped wings in birds and pterosaurs means they cannot fly. And only flightless birds and pterosaurs are able to achieve such giant sizes (Fig. 4).

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

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

Sallen 2016 presents a fascinating flawed look at fish tails

Sallen 2016 reports,
“The symmetrical, flexible teleost fish ‘tail’ has been a prime example of recapitulation — evolutionary change(phylogeny) mirrored in development (ontogeny).”

Sallan’s cladogram (Fig. 1) lays out the traditional cladogram of fish. Note the position of the bichir (Polypterus), at a basal node and the sturgeon + paddlefish (Acipcenser + Polyodon) near the middle.

Figure 1. Cladogram from Sallan 2016 (above) and young fish tails (below).

Figure 1. Cladogram from Sallan 2016 (above) and young fish tails (below).

Unfortunately,
taxon exclusion mars the cladogram of Sallan 2016 according to the the large reptile tree (LRT, 1704+ taxa; Figs. 2, 5). Due to tradition Sallan has chosen the wrong outgroup. Jawless sturgeons and shark-like paddlefish should be the outgroups here, not lungfish-like bichirs (Polypterus), which are highly derived taxa close to lungfish and tetrapods.

Figure 2. Same taxa as above, but rearranged to fit the LRT tree topology.

Figure 2. Same taxa as above, but rearranged to fit the LRT tree topology. Remember, sturgeons, paddlefish and sharks are basal taxa in the LRT. Esox is a catfish related to placoderms.

Salan reports,
“Paleozoic ray-finned fishes (Actinopterygii), relatives of teleosts, exhibited ancestral scale-coveredtails curved over their caudal fins. For over 150 years, this arrangement was thought to be retained in teleost larva and overgrown, mirroring an ancestral transformation series. New ontogenetic data for the 350-million-year-old teleost relative Aetheretmon overturns this long-held hypothesis.”

By contrast,
in the LRT Aetheretmon nests with Pteronsculus (Figs. 5–7)) far from the base of all bony fish, much closer to lobefin fish and tetrapods.

The Sallan point is still made:
Many fish tails do have two parts, especially when hatchlings.

Unfortunately, Sallan does not understand
the topology of the family tree of fish due to taxon exclusion. This is something the LRT minimizes by testing a wider gamut of taxa. As readers know, we see this same taxon exclusion problem all the time in paleontology.

Figure 2. Muskie (Esox) tail ontogeny from Sallan 2016 (middle row). Top row and photo added here.

Figure 3. Muskie (Esox) tail ontogeny from Sallan 2016 (middle row). Top row (to scale) and photo (below) added here. You might remember, Esox is a derived catfish without barbels.

Salan writes,
These two tails appear at a shared developmental stage in Aetheretmon, (Fig. 4) teleosts and all living actinopterygians. Ontogeny does not recapitulate phylogeny; instead, differential outgrowth determines final morphology.”

That appears to be so, but it still needs a valid tree topology.

Figure 3. Fish tail ontogeny in extinct Aetheretmon and extant Monotrete. Note the upper and lower lobes.

Figure 4. Fish tail ontogeny in extinct Aetheretmon and extant Monotrete. Note the upper and lower lobes. In the LRT these two fish are not closely related. Aetheretmon is basal to lobefins. Monotrete is a puffer fish.

Salan speculates:
“The double tail likely reflects the ancestral state for bony fishes.”

No, the ancestral state for bony fish is the heterocercal tail documented by sturgeons and whale sharks, and this goes back to armored osteostracans according to the LRT (Fig. 5).

Figure 5. Subset of the LRT, focusing on fish for July 2020.

Figure 5. Subset of the LRT, focusing on fish for July 2020. Aetheretmon is in the yellow column close to the notch between colors.

Salan speculates,
“Many tetrapods and non-teleost actinopterygians have undergone body elongation through tail outgrowth extension, by mechanisms likely shared with distal limbs.”

Not sure what those ‘mechanisms’ would be, but basal tetrapods and stem tetrapods in the LRT have relatively short, straight tails and elongated bodies with great distances between the fore and hind limbs. Look at Panderichthys.

Figure 5. Aetheretmon is known from the oldest complete growth series for vertebrates.

Figure 6. Aetheretmon is known from the oldest complete growth series for vertebrates.

Figure 6. Pteronisculus, a sister to Aetheretmon in the LRT.

Figure 7. Pteronisculus, a Triassic sister to Early Carboniferous Aetheretmon in the LRT and it is easy to see why.

Sallan is ‘Pulling a Larry Martin’
by putting too much emphasis on one trait without testing all the traits on many more taxa. Only after a valid phylogenetic context is established can one begin to figure out if trait A came before trait B or not.

Sallan goes into great detail describing
the successive stages of growth in Aetheretmon, but this is problematic because the cladogram is invalid. “First things first” is a motto all paleontologists should ascribe to. First get the phylogeny correct. Fish workers are relying on an invalid family tree. The LRT is here to fix that.

Its worth remembering,
many fish on the other branch of bony fish (perch, anglers, etc., Fig. 5, orange right column) bring the pelvic fins beneath the pectoral fins, shortening the gut cavity and elongating the tail to extremes in some cases (oarfish). This is all distinct from the longer torso, shorter tail trend in the stem tetrapod branch of bony fishes (Fig. 5, yellow left column).


References
Sallan 2016. Fish ‘tails’ result from outgrowth and reduction of two separate ancestral
tails. Current Biology 26, R1205–R1225.
White EI 1927. The fish fauna of the Cementstones of Foulden, Berwickshire. Transactions of the Royal Society Edinburgh 55:255–287.

https://www.the-scientist.com/the-nutshell/a-tale-of-two-tails-32394

Shenqiornis: Reconstructing a Mesozoic bird skull

O’Connor and Chiappe 2011
traced (Fig. 1) and reconstructed (Fig. 2) the skull of the enantiornithine bird Shenqiornis mengi (Early Cretaceous; Wang et al. 2010; DNHM D2950-2951). This is one of the few enantiornithines with substantial skull material.

Figure 1. O'Connor et al. traced Sheqiornis like this.

Figure 1. O’Connor and Chiappe 2011 traced Shenqiornis like this.

O’Connor and Chiappe used freehand techniques
to reconstruct Shenqiornis (Fig. 2). This is almost never a good idea as assumptions and biases tend to flavor freehand reconstructions.

Figure 2. O'Connor et al. reconstructed the skull of Sheqiornis freehand.

Figure 2. O’Connor and Chiappe 2011 reconstructed the skull of Sheqiornis freehand. Missing parts are in gray, though they seem to give this bird an antorbital fossa that I don’t see and sister taxa do not have. Scale bar = 1cm.

Long time readers know, it is far better to use the DGS method
(Fig. 3) and simply transfer precisely traced shapes to the reconstruction without bias or forethought. It also permits others to see exactly what you saw in a scattered, crushed fossil.

Figure 3. The skull of Sheqiornis traced and reconstructed using DGS methods.

Figure 3. The skull of Shenqiornis traced and reconstructed using DGS methods. Compare to fig. 1 and 2. Here more bones were identified and more precisely reconstructed. Scale bar = 1 cm.

Given this data,
Sheqiornis nests with Pengornis (Fig. 4) in the large reptile tree (LRT, 1703+ taxa) based on skull traits alone.

Figure 3. Pengornis reconstructed not from tracing, but from cutting out the bones and putting them back together. Color tracing is used only for the skull elements. This holotype specimen does not have the same morphology or proportions that Chiappeavis has and it nests within the Enantiornithes.

Figure 4. Pengornis reconstructed not from tracing, but from cutting out the bones and putting them back together. Color tracing is used only for the skull elements. This holotype specimen does not have the same morphology or proportions that Chiappeavis has and it nests within the Enantiornithes.

If you think things here have been a little strange
over the last 3 weeks, you’re right. My large aging computer zapped out. Meanwhile I was able to handle posts using a small MacBook Pro, but was not able to get to my Adobe graphics software for DGS tracing and reconstructing. I was likewise unable to update the LRT. Things are back to normal now (see Fig. 3 above), so we continue!


References
O’Connor JK and Chiappe LM 2011. A revision of enantiornithine (Aves: Ornithothoraces) skull morphology. Journal of Systematic Palaeontology, 9:1, 135-157, DOI: 10.1080/14772019.2010.526639
Wang X, O’Connor J, Zhao B, Chiappe LM, Gao C and Cheng X 2010. New species of Enantiornithes (Aves: Ornithothoraces) from the Qiaotou Formation in Northern Hebei, China. Acta Geologica Sinica, 84(2):247-256.

wiki/Shenqiornis

New paper, old Chanaresuchus: traditional taxon exclusion issues

A new look at the holotype of Chanaresuchus
by Trotteyn and Ezcurra 2020 provides crisp color photos of the holotype material from several angles, in white light and after µCT scanning.

Unfortunately their small focused cladogram
is a little too small and a little too focused for their taxon list. It might seem large because it includes 115 active taxa from a list of 151 total taxa from (Ezcurra 2016), but, as before, it omits several taxa that would move the thalattosaur, Vancleavea, and the pterosaur, Dimorphodon, out of Archosauromorpha (along with other lepidosaurs like Macrocnemus and Tanystropheus.

Earlier we looked at the many problems in Ezcurra 2016. The largest problem: Ezcurra did not and still does not understand that traditional diapsid taxa are diphyletic and convergent, with some among the Lepidosauria and others starting with Petrolacosaurus and kin within the Archosauromorpha. The Viséan last common ancestor of all reptiles is their last common ancestor.

Earlier we looked at a similar taxon list by Nesbitt 2011 in a 7-part series and demonstrated dozens of scoring errors. After corrections the tree topology came to match the large reptile tree (LRT, 1698+ taxa).

Figure 3. Updated image of various proterosuchids and their kin. When you see them all together it is easier to appreciated the similarities and slight differences that are gradual accumulations of derived taxa.

Figure 1. Updated image of various proterosuchids and their kin. When you see them all together it is easier to appreciated the similarities and slight differences that are gradual accumulations of derived taxa.

From the Trotteyn and Ezcurra 2020 abstract:
“Proterochampsids are one of the several diapsid groups that originated, flourished and became extinct during the Triassic Period. Here we redescribe, figure and compare in detail the holotype of one of these rhadinosuchine species, Chanaresuchus bonapartei from the Chañares Formation. Our new cladistic analyses find stronger support than previous studies for the monophyly of Rhadinosuchinae and the clades that include Doswelliidae + Proterochampsidae and Tropidosuchus + Rhadinosuchinae. Doswelliids are recovered within Proterochampsidae, as the sister taxon to the genus Proterochampsa, in some analyses under implied weights.”

If you find any taxa
in figures 1 and 2 missing from the above list (hint: there are several), those are the taxa Trotteyn and Ezcurra need to add to their next look at proterochampsids.

Figure 2. Cladogram of basal archosauriforms. Note the putative basalmost archosauriform, Teyujagua (Pinheiro et al 2016) nests deep within the proterosuchids. The 6047 specimen that Ewer referred to Euparkeria nests as the basalmost euarchosauriform now.

Figure 2. Cladogram of basal archosauriforms. Note the putative basalmost archosauriform, Teyujagua (Pinheiro et al 2016) nests deep within the proterosuchids. The 6047 specimen that Ewer referred to Euparkeria nests as the basalmost euarchosauriform now.

References
Ezcurra MD 2016.
The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms. PeerJ, 4, e1778. doi:10. 7717/peerj.1778
Trotteyn MJ and Ezcurra MD 2020. Redescription of the holotype of Chanaresuchus bonapartei Romer, 1971 (Archosauriformes: Proterochampsidae) from the Upper Triassic rocks of the Chañares Formation of north-western Argentina.
Journal of Systematic Palaeontology (advance online publication)
doi: https://doi.org/10.1080/14772019.2020.1768167
https://www.tandfonline.com/doi/full/10.1080/14772019.2020.1768167

https://pterosaurheresies.wordpress.com/2016/04/29/basal-archosauromorpha-paper-ezcurra-2016/