The microsaur, Llistrofus, enters the LRT

Llistrofus (Carroll and Gaskill 1978; Gee et al. 2019, Fig. 1) nests with Tuditanus in the large reptile tree (LRT, 1391 taxa), just like it does in the Huttenlocker et al. 2013 analysis (Fig. 2) employed by Gee et all.

Figure 1. Llistrofus is very much like Tuditanus, but with such reduced squamosals that a lateral temporal fenestra appears. Images from Gee et al. 2019.

The problem comes from taxon exclusion
(as usual). In the rest of the Huttenlocker et al. 2009 cladogram (Fig. 2), which Gee et al. 2019 cited as their source for nesting Llistrofus. In the Huttenlocker cladogram there is so much taxon exclusion that the Lepospondyli splits into two clades (maybe three if you count the Eryops incursion).

Figure 2. Cladogram of basal tetrapods from Huttenlocker et al. 2009 with colors added.

Another problem comes from taxon INCLUSION,
because the unrelated reptile, Limnoscelis, is included.

References
Bolt JR and Rieppel O 2015. The holotype skull of Llistrofus pricei Carroll and Gaskill, 1978 (Microsauria: Hapsidopareiontidae). Journal of Paleontology 83(3):471–483.
Carroll RL and Baird D 1968. The Carboniferous amphibian Tuditanus (Eosauravus) and the distinction between microsaurs and reptiles. American Museum novitates 2337: 1-50.
Carroll RL and Gaskill P 1978. The order Microsauria. Memoirs of the American Philosophical Society 126:1–211.
Gee BM, Bevitt JJ, Garbe U and Reisz 2019. New material of the ‘microsaur’ Llistrofus from the cave deposits of Richards Spur, Oklahoma and the paleoecology of the Hapsidopareiidae. PeerJ 7:e6327 DOI 10.7717/peerj.6327

wiki/Tuditanus
wiki/Llistrofus

 

 

Hauffiosaurus: convergent with later plesiosaurs

Updated March 28, 2019
with a new old engraving of Anningasaura.

Two misfit plesiosaurs nest together in the LRT
Earlier we looked at Anningsaura (Fig. 6). Vincent and Benson (2012) reported, “In general morphology, NHMUK OR49202 does not resemble any known plesiosaurian taxon.”

Figure 1. The sisters of Anningsaura, Simosaurus and Pistosaurus. Until today, these provided the only clues as to the post-crania of Anningsaura, of which only the first eight cervicals are known.

Anningasaura 
(originally Plesiosaurus macrocephalus, Lydekker 1889; NHMUK OR49202) represents a completely ‘new’ branch of the plesiosauria in which the orbits virtually cannot be seen in dorsal view and the jugals bend down posteriorly to produce an angled temporal arch (Fig. 1). Moreover the premaxillae were thought to not contact the frontals and the nasals were absent. Benson et al. (2012) created a phylogenetic analysis that nested Anningsasaura at the base of the pliosaur/plesiosaur split with Bobosaurus as the outgroup.

Figure 2. Hauffiosaurus from Vincent 2011 with colors and reconstructions added.

Hauffiosaurus zanoni 
(O’Keefe 2001; Vincent 2011; Early Jurassic; 3.4m long; uncatalogued Hauff museum) is another plesiosaur that, according to Vincent 2011, “does not resemble any known plesiosaurian taxon.” This genus was considered a basal pliosauroid. Here (Fig. 3) the large reptile tree (LRT, 1392 taxa) nests between Anningsaura and Pistosaurus. Benson et al 2012 nested Hauffiosaurus one or two nodes apart from Anningsaura. No taxa in those nodes is currently in the LRT. So the LRT is a close match!

As you might imagine,
the characters in the LRT are not the same as those found in Benson et al. 2012, yet the tree topologies, so much as they can be compared, are nearly identical. This was done without first-hand access to the fossils. So, this methodology works.

Figure 3. Subset of the LRT. Here the clade Eosauropterygia nests Anningsaura with Hauffiosaurus. This nesting demonstrates an early convergence with later pliosaurids.

The skull of Hauffiosaurus is exposed in palatal view
(Fig. 4) and as such gives clear data on the often hidden palatal elements. Overlooked by Vincent 2011, the premaxilla extends to the internal naris, as in other taxa (Fig. 5), like Pliosaurus, also an overlooked connection.

Figure 4. Hauffiosaurus skull in palatal view from Vincent 2011, colors added. Overlooked by Vincent, the premaxilla (yellow) contacts the internal naris

DGS is able to document traits
overlooked by those with first-hand access to the fossils themselves (Figs. 4, 5).

Figure 5. Pliosaurus kevani palate, from Benson et al. 2013, also has an overlooked premaxilla-internal naris contact. Red ellipses encircle the internal nares, probably too small for respiration.

Figure 6. Anningasaura colorized from an old engraving. No other aquatic taxon has such bizarrely curved teeth. This taxon is closely related to Hauffiosaurus, so it provides insight into the lateral view of Hauffiosaurus.

References
Benson RBJ, Evans M, Druckenmiller PS 2012. Lalueza-Fox, Carles. ed. ”High Diversity, Low Disparity and Small Body Size in Plesiosaurs (Reptilia, Sauropterygia) from the Triassic–Jurassic Boundary”. PLoS ONE 7 (3): e31838. doi:10.1371/journal.pone.0031838
Benson RBJ, et al. (6 co-authors) 2013. A giant pliosaurid skull from the Late Jurassic of England. PLoS ONE 8(5): e65989. doi:10.1371/journal.pone.0065989
Dalla Vecchia FM 2006. A new sauropterygian reptile with plesiosaurian affinity from the Late Triassic of Italy. Rivista Italiana di Paleontologia e Stratigrafia 112 (2): 207–225.
O’Keefe RF 2001. A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia: Sauropterygia). Acta Zoologica Fennica 213:1–63.
Vincent P 2011. A re-examination of Hauffiosaurus zanoni, a pliosauroid from the Toarcian (Early Jurassic) of Germany. Journal of Vertebrate Paleontology 31(2): 340–351.
Vincent P and Benson RBJ 2012. Anningasaura, a basal plesiosaurian (Reptilia, Plesiosauria) from the Lower Jurassic of Lyme Regis, United Kingdom, Journal of Vertebrate Paleontology, 32:5, 1049-1063.

wiki/Anningasaura
wiki/Hauffiosaurus

 

Surprising results in a taxon exclusion test

Sometimes competing cladograms don’t match up.
They employ their own taxon lists, their own character lists and their own scores. Bias is intrinsic and unavoidable in character lists, identifying traits and setting scores. Bias only enters taxon lists whenever pertinent taxa are intentionally or accidentally omitted.

Theoretically every _identical_ taxon list
should recover an identical cladogram, no matter the character list (presuming accurate scoring). Practically that doesn’t often happen.

Previously
we looked at various tests for taxon exclusion here, here and here based on intentionally cutting taxa from the large reptile tree (LRT, 1391 taxa, then 1816 taxa).

Taxon exclusion is the only variable
in the following taxon exclusion tests (Fig. 1: 4 frames, 5 seconds each) because all include the same characters and the same scores:

1. Subset of the LRT without deletion
2. Same subset of the LRT with unused taxa deleted
3. Smaller subset with Reptilia deleted
4. Even smaller subset with Reptilia and Lepospondylia deleted

Differences arise
in these four tree topologies, and that surprised me, at first.

Then I continued testing
and realized (as everyone knows already) every included taxon influences every other included taxon. The surprise is just how far that influence extends.

The software takes it on faith
that the first listed taxon is the basal taxon.

After that the software figures out
the most parsimonious order for the rest of the taxa.

These results show the effect of distant unseen taxa
upon the taxa shown in the ‘subset without deletion’ cladogram.

This is also a good test for weaknesses within any cladogram.
Strongly nested taxa appear not to shift.

So which cladogram is most correct?
The cladogram with the most included taxa recovers the most accurate cladogram. That one is 14 steps shorter than the same cladogram with all unseen taxa deleted.

Wherever weaknesses and topology shifting occurs
look for scoring errors. I’ve been finding them and fixing them for seven years. I’m going to keep looking for scores in basal tetrapods to either cement or correct the above tree topology. As always, the LRT is a work in progress.

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Short notes after adding and reexamining more basal tetrapods:

1. Viséan Silvanerpeton is now the last common ancestor of all reptiles, switching places with Gephyrostegus, which shares more traits with the more primitive Eucritta and Tulerpeton.
2. Originally considered a chroniosuchian, Laosuchus now nests between Eryops and the Cochleosaurus–Nigerpeton clade among basal tetrapods.
3. The presumed cranial spines of Stegops are the obtuse squamosals crushed flat. A new reconstruction now nests Stegops with Ariekanerpeton.
4. Long-limbed Kirktonecta now nests basal to short-limbed Sauropleura and snake-like Acherontiscus and their respective clades.
5. Short-limbed Asaphestera now nests with similar Utaherpeton.

Adding taxa adds insight,
while doing so illuminates errors, many of which have now been corrected.

Carnotaurus joins the LRT

Everyone knows Carnotaurus
(Fig. 1; Bonaparte 1985, Bonaparte, Novas and Coria 1990), the slender theropod with skull horns. In the large reptile tree (LRT, 1391 taxa) Carnotaurus nests with Majungasaurus, members of the first clade of giant theropods, the one that includes Spinosaurus, Allosaurus, Ceratosaurus and many others.

That comes as no surprise.
The only contribution I can make to this popular dinosaur is to note the horns arise from laterally extended lacrimals and prefrontals, not laterally extended frontals, as originally proposed (Fig. 1). In stating this, I may be late to the party. If others have already published on this bit of trivia, I am not aware of it. If so, let me know.

Figure 1. Carnotaurus skull from Bonaparte, Novas and Coria 1990 with colors added. Note the traditional frontals are much reduced here. Here the horns are comprised of the lacrimals + prefrontals in patterns typical of basal theropods.

Carnotaurus sastrei (Bonaparte 1985; Bonaparte, Novas and Coria 1990; Late Cretaceous, 70 mya; 7.5m in length) is an abelisaurid theropod dinosaur related to Majungasaurus. Carnotaurus had a shorter, upturned snout, a shorter mandible, frontal horns, a deeper jugal, a narrower skull (below the horns) and a down-turned naris.

References
Bonaparte JF 1985. A horned Cretaceous carnosaur from Patagonia. National Geographic Research. 1 (1): 149–151.
Bonaparte JF, Novas FE and Coria RA 1990. Carnotaurus sastrei Bonaparte, the horned, lightly built carnosaur from the Middle Cretaceous of Patagonia. Contributions in Science. 416: 1–41. PDF

Pholidocercus: a long tailed armadillo-mimic hedgehog

Updated July 25, 2022
with a new nesting for Pholidocercus close to Leptictis.

According to Wikipedia,
“Pholidocercus is an extinct monotypic genus of mammal from the Messel pit related to and resembling the modern-day hedgehog with a single species, Pholidocercus hassiacus. Like the hedgehog, it was covered in thin spines. Unlike hedgehogs, it had scales on its head in a helmet-like formation, and had a long, thick, scaled tail.”

Here
in the large reptile tree (LRT, 2122 taxa) Pholidocercus (von Koenigswald & Storch 1983, Figs 1, 2) nests with Leptictis (Figs 3, 4), a basal Oligocene placental in the lineage of (some) elephant shrews (=sengis), tenrecs and odontocetes.

Figure 1. Only one of the several Messel Pit Pholidocercus specimens. This one has a truncated tail and a halo of soft tissue (pre-spines).

Pholidocercus hassiacus 
(von Koenigswald & Storch 1983; HLMD Me 7577; Middle Eocene) is an extinct sister to Leptictis. Known from several fossils, Pholidocercus has a long thick tail provided with tall neural spines and deep chevrons. The rostrum is short. Soft tissue is preserved as scales on the head in a helmet-like formation and scales on the tail, a pattern convergent with armadillos.

Figure 3. Leptictis skull. Note the change in premolar identity.

Leptictis acutidens
(Leidy 1868, Rose 2006, early Oligocene) is an extinct elephant shrew nesting between the coatimundi, Nasua, and Rhynchocyon. Anagale is a close relative. All are basal placentals with four molars and three premolars. The tail was probably longer than preserved. The tiny manus appears to have only three digits. Note the large calcaneal heel, a trait usually found in digitigrade running mammals, like Rhynchocyon. This clade is basal to odontocete whales like Orcinus.

Figure 4. Extant Nasua, the extant coatimundi, is basal to Pholidocercus, Leptictis and extant Rhynchocyon, the elephant shrew.

This appears to be a novel hypothesis of interrelationships.
If not, please provide a citation so I can promote it here… and the ‘housekeeping‘ of placentals continues.

References
von Koenigswald W and Storch Gh 1983. Pholidocercus hassiacus, ein Amphilermuride aus dem Eozan der “Grube Messel” bei Darmstadt (Mammalia: Lipotyphla). Senchenberg Lethaia 64:447–459.

wiki/Hedgehogs
wiki/Erinaceus
wiki/Echinops
wiki/Pholidocercus

Mongoose trifles

Herpestes, the Egyptian mongoose, 
 (Linneaus 1758; extant; 48-60cm in length) has large carnassials. Herpestes is a lower, shorter-legged ancestor to the raccoon, Procyon, with a relatively shorter rostrum and longer, lower body. Surprisingly, the postfrontal and postorbital are elongated here.

Figure 1. The Egyptian mongoose, Herpestes, develops a postorbital bar arising from the layered postfrontal and postorbital reappearing in this clade. The lacrimal and prefrontal are separated here.

Eupleres from Madagascar 
(Doyère 1835) is the extant Western falnouc, a cat-like mongoose from Madagascar. Note the elongate premaxilla, the gracile mandible, the reduced canine and other rodent-like traits. No postfrontal or postorbital appears here.

Figure 2. Eupleres is a Madagascar mongoose with a long, tree-shrew-like skull with a longer premaxilla and smaller, more widely-space, primitive teeth. No postfrontal or postorbital appears here.

Despite the differences in these two taxa,
the large reptile tree nests them in the same clade along with Prohesperocyon, the Late Eocene pre-mole, and Talpa the living mole (a member of Carnivora, not Insectivora).

References
Doyére LMF 1835. Notice sur un mammifére de Madagascar, formant le type d’un nouveau genre de la famille des Carnassiers insectivores de M. Cuvier. Ann. Sci. Nat. Zool. 4: 270–283.
Linnaeus C von 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

Vestigial fingers on the UNSM 93000 Nyctosaurus

The UNSM 93000 specimen attributed to Nyctosaurus
has only three wing phalanges and the tiny vestigial free fingers have never been looked at using DGS methods before. Well, here they are (Fig. 1).

Figure 1. Closeup of the UNSM 93000 specimen of Nyctosaurus focusing on three vestige free fingers. This is what happens when you no longer need these fingers. You can tell Nyctosaurus from Pteranodon in that the former never fuses the sesamoid (extensor tendon process) to phalanx 4.1. Other wrongly consider this a trait of immaturity.

Nyctosaurus sp. UNSM 93000 (Brown 1978, 1986) was derived from a sister to Nyctosaurus gracilis and phylogenetically preceded the crested Nyctosaurus specimens. Except for the rostral tip, the skull and cervicals are missing. Distinct from Nyctosaurus gracilis, the dorsals of the Nebraska specimen relatively shorter. The scapula and coracoid were more robust. The deltopectoral crest of the humerus most closely resembled that of Muzquizopteryx. Fingers I-III were tiny vestiges. Manual 4.1 extended to mid ulna when folded. Manual 4.4 was probably fused to m4.3 or it was missing and m4.3 became curved.

Figure 2. The UNSM specimen of Nyctosaurus, the only one for which we are sure it had only three wing phalanges.

The pubis and ischium did not touch, as in more primitive nyctosaurs. It would have been impossible for the forelimb to develop thrust during terrestrial locomotion. It was likely elevated or used like a ski-pole.

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The family tree of the Ornithocephalia and Germanodactylia is here. The expanded family tree of the Pterosauria is here.

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References
Brown GW 1978. Preliminary report on an articulated specimen of Pteranodon Nyctosaurus) gracilis. Proceedings of the Nebraska Academy of Science 88: 39.
Brown GW 1986. Reassessment of Nyctosaurus: new wings for an old pterosaur. Proceedings of the Nebraska Academy of Science 96: 47.

 

Roundtable discussion on YouTube: How to be a scientist

I quote-mined the round table video conversation below.

1. Host Carl Zimmer, author
2. Panelist Mariette DiChristina, editor-in-chief, Scientific American
3. Panelist Dany Spencer Adams, developmental biologist
4. Panelist Ivan Oransky, journalist
5. Panellist Massimo Pigliucci, biologist, philosopher

Video caption:
“As a discipline, science aspires to be an evidence-based, non-partisan tool for revealing truth. But science is carried out by scientists, human beings like the rest of us, subject to pressures, preconceptions, and biases. What are the external, non-scientific forces that impact scientific research? Does the current research structure drive focus away from unbiased exploration? What lessons can we draw from the recent crisis of reproducibility afflicting some research areas? In this program, experts discuss the myriad factors scientists face in a highly competitive environment as they seek to uphold and advance the ideals of scientific exploration.”

According to Massimo Pigliucci:

1. “Write your materials and methods first, then your results, then your introduction last.”
2. “Overcome confirmation bias. What if your result is something that is not predicted?”
3. “There’s no incentive to replicate someone else’s results. You want to be the first one to get there. Not the second one. Most journals, especially the high-impact journals want the novel stuff, the sexy stuff, the stuff that nobody’s done before. [Even so…] Two-thirds of papers in top journals never get cited within five years. 
4. “There are 150 applicants for every paid position.” 
5. Some scientists want to see and approve pre-published stories, to check their quotes. 
6. Blogposts represent the direct voice of the scientist. Historically this has been a problem because you’re wasting your time, andyou’re not including other scientists. 

According to Dany Spencer Adams:

1. “Science is one way of learning things.”
2. “If you’re not failing most of the time, you’re not working hard enough.”
3. “Don’t send anything from a Mac to a PC. Don’t update your software within a week of your deadline. Formatting to a journal’s style takes time. Reformatting from one journal to another (after the first rejection) takes more time.”
4. “Only the top 4 percent of applications receive funding from the NSF.” 

According to Ivan Oransky:

1. “Ask yourself, How can I prove myself wrong?”
2. “If a paper is published and no one cites it, does it really matter? So getting published in high-impact journals is important in Academia.”
3. The number of retractions (from fraudulent data collection or misconduct) has dramatically increased, but remains relatively rare. Current record holder: 183 retractions from a single individual. Falsification, Fabrication and Plagiarism: the Triad. Some authors were caught doing there own peer-review, or each others’ peer-reviews in cooperation. His ‘Doing the Right Thing Award’ is given to those who make corrections at some cost to themselves.”

According to Carl Zimmer:

1. “Much time is spent filling out paperwork to get grants.”
2. “Are journalists part of the problem?” 

According to Mariette DiChristina:

1. “Science tries to embrace corrections.
2. “Materials and methods should produce replicable results.
3. “Many of us are click-bait chasers. Invite the researcher to tell the story of how the results came to be, describe the human endeavor. Provide the context.”

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In the old days:
scientists simply wrote their papers without grants, without referees, without competing for journal pages, without waiting for months or years for all this to take place. There were far fewer scientists working back then, and there was more ‘low-hanging fruit’ waiting to be plucked (= discovered). Then again, new ideas were still ridiculed until confirmed.

Today:
scientists produce blogposts, send unpublished, unrefereeed PDFs to ResearchGate.org and write books. Others publish without referees, competing for grants, dealing with students, dealing with administrators, principal investigators or all of the above. Some scientists making contributions are not PhDs.

Readers should gather by now
that sometimes scientists make mistakes, often by the sin of omission (= taxon exclusion) and due to that, they sometimes come to improper conclusions. This happened in the past and it continues to happen in the present. When I make mistakes I correct them. It’s part of the learning process. If nothing else, I hope that readers will take from this blog the idea that all hypotheses should be questioned and all conclusions should be tested. It’s okay to do this, no matter how many PhDs are listed as co-authors. Tradition can be wrong. Sometimes people will despise you for upsetting favorite traditions. A long list of well-known scientists have been despised for their views, hypotheses and theories.

Don’t wait.
The ‘low-hanging fruit’ is quickly disappearing with every new discovery. This is a golden era in paleontology that will someday dry up as questions are answered and topologies are cemented.

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Side note:
Panelist Mariette DiChristina was the online editor-in-chief at Scientific American where Dr. Darren Naish published his Tetrapod Zoology blogpost for several years. Recently they parted ways and Dr. Naish has reported a new interest in non-tetrapod vertebrates (= fish).

I’d like to see Dr. Naish continue his interest in tetrapods, perhaps to ultimately create a wide gamut cladogram of tetrapods and compare it to the results recovered by the large reptile tree at ReptileEvolution.com, which he continues to disparage. Let’s all hope Dr. Naish is not a subscriber to Massimo Pigliucci’s statement #3 (above). To that point, as everyone knows, in EVERY CASE I am ‘the second one’ to describe a taxon. Even so, and as proven here, there are still a good number of discoveries to be made out there.

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Last minute addition:
Dr. Steve Brusatte how new discoveries are presented in the press.

A basal hupehsuchid with a duckbill: YAGM V 1401

Updated September 30, 2021
with new tracings and nesting the YAGM specimen between Wumengosaurus and the rest of the Ichthyopterygia, basal to hupehsuchids.

Cheng et al. 2019
bring us news of a new armored Early Triassic (250 mya) specimen (YAGM V 1401; Figs. 1,2) they attribute to the armored Early Triassic hupehsuchid, Eretmorhipis carrolldongi (Fig. 5; holotype WGSC V26020; Chen et al. 2015). The holotype specimen lacks a skull. The authors considered the new YAGM specimen, complete with skull, conspecific with the WGSC holotype of Eretmorhipis, noting it had small eyes relative to the body and a duckbill-like rostrum.

Instead
the large reptile tree (LRT, 1389 taxa then 1944 taxa now; Fig. 3) nests the YAGM specimen basal to the clade of hupehsuchids, close to Wumengosaurus.

The eyes are actually large relative to the skull,
in the new YAGM specimen (Fig. 2), but the skull is tiny relative to the body. The rostrum is narrow relative to the cranium. Typically that enables binocular vision. The authors did not provide a reconstruction of the skull.

The wide, flat rostrum of the YAGM specimen has an open central area,
like Ornithorhynchus the duckbill platypus (Fig. 4) by convergence. Given that bit of morphology the authors sought to extend the duckbill analog by reporting small eyes relative to the body in the YAGM specimen. That gives them an irrefutable headline, but a little mis-leading given the reconstruction (Fig. 2). The authors suggest Eretmorhipis used mechanoreceptors in the rostrum instead of eyesight. They report, “Apparent similarities include exceptionally small eyes relative to the body, snout ending with crura with a large internasal space, housing a bone reminiscent of os paradoxum, a mysterious bone of platypus, and external grooves along the crura.” That’s pretty awesome! Larry Martin would have enjoyed this list of convergent traits. I have no idea how the ox paradoxum bone fit in the YAGM specimen skull. So it remains a paradox.

Figure 1. Eretmorhipis in situ and line drawing from Cheng et al. 2019. Colored here using DGS methods. Some bones are reidentified here. See figure 2 for matching colors.

The authors created a chimaera
when they added the hands and feet of the holotype WGSC specimen to the new YAGM specimen in their Nature paper. Since the two specimens are not related, that is going to cause confusion. No matter how sure they were, the authors needed a valid phylogenetic analysis to nest their new specimen, now requiring a new generic and specific name.

Figure 2. Reconstruction of Eretmorhipis skull from figure 1, along with in situ specimen and reconstruction from Cheng et al. 2019. Pectoral and pelvic girdles magnified and colored using DGS methods. The skull appears to provide binocular vision due to the narrow rostrum and wide cranium.

Traditional paleontologists need to catch up to the LRT
and start including thalattosauriforms and mesosaurs whenever they study basal ichthyopterygians, like hupehsuchids. Basal taxa are all closely related and all three taxa include a wide variety of morphotypes, including some that converge.

Figure 4. Ornithorhynchus skull with colors added using DGS methods. Note the large opening in the dorsal view of the rostrum, as in Eretmorhipis, by convergence.

It’s also worth noting
that the YAGM specimen has a cleithrum and a ventrally broad clavicle along with an interclavicle and other traits lacking in hupehsuchids.

Figure 5. The holotype specimen of Eretmorhipis carrolldongi WGSC V26020 compared to scale to the figure drawn form Cheng et al. 2019 for specimen YAGM V 1401. Cheng et al. created a chimaera when they added the WGSC specimen hands and feet to the new YAGM specimen without first nesting them together in a cladogram. These two specimens do not nest together in the LRT despite the massive convergence. Don’t try to eyeball taxa. Let the software take the bias out of it.

A word to workers: Don’t try to ‘eyeball’ taxa.
Let the phylogenetic software take the bias out of making a taxonomic determination. We’ve seen professional workers make this mistake before by combining diphyletic turtles, whales, seals, and by miss-nesting Vancleavea, Lagerpeton, Chilesaurus, Daemonosaurus by taxon exclusion. Let’s not forget those who keep insisting that pterosaurs are archosaurs (virtually all traditional workers), again by omitting pertinent taxa.

Figure 6. Mesosaurus origins recovered by the LRT. The fossil record appears to be topsy turvy here with the basal taxa appearing 30 million years later. Fossils are rare and discovery is rarer. Things like this sometimes happen. The YAGM specimen is large, like Mesosaurus, but later (at 250 mya) than Thadeosaurus.

References
Chen X-H, Motani R, Cheng L, Jiang D-Y and Rieppel O 2015. A new specimen of Carroll’s mystery hupehsuchian from the Lower Triassic of China. PLoS One 10, e0126024, https://doi.org/10.1371/journal.pone.0126024 (2015).
Cheng L, Motani R, Jiang D-Y, Yan C-B, Tintori A and Rieppel O 2019. Early Triassic marine reptile representing the oldest record of unusually small eyes in reptiles indicating non-visual prey detection. Nature Scientific Reports Published online January 24, 2019.

Crocodylomorph study omits a long list of basal taxa

Wilberg, Turner and Brochu 2019
bring us the “evolutionary structure and timing of major habitat shifts in Crocodylomorpha.” 

Unfortunately
Wilberg, Turner and Brochu 2019 omitted a long list of basal bipedal crocodylomorpha (Figs. 1, 2), and considered an ingroup, Gracilisuchus, an outgroup. They also considered the unrelated giant rauisuchid, Postosuchus, an outgroup taxon.

Missing from the Wilberg, Turner and Brochu study
are a number of basal Crocodylomorph taxa and their outgroups, as determined by a wide gamut analysis of reptiles (= the large reptile tree = LRT; subset Fig. 1).

Ingroup Crocodylomorpha in the LRT
omitted by Wilberg, Turner and Brochu include: YPM VP 057 103, Pseudhesperosuchus, Carnufex, Trialestes, Lewisuchus, MCZ 4116, Saltopus, Scleromochlus, SMNS 12591, Terrestrisuchus, Tarjadia, Parringtonia, Litargosuchus, Erpetosuchus, SMNS 12352, Pedeticosaurus, Yonghesuchus, Dromicosuchus, Saltoposuchus and Dyoplax.

Outgroups to the clade Crocodylomorpha in the LRT omitted by Wilberg, Turner and Brochu include: Herrerasaurus + Staurikosaurus (at the base of the Dinosauria), PVL 4597 (at the base of the Archosauria = Crocodylomorpha + Dinosauria), Turfanosuchus (proximal outgroup to Archosauria), Decuriasuchus + Pagosvenator (second proximal outgroup to Archosauria).

Figure 2. Subset of the LRT focusing on Crocodylomorpha.

Figure 1. Subset of the LRT focusing on the Crocodylomorpha, dorsal scutes, elongate proximal carpals, bipedality and clades.

Simply adding taxa
solves all these problems and documents a more gradual accumulation of derived traits and major habitat shifts.

Figure 2. Ten basal bipedal crocodylomorphs descending from a sister to Decuriasuchus.

References
Wilberg EW, Turner AH and Brochu CA 2019. Evolutionary structure and timing of major habitat shifts in Crocodylomorpha. Nature.com/scientificreports DOI:10.1038/s41598-018-36795-1

wiki/Crocodylomorpha