Lisowicia: Already superlative, so no need to further exaggerate

A new 4.5 meter long Late Triassic dicynodont has been reported.
Lisowicia bojani
(Sulej and Niedzwiedzki 2018, Late Triassic; Fig. 1) is by far the largest dicynodont now known, greatly superseding the previous record holder, Stahleckeria (von Huene 1935; Fig. 1). That’s fantastic all by itself. So why would a world-famous paleontologist and the Smithsonian website further exaggerate this discovery?

Figure 1. Lisowicia compared to extant elephants and the previous largest dicynodont, Stahleckeria.

Figure 1. Lisowicia compared to extant elephants and the previous largest dicynodont, Stahleckeria, not itself a ‘small and unseen’ taxon, but forgotten or omitted in the present storyline. The young lady in the pink tie-dye shirt is five feet tall.

Online Smithsonian Magazine headlines the story:
“Early Mammals Were Thought to Be Small and Unseen in the Age of Dinosaurs. An Elephant-Sized Fossil Complicates That Story — At a time when proto-mammals and other creatures were getting smaller, this dicynodont bulked up with the thunder lizards”

Lisowicia is indeed elephant-sized,
in length, but not height. Lisowicia had shorter legs, like another dicynodont, bear-sized Stahleckeria (Fig. 1). So… while the early and proto-mammals were indeed small, other  ‘creatures’ were also ‘bulking up‘ in the Late Triassic, including dicynodonts, rauisuchians, erythrosuchians, poposaurs, protorosaurs, phytosaurs and proterochampsids, to name only the terrestrial tetrapods. Even in this company, Lisowicia is still extraordinary in size. On the other hand, and let’s be honest about this… in the Late Triassic Age of Dinosaurs, sauropodomorphs were really the only dinosaurs to also bulk up. The rest remained about human-sized or smaller.

Be careful not to create mythology
when discussing dinosaurs. Keep it real.

Author and paleontologist Dr. Stephen Brusatte
(U. of Edinborough) chimed in with this paragraph of inappropriate surprise and hyperbole: “Before these giant bones were discovered, you would have been called crazy if you ever suggested there were giant, elephant-sized mammal cousins living alongside some of the very first dinosaurs,” he says. “We used to think that after the end-Permian extinction [252 million years ago], when some 90-95 percent of all species went extinct, mammals and their relatives retreated to the shadows while dinosaurs rose up and grew to enormous sizes. That’s the story I tell my students in my lectures. But this new discovery throws a wrench into that simple tale.” 

We “used to think” nothing of the sort! 
If you are a student of Dr. Brusatte, find another professor! Dr. Brusatte has been on the wrong end of many paleo hypotheses. Use keyword “Brusatte” in the little white search box above for details on several past subjects ranging from dinosaur origins to footprint identification to multituberculates.

Brusatte also said in ScienceMag.org, “‘Who would have ever thought that there were giant, elephant-sized mammal cousins living alongside some of the very first dinosaurs?’marvels Stephen Brusatte, a vertebrate paleontologist at The University of Edinburgh.” 

Seems Dr. Brusatte is forgetting about Stahleckeria,
the previous record-holder for largest dicynodont at 3.3 meters in length. A taxon that size is definitely not “relatively in the shadows.” If you’re going to speak to the press, don’t omit pertinent details.

Lisowicia is already unique and spectacular
at twice the height of Stahleckeria. So there is no need to exaggerate the truth or reduce the size of comparables in order to make Lisowicia appear even more unique and spectacular. A comparative graphic like the one above would have made the point without the verbal hyperbole, omission and overkill.

Are dicynodonts really mammal cousins?
In the large reptile tree (LRT, 1337 taxa) dicynodonts and other herbivorous basal synapsids (Anomodontia) split from the carnivorous synapsids that led to mammals immediately following the pelycosaurs. So that’s one node. Basal anomodonts are separated from basal mammals by 12 nodes and then add 5 more nodes to get to Lisowicia nesting as a very derived anomodont.  So an inappropriate comparison to basal mammals is likewise stretching science journalism to an uncalled-for degree. If you want to educate the public, educate the public.

Lisowicia deserves some grand-standing.
Let’s just try to keep it real.

References
Sulej T; Niedźwiedzki G 2018. An elephant-sized Late Triassic synapsid with erect limbs. Science: eaal4853. doi:10.1126/science.aal4853
v. Huene F 1935. Lieferung 1. Anomodontia [Part 1. Anomodontia]. Die Fossilen Reptilien des Südamerikanischen Gondwanalandes. Ergebnisse der Sauriergrabungen in Südbrasilien 1928/29 [The Fossil Reptiles of South American Gondwanaland. Results of the Dinosaur Expeditions in southern Brazil 1928/29]. C. H. Beck’sche Verlagsbuchhandlung, München 1-82

https://en.wikipedia.org/wiki/Lisowicia
smithsonianmag.com/smart-news/elephant-size-mammal-cousin-mingled-dinosaurs
https://en.wikipedia.org/wiki/Stahleckeria

Three metatherian cladograms compared

If you’re interested in dueling cladograms
today you’ll see how two other cladograms (Figs. 1, 2) compete with the large reptile tree (LRT, subset Fig. 3, 1337 taxa) focusing on Metatheria/Marsupialia.

Figure 2. Marsupial cladogram based on Horovitz and xx 2006. Very few fossil taxa are present here.

Figure 1. Marsupial cladogram based on Horovitz and xx 2006. Very few fossil taxa are present here.

Horovitz and Sánchez-Villagra 2003
(Fig. 1) used a trait analysis of mostly extant taxa to create their cladogram. Many prototherian and metatherian fossil taxa are missing here compared to the LRT (Fig. 3) where wombats and kangaroos have separate origins (Dasyurus is a last common ancestor), contra Horovitz and Sánchez-Villagra. And where is Sarcophilus (the Tasmanian devil)?

Figure 2. Marsupialiformes by Williamson et al. 2014 focusing on Cretaceous and Paleogene forms. Most of these are teeth and jaws only. By contrast the LRT includes many extant and recently extinct taxa known from skeletons.

Figure 2. Marsupialiformes by Williamson et al. 2014 focusing on Cretaceous and Paleogene forms. Most of these are teeth and jaws only. By contrast the LRT includes many extant and recently extinct taxa known from skeletons.

Williamson et al. 2014
(Fig. 2) also lack a large number of fossil taxa and appear to avoid extant taxa compared to the LRT (Fig. 3). And where is Ernanodon (the Palaeocene Tasmanian devil)?

Figure 1. Subset of the LRT focusing on basal Mammalia after the addition of several marsupials.

Figure 3. Subset of the LRT focusing on basal Mammalia. Both fossil and extant taxa are included here.

Reconstructions
(Fig. 4) help confirm that a list of sister taxa in a cladogram really do look like they are related to one another and demonstrate a gradual accumulation of traits (in lieu of laboriously examining all the data scores and confirming their validity with a worldwide trip to visit all the fossils firsthand).

Figure 3. A selection of Therian skulls leading to placentals. This is the 'gradual accumulation of traits' recovered by the LRT.

Figure 4. From yesterday’s post, a selection of Therian skulls leading to placentals. This is the ‘gradual accumulation of traits’ recovered by the LRT. 

A few words of wisdom from Neil deGrasse Tyson
“Cognitive bias is all the ways we fool ourselves. Science. The only point of the scientific method is to make sure you are not fooled into thinking that something is true that is not, or thinking that something is not true that is… that is the only point.”

To that end:
Adding taxa to the LRT tests and strains the data within that creates the cladograms presented here (Fig. 3). Errors are exposed and corrections are made. Today, the LRT cladogram remains highly resolved. That pretty much invalidates past criticisms. Today’s criticisms of those who think they are following the scientific method (Figs. 1, 2) are meant to get these authors to add relevant taxa, consider other candidates and options, re-examine their recovered trees, so that when they think something is true it will pass all tests and achieve confirmation and consensus that it is true… until the next study comes along to challenge it.

References
Horovitz I and Sánchez-Villagra MR 2003. A morphological analysis of marsupial mammal higher-level phylogenetic relationships. Cladistics 19: 181–112. doi: 10.1111/j.1096-0031.2003.tb00363.x  PDF
Williamson TE and Brusatte SL and Wilson GP 2014. The origin and early evolution of metatherian mammals: the Cretaceous record. Zookeys. 2014; (465): 1–76.
Published online 2014 Dec 17. doi: [10.3897/zookeys.465.8178]
PMCID: PMC4284630 PMID: 25589872

Really, aren’t we ALL didelphids?

There has been a traditional disconnect
in mammalian paleontology regarding the two transitions between the egg-laying Prototheria, the pouched Metatheria,  and the pouch-less Eutheria. So far as I can tell, only the large reptile tree (LRT, 1334 taxa; Fig. 2) has documented how and which species form transitional links in this chain of mammal evolution (Fig. 1). At present, and for the foreseeable future, didelphids, like Didelphis (the Virginia opossum), Monodelphis (the gray short-tailed opossum) and Caluromys (the wooly opossum) occupy basal nodes at large radiations of metatherians and eutherians in the LRT…hence the title of this post.

Figure 3. A selection of Therian skulls leading to placentals. This is the 'gradual accumulation of traits' recovered by the LRT.

Figure 1. A selection of basal mammal skulls leading to placentals. This is the ‘gradual accumulation of traits’ recovered by the LRT. A third of these are traditional didelphids. Or two-thirds of these are cladistic didelphids. And, if so, then we humans are also didelphids. Haplodectes (IVPP V5235) nests as the basal primate in the LRT.

Traditionally
Didelphidae has been a clade restricted to the opossums without any insight to their eventual descendants… the rest of the marsupials and us placentals. That’s why several mousy and not-so-mousy ‘possums have been added to the LRT recently, to more precisely recover evolutionary patterns in deep time. Amazing that our more or less direct ancestors are still with us today, sometimes hidden in Amazon forests, other times raiding our backyard trashcans and tentatively crossing our highways and byways.

Figure 1. Subset of the LRT focusing on basal Mammalia after the addition of several marsupials.

Figure 1. Subset of the LRT focusing on basal Mammalia after the addition of several marsupials. Red taxa are represented by only a few bones, like mandibles with teeth. Note the proximity of traditional creodonts to the basal placental clade, Carnivora, basal members of which are small, arboreal and opossum-like.

A new taxon in the LRT is Thylophorops
considered by Goin et al. 2009 to be the largest didelphid. Unfortunately, in the LRT, Thylophorops does not nest with Didelphis, but with Oxyaena and Thylacinus (Fig. 2)… themselves descendants of Didelphis with cat-like and wolf-like traits respectively.

Wikipedia reports,
Thylophorops species (as well as several other contemporary opossum genera) show a high degree of speciation towards carnivory compared to the still living didelphines. Their premolar and molar teeth were proportionally larger than those of living opossums and their grinding facets imply a more dedicated shearing action; these have been interpreted as “omnivory leading towards carnivory” in Goin et al. 2009.”

Figure 1. Crowned as the largest didelphid (by not much actually) Thylophorops nests between leopard-like Oxyaena and wolf-like Thylacinus in the LRT.

Figure 3. Crowned as the largest didelphid (by not much actually, but it is a juvenile) Thylophorops lorenzini nests between leopard-like Oxyaena and wolf-like Thylacinus in the LRT. All are shown to scale here.

Unfortunately
there is no reference in Goin et al. to either Oxyaena or Thylacinus. So… taxon exclusion is still an issue with the Goin et al. taxon list. Such problems are largely resolved in the LRT, which tests all possible candidates, and even dozens of fringe candidates that no one else considers, recovering a fully resolved tree based on traits and taxa that extend back to Devonian tetrapods, ultimately relating all descendants to one another.

References
Ameghino F 1908. Las formaciones sedimentarias de la región litoral de Mar del Plata y Chapadmalal part 2
Goin  FJ, Zimicz N, de los Reyes M, Soibelzon L 2009. A new large didelphid of the genus Thylophorops (Mammalia: Didelphimorphia: Didelphidae), from the late Tertiary of the Pampean Region (Argentina). Zootaxa. 2005: 35–46.

wiki/Thylophorops

 

The Tasmanian devil (genus: Sarcophilus) joins the LRT

Maybe best known
from old Warner Brothers cartoons, (Fig. 1), the Tasmanian devil (Sarcophilus harrisii; Boitard 1841; up to 65 cm long) has long been considered the largest living and most carnivorous member of the Dasyuridae (typically insectivorous mouse-to-dog-sized marsupials, but see below). 

Figure 1. The Warner Brothers version of the Tasmanian devil, affectionately called 'Taz' is known to eat a long list of animals...especially rabbits!

Figure 1. The Warner Brothers version of the Tasmanian devil, affectionately called ‘Taz’ is known to eat a long list of animals…especially rabbits!

Typically
a Tasmanian devil will consume about 15% of body weight in food each day. It also makes ‘unearthly screams, coughs and growls’. The dog-like animal has red ears, wide jaws and big sharp teeth that it likes to display. It can sit on its haunches, like a raccoon. Seems to have been the wolverine from down under. No wonder Warner Brothers made such a gluttonous cartoon character! Here’s a 3:12 minute NatGeo special on the Tasmanian devil.

Sarcophilus laniarius ((originally Didelphis ursina Harris 1807) Owen 1839) is the extant Tasmanian devil, traditionally considered the largest dasyurid. Following the extinction of the taller, wolf-like Thylacinus in 1936 Sarcophilus became the largest living carnivorous marsupial.

Figure 2. Tasmanian devil (Sarcophelis) skeleton.

Figure 2. Tasmanian devil (Sarcophilus) skeleton.

According to the Australian Parks and Wildlife webpage
(below) “The famous gape or yawn of the Tasmanian devil that looks so threatening, can be misleading. This display is performed more from fear and uncertainty than from aggression.” 

Figure 3. Sacrophilus skull from Digimorph.org and used with permission. Colors added.

Figure 3. Sacrophilus skull from Digimorph.org and used with permission. Colors added.

Goodbye Marsupialiformes!
In their study of Didelphodon, Wilson et al. 2016 employed the clade Marsupialiformes (Vullo and Gheerbrant 2009) for taxa not included within Marsupialia (living metatheres) and Metatheria. One of the problems with the Wilson et al. taxon list was… taxon exclusion. No placentals were included. The large reptile tree (LRT, 1134 taxa) documents the need for adding placentals and fossil taxa because placentals diverged from arboreal carnivorous metatheres, like Caluromys in the LRT, as we learned earlier here. The opossum, Didelphis, nests as a derived marsupial in Wilson et al. It nests as a basal metathere in the LRT.

Here’s another Tasmanian Devil YouTube video:

Link to further details and sound file from the Australian Parks and Wildlife webpage.

Over the holidays
I have been busily adding taxa to the LRT, mostly small, mouse-like opossums, in order to iron out the phylogenetic issues that arose there. The corrections are solving problems that we will review over the next few days. Today, I can tell you that the Tasmanian devil (genus: Sarcophilus) nests between the smaller extant quoll (genus: Dasyurusno surprise there) and the devil-sized, formerly enigmatic Palaeocene Ernanodon (Fig. 4). If I am not mistaken, Sarcophilus and Ernanodon have never been tested together until now. This pushes the origin of pugnacious little Sarcophilus back to the K-T boundary, and possibly much deeper in time and not restricted to Tasmania or Australia where Sarcophilus fossils have been found that are less than 100,000 years old.

Molecular evidence
suggests devils split from quolls between 10 and 15 million years ago (Krajewski and Westerman 2003).

Figure 4. Now nesting more precisely and closely with Sarcophilus, the extant Tasmanian devil, is Ernanodon from the Palaeocene of China.

Figure 4. Now nesting more precisely and closely with Sarcophilus is Ernanodon from the Palaeocene of China. This enigma taxon was traditionally linked to anteaters, then pangolins. Perhaps Sarcophilus and Ernanodon have never been tested together until now. Note the difference in the feet between the museum mount and the drawing inserts. The inserts look more like those of sister taxa. Repairing such problems is what has to be done to create a high resolution cladogram.

References
Boitard P 1842. L’Ursin de Harris. Le Jardin des plantes: Description et mœurs des mammifères de la Ménagerie et du Muséum d’histoire naturelle. Paris: Gustave Barba. p. 204.
Harris GP 1807. Description of two new Species of Didelphis from Van Diemen’s Land. Transactions of the Linnean Society of London. 9: 174–78.
Krajewski C and Westerman M 2003. Molecular Systematics of Dasyuromorpha. In Jones, Menna; Dickman, Chris; Archer, Mike. Predators with Pouches: The Biology of Carnivorous Marsupials. Collingwood, Victoria: CSIRO Publishing. p. 16.
Vullo R and Gheerbrant E 2009. The oldest modern therian mammal from Europe and its bearing on stem marsupial paleobiogeography. Proceedings of the National Academy of Sciences 106(47):19910-19915.
Wilson GP, Eddale EG, Hoganson JW, Calede JJ and Vander Linden A 2016. A large carnivorous mammal from the Late Cretaceous and the North American origin of marsupials. Nature Communications 7:13734  PDF

wiki/Tasmanian_devil

According to Wikipedia
“Marsupialiformes
[􏰂 Marsupialia sensu Kielan- Jaworoswka et al.] is erected to account for the crown group Marsupialia (extant marsupials and related extinct fossil taxa) plus all stem marsupialiform taxa that are more closely related to them, as their sister taxa, than to Deltatheroida and basal Metatheria. Basal marsupialiforms, such as the North American taxa from the Early/Late Cretaceous, include the stem groups of the crown marsupials. Basal marsupialiforms include primitive Cretaceous taxa previously gathered in the paraphyletic taxon ‘‘Ameridelphia’’.

Metatheria includes Marsupialiformes and Deltatheroida (presumed sister groups), plus basal metatherians, such as Sinodelphys. Unfortunately Sinodelphys nests with the basal prototherian Megazostrodon in the LRT, so that raises a red flag.

Dr J Gauthier lecture video on birds + dinos

If you watch this…
Stay for the brilliant question and answer period at the end.

And…
returning to an earlier subject…
Geologist Randall Carlson reports on Joe Rogan Experience #606 (1:35:44) —  “See, here’s the thing. Modern science does tend to get over specialized. And so what happens is, they guy looking at extinctions might not be looking at glacial melting. The guy looking at glacial melting… the geologist is not looking at what’s going on in the sky. They’re not looking at traditions, you know, traditions from thousands of years ago. What it does is, because of the powerful of this specialization, this specialization is extremely powerful, but the thing of it is… it’s easy to miss the big picture. What that does is, it opens the door for generalists, guys who are just, people who are just, men or women, anybody who is curious about this stuff, look into it and try to see the big picture.”

In other words…
taxon exclusion problems can be solved by a wide gamut analysis of the entire range of tetrapods now known.

Joe Rogan says (1:37:46),
“People love to be able to dismiss anything that’s not mainstream, right?” To which Randall Carlson replies, “Because there’s this cult of authority.” Randall Carlson continues (1:38:40) “They’ve got this idea in their mind that there’s this authority that’s got it all explained, which makes it easy, because if somebody’s got this all explained, then we don’t need to concern ourselves with it or think about it. Right? So, what I see is, ‘Okay… forget about who says what. Look at the facts. Let the facts dictate to us what the meaning of all this is. And let’s look at all points of view.” 

The idea that a meteor impact ended the last Ice Age,
and killed the northern megafauna first proposed by Randall Carlson and others gained new hard evidence with the recent discovery of a Paris-sized crater on the north rim of Greenland. Details and videos here: https://earthsky.org/earth/meteorite-crater-under-greenland-ice

Cau 2018: Evolution of the avian body plan – part 4

We looked at Cau 2018
from a different 3-part perspective earlier here, here and here.

Dr. Andrea Cau 2018 recovers a cladogram of the Theropoda
(Figs. 1-4) focusing on the ultimate appearance of extant birds, represented by Meleagris, the extant turkey (Fig. 4). Many errors accrue in Cau 2018 due to simple taxon exclusion, as you’ll see below. Many clades are not valid when tested in the LRT.

Figure 1. The base of the Cau 2018 cladogram. White boxes are clades that agree with the LRT. Light blue taxa are members of the Phytodinosauria. Yellow taxa are theropods. Red lines indicate invalidated clades. Continues on figure 2.

Figure 1. The base of the Cau 2018 cladogram. White boxes are clades that agree with the LRT. Light blue taxa are members of the Phytodinosauria. Yellow taxa are theropods. Red lines indicate invalidated clades. In the LRT bipedal Crocodylomorpha and Poposauria are successively more distant outgroups to the Dinosauria. Sacisaurus, Silesaurus and Asilisaurus are poposaurs in the LRT. Dromomeron and Lagerpeton are chanaresuchids.  Continues on figure 2.

First of all,
Cau 2018 uses the wrong outgroup taxa (taxon exclusion). In the large reptile tree (LRT, 1327 taxa), which tests all of Cau’s outgroup taxa, the outgroup for the Dinosauria is Crocodylomorpha, specifically the basal bipedal crocs,  represented by one taxon in Cau 2018, Lewisuchus. Only in the LRT does Archosauria include just Crocodylomorpha and Dinosauria.

Invalidated clades:

  1. Pan-Aves – all animals more closely related to birds than to crocodiles (traditionally = Avemetatarsalia) includes pterosaurs, so this clade is a junior synonym for Reptilia. In the LRT, Pan-Aves is a junior synonym for Dinosauria.
  2. Dinosauromorpha – the last common ancestor (LCA) of Lagerpeton, Marasuchus, Pseudolagosuchus and the Dinosauria. In the LRT this is a junior synonym for Archosauriformes –
  3. Dinosauriformes – Originally: Herrerasaurus + Dinosauria. Currently Marasuchus, Silesauridae and the Dinosauria. Silesaurus is a poposaur, nesting outside the Archosauria. So this is an awkward name that includes Poposauria + Crocodylomorpha + Dinosauria in the LRT.
  4. Dracohors – Practically: Silesauridae and the Dinosauria. Definition: “Most inclusivemost inclusive clade containing Megalosaurus, but excluding Marasuchus“(Cau 2018). Same issues arise as in Dinosauriformes. Cau did not include basal bipedal crocs (Fig. 1), which clarify basal dinosaur origins and relations in the LRT.

Also unfortunately Cau 2018 excluded several basal theropods.
Segisaurus and Procompsognathus were not included. These taxa attract the traditional stem-dinosaurs Marasuchus and Guaiabasaurus to this clade. Zuolong nests as a relative to the phytodinosaur, Chilesaurus in the Cau cladogram because the LRT sisters to the basal ornithischian, Chilesaurus, were not included. Adding basal phytodinosaurs shifts Chilesaurus out of the Theropoda and shifts Zuolong to the base of the Marasuchus clade. Pisanosaurus and Daemonosaurus also nest within the Ornithischia in the LRT with taxon inclusion.

Figure 2. From Cau 2018, focusing on basal Theropoda. Taxa also present in the LRT are boxed in white.

Figure 2. From Cau 2018, focusing on basal Theropoda. Taxa also present in the LRT are boxed in white. In the LRT Limusaurus nests with oviraptorids. Masiakasaurus nests in the Tyrannosaurus clade. Coelophysis and Dilophosaurus nest together.  Continues on figure 3.

At the next stage in the Cau 2018 cladogram
(Fig. 2) and in the LRT, Dilophosaurus and Coelophysis nest as basal theropods. Where they differ, Sinocalliopteryx nests at the base of this clade in the LRT, but as the outgroup to the Tyrannoraptora in Cau 2018 (Fig. 3).

Invalidated clades:

  1. Averostra – CeratosaurusAllosaurus , their last common ancestor and all its descendants (Ezcurra and Cuny 2007) is not in the lineage of birds in the LRT. 
  2. Tetanurae – All theropods more closely related to modern birds than to Ceratosaurus. This is a junior synonym of Compsognathidae Cope, 1871 in the LRT. The traditional compsognathids, Sinocalliopteryx, Scipionyx and two Compsognathus taxa nest at basal leaves of several basal theropod clades in the LRT.
Figure 3. Tetanurae. Continues on figure 4.

Figure 3. Tetanurae. Continues on figure 4.

At the next stage
(Fig. 3) Cau nests Sinocalliopteryx with the large Compsognathus. By contrast, the LRT nests Sinocalliopteryx basal to Dracoraptor, Zupaysaurus and Megapnosaurus (taxa excluded by Cau) on one branch, Scipionyx (also omitted by Cau) + Ceratorsauria on the other. To shift Sinocalliopteryx to the large Compsognathus adds 24 steps to the MPT.

Validated clades:

  1. Coelurosauria – theropods more closely related to birds than to carnosaurs, includes Aorun, compsognathidstyrannosaursornithomimosaurs, and maniraptorans. The LRT also recovers this clade.

Invalidated clades:

  1. Tetanurae – (defined as: theropods more closely related to modern birds than to Ceratosaurus). Cau 2018 wrongly includes the basal ornithischian, Chilesaurus at the base of this clade. Cau 2018 also includes Allosaurus and Eustrespondylus in this clade. These nest with Ceratosaurus in the LRT. In any case, as defined, this is a junior synonym of Coelurosauria.
  2. Neotetanurae – defined as: containing Allosauroidea and Coelurosauria, and excluding other tetanurans such as megalosauroids, Same problem as Tetanurae.
  3. Tyrannoraptora – includes tyrannosaursornithomimosaurs, and maniraptorans. In the LRT compsognathids nest at the bases of all these taxa, so this nominal clade is polyphyletic without compsognathids.
Figure 3. Theropods in the lineage of birds modified from Cau 2018.

Figure 4. Theropods in the lineage of birds modified from Cau 2018. Continues on figure 5.

At the next stage
(Fig. 4) Cau 2018 xxx

Validated clades:

  1. Averaptora – Paraves sans Troodontidae + Dromaeosauridae (Cau 2018). The LRT validates this clade (Xiaotingia + Anchiornis + birds)

Invalidated clades:

  1. ManiraptoriformesOrnithomimus + birds, LCA and all descendants (Holtz 1995). In the LRT this clade is a junior synonym for Compsognathidae.
  2. Maniraptora – Sans Ornithomimosauria, this clade is also a junior synonym.
  3. Pennaraptora – The LCA of OviraptorDeinonychus and Passer and all descendants. In the LRT this clade is a junior synonym for Compsognathidae.
  4. Paraves – All theropods more closely related to birds than to oviraptorosaurs. Traditionally this includes Scansoriopterygidae at a basal node. In the LRT the LCA  is Mirischia and more complete Ornitholestes. Scansoriopterygidae nests within Aves in the LRT when all the Solnhofen birds are included in the taxon list. Only one, Archaeopteryx, is included in Cau 2018.
  5. Avialae – Theropods closer to birds than to deinonychosaurs. In Cau 2018 this deletes three scansoriopterygid birds and Xiaotingia. In the LRT Xiaotingia, Ostromia and Eosinopteryx are the proximal outgroup clade to birds.
  6. Pygostylia – intended to encompass all avialans with a short, stubby tail (Chatterjee 1997), but this is a trait that appears several times by convergence. Late defined as the LCA of Confuciusornis + Neornithes. Both are descendants of Archaeopteryx (Wellnhoferia) grandis, which has a long tail and lacks a pygostyle. This confusion in Cau 2018 (and all other bird workers) comes from the traditional exclusion of other Solnhofen birds from analysis. This is where all Cretaceous bird clades had their radiation documented.
Figure 5. Bird subset from Cau 2018.

Figure 5. Bird subset from Cau 2018.

In the final subset of the Cau 2018 cladogram
(Fig. 5) several of the toothed euornithes are wrongly separated from the other toothed Cretaceous birds in figure 4. Patagopteryx nests with missing Struthio in the LRT. Once again, taxon exclusion is the reason for problems in the Cau study. 

Validated clades:

  1. Aves – extant birds (includes Cretaceous toothed birds in the LRT)

Invalidated clades:

  1. Ornithothoraces – (= Enantiornithes + Euornithes) in the LRT these two clades comprise the first split within Aves and both include a specimen of Archaeopteryx at the base. So this is a junior synonym of Aves.
  2. Ornithuromorpha – (= Euornithes, or the most recent common ancestor of all avialans closer to modern birds than to Sinornis.) Since Sinornis is an enantiornithine, this is also a junior synonym of Aves.
  3. Carinatae – (= all birds and their extinct relatives to possess a keel, or “carina”, on the underside of the breastbone used to anchor large flight muscles.) Alternatively, as in Cau 2018, Ichthyornis + extant birds. In the LRT Ichthyornis nests within extant birds.
  4. Ornithurae – (the LCA of Ichthyornis, Hesperornis and extant birds) In the LRT Ichthyornis and Hesperornis and related Cretaceous toothed birds nest within the clade of extant birds.
Figure 1. More taxa, updated tree, new clade names.

Figure 6. Subset of the LRT focusing on theropod dinosaurs.

Phylogenetic analysis
is indeed key to understanding the assembly of the avian body plan. Taxon inclusion is key to any phylogenetic analysis. Unfortunately for Cau 2018, so many taxa were excluded that Cau recovers a less than optimal origin for the Dinosauria, Theropoda and Aves, along with a series of false positive clades, as explained above.

References
Cau A 2018. The assembly of the avian body plan: a 160-million-year long process. Bollettino della Società Paleontologica Italiana, 57 (1), 2018, 1-25. Modena

A small, bipedal Macrocnemus: PIMUZ T4823

It’s a bipedal, but folded specimen
with a skull and neck resting against its own spine (like Langobardisaurus).

The PMUZ T4823 specimen
of Macrocnemus (Peyer 1937; Figs. 1, 2) had such short forelimbs that it foreshadowed one of its more famous fully bipedal relatives, Sharovipteryx (Fig. 3). I even wondered if they were somehow sisters, but the LRT said, ‘no’, they were only convergent.

Figure 1. 'Macrocnemus' specimen PIMUZ T4832 in situ. Having the skull and neck bent back against the spine makes this a good problem for DGS to attempt.

Figure 1. ‘Macrocnemus’ specimen PIMUZ T4832 in situ. Having the skull and neck bent back against the spine makes this a good problem for DGS to attempt. Even colorized, this specimen still needs to be unfolded to make proper sense of its morphology and proportions. Photo from Saller 2016.

This specimen is hard to figure out
without unfolding that long neck (Fig. 2). When that happens, using DGS methods, the T4823 specimen starts to make sense. If you’re like me, sometimes the brain just needs to see things in vivo, not as if it was tucked into an eggshell.

Figure 2. 'Macrocnemus' specimen PIMUZ T4832 lifted from the in situ figure 1 at right, and unfolded at left. Not everything is guaranteed correct here, but it's pretty close. At 72 dpi screen resolution, this image is full scale.

Figure 2. ‘Macrocnemus’ specimen PIMUZ T4832 lifted from the in situ figure 1 at right, and unfolded at left. The skull is shown in situ and reconstructed. Not everything is guaranteed correct here,  The lower pelvis is a big guess because the elements may be tucked under the sacrum. At 72 dpi screen resolution, this image is full scale.

The anterior dorsal ribs of the T4832 specimen were also extra long,
perhaps creating a wide, aerodynamic, pancake-like torso, again, as in Sharovipteryx (Fig. 3) or Draco.

Note the five sacrals that helped support this sprawling lepidosaur (according to the LRT) while bipedal.

The pectoral girdle is tiny with small, disc-like coracoids. Thus, the T4832 specimen was not flapping, like Sharovipteryx (Fig. 3).

There was a soft tissue rostral crest. Soft tissue is impressed everywhere else, too.

Like Sharovipteryx, a pair of large hyoids extend neck skin, creating an aerodynamic strake or throat sac.

That is a very slender set of cervicals for such a large skull. Perhaps most of the bone was preserved below the surface. Remember, this is a cast of the destroyed original. In any case, this was a gracile specimen. If like all other Macrocnemus specimens, it had hollow bones, too.

Figure 2. Cosesaurus was experimenting with a bipedal configuration according to matching Rotodactylus tracks and a coracoid shape similar to those of flapping tetrapods. Long-legged Sharovipteryx was fully committed to a bipedal configuration.

Figure 3. Cosesaurus was experimenting with a bipedal configuration according to matching Rotodactylus tracks and a coracoid shape similar to those of flapping tetrapods. Long-legged Sharovipteryx was fully committed to a bipedal configuration.

This is not the first time
someone has suggested that Macrocnemus was facultatively bipedal. Nopcsa 1931 and Rieppel 1989 thought so, too.

This is not the first time
that a member of the Macrocnemus family became bipedal (Fig. 3). Actually most of the descendants of Macrocnemus were bipedal, whether on land or in the water.

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.

Saller writes (translated by Google form Italian):
PIMUZ T4823: cast of the holotype, originally kept at the Civic Museum of Natural History of Milan (Museum Civico de Storia Naturale in Milano) was destroyed during the Second World War. Exemplary in a bad state of  conservation, described by Peyer (Peyer, 1937). Includes skull, neck, trunk, parts of the limbs and the front portion of the tail.”

Rieppel (1989) writes: 
T2473: Specimen “Besano III” (Peyer, 1937). The specimen was collected in the “Sciti bituminous” of Besano and turned over to the Museum Civico de Storia Naturale in Milano after its description by Peyer (1937),, where it was destroyed during World War II. A cast of the specimen is preserved in Zurich. The specimen is fragmentary, but includes a well-preserved hind limb.”

A renumbered specimen?
Rieppel (1989) makes no mention of PIMUZ T 4822, T4823, T4833 or T4834, but his description of the well-known specimen, A III/208. is listed first and matches this description, so it is likely renumbered in Saller 2016,

References
Li C, Zhao L-J and Wang L-T 2007A new species of Macrocnemus (Reptilia: Protorosauria) from the Middle Triassic of southwestern China and its palaeogeographical implication. Science in China D, Earth Sciences 50(11)1601-1605.
Nopcsa F 1931. Macrocnemus nicht Macrochemus. Centralblatt fur Mineralogie. Geologic und Palaeontologie; Stuttgart. 1931 Abt B 655–656.
Peyer B 1937. Die Triasfauna der Tessiner Kalkalpen XII. Macrocnemus bassanii Nopcsa. Abhandlung der Schweizerische Palaontologische Geologischen Gesellschaft pp. 1-140.
Renesto S and Avanzini M 2002. Skin remains in a juvenile Macrocnemus bassanii Nopsca (Reptilia, Prolacertiformes) from the Middle Triassic of Northern Italy. Jahrbuch Geologie und Paläontologie, Abhandlung 224(1):31-48.
Rieppel, O 1989. The Hind Limb of Macrocnemus bassanii (Nopcsa) (Reptilia, Diapsida): Deverlopment and Functional Anatomy. Journal of Vertebrate Paleontology. 9 (4): 373–387.
Romer AS 1970. Unorthodoxies in Reptilian Phylogeny. Evolution 25:103-112.
Saller F 2016. Anatomia, paleobiologia e filogenesi di Macrocnemus bassanii Nopcsa 1930 (Reptilia, Protorosauria). Alma Mater Studiorum – Università di Bologna Dottorato di Ricerca in Scienze della Terra Ciclo XXVII 206pp.

PIMUZ – Palaeontologisches Institut und Museum, University of Zuerich, Zurigo, Switzerland.