Asiatherium enters the LRT: mammal nomenclature issues follow

Everyone agrees
that Asiatherium (Figs, 1,2) nests close to Monodelphis, Caluromys and placentals. Trofimov and Szalay 1994 agreed. So did Denyer, Regnault and Hutchinson 2020. So did the large reptile tree (LRT, 1729+ taxa, subset Fig. 3).

Figure 1. Asiatherium in situ from Szalay and Trofimov 1996.

Figure 1. Asiatherium in situ from Szalay and Trofimov 1996.

Asiatherium reshetovi (Trofimov and Szalay 1994, Szalay and Trofimov 1996; PIN 3907; Late Cretaceous; 80mya; Figs. 1, 2) is a key Mongolian metathere ancestral to monodelphids and Caluromys, which is ancestral to placentals. It is derived from Triassic sisters to extant late survivors, DidelphisGilronia and Marmosops.

Figure 2. Asiatherium skull slightly modified from Szalay and Trofimov 1996. Colors added here.

Figure 2. Asiatherium skull slightly modified (longer lateral view premaxilla to match dorsal and ventral views) from Szalay and Trofimov 1996. Colors added here.

The problem is,
according to results recovered by the LRT, mammal clade nomenclature needs to go back to basics. Several modern mammalian clade names are found to be junior synonyms of traditional clades in the LRT.

Prototheria (Gill 1872) is a junior synonym
for Monotremata (Bonaparte 1837) in the LRT.

According to Wikipedia, “Prototheria is a paraphyletic subclass to which the orders MonotremataMorganucodontaDocodontaTriconodonta and Multituberculata have been assigned, although the validity of the subclass has been questioned.”

In the LRT Morganucodon is a a marsupial (see below). Docodon is a taxon within Monotremata. Triconodon is a taxon within Monotremata. Multituberculata is a clade within the placental clade Glires (Fig. 4). So, the clade Monotremata is monophyletic and has precedence.

Theria (Parker and Haswell 1897) is a junior synonym
of Marsupialia (Illiger 1811). Metatatheria (Thomas Henry Huxley 1880) is also a junior synonym of Marsupialia.

The late-surviving basalmost marsupial in the LRT (Fig. 4), Ukhaatherium (Fig. 3), has epipubic (marsupial) bones. That long rostrum indicates this taxon is close to monotremes.

Figure 3. Ukhaatherium in situ.

Figure 3. Ukhaatherium in situ.

Unlike the monophyletic clade Monotremata,
a series of nested marsupial clades are present. The last of these gives rise to Placentalia, only one of several that lose the pouch (Fig. 4). New names are proposed here where appropriate:

  1. Marsupialia = Ukhaatherium and kin + all descendants (including placentals)
  2. Paleometatheria = Morganucodon and kin + all descendants.
  3. Didelphimetatheria = Eomaia and kin + all descendants
  4. Phytometatheria = Marmosops and kin + all descendants
  5. Carnimetatheria = Asiatherium and kin + all descendants
  6. Transmetatheria = Caluromys and kin + all descendants
  7. Placentalia = Vulpavus and kin + all descendants
Figure 4. Subset of the LRT cladogram of basal Mammalia. Note the traditional clade Metatheria is a grade with new names proposed here.

Figure 4. Subset of the LRT cladogram of basal Mammalia. Note the new names proposed here.

Basal marsupial taxa are omnivores. 
Derived phytometatheres are herbivores. Derived carnimetatheres are carnivores to hyper-carnivores. Transmetatheres (Carluromys) and basal Placentalia remain omnivores.

In the LRT Eutheria (Gill 1872) is a junior synonym
of Placentalia (Owen 1837). Omnivorous civets like Nandinia are basal placentals. Carnivora is a basal placental clade following basal placental civets.

Competing cladograms
Denyer, Regnault and Hutchinson 2020 recently looked at the marsupial patella, or more specifically the widespread absence or reduction of the kneecap. The authors concluded, “metatherians independently ossified their patellae at least three times in their evolution.”

Unfortunately, Denyer et al. tested Caenolestes, the ‘shrew opossum’. Not surprisingly it nested close to placentals in their cladogram. Caenolestes was earlier nested in the LRT within the placental clade, Glires, closer to shrews than to opossums. It has no pouch, but converges with marsupials in several aspects. Inappropriate taxon inclusion, like Caenolestes, occurs due to taxon exclusion. Excluded taxa would have attracted and removed the inappropriate taxon. Taxon exclusion plagues Denyer et al.

Historically, you may remember,
Bi et al. 2018, while presenting Early Cretaceous Ambolestes, suffered from massive taxon exclusion and traditional bias in attempting to produce a cladogram of mammals. Bi et al. recovered Sinodelphys (Early Cretaceous) and Juramaia (Late Jurassic) as ‘eutherians’. In the LRT both are monotremes.

Other basal mammal cladograms
depend too much on tooth traits. Convergence in tooth traits creates problems, as documented earlier. We’ll look at this problem in more detail soon.

The above subset of the LRT appears to be a novel hypothesis
of interrelationships. If not, please provide a citation so I can promote it.


References
Bi S, Zheng X, Wang X, Cignetti NE, Yang S, Wible JR. 2018. An Early Cretaceous eutherian and the placental marsupial dichotomy. Nature 558(7710):390395 DOI 10.1038/s41586-018-0210-3.
Denyer AL, Regnault S and Hutchinson JR 2020. Evolution of the patella and patelloid in marsupial mammals. PeerJ 8:e9760 http://doi.org/10.7717/peerj.9760
Szalay FS and Trofimov BA 1996. The Mongolian Late Cretaceous Asiatherium, and the early phylogeny and paleogeography of Metatheria. Journal of Vertebrate Paleontology 16(3):474–509.
Trofimov BA and Szalay FS 1994. New Cretaceous marsupial from Mongolia and the early radiation of Metatheria. Proceedings of the National Academy of Sciences 91:12569-12573

New study on Thylacosmilus atrox: “not a marsupial saber-tooth predator”??

Janis et al. 2020
bring us some heretical views regarding Thylacosmilus, the famous saber-toothed marsupial (Fig. 1).

Figure 2. Thylacosmilus skull. Note the deep maxillae in dorsal contact containing giant canine roots. These are not present in Patagosmilus.

Figure 1. Thylacosmilus skull. Note the deep maxillae in dorsal contact containing giant canine roots. These are not present in Patagosmilus.

For those in a hurry:
The Janis et al. study includes a phylogenetic analysis of placental sabertooth cats that nests the saber-toothed marsupial, Thylacosmilus (Fig. 1), at the base of the clade (Fig. 2). In a way, that is true, but this is missing so many transitional taxa that we’re left with apples and oranges. So, that’s not going to work because Janis et al. are testing analogy and convergence, rather than homology. It’s better to test apples and apples, even when dealing with stress tests, etc.

Figure 1. Cladogram from Janis et al. 2020. Note the lack of marsupial taxa, other than Thylacosmilus at the base.

Figure 2. Cladogram from Janis et al. 2020. Note the lack of marsupial taxa, other than Thylacosmilus at the base. Be wary whenever the taxon under review nests at the base of the cladogram.

Lacking here
is a phylogenetic analysis that includes the closest marsupial relatives of Thylacosmilus: 1. Schowalteria (Fig. 3), 2. Vincelestes + Conorytes, 3. Huerfanodon 4. Monodelphis + Chironectes. That’s how they line up in the large reptile tree (LRT, 1698+ taxa). You need related taxa to decipher the phylogenetic bracketing of Thylacosmilus based on homology, not analogy. The last two taxa are extant. One is an omnivore, the other an aquatic carnivore. Among the extinct taxa, Schowalteria, Vincelestes, Conoryctes and Huefanodon all appear to have been marsupial saber-toothed predators, contra the Janis et al. headline. Vincelestes goes back to the Early Cretaceous.

Figure 1. Showalteria. Not much there. Adding more rounds out the skull, a likely marsupial relative of Vincelestes.

Figure 3. Showalteria. Not much there, but enough to nest it with Thylacosmilus. Is this a predator? According to Wikipeia,.. no.

Janis et all. 2020 wrote:
“While the superficial appearance of Thylacosmilus atrox resembles that of placental saber- tooths, its detailed anatomy makes this animal an ecomorphological puzzle, and the analyses performed here show it to be unlike other carnivores, saber-toothed or otherwise”

That’s because they omitted related taxa…where are the comparable marsupials?

“While we can demonstrate that T. atrox could not have been a predator in the mode proposed for the saber-toothed feliform carnivorans, it is challenging to propose an alternative mode of life.”

That’s because they omitted related taxa…where are the comparable marsupials?

“We note that, while there is often the temptation to shoehorn an extinct animal into the ecomorphological role of an extant one (see Figueirido, Martín-Serra & Janis, 2016)—or even, as in this case, the proposed ecomorphological role another extinct animal—T. atrox may well have had no analogs in the extant or extinct fauna.

That’s because they omitted related taxa…where are the comparable marsupials?

“We extend this discussion of extinct animals without living analogs in the conclusions. Here we present some ecomorphological hypotheses for T. atrox that align with the peculiarities of its anatomy.”

  1. We note that the unusual subtriangular shape of these canines makes them appear more like a claw than a blade; and, like a claw, they appear well-adapted for pulling back.
  2. Our biomechanical study shows that both the skull and the canines of T. atrox are better in resisting pull back stresses than those of S. fatalis.
  3. The small infraorbital foramen of T. atrox supports the hypothesis that its canines were not used for killing prey, as it would not require such careful and precise positioning of the canines.
  4. The postcanine teeth of T. atrox exhibit blunted tip wear, unlike the shearing wear on the teeth of carnivores that specialize on flesh
  5. T. atrox was clearly not a bone-crusher: this type of diet is contraindicated by the DMTA analysis and the lack of cranial specializations (including evidence for powerful jaw adductors) seen in extant bone-crushers
  6. T. atrox had less powerful jaw adductor and head depressor muscles than placental saber-tooths. The cervical and caudal cranial anatomy are not indicative of the ability for extreme head elevation and forceful head depression, as observed in the anatomy of placental saber-tooths, implicated in those carnivores for a predatory head strike.
  7. The virtual absence of incisors (certainly the absence of a stout incisor battery) in T. atrox is challenging for the hypothesis of a cat-like mode of feeding, as it would have been unable to strip flesh from a carcass or transport its prey.

Janis et al. wonder:
“Could [soft internal organs] have been the preferred diet of the marsupial saber-tooth?”

Janis et al. propose:
“Incisor loss or reduction in mammals is correlated with the use of a protrusible tongue in feeding, as seen in myrmecophageous mammals.”

Janis et al. propose:
“T. atrox has been ‘‘shoehorned’’ (see Figueirido, Martín-Serra & Janis, 2016) into the saber-tooth ecological role: much less attention has been paid to the way in which this animal differs in its morphology from placental saber-toothed predators, making a similar type of predatory behavior unlikely.

“We advance the suggestion that it was not an active predator, but rather relied on the use of existing carcasses, deploying its large canines for carcass opening rather than for killing, a hypothesis supported by our biomechanical analyses that show superior performance in a ‘‘pull-back’’ scenario.”

“Thylcosmilus atrox was a very different type of carnivorous mammal than the placental saber-tooths: the oft-cited convergence with placentals such as Smilodon fatalis deserves a rethink, and the ‘‘marsupial saber-tooth’’ may have had an ecology unlike any other known carnivorous mammal.”

Figure 3. Maximum gape of Thylacosmilus.

Figure 4. Maximum gape of Thylacosmilus. At upper left is the placental, Smilodon, for comparison.

Geology = Environment
Thylacosmilus was found in a vast Miocene tidal flat environment with a wide variety of terrestrial and shalllow aquatic taxa. So that doesn’t help much.

Saving the best for last: getting back to Late Cretaceaous Schowalteria
Wikipeda report, “It is notable for its large size, being among the largest of Mesozoic mammals,[ as well as its specialization towards herbivory, which in some respects exceeds that of its later relatives.” This is based on tooth wear, with nearly all crowns gone (Fig. 3) in the only specimen known. Traditionally Schowalteria has been allied with styinodonts (Carnivora close to seals, but not to sea lions) and to taeinodonts (which the LRT found to be poylphyletic). Certainly, what little is known of Schowalteria is similar to these taxa. Others have omitted these LRT sisters in their analyses. Janis et al. omit the word ‘sister’ from their text.

Figure 1. Patagosmilus to scale alongside Hadrocodium. These sabetooth taxa are not directly related to Thylacosmilus in the LRT.

Figure 5. Patagosmilus to scale alongside Hadrocodium. These sabetooth taxa are not directly related to Thylacosmilus in the LRT.

Patagosmilus has been called a sister to Thylacosmilus,
but the LRT nested Patagosmilus (Fig. 5) with the tiny basal therian, Hadrocodium (Fig. 5) as we learned earlier here. Taxon inclusion produces surprises like this.

At times like this it’s good to test.
Deletion of Thylacosmilus changes nothing in the LRT. Deletion of Schowalteria changes nothing in the LRT.

In my opinion
it was great that Janis et al. 2020 tested Thylacosmilus with its placental analogs, but they should also have tested Thylacosmilus with its marsupial homologs.


References
Janis CM, Figueirido B, DeSantis L, Lautenschlager S. 2020. An eye for a tooth: Thylacosmilus was not a marsupial ‘‘saber-tooth predator’’. PeerJ 8:e9346 http://doi.org/10.7717/peerj.9346

https://en.wikipedia.org/wiki/Ituzaing%C3%B3_Formation

https://pterosaurheresies.wordpress.com/2018/12/20/marsupial-sabertooth-taxa-are-polyphyletic/

Adalatherium: this ‘crazy beast’ suffers from taxon exclusion… and hyperbole

Figure x. Adalatherium diagram, added later.

Figure x. Adalatherium diagram, added later.

Figure 1. Adalatherium mount.

Figure 1. Adalatherium mount. Compare to Paedotherium in figure 2. Both have large, rodent-like incisors, lack an thumb and share a high presacral count, among many hundred other synapomorphies. Note: the prepubes here are epipubes in the paper.

Krause et al. bring us a complete and articulated skeleton
from the latest Cretaceous of Madagascar they call Adalatherium hui (=”crazy beast”, Fig. 1). Added to the large reptile tree (LRT, 1678+ taxa; subset Fig. 3), Adalatherium nests with Miocene Paedotherium (Fig. 2), a metatherian taxon known since 1888 with homologous large rodent-like incisors and retained coracoids. Regrettably this taxon was omitted from the Krause et al. cladogram (Fig. 4).

Figure 2. Miocene Paedotherium was excluded by Krause et al. It nests with Late Cretaceous Adalatherium in the LRT.

Figure 2. Miocene Paedotherium was excluded by Krause et al. It nests with Late Cretaceous Adalatherium in the LRT.

Paedotherium typicum (Burmeister 1888, Cerdeño E and Bond M 1998; Miocene-Pleistocene) was originally considered a rabbit-like typothere notoungulate, but here nests between Dasyuroides and Phalanger among the marsupials. The Cretaceous taxa, Vintana and Groeberia are more closey related, hinting at the probable Jurassic origin of Paedotherium.

Figure 7. Subset of the LRT focusing on Metatheria (marsupials) including Paedotherium and Adalatherium.

Figure 3. Subset of the LRT focusing on Metatheria (marsupials) including Paedotherium and Adalatherium. Red taxa are known from too few traits to enter the LRT, but tests show they nest as shown.

By contrast with the LRT, 
Krause et al. considered their discovery a member of the ‘Gondwanatheria’ and therefore a basal mammal between Prototheria (duckbills and echidnas) and Metatheria (marsupials) (Fig. 4), still close to Vintana, the closest included taxon known from more than teeth.

Figure 5. Cladogram from Krause et al. 2020 nests Adalatherium with several paedotheres, but omits Paedotherium.

Figure 4. Cladogram from Krause et al. 2020 nests Adalatherium with several paedotheres, but omits Paedotherium.

From the abstract:
“To our knowledge, the specimen is the most complete skeleton of a Gondwanan Mesozoic mammaliaform that has been found, and includes the only postcranial material and ascending ramus of the dentary known for any gondwanatherian. A phylogenetic analysis including the new taxon recovers Gondwanatheria as the sister group to Multituberculata.”

This is a red flag. In the LRT multituberculates are members of the clade Glires a placental clade that includes tree shrews and rodents. Krause et al. omitted the closest taxa in the LRT to the multituberculates.

Figure 2. From Krause et al. 2020, Adalatherium in situ sans matrix.

Figure 5 From Krause et al. 2020, Adalatherium in situ sans matrix.

Large rodent-like incisors, coupled with procoracoids, coupled with epipubes,
narrowed the taxonomic focus for the Krause team, but narrowed it a little too far. Overlooked Paedotherium (Fig. 2) shares those traits and hundreds more. The LRT minimizes exactly this type of taxon exclusion by including such a wide gamut of taxa that keeps getting wider and deeper with every new taxon. The similarities are obvious.

Figure 4. Adalatherium skull in 3 views from Krause et al. 2020.

Figure 6. Adalatherium skull in 3 views from CT µscans in Krause et al. 2020.  Compare to Paedotherium in figure 2.

From the abstract:
“The skeleton, which represents one of the largest of the Gondwanan Mesozoic mammaliaforms, is particularly notable for exhibiting many unique features in combination with features that are convergent on those of therian mammals. This uniqueness is consistent with a lineage history for A. hui of isolation on Madagascar for more than 20 million years.”

Not ‘unique’ and not ‘convergent’ with those of therian mammals—Adalatherium IS a therian mammal… with a procoracoid and epipubes.

Don’t rely on a short list of traits.
That would be like ‘Pulling a Larry Martin.” Don’t rely on dental traits. Don’t rely on genes. Just expand your taxon list and let the software decide where to nest new taxa. Omitting pertinent taxa is a common issue in paleontology. Not sure what drives it other than headlines in this case.

After all the work involved in discovering
and recovering Adalatherium, expanding the taxon list would have been the easiest thing to do… and, as usual, the most important. Simply omitting taxa too often produces erroneous conclusions, turning a wonderful discovery, kept under wraps and studied for twenty years in prestigious institutions into an embarrassing error published in Nature and widely publicized around the world (links below).

Earlier we talked about the origin of major mammal clades
in the Jurassic and Cretaceous (Fig. 7). Adalatherium is just one of many already known and many to come.

Figure 1. Select basal cynodonts and mammals set chronologically. The divergence times for placentals (Eutheria), marsupials (Metatheria) and monotremes (Mammalia) are estimated here.

Figure 7. Select basal cynodonts and mammals set chronologically. The divergence times for placentals (Eutheria), marsupials (Metatheria) and monotremes (Mammalia) are estimated here.

Is Adalatherium the oldest mammal found in the Southern Hemisphere?
No. Brasilitherium and Brasilodon (Fig. 7) both from Brazil, are known from the Norian (Late Triassic) more than twice as old as Adalatherium. We also have seven placentals (Fig. 7) from the Late Jurassic of China and older marsupials from China and England.

According to Science Alert (link below):
“Exactly what factors induced the craziness of the crazy beast isn’t fully clear, but a 20-year-long analysis of the remains (the fossil was first discovered in 1999) indicates it is indeed a strange creature. Knowing what we know about the skeletal anatomy of all living and extinct mammals, it is difficult to imagine that a mammal like Adalatherium could have evolved,” says vertebrate palaeontologist David Krause from the Denver Museum of Nature & Science, who helped find the skeleton during a field expedition in Madagascar in 1999. “It bends and even breaks a lot of rules.”

“Strange… crazy… difficult to imagine…”
this is all hyperbole. When Paedotherium is added to the taxon list, none of this is strange… and there goes the headline… and the generic name…

Continuing from Science Alert
“Part of the weirdness is the primitive septomaxilla bone in its snout region – a feature that disappeared 100 million years earlier in the ancestors of living modern mammals.” 

“It also had more openings (called foramina) in its cranium than any known mammal, the researchers say, which may have enhanced the sensitivity of its snout and whiskers, by enabling passage for nerves and blood vessels through the skull.”

“The animal had strangely bowed leg bones, too, and researchers aren’t sure whether it used its limbs for digging, or running, or even other kinds of locomotion. Then there are the teeth. The strangeness of the animal is clearly apparent in the teeth – they are backwards compared to all other mammals, and must have evolved afresh from a remote ancestor,” Evans explains.

Backwards? Does that mean more primitive?
Let’s assume the latter. On that point, the teeth of Paedotherium are similar.

Bottom line:
Adalatherium is just a minor variation on a traditionally overlooked taxon known for over 100 years. Chronologically it’s not that old. Phylogenetically it’s not that crazy, strange or bizarre. Omitting taxa remains THE MOST COMMON error in academic papers. Let’s fix that.


References
Krause DW et al. (12 co-authors) 2020. Skeleton of a Cretaceous mammal from Madagascar reflects long-term insularity. Nature (advance online publication DOI: https://doi.org/10.1038/s41586-020-2234-8
https://www.nature.com/articles/s41586-020-2234-8

wiki/Adalatherium

News:

https://www.macalester.edu/news/2020/04/geology-professors-rare-fossil-discovery-in-madagascar-featured-in-scientific-journal-nature

https://phys.org/news/2020-04-marooned-mesozoic-madagascar-million-year-old-crazy.html

https://www.washingtonpost.com/science/2020/04/29/mammal-skeleton-adalatherium-hui/

https://www.nytimes.com/reuters/2020/04/29/world/africa/29reuters-science-crazybeast.html

https://www.livescience.com/ancient-bizarre-mammal-madagascar.html

https://www.sciencealert.com/crazy-beast-of-gondwana-may-be-oldest-mammal-skeleton-found-in-southern-hemisphere

Recalibrating clade origins, part 4

Earlier
we looked at the first part and second part and third part of Marjanovic’s 2019 chronological recalibration of vertebrate nodes. Today we continue in part 4 of 5.

Mammalia (Prototheria + Theria)
Based on the literature, Marjanovic 2019 considers morganucodontans and tiny Hadrocodium to be mammalomorphs, not mammals. He is unsure about haramiyidans. With regard to the first dichotomy of mammals, he reported, “I recommend a hard minimum age of 179 Ma for this calibration.”

By contrast the large reptile tree (LRT, 1630+ taxa) nests Morganucodon (Late Triassic, 205 mya), Hadrocodium (Early Jurassic) and Henosferus (Middle Jurassic) together in the most basal subclass within Theria, part of the first dichotomy within Mammalia. Marjanovic considered Henosferus one of the oldest uncontroversial mammals at 179 mya. Megazostrodon is a late surviving (early Jurassic) last common ancestor taxon of all mammals in the LRT. It must have appeared prior to Morganucodon in the Late Triassic.

Theria (Metatheria + Eutheria)
Marjanovic reports, “The oldest securely dated eutherian is Ambolestes at 126 Ma.” Then he reports, “Accepting that Juramaia is not from the Lanqi Fm, I propose 160 Ma as the soft maximum age of this calibration.”

By contrast, Morganucodon (Late Triassic, 210mya) nests as the oldest therian. Ambolestes nests with Didelphis, the opossum, within the Theria, not Eutheria.  Thereafter the traditional Metatheria splits in three clades in the LRT, a largely herbivorous branch with Glironia and Marmosops at its base, and a largely carnivorous branch with Monodelphis and Chironectes at the base of one branch and Caluromys + Placentalia at yet another. So, while Caluromys (Fig. 3) retains a pouch, it is also the last common ancestor of all placentals.

Figure 1. Pteropus and Caluromys compared in vivo and three views of their skulls. Caluromys is in the ancestry of bats and shows where they inherited their inverted posture.

Figure 1. Pteropus and Caluromys compared in vivo and three views of their skulls. Caluromys is in the ancestry of bats and shows where they inherited their inverted posture.

Marjanovic often errors by not including extant taxa that are more primitive than extinct taxa that are older. This comes back to bite him several times, especially so when he relies on a single fossil tooth rather than a living animal he can hold. The LRT tests both living and extinct taxa to minimize taxon exclusion.

Marjanovic discusses the possibility that Sinodelphys is the oldest known metatherian, but Sinodelphys nests as one of the most primitive prototherians in the LRT, as we learned earlier here.

Placentalia (Atlantogenata + Boreo(eu)theria)
In the world of gene studies, Atlantogenata include the highly derived elephants and anteaters. The Boreoeutheria include the highly derived whales, humans and hooved mammals. Genomic studies deliver false positives, and these are among the most blatant, so ignore these. They don’t deliver a gradual accumulation of derived traits.

By contrast, in the LRT the first dichotomy in the placentalia splits arboreal Vulpavus from arboreal Nandinia and thereafter arboreal Carnivora (mongooses and raccoons) from arboreal Volantia (bats and colugos) + arboreal Primates and the rest of the Placentalia. All of these civet-like and tree opossum-like taxa look like Caluromys (Fig. 1), as you can see. Elephants and anteaters come later. Adding living taxa to Marjanovic’s search for primitive placentals would have helped clarify his research and conclusions, preventing him form perpetuating old myths.

Carnivora (Feliformia + Caniformia)
Marjanovic errs by reporting the basal dichotomy within Carnivora splits cats from dogs.

By contrast in the LRT cats and dogs are closely related and derived taxa, not basal. As mentioned above, civets, mongooses and raccoons are basal Carnivora.

Euarchontoglires/Supraprimates (Gliriformes + Primatomorpha)
Marjanovic discusses several poorly preserved, sometimes one tooth only, fossil taxa from the early Paleocene (65mya). Some of these are anagalids, which nest at the base of yet another clade in the LRT, the one with tenrecs and odontocetes (toothed whales).

By contrast in the LRT lemur-like adapids appear at the base of the Primates. Tree-shrews appear at the base of the Glires.

Marsupialia (Didelphimorphia – Paucituberculata + Australidelphia)

  • Didelphimorphia = opossums from North America
  • Paucituberculata = South American marsupials, sans Dromiciops
  • Australidelphia = Australian and Asian marsupials, plus Dromiciops

Marjanovic reports, “I therefore propose 55 Ma as a probably overly strict hard minimum age for this calibration.” He later reports, “Rather than the beginning of the Maastrichtian, I propose the beginning of deposition of the Lance and Hell Creek formations, where Glasbius has been found, as the hard maximum age for this calibration, which I estimate as 68 Ma.”

See Figure 1 for a different three-part marsupial split from the LRT. Dromiciops is only one of many similar herbivorous marsupials. Middle Late Cretaceous Asioryctes is a basal member of the largely herbivorous clade. Early Cretaceous Vincelestes is a basal member of the largely carnivorous clade. So Middle to Late Jurassic (175mya) is a better estimate for the genesis of marsupial diversity. That means marsupials dispersed during the Pangean era without the need of an oceanic dispersal.

Marjanovic mistakenly reports, “Marsupials, other metatherians and indeed other therians are wholly absent from the Late Cretaceous mammaliform record of South America, which consists instead of gondwanatherian haramiyidans and a very wide variety of meridiolestidan stem-theriiforms.”

  • Meridiolestida = non-therian mammals (= Prototheria, Montremata) seems to be based on tooth traits. Cronopio and Necrolestes are among the only tested taxa also  found in the LRT. Cronopio is an omnivorous member of the pre-metatherian Theria in the LRT. Necrolestes is a basal member of the placental clade, Glires, derived from the treeshrew Tupaia in the LRT. So, again, we have a mismatch due to not testing all the mammals against all the mammals. That is what makes the LRT such a powerful tool that should be more widely used to avoid such old school mythology.

More tomorrow as we conclude part 5 of 5.


References
Marjanovic D 2019. Recalibrating the transcriptomic timetree of jawed vertebrates.
bioRxiv 2019.12.19.882829 (preprint)
doi: https://doi.org/10.1101/2019.12.19.882829
https://www.biorxiv.org/content/10.1101/2019.12.19.882829v1

SVP abstracts – Ambolestes and the origin of placentals

Bi S-D et al. 2019 discuss Early Cretaceous Ambolestes
(Figs. 1, 2) and the Early Mesozoic marsupial/placental split.

Figure 1. Ambolestes tracing from Bi et al. 2018.

Figure 1. Ambolestes tracing from Bi et al. 2018.

From the abstract:
“Extant placental and marsupial mammals are the dominant vertebrates in many ecosystems, which makes the placental-marsupial dichotomy a significant event in Earth’s history.”

The large reptile tree (LRT, 1592 taxa) splits placentals from marsupials as shown below (Figs. 3, 4). The Early Cretaceous marsupial Bishops splits from the placental outgroup taxon, the extant marsupial Caluromys (Fig. 6). More timely, derived placental multituberculates, like Megaconus (Fig. 5), have been found in Middle Jurassic strata. That means a long line of undiscovered small, arboreal, placentals extends back to the Late Triassic/Earliest Jurassic.

Figure 3. Ambolestes skull reconstructed. Jaw tips restored.

Figure 2. Ambolestes skull reconstructed. Jaw tips restored.

Bi et al. continue:
“Molecular estimates of the divergence of placentals and marsupials (and their broader clades Eutheria and Metatheria) fall primarily in the Jurassic.”

Since Early Jurassic Megazostrodon is the proximal outgroup for all mammals, and Early Triassic Morganucodon is a marsupial, and Middle Jurassic Megaconus the LRT supports a Late Triassic split for placentals and marsupials.

Figure 1. Select basal cynodonts and mammals set chronologically. The divergence times for placentals (Eutheria), marsupials (Metatheria) and monotremes (Mammalia) are estimated here.

Figure 3. Select basal cynodonts and mammals set chronologically. The divergence times for placentals (Eutheria), marsupials (Metatheria) and monotremes (Mammalia) are estimated here. Note the large gaps of time in which fossils are not known.

Bi et al. continue:
“In support, the oldest purported eutherian, Juramaia, is reported to be from the early Late Jurassic (160 million-years ago) of Liaoning Province, northeastern China.”

In the LRT (subset Fig. 1) Juramaia nests as a basal prototherian, an egg laying basal mammal.

“The oldest purported metatherian, Sinodelphys, is 35 million-years younger from the
Early Cretaceous Jehol Biota also in Liaoning Province, northeastern China.”

In the LRT Sinodelphys is another monotreme.

“In 2018, we reported a new eutherian, Ambolestes zhoui, also from the Jehol Biota. The fossil, a nearly complete skeleton, preserves anatomical detail unknown from contemporaneous eutherians including the hyoid apparatus and ectotympanic. The complete hyoid is the first known for any Mesozoic mammaliaform, and the ectotympanic resembles that in some extant didelphid marsupials.”

In the LRT (Fig. 1) Ambolestes (Figs. 3, 4) is a metathere/marsupial close to the extant Virginia opossum, Didelphis.

Figure 1. Subset of the LRT focusing on the Kynodontia and Mammalia. Non-eutherian taxa in red were tested in the LRT but not included because they reduce resolution. Eutherian taxa in red include a basal pangolin and derived xenarthran, clades that extend beyond the bottom of this graphic. The pink clade proximal to mammals was considered mammalian by Lautenschlager et al. due to a convergent mammalian-type jaw joint.

Figure 4. Subset of the LRT focusing on the Kynodontia and Mammalia. Non-eutherian taxa in red were tested in the LRT but not included because they reduce resolution. Eutherian taxa in red include a basal pangolin and derived xenarthran, clades that extend beyond the bottom of this graphic. The pink clade proximal to mammals was considered mammalian by Lautenschlager et al. due to a convergent mammalian-type jaw joint.

Bi et al. continue:
“In our phylogenetic analysis concentrating on the eutherian-metatherian 
dichotomy, the closest relative of Ambolestes was Sinodelphys, and both fell within Eutheria.”

As shown above, the LRT does not confirm that hypothesis of interrelationships.

Figure 1. Subset of the LRT focusing on Glires and subclades within.

Figure 5. Subset of the LRT focusing on Glires and subclades within.

Bi et al. continue:
“With Sinodelphys as a eutherian, postcranial differences formerly thought to indicate different invasions of a scansorial niche by meta and eutherians in Jehol are only variations among the early members of the placental lineage. Additionally, the earliest known metatherians are approximately 15 million years younger than previously thought and their

fossils, isolated teeth and fragmentary jaws, are from North America. Our tree results in a 50 million-year ghost lineage for Metatheria, accepting the 160 million-years age for Juramaia. 

The LRT confirms a 210 mya origin for Metatheria, starting with Morganucodon, so no ghost is necessary.

Figure 8. Caluromys, the largest of the mouse opossums, to scale with its LRT sister, Vulpavus, a basal member of Carnivora.

Figure 6. Caluromys, the largest of the mouse opossums, to scale with its LRT sister, Vulpavus, a basal member of Carnivora and Placentalia.

Bi et al. continue:
“A possibility raised elsewhere is that the age of Juramaia is incorrect; rather than Late Jurassic, perhaps it is from the Early Cretaceous Jehol Biota. In our study, Juramaia is in a clade with Albian/Aptian Prokennalestes and Late Cretaceous eutherians by having a more molariform ultimate upper premolar. In contrast, Ambolestes, as in the outgroups, has a non-molariform ultimate upper premolar. Although resolution of this intriguing debate is not currently possible, our understanding of the issues has been furthered by the discovery of Ambolestes.”

As shown above, the LRT does not confirm the Bi et al. hypothesis of interrelationships.


References
Bi S-D et al. 2019. The Early Cretaceous eutherian Ambolestes and its implications for the Eutherian/Metatherian dichotomy. Journal of Vertebrate Paleontology abstracts.

Morganucodon and Kuehneotherium are mammals, not stem-mammals

Newham et al. 2019 report,
“Surprisingly long lifespans and low femoral blood flow suggest reptile-like physiology in key Early Jurassic stem-mammals.

Abstract:
“There is uncertainty regarding the timing and fossil 5 species in which mammalian endothermy arose, with few studies of stem-mammals on key aspects of endothermy such as basal or maximum metabolic rates, or placing them in the context of living vertebrate metabolic ranges. Synchrotron X-ray imaging of incremental tooth cementum shows two Early Jurassic stem-mammals, Morganucodon and Kuehneotherium, had lifespans (a basal metabolic rate 10 proxy) considerably longer than comparably sized living mammals, but similar to reptiles, and that Morganucodon had femoral blood flow rates (a maximum metabolic rate proxy) intermediate between living mammals and reptiles. This shows maximum metabolic rates increased evolutionarily before basal rates, and that contrary to previous suggestions of a Triassic origin, Early Jurassic stem-mammals lacked the endothermic metabolism of living mammals.”

That conclusion would be true
if their cladogram was correct. Unfortunatley, it was not.

Figure 1. Subset of the LRT focusing on Basal Mammalia including Creodonta.

Figure 1. Subset of the LRT from 2018 focusing on Basal Mammalia including Morganucodon and Kuehneotherium.

According to
the large reptile tree (LRT, 1579 taxa; subset Fig. 1), Kuehneotherium (Fig. 2) is a basal protothere mammal (= monotreme) in the lineage of echidnas and platypuses. Morganucodon is a very basal metathere mammal (= marsupial). The Virginia opossum, Didelphis, is the most closely related extant taxon in the LRT.

Figure 1. Brasilodon compared to Kuehneotherium, Akidolestes and Ornithorhynchus, the living platypus.

Figure 2. Brasilodon compared to Kuehneotherium, Akidolestes and Ornithorhynchus, the living platypus.

Here’s a data point of interest:
Newham et al. report, “Only the short-beaked echidna Tachyglossus aculeatus, a monotreme with long lifespan and low metabolic rate, exceeds the Kuehneotherium, but not Morganucodon, distance above the mammalian mean.” And THAT is reflected in the LRT. I also note the platypus, Ornithorhynchus, is not mentioned in the text, only in the citations. Same with Didelphis.

So what does that do to the results?
Seems like the Newham et al. study is suffering from taxon exclusion and an invalid traditional understanding of basal mammal interrelations. Unfortunately Professor MJ Benton is a co-author, infamous for taxon exclusion and guiding his students and any protégé to do the same.

Please tell Elis Newham et al.
to add the platypus and opossum to their study and get back to us! Don’t let this work become another waste of time due to taxon exclusion.


References
Newham E et al. (19 co-authors) 2019. Reptile-like physiology in Early Jurassic stem-mammals. bioRxiv preprint http://dx.doi.org/10.1101/785360

Hegetotherium and Pachyrukhos: not ungulates and not notoungulates

Hegetotherium and Pachyrukhos
were recently redescribed by Seoane and Cerdeño 2019 who considered them to be members of the Notoungulata, an invalidated polyphyletic clade with former members now nesting in various hooved marsupial and hooved placental clades.

Traditionally notoungulates are considered placentals and ungulates.
Seoane and Cerdeño report, “Hegetotheriidae is one of the most derived clades in the Order Notoungulata, the most abundant and diverse group of South American native ungulates.” The key word in there is ‘diverse’. Notungulates are SO diverse some of them are not related to the others.

Figure 1. Image from Cassini 2013. Pink taxa are marsupials. Others are placentals.

Figure 1. Image from Cassini 2013. Pink taxa are marsupials. Others are placentals.

We looked at Hegetotherium,
earlier. In the large reptile tree (LRT, 1517 taxa) Hegetotherium nests with Mesotherium and Interatherium at the base of the marsupial Toxodon clade, derived from the wombat (Vombatus) clade. All those are derived from the Paedotherium clade (e.g. Paedotherium, Phalanger, Petaurus and Thylacoleo). In Seoane and Cerdeño, Paedotherium is a taxon nesting close to Pachyrukhos, a taxon not included in the LRT.

The Seoane and Cerdeño taxon list also includes
PaedotheriumMesotherium and Hegetotherium, but not InteratheriumToxodon, Phalanger, Petaurus and Thylacoleo. So taxon exclusion and lacking a wide gamut viewappear to be twin problems here. Seoane and Cerdeño did not realize the taxa in their study were marsupials close to phalangers and wombats. They assumed, by tradition, they were dealing with placental ungulates, close to cows and deer.


References
Cassini G 2013. Skull Geometric Morphometrics and Paleoecology of Santacrucian (Late Early Miocene; Patagonia) Native Ungulates (Astrapotheria, Litopterna, and Notoungulata). Ameghiniana 50 (2):193–216. DOI: 10.5710/AMGH.7.04.2013.606
Seoane FD and Cerdeño E 2019. Systematic revision of Hegetotherium and Pachyrukhos (Hegetotheriidae, Notoungulata) and a new phylogenetic analysis of Hegetotheriidae. Journal of Systematic Palaeontology http://dx.doi.org/10.1080/14772019.2018.1545146

Dactylopsila, the striped possum, enters the LRT

Dactylopsila trivirgata (Gray 1858) is the extant striped possum (Fig. 1), closely related to the sugar glider, Petaurus and the marsupial lion, Thylacoleo (below), according to the large reptile tree (LRT, 1412 taxa). Dactylopsila is an arboreal marsupial with a prehensile tail the size and proportions of a placental squirrel. The fourth finger is elongated and used to extract beetles and caterpillars from tree bark, analogous to the extant aye-aye, Daubentonia. Dactylopsila, also eats leaves, fruit and small vertebrates.

By convergence
Dactylopsila has similar teeth and overall proportions to the extinct arboreal placental Apatemys (Fig. 2).

Figure 1. Dactylopsila skull in 3 views, plus in vivo. Comparisons to the extinct arboreal placental Apatemys (figure 2) are intriguing, showing convergence.

Figure 1. Dactylopsila skull in 3 views, plus in vivo. Comparisons to the extinct arboreal placental Apatemys (figure 2) are intriguing, showing convergence.

For comparison, we recently looked at Apatemys
here as it relates to the extant shrew opossums Caenolestes and Rhyncholestes, now nesting as apatemyid placentals in the LRT, rather than as traditional didelphid marsupials. The convergence is powerful here. Despite the phylogenetic distance, only 12 extra steps are needed to nest caenolestids with basal didelphids.

Figure 3. Apatemys skull in situ and reconstructed shares several similar traits with the extant striped opossum, Dactylopsila, including a squirrel-like size, elongate fingers and similar teeth.

Figure 2. Apatemys skull in situ and reconstructed shares several similar traits with the extant striped opossum, Dactylopsila, including a squirrel-like size, elongate fingers and similar teeth.

The nesting of Dactylopsila
close to Petaurus (Fig. 3) is not controversial.

Figure 1. Subset of the LRT showing the nesting of Dactylopsila, the striped opossum.

Figure 3. Subset of the LRT showing the nesting of Dactylopsila, the striped opossum, with Petaurus the sugar glider and Thylacoleo, the marsupial lion.

The problem continues to be
the traditional nesting of the marsupial lion, Thylacoleo (Fig. 4), as a member of the wombats (Vombatiiformes), rather than the Phalangeriformes and Petauroidea, as recovered by the LRT (Fig. 3), which points to a bigger problem…

Nowhere in traditional taxon lists
will you find interatheres, toxodontids and creodonts. All these taxa need to be tested in traditional metathere trees because the LRT has tested them and they nest with metatheres. It’s a good time for a confirmation or a refutation. PhD students… are you looking for a good subject to write about for your dissertation?

Figure 2. Thylacoleo skeleton compared to Petaurus skeleton to scale.

Figure 4. Large Thylacoleo skeleton compared to small Petaurus skeleton to scale. Dactylopsila is similar in size to Petaurus.

Here, again,
is where tradition, opinion and bias have, so far, trumped testing. Taxon exclusion needs to be tested with taxon inclusion. The list of taxa needing testing is provided by the LRT.


References
Gray JE 1858. List of species of Mammalia sent from the Aru Islands by Mr A.R. Wallace to the British Museum. Proceedings of the Zoological Society of London. 26: 106–113.

wiki/Striped_possum – Dactylopsia trivirgata

Palorchestes and Diprotodon enter the LRT

Two giant odd-looking metatherians,
Palorchestes (Fig. 1, as large as a horse) and Diprotodon (Fig. 2, as large as a hippo), enter the large reptile tree (LRT, 1406 taxa, subset Fig. 3) midway between kangaroos and wombats. So, that settles that conundrum. They’re not wombats and they’re not kangaroos. 

When I was creating the 1986 book,
Giants of Land, Sea and Air ~ Past and Present, I added the ‘giant kangaroo’ next to the largest living kangaroo, Macropus. Less was known back then. I used an extant kangaroo for a model and scaled it up. Now we all know better.

Figure 1. The odd skull of tapir-mimic Palorchestes in 3 views. Colors added.

Figure 1. The odd skull of tapir-mimic Palorchestes in 3 views. Colors added. Dark blue imagines a flexible tapir-like proboscis.

Wikipedia reports, 
“Sir Richard Owen first found what he thought was the fragmentary jaw of a prehistoric kangaroo. It was not until more postcranial elements were found did anyone realize that Palorchestes was actually a different kind of diprotodontid, and not a kangaroo.”

Along with traditional diprotodontids, 
(wombats, koalas and kangaroos) the LRT adds Middle Miocene interatheres and Pliocene toxodons to the wombat clade. This menagerie of morphologies are all herbivores. The last two are former notoungulates.

Figure 2. Diprotodon museum mount and dorsal views of the manus and pes.

Figure 2. Diprotodon museum mount and dorsal views of the manus and pes.

Diprotodon optatum (Owen 1838; Pleistocene 1.5–0.05 mya; 3m in length) is the largest known marsupial of all time. Traditionaly the eight species assigned to Diprotodon nest with wombats and koalas, but here they nest between kangaroos and wombats. The pedes turn inward such that digit 5 is the anteriormost toe on this graviportal beast.

FIgure 4. Diprotodon skull with colors added. This taxon nests midway between wombats and kangaroos.

FIgure 3. Diprotodon skull with colors added. This giant taxon nests midway between wombats and kangaroos.

Palorchestes azael (Owen 1873; Miocene to Pliocene; 2m in length; Figs. 1, 4) had a tapir-like face, likely sporting a similar long proboscis. The lower jaw had a long symphysis, perhaps indicating a protrusible tongue, like an anteater. Large claws tipped the forelimbs (which I have not seen yet, but for the drawing below). Fossils are rare and incomplete.

Figure 5. Palorchestes by Murray 1986. The post-crania is similar to Diprotodon here, perhaps not this completely known.

Figure 4. Palorchestes by Murray 1986 or 1990. The post-crania is illustrated similar to that of Diprotodon, but perhaps not this completely known.

Figure 1. Subset of the LRT focusing on Metatheria after the addition of Diprotodon and Palorchestes. Some new clades are proposed here.

Figure 5. Subset of the LRT focusing on Metatheria after the addition of Diprotodon and Palorchestes. Some new clades are proposed here.

Propalorchestes novaculacephalus (Murray 1986; Trusler and Sharp 2016; Miocene) is a smaller, earlier and plesiomorphic relative of Palorchestes. So far I’ve only seen skull data.

Figure 4. Propalorchestes, the sister to Palorchestes in all analyses, looks more like its kangaroo kin than the other two do.

Figure 6. Propalorchestes, the sister to Palorchestes and Diprotodon in all analyses, looks more like its kangaroo kin than the other two do.

Trusler and Sharp 2016 report,
“Propalorchestes (Middle Miocene) cranial morpholgy, suggests a significantly earlier origin for the highly derived facial anatomy in the Palorchestidae.” 

Given the Middle Miocene appearance of Interatherium,
(Fig. 6) nesting nearby, that seems reasonable.

Figure 2. Interatherium is the surprising ancestor of kangaroos, with a special affinity to the short-face kangaroo.

Figure 6. Interatherium is the surprising ancestor of kangaroos and toxodons, with a special affinity to the short-face kangaroo, Procoptodon.

A few new clade names are proposed here.
Given that the traditional clade Metatheria is no longer monophyletic, unless it also includes the Eutheria, the following clade names are proposed here for the two major monophyletic metatherian-grade clades, one largely herbivorous, the other larger carnivorous:

  1. Phytometatheria, defined as Asioryctes, Glironia, their last common ancestor and all descendants. These include the Diprotodontia listed above and many more, including the omnivores, Petaurus, the sugar glider and its sister Thylacoleo, the marsupial ‘lion’. Docofossor, from the Middle Jurassic, and Anebodon, from the Early Cretaceous are clade members.
  2. Carnimetatheria, defined as Monodelphis, Thylacosmilus, their last common ancestor and all descendants. These include traditional members of the clade, Creodonta, like Oxyaena and Borhyaena. Vincelestes is an Early Cretaceous member, so the genesis of this clade also extends into the Jurassic.

Eomaia, from the Early Cretaceous, and Agilodocodon, from the Middle Jurassic, are sisters to the last common ancestor of both clades.


References
Mackness BS 2008. Reconstructing Palorchestes (Marsupialia: Palorchestidae) – from Giant Kangaroo to Marsupial ‘Tapir’. Proceedings of the Linnean Society of New South Wales, 130, 21-36.
Murray PF 1986. Propalorchestes novaculacephalus gen et sp. nov., a new palorchestid (Marsupialia: Palorchestidae) from the mid Miocene Camfield Beds, Northern Territory Australia. The Beagle, Records of the Northern Territory Museum of Arts and
Sciences 3(1): 195–211.
Murray PF 1990. Primitive marsupial tapirs (Propalorchestes novaculacephalus Murray and Propalorchestes ponticulus sp. nov.) from the mid Miocene of North Australia. (Marsupialia: Palorchestidae) The Beagle, Records of the Northern Territory Museum of Arts and Sciences 7(2): 39–51.
Owen R 1838. Letter in TL Mitchell, Three expeditions into the interior of Eastern Australia. London.
Owen R 1870. On the fossil mammals of Australia. Part III. Diprotodon australis, Owen. Philosophical Transactions of the Royal Society of London. 1870;160:519–578. doi: 10.1098/rstl.1870.0023.
Owen R 1873. On the fossil mammals of Australia. Part IX. Family Macropodidae: Genera Macropus, Pachysaigon, Leptosaigon, Procoptodon, and Palorchestes. Philosophical Transactions of the Royal Society of London 164, 783-803.
Price GJ 2009. Taxonomy and palaeobiology of the largest-ever marsupial, DiprotodonOwen, 1838 (Diprotodontidae, Marsupialia). Zoological Journal of the Linnean Society, 2008, 153, 369–397.
Trusler P and Sharp AC 2016. Description of new cranial material of Propalorchestes (Marsupialia: Palorchestidae) from the Middle Miocene Camfield Beds, Northern Territory, Australia. Memoirs of Museum Victoria 74:291–324.

wiki/Diprotodon
wiki/Palorchestes
wiki/Propalorchestes

https://www.nationalgeographic.com/science/phenomena/2010/10/06/its-a-kangaroo-its-a-llama-no-its-palorchestes/

https://www.wired.com/2010/10/its-a-kangaroo-its-a-llama-no-its-palorchestes/

Hey! Some of those Miocene ‘ungulates’ are marsupials!

More heresy today
courtesy of taxon inclusion.

Cassini 2013
looked at several traditional Miocene South American ‘ungulates’ (Fig. 1) unaware that these taxa do not nest in monophyletic clade any more specific than Theria in the large reptile tree (LRT, 1401 taxa). Cassini was reporting the results of “an ecomorphological study based on geometric morphometrics of the masticatory apparatus.” So he was working from prior cladograms and focusing on the mechanics of eating.

Figure 1. Image from Cassini 2013. Pink taxa are marsupials. Others are placentals.

Figure 1. Image from Cassini 2013. Pink taxa are marsupials. Others are placentals.

Earlier
here and here the traditional clade Notoungulata was splintered by the LRT into several clades, some among the marsupials, other among the placentals.

Traditional ‘Litopterna’
Diadiaphorus (Fig. 1) nests at the base of this clade. Theosodon (Fig. 1) nests as a derived taxon. Also included, but not listed: Chalicotherium and other chalicotheres.

Considering its member taxa,
the clade Litopterna (Ameghino 1889) is a junior synonym for Chalicotheridae (Gill 1872) in the LRT.

Considering its member taxa,
the clade Astrapotheria (Lydekker 1894) is a junior synonym for Meniscotheriinae (Cope 1882) and both nest within Phenacodontidae (Cope 1881).

Interatheriidae (Ameghino 1887) traditionally includes Interatherium, Protypotherium, Miocochilius and other taxa listed here. In the LRT Interatherium nests close to the ancestry of the Toxodon clade + the kangaroo clade within Metatheria. By contrast, Protypotherium and Miocochillus nest with Homalodotherium deep within the Eutheria. Homalodotherium traditionally nests with the the metatherian Toxodon. According to the LRT, all the above taxa developed similar enough traits by convergence that all were mistakenly lumped together in the invalid placental clade ‘Notoungulata’.

This is not the first time
metatherians were split from convergent eutherians. Most creodonts are marsupial predators, phylogenetically distinct from their traditional sisters in the clade Carnivora, within the clade Eutheria (Placentalia).

New taxa added to the LRT:

  1. Hegetotherium (Fig. 1) nests with Mesotherium between Interatherium and the Toxodon clade in the Metatheria. 
  2. Diadiaphorus (Fig. 1), the horse-mimic, nests at the base of the Litopterna/Chalicotheriidae, just basal to Litolophus.

I did not know these two, so I added these two to better understand them.

References
Cassini G 2013. Skull Geometric Morphometrics and Paleoecology of Santacrucian (Late Early Miocene; Patagonia) Native Ungulates (Astrapotheria, Litopterna, and Notoungulata). Ameghiniana 50 (2):193–216. DOI: 10.5710/AMGH.7.04.2013.606