The spectacled bear (Tremarctos) is not a ‘bear’ in the LRT

Summary of today’s post:
Convergence is rampant in the clade Carnivora, and elsewhere, too, as longtime readers already know only too well. Even so, the LRT (Fig. 3) lumps and splits them all.

Figure 1. Tremarctos ornatus, the spectacled bear of South America, nests with the South American bush dog (Fig. 2) in the LRT (figure 3).

Figure 1. Tremarctos ornatus, the spectacled bear of South America, nests with the South American bush dog (Fig. 2) in the LRT (figure 3).

Most mammal workers consider the spectacled bear,
South America’s only ‘bear’ (genus: Tremarctos ornatus; Fig. 1), a singular bear, genetically and phylogenetically distinct from all other bears. That’s why I added it to the LRT (Fig. 3), where no taxon stands alone.

Figure 2. The South American bush dog, Speothos, nests with the South American spectacled bear, Tremactos, in the LRT.

Figure 2. The South American bush dog, Speothos, nests with the South American spectacled bear, Tremactos, in the LRT.

Surprisingly,
or perhaps not surprisingly, given their geographic proximity, the South American spectacled bear, Tremarctos (Fig. 1), did not nest with the other bears, like Ursus and Arctodus (Fig.3). Instead it nested with the South American bush dog, Speothos (Fig. 2). One is big, the other not so big.

Figure 2. Tremarctos skull in 3 views.

Figure 2. Tremarctos skull in 3 views.

Both the spectacled bear and bush dog are primitive
to the clade of cats + dogs + hyaenas in the LRT (Fig. 3). So, if you’re counting, that makes three origins for carnivores we call ‘bears’. In that regard ‘bears’ are similar to ‘turtles‘ (2 origins),  ‘whales‘ (2 to 3 origins), ‘diapsids‘ (2 origins) and ‘synapsids‘ (2 origins).

Figure 3. Tremarctos nest with Speothos in this subset of the LRT.

Figure 3. Tremarctos nest with Speothos in this subset of the LRT.

Distinct from prior cladograms,
in the large reptile tree (LRT, 1734+ taxa; subset Fig. 3) the South American ‘bear’ (Tremarctos) nests with the South American bush dog (Spetheos). Both nest at the base of the dog + cat + hyaena clade, several nodes apart from extant bears, like Ursus, and the extinct short-face bear, Arctodus, which arises from the wolverine (Gulo).

Figure 2. Speothos, the South American bush dog, skeleton and in vivo.

Figure 2. Speothos, the South American bush dog, skeleton and in vivo.

Speothos veanticus 
(Lund 1842; up to 75cm in length) is the extant South American bush dog, traditionally considered a basal dog. Here Speothos nests at the base of cats + hyaenas + dogs. Miacis is a similar sister basal to sea lions, both derived from another short-legged carnivore, MustelaSpeothos was first identified as a fossil, then as a living taxon. Webbed toes allow this genus to swim more effectively.

Tremarctos ornatus
(Cuvier 1825) is the extant spectacled bear. Not related to other bears, here it nests with another South American member of Carnivora, Speothos, at the base of cats + dogs + hyaenas + aardwolves.

Figure 6. The South American bush dog, Speothos, nests with Tremarctos, at the base of the cat-dog-hyaena clade in the LRT.

Figure 6. The South American bush dog, Speothos, nests with Tremarctos, at the base of the cat-dog-hyaena clade in the LRT.

This may be a novel hypothesis of interrelationships.
If not please provide the prior citation so I can promote it here. Testing taxa that have never been tested together before is what the LRT does.


References
Cuvier F 1825.  In: Geoffroy Saint-Hilaire E.; Cuvier F. (eds.) Histoire naturelle des mammifères, avec des figures originales, coloriées, dessinées d’après des animaux vivans: publié sous l’autorité de l’administration du Muséum d’Histoire naturelle (50). A. Belin, Pari
Lund PW 1842. Fortsatte bernaerkninger over Brasiliens uddöde dirskabning. Lagoa Santa d. 27 de Marts 1840. Kongelige Danske Videnskabernes Selskab Afhandlinger 9:1-16.
wiki/Bush_dog
wiki/Spectacled_bear

Mellivora enters the LRT in a clade of giant honey badgers

Finally we know more about an extinct placental clade
that no one else recognized as an extinct placental clade. Clade members in the LRT included Patriofelis, Sarkastodon and Kerberos (Fig. 1). Now a living member, the honey badger, Mellivora capensis (also Fig. 1), enters the LRT within this clade.

Marsupials or placentals?
The problem is: these three extinct hyper-carnivores have been traditionally considered creodonts and within that clade: hyaenodonts and oxyaenids.
In the large reptile tree (LRT, 1730+ taxa) creodonts are marsupials. Distinct from them, but convergent in many ways, Mellivora, Patriofelis, Sarkastodon and Kerberos nest as clade members within the placental clade, Carnivora. This newly recognized honey badger clade nests between hyper-carnirorous wolverines + short face bears and the stylinodontid + earless seal clade

The placental honey badger clade
dentally converges with the marsupial creodont clade. Don’t put your trust in teeth, as we learned earlier.

According to BioWeb.uwlax.edu
honey badgers are members of the weasel clade, Mustelidae, apart from other mustelids. In the LRT, all derived members of Carnivora, including cats, dogs, bears, seals and sea lions are all derived from the mink/weasel (genus Mustela).

Figure 1. The honey badger clade, Kerboros, Patriolfelis and Sarkastodon. The only living representative is Mellivora to scale.

Figure 1. The honey badger clade, Kerberos, Patriolfelis and Sarkastodon. The only living representative is Mellivora to scale.

Mellivora capensis (originally Viverra capensis Scherber 1777; Fig. 2) is the extant honey badger or ratel, traditionally considered close to weasels. This carnivore has few natural predators because of its thick skin and ferocious defensive abilities.

Figure 1. The honey badger (Mellivora capensis) skull.

Figure 2. The honey badger (Mellivora capensis) skull.

Imagine the unreasonable viciousness of a honey badger
expanded to the size of Sarkastodon (Fig. 1).

Figure 2. The honey badger (Mellivora capensis) skeleton.

Figure 3. The honey badger (Mellivora capensis) skeleton.

This 3:20 minute honey badger video on YouTube
went viral (95.5 million views) awhile back. Quite the character, now finally understood phylogenetically.

The LRT solves problems
others don’t even think about. Adding taxa is the solution to many phylogenetic problems.


References
Schreber, JCDv 1777. “Das Stinkbinksen”. Die Säugethiere in Abbildungen nach der Natur mit Beschreibungen. Erlangen: Wolfgang Walther. pp. 450–451.

wiki/Honey_badger
wiki/Oxyaenidae

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/

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

Daphoenus: basal to only one kind of bear-dog in the LRT

Today’s post
was inspired by a recent PBS Eons YouTube video (link below) on bear-dogs. Earlier we learned that not all bear-dogs are related to one another.

FIgure 1. Skeleton of Daphoneus.

FIgure 1. Skeleton of Daphoenus, basal to Amphicyon major, about the size of a coyote. This mount is digitigrade, but some sources report it was plantigrade, based on fossil footprints.

Daphoenus is correctly mentioned as a basal bear-dog.
It’s important to note, though, that bears are not related to dogs in the large reptile tree (LRT, 1619+ taxa). Cats and hyaenas are closer to dogs and some bear-dogs are more closely related to hyaenas and hyaenodonts (marsupials) in the LRT.

Figure 1. Two skulls attributed to Daphoneus, one with colors added.

Figure 2. Two skulls attributed to Daphoenus, one with colors added. Skull length 20cm.

Daphoenus vetus (Leidy 1853; Middle Eocene to Middle Miocene, 37-16mya). Like related dogs (genus: Canis) this mid-sized predator dug burrows for offspring nesting and hiding sites. Here it nests basal to Amphicyon major, a bear-dog related to dogs.

You can learn more
about bear-dogs here, here and here.


References
Leidy J 1853. Observations on a collection of fossil Mammalia and Chelonia from the Mauvaises Terres of Nebraska. Proc. Acad. Nat. Sci. Philad., 6: 392–394.

wiki/Daphoenus

The bush dog, first known as a fossil, enters the LRT

Figure 1. Speothos is the living bush dog from South America.

Figure 1. Speothos is the living bush dog from South America. This taxon is basal to cats + dogs + hyaenas.

The South American bush dog
Speothos veanticus (Lund 1842; up to 75cm in length; Figs. 1, 2) is traditionally considered a basal dog (family: Canidae). Here Speothos nests at the base of cats + hyaenas + aardwolves + dogs. Miacis is a similar sister basal to sea lions and both are derived from another short-legged carnivore, the European mink, Mustela. Speothos was first identified as a fossil, then as a living taxon. Webbed toes allow this genus to swim more effectively.

Figure 2. Speothos, the South American bush dog, skeleton and in vivo.

Figure 2. Speothos, the South American bush dog, skeleton and in vivo.


References
Lund PW 1842. Fortsatte bernaerkninger over Brasiliens uddöde dirskabning.Lagoa Santa d. 27 de Marts 1840. Kongelige Danske Videnskabernes Selskab Afhandlinger 9:1-16.

wiki/Bush_dog

 

The grrrr…izzly bear enters the LRT

Distinct in skull shape
from the polar bear (Ursus maritimus), the grizzly bear (Ursus arctos) (Fig. 1) had me wondering if perhaps it would nest with dogs like Canis in the large reptile tree (LRT, 1417 taxa). After all there are such things as bear-dogs (genus: Amphicyon). We also looked at the short-face bear (genus: Arctodus) derived from the wolverine (genus: Gulo).

Figure 1. Ursus arctos, the grizzly bear, nests with Ursus maritimus, the polar bear in the LRT, as expected.

Figure 1. Ursus arctos, the grizzly bear, nests with Ursus maritimus, the polar bear in the LRT, as expected.

Alas, U. arctos nested with U. martimus.
Both are bears. Both are derived from mink-weasels like Mustela (extant) and sea weasels like Puijila (Late Oligocene) + Neotherium (Middle Miocene), not dogs.

Ursus arctos (Linneaus 1758 ; up to 3m in length) is the extant grizzly bear. It has a deeper face than U. maritimus, yet nests as a sister taxon here.

Figure 2. Skull of Ursus maritimus, the polar bear. It's worthwhile noting the similarities and differences, which are more distinct than just the colors of their furry coats.

Figure 2. Skull of Ursus maritimus, the polar bear. It’s worthwhile noting the similarities and differences, which are more distinct than just the colors of their furry coats.


References
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

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.

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.

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.

The Miacis-Mustela split within Carnivora

Nesting as the proximal outgroup to all placentals in the LRT
is the slinky, omnivorous, often inverted marsupial didelphid, Caluromys. So that’s the morphology we start with. In the large reptile tree (LRT, 1376 taxa; subset in Fig. 2) Carnivora is the first placental clade to split off. Earlier we looked at the similarity in skulls between Caluromys and didelphid-like basalmost Carnivora, Volitantia, Primates, Glires and Maelestes (at the base of the tenrec-odontocete clade).

Always seeking ‘a gradual accumulation of derived traits’,
basal Carnivora, like civets (e.g. Nandinia) in the LRT are likewise slinky, omnivorous and often inverted. That starts to fade away with the raccoons, Procyon and Ailurus and later evolves to hypercarnivory in the extant mongoose (Herpestes). Based on the appearance of the mongoose sister, Cryptoprocta in Madagascar (135 mya) along with the Paleocene appearance of derived Carnivora, like Miacis and Palaeosinopa, basal Carnivora had their genesis early in the Mesozoic.

Gray 1821 defined Vivveridae
as consisting of the genera ViverraGenettaHerpestes, and Suricata. All tested taxa are basal members of the Carnivora in the LRT (subset in Fig. 2), so this clade is paraphyletic. Bowdich 1821 defined the clade Carnivora as it is used today.

Most derived Carnivora forsake their veggies
as they become highly specialized for predation. Two clades diverge from a common mongoose-like ancestor: one from a sister to Late Paleocene Miacis (Fig. 1), the other from a sister to Mustela, the European mink. Both are small, long-torsoed and short-legged still resembling the placental outgroup taxon, Caluromys.

Figure 1. Mustela and Miacis (the mink/weasel) compared to scale.

Figure 1. Mustela and Miacis (the mink/weasel) compared to scale.

In the LRT
Miacis is basal to the clade of sea lions, dogs, cats, hyaenas and kin (Fig. 2).

Miacis parvivorus (Cope 1872; Heinrich et al. 2008; 30cm in length; Late Paleocene-Late Eocene) was originally considered a pre-carnivore, but here nests as a derived member of the Carnivora, arising from a Mesozoic sister to Herpestes, the mongoose. It was a sister to Mustela and Hyopsodus in the LRT. Miacis had a full arcade of 11 teeth (x4), but the canines and carnassial were smaller. Miacis had retractable claws, like a cat, and was likely arboreal.

In the LRT
extant Mustela is basal to the clade of wolverines, bears, seals and kin (Fig. 2).

Mustela lutreola (Linneaus 1761; extant European mink; up to 43cm in length) is a fast and agile animal related to weasels and polecats. Mustela lives in a burrow. It swims and dives skilfully. It is able to run along stream beds and stay underwater for one to two minutes. Mustela is basal to PuijilaUrsus and other bears, Phoca and other seals.

Importantly 
note the relatively close affinity of dogs (Canis) and cats (Panthera), in the LRT. That becomes a factor in a genomic study below.

Figure 3. Subset of the LRT focusing on Carnivora, the basalmost eutherian clade. Talpa is the European mole. Shrews and shrew-moles nest within the clade Glires.

Figure 2. Subset of the LRT focusing on Carnivora, the basalmost eutherian clade. The two derived clades arising from Mustela and Miacis are shown here.

 

 

How does the clade Carnivora look to traditional paleontologists?
Flynn et al.2005 (Fig. 3) attempted to “assess the impact of increased sampling on resolving enigmatic relationships within the placental clade, Carnivora, by using genomic testing” (so no fossils there). In Flynn et al. the extant Carnivora have their first dichotomy splitting cats from dogs (which are also closely related in the LRT, Fig. 2). No outgroup appears in the Flynn et al. cladogram, which mixes primitive and derived taxa, relative to the LRT. Note, seals + sea lions are monophyletic when fossils are not included. Minks are highly derived here, the opposite of the topology in the LRT. So some relationships are simply inverted, which sometimes happens when the outgroup is not correctly defined.

Figure 4. Carnivora according to Flynn et al. 2005 based on genomic testing.

Figure 3. Carnivora according to Flynn et al. 2005 based on genomic testing. Cryptoprocota is a ‘Malagasy carnivore.”

Once again,
genomic testing does not replicate phenomic testing in deep time. That’s why the LRT is here. So you can test traits vs. genes, always seeking ‘a gradual accumulation of traits’ that echoes or models evolutionary events, without relying on the hope and faith that must come from any analysis that omits fossil taxa. The LRT also provides a list of outgroup taxa back to Devonian tetrapods.

Based on a trait list,
or a photo (Fig. 1), it is easy to see that Miacis and Mustela are closely related. However, in phylogenetic analysis each of these sisters nest at the base of a different derived clade of Carnivora. Cats and dogs remain closely related in the LRT, but both are highly derived relative to the outgroup and basal taxa. The LRT reveals cats are convergent with basal Carnivora, like the cat-like civets.

References
Bowdich TE 1821. An analysis of the natural classifications of Mammalia, for the use of students and travelers. 115 pp.
Cope ED 1872. Third account of new vertebrata from the Bridger Eocene of Wyoming Territory. Proceedings of the American Philosophical Society 12(86): 469-472.
Flynn JJ, Finarelli JA, Zehr S, Hsu J, Nedbal MA 2005. Molecular phylogeny of the Carnivora (Mammalia): Assessing the impact of increased sampling on resolving enigmatic relationships. Systematic Biology. 54 (2): 317–37.
Heinrich RE, Strait SG and Houde P 2008. Earliest Eocene Miacidae (Mammalia: Carnivora) from northwestern Wyoming. Journal of Paleontology. 82 (1): 154–162.
Linneaus C von 1761. Fauna Suecica sistens Animalia Sueciae Regni: Mammalia, Aves, Amphibia, Pisces, Insecta, Vermes. Distributa per Classes, Ordines, Genera, Species, cum Differentiis Specierum, Synonymis Auctorum, Nominibus Incolarum, Locis Natalium, Descriptionibus insectorum. Editio altera, auctior. Stockholmiae: L. Salvii, 48 + 578 pp.,

wiki/Mustela
wiki/Miacis
wiki/Hyopsodus
wiki/Carnivora

Machaeroides and Kerberos enter the LRT

Machaeroides and Kerberos enter the LRT
as related to one another, and both basal to clades within the Carnivora, apart from prior sister candidates. Apparently taxon exclusion was a problem in earlier analyses. Taxon exclusion is minimized in the large reptile tree (LRT, 1364 taxa).

Figure 1. Subset of the LRT focusing on the Mustela clade within the Carnivora with the addition of Kerberos and Machaeroides.

Figure 1. Subset of the LRT focusing on the Mustela clade within the Carnivora with the addition of Kerberos and Machaeroides.

Machaeroides eothen (Matthew 1909; early Eocene, 56mya) has been difficult to nest, with some experts labeling this genus close to Oxyaena, a marsupial creodont. With more taxa sabertooth Machaeroides nests at the base of the StylinodonPsittacotherium clade within the clade Carnivora. Canines are emphasized in this clade. The maxilla contacts the orbit above the lacrimal.

Figure 2. Two Machaeroides skulls in the three views.

Figure 2. Two Machaeroides skulls in the three views.

Kerberos langebadreae (Solé et al. 2015; Middle Eocene, 45 mya) was originally described as sister to the marsupial Hyaenodon. Here Kerberos nests at the base of the Sarkastodon and Patriofelis clade within the larger placental clade, Carnivora. The skull is lower and longer and includes more premolars along with smaller canines.

Figure 3. Kerberos skull in 3 views and colored using DGS methods.

Figure 3. Kerberos skull in 3 views and colored using DGS methods. Perhaps the posterior skull was lower in vivo to match the jaw joint.

References
Matthew WD 1909. The Carnivora and Insectivora of the Bridger Basin, middle Eocene. Memoirs of the American Museum of Natural History 9:289-567.
Solé F, Amson E, Borths M, Vidalenc D, Morlo M, Bastl K 2015. A New Large Hyainailourine from the Bartonian of Europe and Its Bearings on the Evolution and Ecology of Massive Hyaenodonts. (Mammalia). PLoS ONE 10(9): e0135698.
doi:10.1371/journal.pone.0135698