The short-faced bear (Arctodus) is a giant wolverine in the LRT.

Yesterday we looked at three bears, Ursus, Arctodus (Fig. 1) and Ailuropoda (the polar bear, the short-faced bear and the panda bear). They do not form a single bear clade in the large reptile tree (LRT, 1299 taxa), but each is more closely related to small weasels and grew to bear-size by convergence.

For instance,
Arctodus is most closely related to today’s wolverine (Gulo gulo, Figs. 1, 2) among tested taxa, and the similarities are immediately apparent. Have they ever been tested together before? Let me know if this is so.

Figure 1. Arctodus (shor-faced bear) skeleton compared to the smaller Gulo (wolverine) skeleton. Both have similar proportions. Arctodus is larger than 3m, while Gulo is about 1m in length.

Figure 1. Arctodus (shor-faced bear) skeleton compared to the smaller Gulo (wolverine) skeleton. Both have similar proportions. Arctodus is larger than 3m, while Gulo is about 1m in length.

Arctodus simus (Leidy 1854; Cope 1874; up to 3 to 3.7m tall) is the extinct short-faced bear, one of the largest terrestrial mammalian carnivores of all time. Long limbs made it a fast predator. Being related to the wolverine made it short-tempered and dangerous.

Figure 2. Long-legged Gulo, the wolverine, is most similar to Arctodus, the short-faced bear in the LRT.

Figure 2. Long-legged Gulo, the wolverine, is most similar to Arctodus, the short-faced bear in the LRT. That’s a penile bone, not a prepubis.

Gulo gulo (Linneaus 1758; up to 110 cm in length) is the extant wolverine, a ferocious predator resembling a small bear. Note the tail length is midway between the long tail of weasels and the short tail of birds.

Figure 1. Subset of the LRT focusing on the Carnivora with tan tones on the bears newly added.

Figure 3. Subset of the LRT focusing on the Carnivora with tan tones on the bears newly added.

The red panda
(Ailurus) was also added to the LRT (Fig. 3) and, to no one’s surprise, nests with the raccoon, Procyon apart from the giant panda.

Figure 4. Gulo skull in lateral and dorsal views. Compare to Arctodus in figure 5.

Figure 4. Gulo skull in lateral and dorsal views. Compare to Arctodus in figure 5. The male skull has the larger and longer parasagittal crest.

The skulls of Gulo and Arctodus
(Figs. 4, 5) despite their size differences, are quite similar. Both display sexual dimorphism.

Figure 5. Arctodus (short-faced bear) skull in lateral view. Compare to figure 4.

Figure 5. Arctodus (short-faced bear) skull in lateral view. Compare to figure 4.

Taxon inclusion
sheds light on phylogenetic interrelationships.

If you have an interest in wolverine evolution,
I suggest you use the keyword “Gulo” or you’ll end up learning about Marvel’s superhero, also named Wolverine.

References
Cope ED 1879. The cave bear of California. American Naturalist 13:791.
Leidy 1854. Remarks on Sus americanus or Harlanus americanus, and on other extinct mammals. Proceedings of the Academy of Natural Sciences of Philadelphia 7:90.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

wiki/Gulo
wiki/Short-faced_bear

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These three ‘bears’ are not monophyletic

More heresy:
When I added three bears (polar, short-face and panda (= Ursus, Arctodus and Ailuropoda) to the large reptile tree (LRT, 1298 taxa) they nested apart from dogs and bear-dogs AND they did not nest together. Rather all three arose from separate types of weasels (= Mustela, Puijila, and Gulo).

Figure 1. Subset of the LRT focusing on the Carnivora with tan tones on the bears newly added.

Figure 1. Subset of the LRT focusing on the Carnivora with tan tones on the bears newly added.

Ailuropoda melanoleuca (David 1869) is the extant giant panda. Here it nests between the weasel, Mustela and the rest of the bear/seal clade. This odd carnivore eats bamboo. The centrale extends beyond the wrist forming a new medial digit, the panda’s ‘thumb’.

Ursus maritimus (Phipps 1774; up to 3m in length) is the extant polar bear, a hypercarnivore restricted to cold climates. Bears split from other Carnivora, specifically the giant weasel, Puijila, some 38mya.

Arctodus simus (Leidy 1854; Cope 1874; up to 3 to 3.7m tall) is the extinct short-faced bear, one of the largest terrestrial mammalian carnivores of all time. Here it nests as a giant wolverine (genus: Gulo, also newly added). Long limbs made it a fast predator.

More details on these taxa coming soon.

References
Cope ED 1879. The cave bear of California. American Naturalist 13:791.
Kellogg AR 1931. Pelagic mammals of the Temblor Formation of the Kern River region, California. Proceedings of the California Academy of Science 19(12):217-397.
Kohno N, Barnes LG and Hirota K 1994. Miocene fossil pinnipeds of the genera Prototaria and Neotherium (Carnivora; Otariidae; Imagotariinae) in the North Pacific Ocean: Evolution, relationships and distribution. The Island Arc. 3(4): 285–308. doi:10.1111/j.1440-1738.1994.tb00117.x
Kumar V et al. 2017. The evolutionary history of bears is characterized by gene flow across species. Nature.com/scientificreports. 7:46487
Leidy 1854. Remarks on Sus americanus or Harlanus americanus, and on other extinct mammals. Proceedings of the Academy of Natural Sciences of Philadelphia 7:90.
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.,
Phipps CJ 1774. A voyage towards the North Pole: undertaken by His Majesty’s command. J. Nourse, London.

wiki/Ursus
wiki/Puijila
wiki/Neotherium
wiki/Mustela
wiki/Giant_panda
wiki/Short-faced_bear

 

The walrus (genus: Odobenus) joins the LRT

No surprises here.
Odobenus, the walrus (Figs. 1, 2), nests with the seal, Phoca, in the large reptile tree (LRT, 1280 taxa). But I think you’ll see, the division between seals and walruses runs deep, perhaps with some parallel development of the flippers, fat, etc.

Figure 1. Walrus skeletons, swimming and walking, plus a view of the teeth, which barely erupt and cannot be seen in lateral view.

Figure 1. Walrus skeletons, swimming and walking, plus a view of the teeth, which barely erupt and cannot be seen in lateral view. Yes, that extra bone between the legs of the lower specimen resides in the penis.

Odobenus rasmanus (Linneaus 1758) is the extant walrus. The canines are much enlarged here. The other teeth are flat and barely erupt. The naris is elevated. The jaw joint is aligned with the bottom of the jaw and the retroarticular process is much reduced. The scapula is robust.

FIgure 2. Walrus skull with bones colorized.

FIgure 2. Walrus skull with bones colorized.

Walruses eat bivalve mollusk scraped from the sea floor bottom. 
According to Wikipedia, “The walrus’s body shape shares features with both sea lions (eared seals: Otariidae) and seals (true seals: Phocidae). As with otariids, it can turn its rear flippers forward and move on all fours; however, its swimming technique is more like that of true seals, relying less on flippers and more on sinuous whole body movements.[4] Also like phocids, it lacks external ears.” Earlier the LRT recovered separate terrestrial ancestors for seals and sea lions.

Figure 3. Ancestral walrus taxa from Robert Boessenecker. See references below.

Figure 3. Ancestral walrus taxa to scale from Boessenecker. 2014. Compare Neotherium to Puijila in figure 4. Neotherium nests closer to bears.

Neotherium (Fig. 3)
shares a long list of traits with Puijila, which was originally hailed as a last common ancestor for seals, sea lions and walruses (Fig. 4). In the LRT Pujilia is not basal to sea lions. In the LRT Neotherium nests with Ursus, the bear, not with Odobenus, the walrus.

What are the giant canines used for?
According to Wikipedia, “Tusks are slightly longer and thicker among males, which use them for fighting, dominance and display; the strongest males with the largest tusks typically dominate social groups.  Tusks are also used to form and maintain holes in the ice and aid the walrus in climbing out of water onto ice. Analyses of abrasion patterns on the tusks indicate they are dragged through the sediment while the upper edge of the snout is used for digging.”

You can think of walruses
as aquatic bears or aquatic stylinodontids (Fig. 4). Ursus and Neotherium are sisters to the last common ancestor (LCA) of walruses and stylinodontids with Puijila the LCA of bears and walruses.

Figure 4. Ursus maritimus compared to ancestral and related taxa, Mustela, Puijila and Stylinodon. Seeing them together makes comparisons easier.

Figure 4. Ursus maritimus compared to ancestral and related taxa, Mustela, Puijila and Stylinodon. Seeing them together makes comparisons easier.

Figure 5. Puijila nests down the line from the walrus, a trait you can see it its profile and general morphology. Compare to Neotherium in figure 4.

Figure 5. Puijila nests down the line from the walrus, a trait you can see it its profile and general morphology. Compare to Neotherium in figure 4.

References
Boessenecker R 2014. The evolutionary history of walruses, parts1–5:

  1. http://coastalpaleo.blogspot.com/2014/08/the-evolutionary-history-of-walruses.html
  2. http://coastalpaleo.blogspot.com/2014/08/the-evolutionary-history-of-walruses_26.html
  3. http://coastalpaleo.blogspot.com/2014/09/the-evolutionary-history-of-walruses.html
  4. http://coastalpaleo.blogspot.com/2014/09/
  5. http://coastalpaleo.blogspot.com/2014/11/the-evolutionary-history-of-walruses.html

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.

wiki/Walrus

Bears are giant weasels

This post
and the two previous ones here and here were prompted by a YouTube video on Bear-dogs. Today we’ll talk about bears and their place in the cladogram of the Carnivora. Turns out they are not related to dogs (contra Matthews 1930, Wang 1994), so there should be no such thing as a bear-dog (contra Tomiya and Tseng 2016). Taxon exclusion, as usual, is the problem with these earlier, more focused studies.

Figure 1. Traditional family tree of dogs, bears and their allies from Matthew 1930 reprinted in Wang 1994. This is invalidated when more taxa are added in the LRT.

Figure 1. Traditional family tree of dogs, bears and their allies from Matthew 1930 reprinted in Wang 1994. This tree is invalidated when more taxa are added in the LRT.

DNA has it backwards.
Flynn et al. 2005 recovered extant Carnivora relationships, but nested cats and dogs at the base of the clade (Fig. 2). Count the toes. Basal taxa, like weasels, have five toes in contact with the substrate. And which taxa look most like the outgroup arboreal didelphids? Civets and weasels. And where are the civets? They were not included. Ironically, this is an example of DNA matching trait analysis, except Flynn et al. reversed the order, had the cladogram upside-down. Of course, the lack of fossils obscures more precise relationships and omits many key extinct taxa. We looked at problems with DNA cladograms here, here and here.

Figure 1. Carnivora based on a molecular phylogeny in Flynn 2005. Compare to same clade in figure 2.

Figure 2. Carnivora based on a molecular phylogeny in Flynn 2005. Compare to same clade in figure 2. This one is upside down by comparison to the LRT. Weasels and raccoons should be more primitive.

By contrast
the large reptile tree (LRT, 1278 taxa; subset Fig. 3) nest cats and dogs as the most highly derived members of the Carnivora. They only have four toes in contact with the substrate and they look different than outgroup didelphids. And they are highly arboreal. Civets (genus: Nandinia) and vulpavids (genus: Vulpavus) nest at the base of the Carnivora in the LRT (Fig. 3). Civet-like arboreal didelphids (genus: Caluromys) are outgroups.

Bears,
like Ursus maritimus (= polar bear; Fig. 4) nest between the weasels (genera: Mustela and Puijila) and the giant weasels (genus: Stylinodon) with teeth that continued growing throughout its lifetime and giant canines that came to resemble rodent-like incisors. The aquatic forms, Palaeonsinopa and seals like Phoca are bear cousins.

Figure 3. Subset of the LRT focusing on Carnivora, a basal placental mammal clade. Note cats and dogs in derived nodes.

Figure 3. Subset of the LRT focusing on Carnivora, a basal placental mammal clade. Note cats and dogs in derived nodes. Miacis is basal to sea lions, Amphicynodon is basal to stylinodontids.

Puijila
(Rybczynski et al., 2009) was originally considered “a walking seal”, but here links weasels to bears and weasels to seals (but not sea lions, contra Rybczynski et al., 2009, because the Pinnipedia is diphyletic).

Remember:
(Don’t trust teeth alone because they change with diet. Always score traits for the entire skull and body whenever possible to get the closest possible relatives from a long list of candidates).

Figure 4. Ursus maritimus compared to ancestral and related taxa, Mustela, Puijila and Stylinodon. Seeing them together makes comparisons easier.

Figure 4. Ursus maritimus compared to ancestral and related taxa, Mustela, Puijila and Stylinodon. Seeing them together makes comparisons easier.

Earlier we looked at another pair of giant weasels, now also allied to bears, the traditionally enigmatic Stylinodon (Fig. 5) and Psittacotherium.

Let’s talk about the traditional origin of bears.
There is a mink-sized early Oligocene taxon known from the front half of a skull, Amphicynodon (Fig. 5; Wang , McKenna and Dashzeveg 2005) that has been the traditional ancestor of bears. In the LRT Amphicynodon nests close to bears, but closer to Stylinodon and Psittacotherium, taxa never tested with Amphicynodon before.

Figure 5. Amphicynodon skull from Wang et al. 2005, restored with colors.

Figure 5. Amphicynodon skull from Wang et al. 2005, restored with colors. Note the similarity to the bear-sized Stylinodon in figure 4, rather than the bear in figure 4.

Earlier the LRT split seals from sea lions. Both arose from separate clades of terrestrial ancestors with a last common ancestor near Herpestes, the mongoose.

Earlier the LRT nested Vulpavus close to the outgroup marsupial, Caluromys.

References
Flynn JJ, Finarelli JA, Zehr S, Hsu J and 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.
Matthew WD 1930. The Phylogeny of Dogs, Journal of Mammalogy 11(2):117–138,
Rybczynski N, Dawson MR and Tedford RH 2009. A semi-aquatic Arctic mammalian carnivore from the Miocene epoch and origin of Pinnipedia. Nature. 458 (7241): 1021–24.
Wang X 1994. Phylogenetic systematics of the Hesperocynoninae (Carnivora: Canidae). Bulletion of the American Museum of Natural History 221: xx pp. PDF
Wang X, McKenna MC and Dashzeveg D 2005. Amphicticeps and Amphicynodon
(Arctoidea, Carnivora) from Hsanda Gol Formation, Central Mongolia and Phylogeny of
Basal Arctoids with Comments on Zoogeography. American Museum Novitates 3483:17pp.
Wang  X and Tedford RH 2008. How dogs came to run the world. Natural History 117(6):18–23.

wiki/Polar_bear
wiki/Bear#Evolution
wiki/Stylinodon
wiki/Mustela
wiki/Ursus
wiki/Psittacotherium
wiki/Wortmania
wiki/Puijila
wiki/Amphicynodon

Epicyon: the largest known canid? Let’s compare.

This post
and the one from yesterday were prompted by a YouTube video on Bear-dogs (Fig. 1, click to play) featuring such bone-crushing dogs as Epicyon (Fig. 2) considered by bear-dog afficiandos as one of the largest, if not THE largest bear dog.

Turns out Epicyon is not the beardog with the largest skull.
Amphicyon takes the prize (if the scale bars are correct!), but, then again, look, it is no larger than the extant Siberian wolf (Canis lupus, Fig. 2). So why bring up superlatives and ‘bear-dog’ comparisons in PBS videos when Epicyon and Amphicyon are just wolfish genera of wolfish size?

Figure 2. Epicyon compared to Amphicyon,Ysengrinia and Canis lupus, the Siberian wolf. They are all about the same size.

Figure 2. Epicyon compared to Amphicyon,Ysengrinia and Canis lupus, the Siberian wolf. They are all about the same size. Another species of Ysengrinia (jawbone only) is placed upon Y. americana.

Another specimen attributed to Amphicyon,
(A. galushi, Hunt 2003; Fig. 3), nests not with dogs, but with hyaenas, if given the opportunity. That’s the value of the large reptile tree (LRT, 1278 taxa). It provides to every one of its taxa the opportunity to nest anywhere on a huge and growing tree. So, congratulations Amphicyon bear-dog lovers, we have a wastebasket genus here.

But wait… it gets worse.

FIgure 2. Amphicyon galuschai nests closer to hyaenas, like Crocuta in the LRT.

Figure 3. Amphicyon galuschai nests closer to hyaenas, like Crocuta in the LRT. Drawing from Hunt 2003.

Yet another specimen attributed to Amphicyon
nests not with dogs, nor placentals, but with basal marsupial carnivores known as creodonts or arctocyonids (Fig. 4). We looked at that issue here a year ago. Funny that I chose the outlier to nest the genus. Over the last few days I discovered the convergence in several taxa attributed to this genus by testing other specimens attributed to this genus.

Figure 3. Amphicyon compared to basal marsupial carnivores (Creodonta) including a marsupial specimen mistakenly assigned to Amphicyon.

Figure 4. Amphicyon compared to basal marsupial carnivores (Creodonta) including a marsupial specimen mistakenly assigned to Amphicyon to scale. This purported Amphicyon nests with Arctocyon and Thylacinus, two dog-like opossum descendants.

Amphicyon longiramus (Lartet 1836, Blainville 1841; Mid-Miocene to Pliocene, 16–9mya; up to 2.5m; Fig. 3) is the wide ranging bone-crushing, ‘bear-dog’. This is a wastebasket taxon with some specimens (A. longiramus) related to dogs, others (A. galushi) related to hyaenas (maybe that’s where the bone-crushing aspect came in), while still others (lower right above) nesting between Arctyocyon and Thylacinus among the marsupials.

Figure x. An early borophagine and a larger later one, Epicyon.

Figure x (added after initial publication). An early borophagine. Arachaeocyon and a larger later one, Borophagus, animated from Wang 1994. Now, those are bone-crushing molars! Note the relatively smaller auditory bulla in the larger genus. Neither have been added to the LRT.

Hunt 2003 
also found felid (cat-like) traits in the skeleton of Amphicyon galuschai (Fig. 3), the specimen that nests with hyaenas here (Fig. 7). “The North American species of Amphicyon (A. galushai, A. frendens, A. ingens) most likely adopted ecological roles similar to the large living felids (in particular, the lion Panthera leo). Their robust skeleton with powerful forelimbs, massive clawed feet, heavily muscled jaws with large canines, and a composite crushing/shearing dentition suggest a mobile predator that most likely stalked and ambushed prey from cover, overpowering its victims through sheer size and strength.”

Figure 6. A large Canis lupus to scale with Amphicyon major.

Figure 5. A large Canis lupus to scale with Amphicyon major.

Amphicyonidae was erected by Haeckel (1886) who thought the clade was more closely related to ursids (bears). Wikipedia reports, “there is increasing evidence that they may be basal caniforms.”  Statements like this, even tentative statements like this, suffer from taxon exclusion, a problem that is minimized by the LRT based on its wide gamut of included taxa. Tomiya and Tsend (2016, Fig. 6) suffers distinctly from taxon exclusion.

Figure 7. Tomiya and Tseng 2016 suffers from taxon exclusion. None of the taxa discussed in the text is listed here, and vice versa, other than Miacis,

Figure 6. Tomiya and Tseng 2016 suffers from taxon exclusion. None of the taxa discussed in the text is listed here, and vice versa, other than Miacis, which is ancestral to sea lions, not dogs nor bears nor beardogs in the LRT.

A subset of the LRT
(Fig. 7) brings relationships into clarity because such a wide gamut of taxa are tested and nested in full resolution. Not sure why this continues to be controversial and heretical when it resolves so many long-standing issues in full resolution and includes every option.

Figure 3. Subset of the LRT focusing on Carnivora, a basal placental mammal clade. Note cats and dogs in derived nodes.

Figure 7. Subset of the LRT focusing on Carnivora, a basal placental mammal clade. Note cats and dogs in derived nodes.

One more in this series coming tomorrow
as we nest bears in the LRT, not with dogs, nor with raccoons.

References
Blainville HM 1841. Osteographie et description iconographique des Mammiferes récentes et fossiles (Carnivores) 1, 2 Paris.
Hunt RM 2003. Intercontinental Migration of Large Mammalian Carnivores: Earliest Occurrence of the Old World Beardog Amphicyon (Carnivora, Amphicyonidae) in North America. Bulletin of the American Museum of Natural History. 279: 77–115. doi:10.1206/0003-0090(2003)279<0077:c>2.0.co;2.
Lartet E 1836. Nomenclature des mammife`res et des coquilles qu’il a trouve´s dans un terrain d’eau douce pre`s de Simorre et de Sansan (Gers). Bulletin de la Société Géologique de France 7: 217–220.
Tomiya S and Tseng ZJ 2016. Whence the beardogs? Reappraisal of the Middle to Late Eocene ‘Miacis’ from Texas, USA, and the origin of Amphicyonidae (Mammalia, Carnivora). Royal Society Open Science. DOI: 10.1098/rsos.160518
Wang X-M and Tedford RH 2008. Dogs: Their Fossil Relatives and Evolutionary History. New York: Columbia University Press, p10-11, 29

wiki/Amphicyon
wiki/Ysengrinia
wiki/Epicyon

Hesperocyon: more cat than dog. Prohesperocyon: more mongoose than dog.

This post
and the next one (coming tomorrow) were prompted by a YouTube video on Bear-dogs (Fig. 1, click to play) that promoted both Prohesperocyon (Fig. 2, Wang 1994; “before Western dog”) and Hesperocyon (Scott 1890, “Western dog”) as basal dogs (clade: Canidae).

Cats and dogs are close relatives
in the large reptile tree (LRT, 1277 taxa). Aardwolves (genus: Proteles) nest with dogs and hyaenas (genus: Crocuta) nest with cats.

Prohesperocyon (Fig. 2) nests between raccoons and mongooses + moles, not with dogs (Fig. 4).

Hesperocyon (Figs. 3, 5) nests with Panthera, the lion (Fig. 6), rather than Canisthe wolf (Fig. 7).

Unfortunately,
the PBS Eons video (Fig. 1) was working from old data (Wang 1994) suffering from taxon exclusion.

Figure 1. Prohesperocyon was considered a basal dog in the video, but here nests between raccoons and mongooses + moles.

Figure 2. Prohesperocyon was considered a basal dog in the video, but here nests between raccoons and mongooses + moles.

Wang 1994 reported, “The subfamily Hesperocyoninae includes the oldest and most primitive members of the Canidae.” The LRT could not validate that statement (see Fig. 4) because either Hesperocyoninae is polyphyletic or it is a junior synonym for Carnivora.  Wang reported, “A phylogenetic analysis is performed using cladistic methodology, with Miacis as an outgroup.” In the LRT Miacis is basal to sea lions and Prohesperocyon nests as an outgroup to Miacis.

Figure 1. Hesperocyon skeletons. Note the upraised claws.

Figure 3. Hesperocyon skeletons. Note the upraised claws. That long pink bone between the legs in the photo is a baculum or penis bone.

For Hesperocyon,
the short, steep facial profile, high postorbital processes of the jugal, the extremely large upper molar 1, the longer braincase, the elevated cat-like way that Hesperocyon carried its claws, and a long suite of other traits all nest Hesperocyon with cats, not dogs (Fig. 4).

Figure 3. Subset of the LRT focusing on Carnivora, a basal placental mammal clade. Note cats and dogs in derived nodes.

Figure 4. Subset of the LRT focusing on Carnivora, a basal placental mammal clade. Note cats and dogs in derived nodes.

Some specimens wrongly attributed to Hesperocyon
that have a longer muzzle may be related to dogs, but not the specimen data presented here (Figs. 3, 5).

Figure 2. Two Hesperocyon skulls in lateral view. Note the short, high muzzle, the raised postorbital process of the jugal, the giant, cat-like upper molar.

Figure 5. Two Hesperocyon skulls in lateral view. Note the short, high muzzle, the raised postorbital process of the jugal, the giant, cat-like upper molar.

Don’t let the names fool you.
Even the raccoon (genus: Procyon) has a dog-oriented name (= “before dog”). Worse yet cats and hyaenas are more closely related to dogs than is the “before dog” or the “Western dog.”

Figure 1. Panthera leo skull and skeleton. This taxon nests basal to hyenas + wolves.

Figure 6. Panthera leo skull and skeleton. This taxon nests with hesperocyon in the LRT.

That’s why the LRT is here.
To clarify traditional relationships with more inclusive testing of a wider gamut of taxa.

I hope you’ll agree that it is indeed odd,
that even the strongest of clues, like the well-documented retractable claws of Hesperocyon (also mentioned in the PBS Eons video (Fig. 1), were not cause enough for mammal workers to take another look at their cladograms and paradigms. BTW, retractable claws are not a trait scored by the LRT.

Figure 3. Canis lupus, the wolf, nests as a sister to Crocuta in the LRT.

Figure 7. Canis lupus, the wolf, nests as a sister to Crocuta in the LRT.

We’ll take a look at the big bear-dogs tomorrow,
but you can get a sneak peek here (Fig. 4).

References
Scott 1890 WB. Hesperocyon. The dogs of the American Miocene. Princeton Coll. Bull., 2(2):37–39.
Wang X 1994. 
Phylogenetic systematics of the Hesperocyoninae (Carnivora, Canidae). Bulletin of the American Museum of Natural History. 221: 1–207.

wiki/Hesperocyon
wiki/Prohesperocyon

SVP abstracts 2017: Are pinnipeds (seals/sea lions) monophyletic?

Earlier the large reptile tree (LRT, 1050 taxa) invalidated the former clade Pinnipedia (seals and kin) as it split it into two clades, each derived from separate terrestrial limbed ancestors. Now comes this well written abstract from Paterson et al. 2017 that brings up all the right questions. The question is, did it have the right outgroups? I like how they say they are going to test tradition with genes and fossils. Unfortunately, they might lack a few pertinent outgroup taxa.

Figure 1. Phoca the phocid seal is most closely related to Palaeosinopa of all tested taxa.

Figure 1. Phoca the phocid seal is most closely related to Palaeosinopa of all tested taxa.

From the Paterson et al. abstract:
“Monophyly of pinnipeds is well-established. However, it is difficult to reconcile a monophyletic origin of pinnipeds with the disparate locomotor modes and associated skeletal morphologies observed between the extant families. Furthermore, the fossil record suggests many of the conventional pinniped synapomorphies arose independently, as many are not present in fossil taxa (Eotaria, Prototaria, Devinophoca) that have been firmly established as early-diverging crown members of the three extant families (e.g., homodont dentition, loss of fossa muscularis, reduction of nasolabialis fossa, loss of M2/m2, fusion of tibia and fibula, reduction of fossa for teres femoris).

“Herein, we test the hypothesis that otarioids (otariids + odobenids) and phocids share a common ancestor that was not yet fully aquatic. In the present analysis, a total evidence approach was employed to investigate the relationships of 19 extant and 37 fossil caniforme genera. Our analysis sampled five genes totalling 5490 bp and 184 morphological characters, sampled relatively evenly across morphological partitions (cranial, dental, postcranial). With Canis as an outgroup, Bayesian inference produced strong support for a monophyletic origin of pinnipeds, and recovered Puijila and Potamotherium as early-diverging pinnipedimorphs

(Ursidae(Musteloidea(Potamotherium(Puijila(Enaliarctos, (Desmatophocidae(Phocidae,(Odobenidae, Otariidae)))))))). Similar results were obtained from Bayesian and parsimony analyses of a morphology-only data set, a cranial-only data set, a craniodental-only data set, and a post-cranial-only data set. Bayesian inference of morphology-only partitions recovered Mustelavus and a sister grouping of Allocyon + Kolponomos along the stem to later-diverging pinnipedimorphs. The parsimony analysis recovered 20 synapomorphies of Potamotherium + Puijila + Pinnipedimorphs, and nine synapomorphies for a crown group Pinnipedia, to the exclusion of the pinnipedimorphs. In spite of a reinterpretation of the plesiomorphic state of many previously proposed pinniped synapomorphies, there remain more than enough pinniped synapomorphies to exclude the semi-aquatic  pinnipedimorphs, thereby challenging our hypothesis of a dual origin of flippers. However, this may be an artifact of a Bayesian model of morphological inference which, among other limitations, cannot model direction evolution, and thus, may be incapable of capturing parallel evolution in such a context.”

Figure 3. Zalophus, an otariid seal, is most closely related to Hyoposodus among tested taxa in the LRT

Figure 2. Zalophus, an otariid seal lion, is most closely related to Hyoposodus among tested taxa in the LRT. Seals and sea lions are incredibly alike. It’s a tribute to the authority of the LRT that it was able to separate these two clades, both derived from distinct and different terrestrial ancestors.

I don’t have their complete taxon list. 
If it includes the pertinent taxa that split the Pinnipedia, then we’ll have to reexamine the data. If not, it’s still worth comparing.

Their choice of
Canis (the wolf/dog) as an outgroup is a weakness. They should have let a large gamut of mammals decide the outgroup(s) for pinnipeds. I don’t see Palaeosinopa in their published taxon list, but it might be in there somewhere. In the LRT it nests with phocids, like Phoca and the limbed carnivore, PuijilaI don’t see Miacis and Hyopsodus in their taxon list. In the Paterson et al. study Enaliarctos nests basal to all extant pinnipeds, but in the LRT, Enaliarctos nests with Miacis, Hyopsodus and Zalophus, the California sea lion, an otariid. So, it looks like taxon exclusion is present here, yet again. Paterson et al. appear to be missing some pertinent outgroups. The last common ancestor of seals and sea lions goes back to something like Herpestes, the mongoose, and/or Procyon, the raccoon.

Seals and sea lions are incredibly alike.
It’s a tribute to the authority of the LRT that it was able to separate these two clades, both derived from distinct and different terrestrial ancestors.

References
Paterson RS et al. 2017. The evolution of pinnipeds from a terrestrial ancestor: the possibility of parallel evolution within a monophyletic framework. SVP abstracts 2017.