Eric Shipton yeti snowprint revisited

So odd, so different,
it might just be real. It all started with a photograph by Eric Shipton from decades ago of a single large footprint in the snow of the Himalayan Mountains (Fig. 1). Here I simply added bones based on the apparent primate nature of the trackmaker and included gorilla pedal data for comparison.

Figure 1. Eric Shipton snowprint of Yeti with hypothetical bones and PILs applied. At top is pes of Gorilla. Ice pick for scale. The impressions of digits 2 and 3 indicate logical interpretation with toe drag to avoid broken toe /#2 and nussubg toe #3 impression.

Distinct from human tracks,
the big toe of the Himalayan trackmaker is much bigger and does not extend as far as in humans. The tracks is wider than in humans. Digit 2 appears to be shorter than in humans.

Several years ago an expert of yeti and bigfoot, Dr. Jeff Meldrum,
appeared on ‘Joe Rogan Questions Everything’ #2 with Duncan Trussell (audio only, click to listen via YouTube). While Joe and Duncan tried to add levity to the discussion, Dr. Meldrum portrayed the facts as he knew them, keeping speculation to a minimum.

We touched on this subject
about a year ago earlier here.

New yeti tracks?

Photos from Mountaineers in the Indian Army
show several long (32″) prints in the snow, one directly in front of the other. The New York Times covered the story (see citation below).

Figure 1. 2019 yeti tracks found in Nepal and posted online. That’s an ice pick alongside for scale. Is this a combo track? See text.

These are definitely not bear tracks.
The large digit 1 tells us they were made by a primate… if this is a single impression.

The only question is…
did the primate use its own feet to make foot tracks, or was it wearing yeti shoes? Or is this a combination track?

Unfortunately
only one footprint is shown. It would have been more useful to see a complete set, to see if there was a right foot also, and what variation there might be as the trackmaker navigated the terrain, its own weight shifts, etc.

It’s a nice first step.
To its credit, the trackmaker had parallel interphalangeal lines (PILs). Cheap knock-offs and fakes generally overlook this detail. The NY Times.com story suggests it is a combination track from a mama bear and her cub. We should consider all possibilities.

---

References
NY Times.com story

Gorilla skull compared

Today’s blog is essentially a silent movie.
Just sit back and compare these two skulls: Gorilla gorilla vs. Homo sapiens. Note the differences AND the similarities.

Figure 1. Gorilla skull with DGS colors applied to distinguish the bones. Compare to Homo sapiens in figure 2.

Figure 2. Labeled skull bones in Homo sapiens.

Some subtle points you may have missed:

1. Human upper canines are not behind the lower canines
2. Human incisors are larger than the canines
3. The pterygoid is visible through the orbit
4. The rims and ridges around the temporal opening in Gorilla are anchors for jaw muscles, all reduced in Homo.
5. The bridge of the nose in Homo is lacking in Gorilla
6. Perhaps I missed a few you’ll notice…

Olympian Michael Phelps and the aquatic ape hypothesis

According to Wikipedia (abridged)
“The aquatic ape hypothesis (AAH) is the idea that the ancestors of modern humans were more aquatic. The hypothesis in its present form was proposed in 1960 by Alister Hardy. Though ignored or derided by the majority of workers, a few suggest in the last five million years humans became dependent on essential fatty acids and iodine, which are found in abundance in sea resources. Efficient function of the human brain requires these nutrients. The “aquatic ape” proposal is more popular with the lay public than with scientists.”

FIgure 1. GIF movie of Michael Phelps, gold medal winner in Olympic swimming, compared to Ardipithecus skeleton, not to scale.

We don’t have the nasal bones
for Ardipithecus. So it is possible that they were not flat, but arched, as in humans. And in humans, the ventral opening of the nostrils prevents water from entering the air passage whenever underwater.

Figure 4. Ardipithecus is a transitional taxon between Pronconsul and Homo. We don’t have the nasal bones for Ardipithecus (in gray), so they could have arched to create a protruding nose with ventral nostrils.

Hardy argued aquatic adaptations in humans include:

1. lack of body hair
2. subcutaneous fat (but captive apes have levels similar to humans.
3. location of the trachea in the throat rather than the nasal cavity
4. the human propensity for front-facing copulation
5. tears and eccrine sweating
6. bipedalism as an aid to wading
7. tool use evolved out of the use of rocks to crack open shellfish
8. selection for wading, swimming and diving in procurement of aquatic food distinct from the jungle niche leading to chimps.

So what does Olympian Michael Phillips have to do with Ardipithecus?

1. Both have a wider ‘wingspan’ than height.
2. Both have a long trunk and relatively short legs.

Admittedly,
this is just ‘cocktail-chatter,’ and will probably always be ‘cocktail-chatter.’

FIgure 2. Primate cladogram with the addition of Aegyptopithecus, Pan, Gorilla, Ardipithecus and Indri. The topology of the LRT did not change with these additions.

The addition of the five primates, Indri, Aegyptopithecus, Pan, Gorilla and Ardipithecus to the large reptile tree (LRT, 1172 taxa, subset Fig. 2) recovers nothing controversial and does not change the LRT topology of the primates.

References
Hardy A 1960. Was Man More Aquatic in the Past? New Scientist 7(174):642–645.

wiki/Aquatic_ape_hypothesis

 

Added November 10, 2020
The following link to a Joe Rogan podcast
features author, Kermit Pattison talking for two hours about Ardipithecus in his book ‘Fossil Men: The Quest for Oldest Skeleton and the Origins of Humankind’.

Proconsul, Pan and Homo: face changes

Just some musings today
over chimps and humans (Fig. 1) and some other higher primate skulls (Figs. 2, 3). Chimps have not yet made it into the large reptile tree (LRT, 1068 taxa), but they will someday.

The tradition is
to consider chimps (genus: Pan) the starting point in human (genus: Homo) evolution and to make comparisons between the two. Once again, taxon exclusion becomes a problem.

The actual starting point
is closer to an extinct ancestor of both, Proconsul (aka: Dryopithecus; Hopwood 1933; 18–14mya; Figs. 2, 3) a genus that resembled a chimp, but did not knuckle-walk (Fig. 3) and lacked brow ridges, both traits retained by Homo.

Figure 1. Chimp baby and human baby compared to chimp adult and human adult. Pupils are aligned. Everything else morphs. See text for details.

 

Question #1 today is…
What changes can we see in the face of a human compared to a chimpanzee?

1. Forehead present (housing more cerebral frontal matter)
2. Longer and protruding nose with ventral nostrils (better for underwater)
3. Shorter nose-to-lip distance with philtrum (medial furrow)
4. Chin boss (deeper in adults)
5. Internal lip tissue externalized
6. Shorter muzzle
7. Thicker, less patchy and eternally growing cranial hair (+ beard on males)
8. The rest of the face (and most of the body) hairless
9. Smaller iris vs. sclera (whites of the eyes)
10. Smaller ears
11. Fewer wrinkles on breeding adults and babies
12. Brow ridges absent, replaced by decorative eyebrows
13. Maturity does not include a change of face color
14. Not visible: smaller canines
15. Lower cheekbones (jugal, zygomatic arch) relative to tooth row

It looks like the ears are lower in humans, but relative to the eyes and nose, they are not.

Figure 2. The skulls of Pan (the chimp), Proconsul and Homo (the human) for comparison.

Question #2 today is…
What changes can we see in the face of a chimp (Pan) compared to Proconsul?

1. Loss of forehead in Pan compared to Proconsul
2. Nose unknown in Pronsul, but bones are shorter and flatter in Pan
3. Longer nose-to-lip distance in Pan
4. Chin, absent, as in Proconsul
5. Internal lip tissue unknown in Proconsul
6. Muzzle the same in Pan, less above, but more below the nose
7. Hair unknown in Pan
8. Skin unknown in Pan
9. Eyes unknown in Proconsul, but note their relatively higher placement in Pan
10. Ears unknown in Proconsul
11. Wrinkles unknown in Proconsul
12. Brow ridges present in Pan, absent in Pronsul
13. Skin color unknown in Proconsul
14. Canines slightly larger in Pan
15. Higher jugal relative relative to tooth row (= taller premaxilla and maxilla) and coronoid process of mandible

Figure 3. Proconsul displays primitive traits for chimps and humans. It did not walk on its knuckles

And then there’s one more transitional taxon
Ardipithecus (Fig. 4) nesting somewhere between Proconsul and Homo. 

Figure 4. Ardipithecus is a transitional taxon between Pronconsul and Homo.

In Ardipithecus,
compared to Proconsul, we find larger eyes, a larger, lower nose, smaller canines, and an overall shorter/wider face… and a pelvis more appropriate for an upright stance, freeing the long arms to do something else, like carrying everything from infants to water to weapons to belongings. This is where we lost our hair, became long distance runners, developed sweat glands, and became wanderers.

Figure 5. Ardipithecus in lateral view compared to Australopithecus and Homo (ghosted out).

 

 

References
Hopwood AT 1933a. Miocene primates from British East Africa. Annals and Magazine of Natural History (Series 10), 11, 96-98.
Hopwood AT 1933b. Miocene primates from Kenya. Journal of the Linnean Society of London. Zoology 38:437–464.

https://en.wikipedia.org/wiki/Proconsul

 

Where does Rooneyia nest on the primate cladogram?

Rooneyia viejaensis (Kirk et al. 2014; Late Eocene, 40 mya; Fig. 2) is a basal primate known from a nearly complete skull. Everyone agrees on that. Where Rooneyia nests within the Primates is the point of contention.

FIgure 1. Subset of the LRT focusing on the primate/bat clade. Rooneyia nests between lemurs and higher primates.

Kirk et al. 2014 report: 
“Rooneyia viejaensis is a North American Eocene primate of uncertain phylogenetic affinities. Although the external cranial anatomy of Rooneyia is well studied, various authors have suggested that Rooneyia is a stem haplorhine, stem strepsirrhine, stem tarsiiform, or stem anthropoid.”

The large reptile tree (LRT, 1051 taxa) nests Rooneyia between lemur-like Notharctus and all higher primates, including tarsiers like Tarsius and Darwinius. Granted there are not very many primates on the LRT. Nevertheless, those are the current results. So the LRT indicates or suggests that Rooneyia is a stem hapolorhine, stem strerpsirrhine, stem trasiiform AND stem anthropoid. I’ll have to add more taxa in these clades to make a more precise recovery.

Figure 2. Rooneyia images from Digimorph.org and used with permission. White background and overlying DGS colors added here. The basal tree shrew/primate, Ptilocercus, is shown to scale. The postorbital bar and canine depth on Rooneyia are imagined. Does not color help one understand the bones so much better and more quickly?

References
Kirk EC, Daghighi P, Macrini TE, Bhullar B-AS and Rowe TB 2014. Cranial anatomy of the Duchesnean primate Rooneyia viejaensis: new insights from high resolution computed tomography. Journal of Human Evolution, 74, 82-95). online here.

Goodbye Scrotifera. Goodbye Euarchontaglires. Goodbye Scandentia. etc. etc.

Updated January 5, 2021
with the note that tree shrews (Scandentia) is indeed a monophyletic clade that also includes whales, horses, bats, every placental other than Carnivora and some post-marsupial civets.

Earlier the large reptile tree
found that several former clades, like Parareptilia, Pterodactyloidea, Cetacea, Testudinata (Chelonia) Notoungulata, Pseudosuchia, Ornithodira and Pinnipedia were not monophyletic… and that list keeps growing.

The large reptile tree (LRT, 1044 taxa) does not replicate the following mammalian clades:

1. Scandentia – tree shrews: yes, closely related, but at the bases of different clades… unless this clade also includes all placentals sans Carnivora and a few post-marsupial civets.
2. Euarchontaglires – rodents, rabbits, tree shrews, flying lemurs and primates,  (Fig. 1)
3. Euarchonta – tree shrews, flying lemurs, primates and plesiadapiformes.
4. Glires – rodents, rabbits
5. Scrotifera – Eulipotyphla (see below), bats, pangolins, Carnivora, Euungulata (including whales)
6. Eulipotyphla – hedgehogs, shrews, solenodons, moles (moles are Carnivora))
7. Euungulata – perissodactyls, artiodactyls (including whales)
8. Tenrecidae – tenrecs, some are closer to shrews, others closer to odontocetes
9. Macroscelidea – elephant shrews, some are closer to tenrecs
10. Primates – Plesiadapiformes and extant primates, including Daubentonia (the aye-aye. No giant anterior dentary teeth in valid primates.
11. there are a few more I’m overlooking. I’ll add them as they come to me.

Figure 1. Subset of the LRT focusing on basal placentals, including multituberculates.

Let’s focus on Plesiadapiformes
Bloch et al. 2007 found plesiadapiforms (Plesiadapis, Carpolestes and kin) more closely related to primates than to any other group. They did not test against rodents and multituberculates. The LRT does not replicate these results, but finds plesiadapiforms more closely related to multituberculates and rodents when included.

According to Bloch & Boyer 2002
“Plesiadapiforms share some traits with living primates, including long fingers well designed for grasping, and other features of the skeleton that are related to arboreality.” That’s fine, but there are other taxa in the tree topology with long fingers, too.

Paromomyidae
Krause 1991 reports, “Paromomyids …have long been regarded by most workers as members of the Plesiadapiformes.” Again, the LRT does not support this, but nests Paromomyids, like Ignacius (Fig. 2), with rodents, like Mus and Paramys. Paromomyids have squared off and flat molars, but Paromomys does not.

Figure 2. The skull of Ignacius nests with other rodents, not plesiadapiformes. Ironically it is closer to the squirrel-like Paramys than to Paromomys.

Beard 1990 thought paromomyids,
as plesiadapiforms, where close to colugos or “flying lemurs”. The LRT (Fig. 1) does not support this relationship. Rather paromomyids, like Ignacius, were squirrel-like, able to scamper both in the trees and on the ground. Ignacius graybullianus (USNM 421608, Fig. 1) is a new taxon that nests as a basal rodent in the LRT.

Figure 3. Ignacius clarkforkensis known parts.

Remmber, no primates 
have giant anterior dentary teeth. The aye-aye, Daubentonia, has such teeth, but the LRT finds it nests with Plesiadapis and multituberculates and rodents, not primates. Yes, plesiadapiformes and Ignacius had long limbs, big brains and binocular vision, but by convergence with primates.

References
Beard KC 1990. Gliding Behavior and palaeoecology of the alleged primate family Paromomyidae (Mammalia, Dermoptera). Nature 345, 340-341.
Bloch J, Silcox MT, et al. 2007. New Paleocene skeletons and the relationship of plesiadapiforms to crown-clade primates.  Proceedings of the National Academy of Science 104, 1159-1164.
Kay RF, Thewissen JG and Yoder, AD 1992. Cranial anatomy of Ignacius graybullianus and the affinities of the Plesiadapiformes. American Journal of Physical Anthropology. 89 (4): 477–498. doi:10.1002/ajpa.1330890409.
Krause DW 1984. Mammal Evolution in the Paleocene: Beginning of an Era. In: Gingerich, P. D. & Badgley, C. E. (eds.): Mammals: notes for a short course. Univ. of Tennessee, Department of Geological Sciences.
Krause DW 1991. Were paromomyids gliders? Maybe, maybe not. Journal of human evolution 21:177-188.

In honor of Mother’s Day…

We have a pregnant
plesiosaur (Fig. 1; O’Keefe and Chiappe 2011; LACM 129639; Late Cretaceous, 78 mya)…

Figure 1 Pregnant Polycotylus (LACM 129639) from O’Keefe and Chiappe 2011.

and a pregnant primate (Fig. 2) very dear to my heart.

Figure 2. My daughter Stephanie one week before giving birth to grandson James (nickname: Jet) and about three years ago.

Being a mom goes way, way back
In our lineage, first cells stuck together, flagella out (Fig. 3). Then four cells stuck together. Then eight. Ultimately hundreds stuck together creating a sphere, or blastula. And little blastulas formed inside until they were large enough to break free.

Figure 3. Blastula from the book, “From the Beginning” by Peters 1991.

Plesiosaurs and primates capable of understanding prehistory
followed shortly thereafter. The basics of being a mother haven’t really changed much in the last few billion years.

References
O’Keefe FR and Chiappe LM 2011. Viviparity and K-selected life history in a Mesozoic marine plesiosaur (Reptilia, Sauropterygia). Science. 333 (6044): 870–873. doi:10.1126/science.1205689.
Peters D 1991. From the beginning – the story of human evolution. Little Brown. 128 pp. Online here.

wiki/Polycotylus

What is Darwinius?

Franzen et al. 2009
reported on a well-preserved small primate from 50mya named Darwinius.

From the Franzen et al. 2009 conclusion:
“Darwinius masillae represents the most complete fossil primate ever found, including both skeleton, soft body outline and contents of the digestive tract. Study of all these features allows a fairly complete reconstruction of life history, locomotion, and diet. Any future study of Eocene-Oligocene primates should benefit from information preserved in the Darwinius holotype. Of particular importance to phylogenetic studies, the absence of a toilet claw and a toothcomb demonstrates that Darwinius masillae is not simply a fossil lemur, but part of a larger group of primates, Adapoidea, representative of the early haplorhine diversification.”

In a published comment Beard 2009 wrote:
“Unbridled hoopla attended the unveiling of a 47-million-year-old fossil primate skeleton at the American Museum of Natural History in New York on 19 May. Found by private collectors in 1983 in Messel, Germany, the press immediately hailed the specimen as a “missing link” and even the “eighth wonder of the world.”

“Overall proportions and anatomy resemble that of a lemur, and the same is true for other adapiform primates. A new genus and species of adapiform primate, Darwinius masillae (Franzen et al., 2009; Eocene, 50 mya ). The adapids are a branch of the primate tree that leads to modern lemurs. Ida would have to have anthropoid-like features that evolved after anthropoids split away from lemurs and other early primates. Here, alas, Ida fails miserably.” The reasons for that “fail” were not listed in the Beard note.

Taxon exclusion?
The large reptile tree, (LRT, 896 taxa), currently tests only a few primates. At this stage, Darwinius does indeed nest at the base of higher primates (simians), alongside Tarsius, the extant tarsier, but there are many dozen primate taxa that have not been included in the LRT.

Figure 1. Darwinius overall plus an X-ray showing the transition from milk teeth to adult teeth in this juvenile specimen.

In the LRT,
nesting only a few primates at present, the adapid prosimian, Notharctus, is basal to higher primates including humans (genus Homo). Tarsius, the tarsier, nests between Notharctus and Proconsul, a basal anthropoid (ape). Darwinius nests with Tarsius, but lacks the many specialized autapomorphies that characterize extant tarsiers like:

1. oversized eyes
2. distally fused tibiafibula
3. elongated pedal digits 4 and 5.
4. hyperelongated astragalus and calcaneum
5. cervicals insert further beneath the skull

Figure 2. Tarsius, the extant tarsier. Note the several autapomorphies displayed here vs. the many plesiamorphies in Darwinius.

Wikipedia reports
“Most experts hold that the higher primates (simians) evolved from Tarsiidae, branching off the Strepsirrhini before the appearance of the Adapiformes.” If true, Darwinius is close to the lineage of humans. “A smaller group agrees with Franzen et al. that the higher primates descend from Adapiformes (Adapoidea). The view of paleontologist Tim White is that Darwinius is unlikely to end the argument.” 

NBC news reports,
here that “Ida is as far removed from the monkey-ape-human ancestry as a primate could be, says Erik Seiffert of Stony Brook University in New York. The new analysis says Darwinius does not belong in the same primate category as monkeys, apes and humans. Instead, the analysis concluded, it falls into the other major grouping, which includes lemurs.”

Nature reports on the “media frenzy”
here in a paper entitled: “A hyped-up fossil find highlights the potential dangers of publicity machines.  To be fair, the authors’ claims at the press conference were appropriately measured. Nonetheless, the researchers were fully involved in the documentaries and the media campaign, which associate them with a drastic misrepresentation of their research.”

“Another damaging aspect of the events was the unavailability of the paper ahead of the press conference and initial media coverage. This prevented scientists other than those in the team from assessing the work and thereby ensuring that journalists could give a balanced account of the research.

“There is no reason to think that PLoS ONE’s editors and reviewers did less than their duty to the paper. Nonetheless, the clock was ticking at the time of submission.”

“In principle, there is no reason why science should not be accompanied by highly proactive publicity machines. But in practice, such arrangements introduce conflicting incentives that can all too easily undermine the process of the assessment and communication of science.”

The primate experts can hash this out.
At present, with so few primates tested, Darwinius is still a candidate to be at the transition from prosimian to simian in the LRT, as it presently nests… until additional taxa knock it out.

Added within minutes of posting
I ran across this reference:
Gingerich PD et al. 2010. Darwinius masillae is a Haplorhine — Reply to  Williams et al. (2010). Journal of Human Evolution. 59(5)574-576 where they report, “Williams et al. (2010) imply that ‘total evidence’ means study of hundreds of characters in a great many taxa. However, total evidence is about combining data before analysis and not about the size of the resulting matrix. “We agree with Seiffert et al., 2009 and Williams et al., 2010, and others that there is a strepsirrhine–haplorhine dichotomy in primate evolution. We employ the same cladistic methods. We accept that total evidence drawn from many sources is advantageous. Why then do we reach such a different conclusion about the systematic position of Darwinius? Given that our methods are the same, then our contrasting results can only be explained by differences in the number and balance of taxa chosen for study, the character matrix used to analyze higher-level primate phylogeny, the outgroup chosen to root a phylogenetic network, or some combination of these.”
More details on their arguments are found here.

References
Beard C 2009. Why Ida is fossil is not the missing link. Comment, NewScientist.
Online here.
Franzen JL, Gingerich PD, Habersetzer J, Hurum JH, Von Koenigswald W and Smith BH 2009. Complete primate skeleton from the Middle Eocene of Messel in Germany: morphology and paleobiology PLoS ONE. 4 (5): e5723.

wiki/Darwinius

nature.com article that touches on Darwinius

 

Pangolins nest as basal precocial placentals in the LRT

Updated May 3, 2022.
Click here to see the latest nesting of pangolins as basal precocial placentals when the LRT has grown to 2083 taxa.

Figure 2. Two subsets of the LRT focusing on bats and pangolins.

Note added July 31, 2016:
The addition of more taxa preserves the close relationship of pangolins to primates, 

Note added June 20, 2018
The reevaluation of Zhangheotherium as a basal pangolin nests this clade between dermopterans and bats. Click here for more details.

At present, the large reptile tree (LRT) includes very few mammals
so keep that in mind. The LRT (now at 704 taxa) is also not fine tuned to mammal traits, like molar shapes, so keep that in mind.

So here it is:
the large reptile tree nests the pangolin, Manis, with the basal lemur, Notharctus. And Notharctus is derived from basal carnivores like Vulpavus.

Pangolins have been difficult to nest.
Recent DNA tests (Murphy et al. 2001, Beck et al. 2006) nested pangolins with carnivores, but could be no more specific than that because fossil taxa cannot be tested for DNA.

Here’s the early morphological evidence
linking Manis to Notharctus using traits that are NOT in the LRT.

1. Flexible vertebral column – pangolins use to roll up, lemurs use to wind up then jump from tree to tree and land without a jolt
2. Circumorbital ring in some species of pangolin
3. Long, clawed fingers (toes), short opposable thumb (big toe)
4. Procumbent dentary teeth at tip (some species)
5. Arboreal habitat
6. Prehensile tail
7. One usually, but up to three infants born at a time.
8. Infants ride mother’s back and tail

Figure 1. Notharctus, an Eocene adapid (lemur) and likely sister to Manis.

Figure 2. Manis, the Chinese Tree Pangolin along with other views of other pangolins

Manis/Notharctus synapomorphies from the LRT:

1. Dorsal nasal shape: widest at mid length (here posterior to mid length, but identical in Manis and Notharctus).
2. Pmx/Mx notch: > 45º
3. Posterolateral Pmx not narrower than nares
4. Mx ventrally convex
5. Fr/Pa suture straight and > Fr/Na suture width (with Homo, too)
6. Posterior parietal angle in dorsal view > 40º to transverse plane
7. Suborbital fenestra (with Homo, too)
8. Ectopterygoid, cheek process larger (with Homo, too)
9. Ectopterygoid continues aligned along pterygoid lateral edge
10. Premaxillary teeth tiny to absent
11. Cervical centra taller than long (with Homo, too)
12. Cervicals cerntra decrease toward skull
13. Femuir < half glenoid – acetabulum length
14. Pedal 3.1 > p2.1
15. Longest pedal digits: 3 and 4
16. Metatarsals 2 and 3 align with mt1
17. Metatarsals 3 and 4 align with mt5

There are several traits
in the LRT that pangolins share with people to the exclusion of lemurs, all by convergence, so not worth going into.

Some atavisms (genetic reversals) in Manis
that most other mammals don’t have include the following:

1. Chevrons
2. Scales
3. Low to absent coronoid process
4. Elongate caudal transverse processes

The important thing here
is that given the opportunity to nest with the basal carnivores, Vulpavus, Nandinia and Chriacus, Manis nested instead with Notharctus.

Keratin scales
What opossums and rats have on their tails, pangolins have all over their bodies.

The order of the loss of facial bones
provides clues to the chronology of evolutionary events in pangolins. The loss of the lateral temporal bar (posterior jugal + squamosal) occurred in all pangolins, but the loss of the jugal is apparent in ground forms, so this was a trees down order, with burrowing following tree climbing. The clavicle is also lost in pangolins.

Diet: ants and termites.
So this is what happens when a lemur changes diet and becomes solitary, and depends on sense of smell, rather than sight. Elongate tongue is convergent with that of chameleons, woodpeckers, anteaters and nectar bats. Some pangolins burrow. Loss of the lower temporal bar and loss of most of the jugal in some species goes along with loss of the coronoid process in this anteater. Manis doesn’t need chomping muscles. Nor does it need speed and leaping ability. Given an ant diet and solitary social life, perhaps that makes it easier to visualize how Manis could be derived from a more active, social lemur-like ancestor.

So…here’s the evolutionary scenario:

1. Vicious and crafty arboreal carnivore: Vulpavus
2. Frisky and social arboreal omnivore: Notharctus
3. Slow and antisocial arboreal (grading to burrowing) anteater: Manis

New data:

Figure 1. Basal placentals at two scales, all arising from a Middle Jurassic sister to Monodelphis, based on the Earliest Cretaceous appearance of Zhangheotherium, in the lineage of pangolins.

Figure 1. Subset of the LRT focusing on basal placentals, including bats.

References
Murphy WJ., et al. 2001-12-14. Resolution of the Early Placental Mammal Radiation Using Bayesian Phylogenetics. Science 294 (5550): 2348–2351. doi:10.1126/science.1067179. PMID 11743200.
Beck R, Bininda-Emonds ORP, Cardillo,M; Liu, F-G and  Purvis A 2006. A higher-level MRP supertree of placental mammals. BMC Evolutionary Biology 6 (1): 93. doi:10.1186/1471-2148-6-93. PMC 1654192. PMID 17101039.

wiki/Pangolin