The Cave Lion (Panthera spelaea and Panthera fossilis)

[Smilodon-Rex]

(10-23-2018, 06:31 AM)Ghari Sher Wrote:

(10-23-2018, 02:19 AM)tigerluver Wrote:

(10-22-2018, 05:29 AM)Ghari Sher Wrote: Hello,
I'm an amateur enthusiast who's been enamoured by the lions of the Pleistocene ever since I first read about them, and I've found it hard to find many in-depth online discussions about them (this being on of the few). Great to find this forum, and there's quite a few new things I've learned from reading this thread.

Quite an interesting thing that Panthera fossilis has been suggested to not even be directly ancestral to spelaea - I wasn't aware of that.
But in regards to the hypothesis that atrox is derived directly from fossilis, with the being more distantly related to spelaea, there is a paper that comes to mind regarding this, Barnett's 2009 genetic study. It doesn't seem to have been mentioned in this discussion, but maybe I've missed it.
He used sequences from both Eurasian and North American Pleistocene lions and found that spelaea and atrox were actually very close:

*This image is copyright of its original author

He estimates that the two lineages diverged about 337,000 years ago (194,000-489,000 range), and evidence suggests atrox descended from a population of Beringian spelaea which entered North America and was subsequently isolated.


https://www.zin.ru/Labs/theriology/eng/s...l_2009.pdf

That split seems to be a bit too young for the hypothesis of atrox deriving directly from fossilis (though there is some temporal overlap in the ranges), and being more distant to spelaea.

Wonderful to have you here @ghari_sher! It's always exciting to meet another enthusiast of the extinct felines. Thank you for sharing the literature as well, I'll file that in the thread's library soon. I also love the name. Never thought of the translation of cave lion into Hindi/Urdu until I read your name.

On the discrepancy between the P. atrox, P. fossilis, and P. spelaea theories... The Barnett et al. (2009) work was essentially updated in Barnett et al. (2016) to increase both temporal distance of the split between the P. spelaea and P. leo lineages and recognize P. spelaea as a unique species if I remember correctly. Barnett et al. (2016) pushed back the divergence date for P. spelaea to over 2 MYA (see the opening post of the thread), which would be older than the oldest P. fossilis. With that they inferred P. fossilis to be somewhere on the continuation of the P. spelaea branch. Such would be in accord with Marciszak et al. (2014) as well as the new Argant work. 

Posts #20 and #22 in this thread attempt to reconcile the current theories on the cave lion lineage over the phylogeny provided by Barnett et al. (2016). 

The similarities between P. atrox and P. fossilis as reported by Sotnikova and Foronova (2014) are interesting in that the morphology hints that the advanced traits of P. spelaea were not as present in P. atrox. That would leave two scenarios, an evolutionary reversal or the more recent P. spelaea was not involved in populating the range of P. atrox. Evolutionary reversals have yet to show up in Panthera thus the latter would likely be more accurate in my opinion. The main issue is that fossils of the cave lion lineage from 1-2 MYA are missing, thus we do not know what the most primitive form of true cave lion looked like. Please let us know what you think!

And to you as well!
Thanks! Haha, I didn't think anyone would understand that name, and that it would just be assumed to be my real name or something(it isn't). I was just trying to think of a name for my WildFact profile and thought "Cave lion" was a bit too dull, so I just decided to call myself "cave lion" in Urdu(virtually indistinguishable from Hindi) instead of English. I know, how creative. Yeah, they've come to be my favourite animal, for reasons unclear even to me.

I was about to mention how his 2016 paper was an update to his 2009 one, particularly in respect to the split date, but I couldn't find any explicit mention of a split date between extant and Pleistocene lions in his 2009 paper as I wrote my reply (maybe I missed it) so I just left it out. I would definitely make a caveat as to whether or not his estimates for the split date between atrox and spelaea  are accurate, since he used far shorter sequences from both cats than the mitochondrial genomes he was able to piece together in his 2016 paper, which gave far deeper estimates for the divergence of leo from spelaea (and co.) than the short sequences from the earlier one, so perhaps if we get better-quality DNA from atrox and compare it with the two mitogenomes available thus far, the split between it and spelaea might also become much deeper, allowing compatibility with the other hypotheses. A possibility worth considering, I suppose.

Interesting that it's spelaea which has the derived traits, not atrox. A friend of mine, under the view of the Barnett (2009) hypothesis of atrox and spelaea (though who acknowledges the deep split with extant lions demonstrated by Barnett (2016)), has commented about how he feels that atrox is more derived given its very leggy, cursorial proportions which are absent in spelaea whence it was apparently derived, which in turn resembles modern lions much closer in terms of limb proportions, and thereby apparently possessed the "ancestral" build. It would indeed be interesting if the atrox-like cursorial build is the primitive trait, and spelaea was evolving in parallel to leo. This of course, is under the view supported by Barnett, Marciszak and Argant. It would be interesting if fossilis was the cat which gave rise to atrox, not spelaea, that would certainly explain the shared cursorial proportions and robusticity. Perhaps we can get a deepening of the split between atrox and spelaea if we get any larger sequences from atrox, which might get us into a split range venturing into the realm of fossilis.

It would be of great use if we did get DNA from fossilis. My hunch is that the Sima de los Huesos remains (mentioned in Argant's recent paper) is not a bad place to look, since both the full mitogenome of a >300,000 year old cave bear, and more recently DNA sequences from humans (Homo neanderthalensis) even older than that (and of a similar age to the lion remains), have been successfully obtained from the site.
http://www.pnas.org/content/pnas/early/2...0.full.pdf
https://www.nature.com/articles/nature17405
As it stands, we can only be hopeful.

Hi guys, so how do you think the connection between Panthera atrox and Panthera youngi ？according to the research, Panthera youngi may belongs to the Asian fossil lion's population(panthera leo fossil),  and it is widely recognized that Panthera youngi was the Panthera atrox's ancestor, perhaps Panthera atrox just owned the independent lineage until 30000 years gao, before this it may just the gigantic Panthera youngi
As a matter of fact, all of the prehistoric lions can be called"Spelaea" in vast, especially when you point to Eurasia, however, even the real Panthera spelaea, it may has inner differences which bigger than modern panthera, when spelea developed into 100 thousands years ago later, it looked more likely to be a tiger, so why the spelea would be exchanged ? there is a imagination that Spelea may be a hybrid species which continues other panthera's lineage.

*This image is copyright of its original author

The prehistoric lion's range in North America ,  the Alaska was the Spelea's territory, while the mainland USA and Mexico were belonged to the Atrox, but both of them also covering the Yukon, so there may have a possibility that it may have hybrid record between Spelea and Atrox in Yukon.

*This image is copyright of its original author

Lion's fossil record location in North America Reply