The Cave Lion (Panthera spelaea and Panthera fossilis)

[tigerluver]

(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! Reply