Panthera leo atrox or Panthera atrox?

[Infinity Blade]

This one's been bugging me for some time.

It appears that there's some controversy as to whether or not the American lion really is a subspecies of lion or a distinct species. And IIRC, on Carnivora, I think blaze said the latter was most likely the case (I don't really remember, maybe I misinterpreted his comment). So...is there anything that points out which it was? Also, what of the Eurasian cave lion? The same problem appears to apply to it too.

[blaze]

This is what the most recent molecular analysis (Barnett et al. 2009) has to say on the matter:

Interestingly, there is also no evidence for genetic interchange between cave lions and modern lions, despite a long term contact zone in the near east (Fig. 1; Kurtén 1968; Burger et al. 2004). These observations are consistent with the suggestion that the three forms may represent separate species, rather than subspecies (Soitnikova, Kikolskiy 2006). However, pronounced mitochondrial phylogeographical structure has also been observed in Pleistocene eastern Beringian brown bear populations, albeit for much shorter time periods (Barnes et al. 2002). To fully resolve the species status of the three lion forms, it will be necessary to include both nuclear and morphological data.

So who knows, at the moment might be a subjective decision but the truth is that all 3 form a clade and by number of generations they are much closer to each other than they are to any of the other proper species of Panthera as they diverged from leopards some 1-1.6 million years ago.