There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
I haven't read of any direct date given to P. spelaea of Alaska. P. atrox supposedly becoming genetically distinct 340 kya, so P. spelaea likely made to Alaska a bit before, but likely after, P. fossilis, thus its expansion was severely limited.
In skull, P. spelaea is robust as it gets. I can't say if the body proportions ditched cursoriality for stockiness, but the one female skeleton present by Deidrich doesn't indicate this shift, but this is a European specimen if I remember correctly. The late Ural P. spelaea may have at least gotten close to the P. fossilis maximum. On top of this skull there's a 465 mm femur from NW Germany, just a bit smaller than the 470 mm P. fossilis one. The European and early Russian form probably didn't get that big as the giant predator niche was already taken by P. fossilis.
The lion clad probably ecologically capped the size of many other felids, as where they were not present, other felids grew to be as big as them (S. populator, P.t. soloensis), but when they were there, S. fatalis size looked to be the best you could get. Evolutionarily successful until whatever happened 10 kya.