Pleistocene and/or earlier Lions of Africa and Asia

I am interested in prehistoric lions. Current literature and studies seem to be limited to lions of the northern latitudes, namely, P. l. fossilis, spelaea and atrox. Although prehistoric lion fossils are most certainly found in Africa (lions originated there, didn't they?), I could not find any studies or papers describing them, or any prehistoric lions that might have been unearthed in Asia (the only exeption being Panthera leo youngi/P. youngi).

I don't understand why no one is interested in describing these direct ancestors and closest relatives of the modern lions.

I would really like to know 'who' were these prehistoric lions in Africa & Asia, are there any further subspecies classifications, were they larger than modern lions like their northern cousins, what were their morphology?