The taxonomy of these bears has variously placed some of the genera in other bear lineages such as Hemicyoninae and Ursavinae.[1][2]
Recent papers support their inclusion with giant pandas as members of Ailuropodinae based on diagnostic features like
large cheek teeth
parastyle fourth premolar with an enlarged inner lobe
wide first and second molars being
high mandible, with respect to the lower tooth row.
They are unlike their closest living relative, the giant panda (Ailuropoda melanoleuca) which evolved into a highly specialized bamboo-eater: The evolution of agriotheriins lead to the group becoming large, hypercarnivorous bears that had adaptations of cursoriality unique in the evolutionary history of bears.[3][4]
References
^Hunt, R.M. (1998). "Ursidae". In Jacobs, Louis; Janis, Christine M.; Scott, Kathleen L. (eds.). Evolution of Tertiary Mammals of North America. Vol. 1, Terrestrial carnivores, ungulates, and ungulate-like mammals. Cambridge, UK: Cambridge University Press. pp. 174–195. ISBN0-521-35519-2.