*************************
NOTE: All sketches were scanned from the cited sources. Some originals showed more detail than others. Hence, features showing up in one diagram may be lacking in another, due either to the artist not including more detail, or the skull itself being only fragmentary.
Figure 2:1. Skulls of Agriotherinae
Ursavus (possibly via U. depereti) gave rise to Indarctos and Agriotherium 15-25 MYA 
(Fig. 2:3) (Erdbrink 1953; (Kurte'n 1976, 1968; Kurte'n & Anderson 1980; O'Brien et al. 1985; Mayr 1988).
(Fig. 2:3) (Erdbrink 1953; (Kurte'n 1976, 1968; Kurte'n & Anderson 1980; O'Brien et al. 1985; Mayr 1988). Indarctos
As Indarctos gradually became more herbivorous, its carnivorous dentition was replaced by larger molars, its zygomatic arches broadened for greater lateral grinding-chewing, and its sagittal crest rose, providing more surface area for attachment of temporal chewing muscles. (Wolff 1978). Indarctos occupied North America at least as far south as Florida during the Hemphillian, although it may have survived longer in Asia (Kurten 1976).
Asian Indarctos gave rise to panda bears, of which one species survives (Erdbrink 1953; Wurster 1969; Wolff 1978; Thenius 1979; Mayr 1988). Others believe that the panda bears' ancestor is Agriarctos. The relationship between Indarctos and Agriarctos is unclear.
Agriotherium
Indarctos also gave rise to Agriotherium) (Hendey 1977), a genus that ranged through North America from California east to Florida, from Nebraska south to Mexico during the Hemphillian and possibly Villafranchian periods of the Pliocene (Dalquest 1986). Agriotherium lived in Europe during the Astian (Kurte’n 1966). Its descendants were the only bears to penetrate Africa farther south than the Atlas Mountains. They may have once occupied much of that continent during the early to mid-Pliocene , (Erdbrink 1953; Hendey 1977, Savage & Long ____).
Agriotherium had a short palate (shorter even than its descendent Arctodus) and short molars (Dalquest 1986; Hendey 1977). At least 2 species A. coffeyi and A. africanum had their carnassials and M1 trigonid adapted for shearing meat, much like the teeth of a modern wolf (Canis lupus). Other Agriotherium species had more robust premolars (a bit like those of a hyena), suggesting adaptation to scavenging (Kurte’n 1968); indeed some specimens were once classified as Hyenarctos (Erdbrink 19543). This short felid-like palate, carnivorous dentition, and presence of a premasseteric fossa, led to speculation that Agriotherium is ancestral to Tremarctinae. Dalquest (1986) disagreed due to differences in certain dental traits between the taxa. Erdbrink (1953) argued that Agriotherium left no descendents, going extinct by the early Pleistocene (Kurte’n 1968).
Chapter 2. AGRIOTHERINAE