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Quote:The dire wolf was one of the successful top predators in North America during the Pleistocene. It is best known from the southern part of North America, and it even immigrated to South America. Fossils of dire wolves are very rare north of 42° North latitude in North America. That distribution supported the belief that the low temperatures and ice sheets in the higher latitudes of North American formed an insurmountable barrier for the dispersal of dire wolves. Here we report the first record of the dire wolf fossil in Eurasia. The fossil is a partial mandibular fragment with a tooth recovered from a Late Pleistocene underwater sand mine site near the city of Harbin in Northeastern China. Other mammalian fossils from the same site suggest that this dire wolf coexisted with the typical Mammuthus-Coelodonta fauna of Eurasia. The newly discovered specimen has a huge m1; much larger than gray wolves and other large canids from the same region. The massive m1 trigonid accounts for a high percentage of its overall length. The m1 talonid is reduced, but retains a small entoconid. The m2-3 alveoli suggest that the two teeth were smaller than those of the gray wolf. The combination of these morphologies is present only in the dire wolf. When the body mass spectra of medium and large-bodied carnivores from Asia and North America were compared, the Asian dire wolf occupies a position nearly overlapping the spotted hyena (Crocuta crocuta ultima). During the Late Pleistocene, C. crocuta ultima was one of the most widely distributed and dominant carnivores in Asia. Competition from hyenas may have kept dire wolf Asian populations at very low levels leading to their rarity as fossils rare in Asia.

Quote:Herein, we present a study of an interesting sample of fossils of the giant amphicyonid Megamphicyon giganteus (Schinz, 1825) from the Spanish middle Miocene (MN6) site of Carpetana (Madrid city), obtained during public works for the Madrid underground in 2008. Although the dentition of this species is known from other sites, the postcranial bones are very poorly known, and the new material provides new data on the locomotor adaptations of this spectacular predator, and allows an estimation of its body mass, which would be around 600 kg. Surprisingly, despite this giant size, the morphology of both femur and tibia shows that this animal exhibited higher cursorial capacity than large extant carnivorans, such as bears, which together with a high degree of pronation/supination movement of the forearm, reveals adaptations of M. giganteus to occupy the niche of active top predator in middle Miocene ecosystems.