| Popis: |
The ursid fossils collected from Saint Jacques include Pachycynodon tedfordi, new species, Amphicynodon sp., and Cephalogale sp. The distinctive features of Pachycynodon tedfordi are: short premolar series relative to molars, diastemata between c and p1 and among premolars very short or absent, distinct cingula on p1–p4, well-developed posterior accessory cuspids on p2–p4, long and narrow m1 with relatively high protoconid, metaconid lower than paraconid, and relatively long m2 without distinct paraconid. Four genera (Amphicticeps, Amphicynodon, Pachycynodon, and Cephalogale) representing two subfamilies (Amphicynodontinae and Hemicyoninae) have been discovered in the Oligocene of Asia. The last three are genera common to Asia and Europe, and indicate migration. Based on the ursid and other mammalian fossils, the deposits at Loc. 77046 near Saint Jacques are determined as Oligocene in age, and those at Loc. 77046.5 are late early Oligocene. Migration of ursids between Asia and Europe occurred in ... |
