Taxonomic identification bunoselenodont and lophodont ungulated from the Khorat Sand Pits

Abstract

In the Nakhon Ratchasima province, Northeastern part of Thailand, fossil mammals bearing bunoselenodont and lophodont teeth were found last year during the sand mining operation in Phimai and Chalermprakiat sand pit near the Mun river. These vertebrate fossils in these sand pits have never been studied before. Therefore, the study can provide information regarding the taxonomic status of fossils. In this study, the material composes of 3 left mandibles and 1 right mandible of bunoselenodont ruminants and isolated P3 and M3 of lophodont ungulates. On the basic of dental morphologies, three mammalian fossils were identified: tragulids ( Dorcabune cf. nagrii and Dorcatherium cf. Minus) and a small- bodied deinotherid (Prodeinotherium sp.). Based on the biochronology achieved from all related taxa, the age of these fauna ranges between 14.2-5.9 Ma (Middle Miocene to Late Miocene) and the paleoenvironments corresponded to mesic/ woodlands. Our taxonomic identification of these fossils suggests Pakistanis and Chinese relatives that possibly migrated to Thailand during the Miocene. However, this discovery represents the first records of Miocene tragulids and deinotherids in Thailand.