Amebelodon

Amebelodon is a member of a diverse group of primitive proboscideans called gomphotheres, a group that also gave rise to the modern elephants and their close relative the mammoth. The most striking attribute of this animal is its lower tusks, which are narrow, elongated,and distinctly flattened with the degree of flattening varying among the different species. Amebelodon first appeared in the Great Plains and Gulf Coast regions of North America during the late Miocene, roughly between 9 and 8 million years ago, and apparently became extinct on this continent sometime around 6 million years ago. It managed to migrate to Asia via theBering land bridge where it has been found in a number of late Miocene sites, particularly in China. The youngest record of Amebelodon is from a 5 million year old site in North Africa.

http://en.wikipedia.org/wiki/Amebelodon