When this inland sea retreated, Hamilton hypothesizes, the Amazon dolphins remained in the riverbasin, evolving into striking creatures.
哈密尔顿推测，当这片内陆海退去，亚马逊河豚在流域留了下来，逐渐进化为一种恐怖动物。
2
The giant freshwater Mekong River stingray is just one of many mega fish species that could be threatened by dam-building plans in the Mekong RiverBasin.
湄公河流域的筑坝计划将会威胁到很多巨型鱼类，这种巨型淡水黄貂鱼只是其中一种。
3
There is a flood in the riverbasin in the South this summer.