Have found one in short Range from Milden - in the middle of the Navar-Steppe
And btw..
http://bdocodex.com/cn/theme/5031/
That Crab is in front too!
@that Link you have a Tutorial, to get Knowledge from the Crab, and his 3-4 Adds, what he spawn ;c)
So you can do 2 Thinks here Parallel ;c)

Respawn time is around 130 seconds.