Someone on here recently said that most odd tools that cannot be readily identified end up being leather tools.
I looked in Salaman, and these pliers look very similar to pliers/tongs that are used for handling and lifting heavy hides. They did not have the triangular thing, but I can see where that would give you extra grip in addition to the front jaws. Is the arm on the back a locking mechanism? That would also help if used for that purpose.