(Spoilers await); What's the golden auryx? and Dar's family...

What's the golden auryx?

At first I thought it was going to be an oryx but then we were shown it was a bird... Obviously they had to use a real bird, a real bird not known as a golden auryx... What was the bird's species? Anyone knows?

and Dar's family was transformed into which animals? the mother into the golden auryx, for instance...