Why would all life not have evolved to look more like the rocks that litter the landscape in that area?
As a matter of fact, with how much iron there is, i would expect these theoretical creatures would be very heavy and rather robust, as well.
There is a story of an Indian tribe out east that was called the "Panther" people because of the way they talked (sounded like a panther).
They were reputed to be very large, have lots of teeth, and "bones of iron". They were reputed to eat some of the rocks in the local river, which
are very iron rich.
Can't recall where I heard this story, but it seems relevent somehow to my prior comment.
Regardless, if there were creatures, I would expect to see them use the rocks to provide camoflauge opportunity. That is what my Earthly point of
reference says, anyway.