This ceramic inlay I bought in the South West and never knew quite what to make of it.
Now I have a theory. The large tail is for propulsion in water. The 4 fins have turned into digits useful for locomotion along the ground - no opposable digit would be required at this stage. The horn on the mouth would be used by the animal to announce itself on its transition to land - the artists fantasy.
This theory is of course very speculative, however on first glance I thought this was a strange sea creature that was somehow important to life.. and the match up with the fossil record really is amazing.. I credit the Native American naturalist intuition for the strength of this correlation with the fossil record.