Mishipishu means "Water Panther" in Ojibway language. Amerind oral traditions describe this creature as having had a saw-blade back, reddish fur, and a "great spiked tail" which he used as a weapon.
Vine Deloria noted ("Red Earth, White Lies") that was a basic description of a stegosaur. Granted the image has horns and a stegosaur didn't; Indians were always in the habit of touching those glyphs up every few years and the horns were ae many centuries after the creature itself died out by an artist who figured he needed them.
Louis and Clark noted that their Indian guides were in mortal terror of those kinds of glyphs around the Mississippi, the original meaning of the glyphs was "Caution, one of these things LIVES here!"
Both the Amerind glyphs (there are numerous others) and the soft tissue turning up in dinosaur remains tell the same story; the thing about the 65,000,000 years is a bunch of BS.
Soft tissue in dinosaur remains appears to be naturally mummified.
The rarity of such finds suggests the right processes did not occur very often.
North American glyphs confirm what we know from virtually every other culture: humans are highly imaginative, and just love to embellish a great story.
;-)