Who knows?
Maybe the "snake like" creature (the author's own word) did not use so-called protofeathers for heat or as a exapatation at all but instead it wore down it's teeth chomping on turtles towards the softshell kind spreading it's "wings" on the water surface so as to entice turtles up the water column and thus become prey.
There are so many possibilities for looking into relations, but we popularly tend not to explore them because our feelings get the better of our lack of observations of the modern day relative forms.