Yesterday's Oglaf (link, since this particular comic is SFW, although most are not) featured a gargantuan worm bursting out of the earth—a gargantuan worm that looks a lot like the sand worms for the 1984 David Lynch Dune film, particularly around the mouthparts, with their triangular flaps and three- (or four-)fold radial symmetry.
Had it not been for the recent Dune films, it would not really have occurred to me that the mouth structure of a sand worm did not have to look like this. Actually, when I first read the book, I had a different view in my head, but since 1984, Lynch's version has been the default. That I had a toy worm (named George) from the toy collection based on the films probably had something to do with this.
However, there have been other appearance of worms with the same mouths and ridges in the intervening years. One that immediately sprang to mind was the first death in the 1990 video game The Immortal.
I think the imagery from Lynch's film was pretty influential. There is some information available online about the concept art and visual designs that were developed for the movie. For example, this is a concept model for the movie's sand worms, which has notably smaller and less symmetric jaws (?) than the final version.
Was this influential depiction of the worm mouthparts completely original to Lynch's production, or were there older influences that the filmmakers were drawing on?