Also, I thought I’d found something insightful below (the idea that possibly they were by Jodo himself), but it appears… not?
Good work, Detective Enzyme! Downplay your finding all you want, it´s in fact the best clue we have for now. I will post it here to save people who are interested a click:
No artist is credited but the naive style rules out both Moebius and HR Giger (who arrived late to the project in any case). Best bet is either Jodorowsky himself—in 1967 he was writing and illustrating a comic strip, Fabulas Panicas—or Jodorowsky’s colleague from the Panic Movement days, Roland Topor. In the early 70s Topor was working with René Laloux on the animated SF film Fantastic Planet.
Good work, Detective Enzyme! Downplay your finding all you want, it´s in fact the best clue we have for now. I will post it here to save people who are interested a click:
Source: https://dangerousminds.net/comments/sketches_for_jodorowskys_dune_i