Good article and interesting website. Thanks!
I've read some of the sequels to Dune, but going past the first two probably isn't worth it for any except fervent fans.
Other than the sandworms, a large proportion of the life forms of Arrakis seemed to be imports from Earth deserts. In fact, other than the worms, I can't remember anything else living there that was actually alien.
Oddly, the history of the planet implied that it was once a green world, which makes me wonder if the sandworms weren't an import or genetic creation. I haven't read enough of the other books to know if this was covered in any sequels or prequels.