Yourellian

Yourellians or Ureallians, a race of large, slime-covered and deformed aliens, with green skin and gills, hunted and trapped Wookiees on Yavin. They spoke the Wookiee language.

Behind the scenes
Yourellians were described in George Lucas's rough draft for the original movie. Han Solo was originally a "Ureallian" (the spelling varies). He is encountered at Gordon, in a cantina, and joins the heroes. A different, villanous group were later encountered on Yavin by the protagonists and defeated, rescuing Chewbacca.