I'm looking for the title and author a SciFi book which has been bugging me for decades that I think went to paperback in the mid '80s. I barely remember the gist of the story, or even if it was a good book, but its tied up in my memories of Herbert's Lazarus Effect (I keep thinking its set on a planet named Pandora) so it might also be an 'H' Author as I was systematically going through the library's paperback SciFi section at that time.
The plot has something to do with giant iguana-like lizards who make spiral patterns. I think they were a menace being eradicated by planetary colonists but at the end of the book the final scene is something like the lizards and their human partners are being welcomed into the galactic federation. I know, not much to go on :P.