I suppose the fact it's probably a cold desert, not a particularly hot desert, means there would be some fauna overlap between the desert and polar habitats.

"not but smooth flesh" Naught but smooth flesh.
"purplery" I figure that's a joke about so many flora on Sagan 4 being purple rather than green. I suggest adding that as joke jargon to a Sagan 4 glossary.
"to the later" should b "to the latter".

I wonder if Seashrogs are a predator. They vaguely resemble some of its prey species, including Serpungoes. (Serpungos?)

Made the changes, and yes, referring to the flora as purplery instead of greenery was intentional, given how much their is. As for seashrogs, that is possible, but I'd leave that to dorite to decide if they would hunt these.