Ok, so my brain has been picked by Ben, sorry for the late response. The book is referring to a time when Atelopus varius and A. flavescens were still commonly imported from their native countries, neither of which still export them and in fact, A. varius in Costa Rica is completely extinct except one population. The pictures you see in Wall's books of A. varius may very well be extinct.
While both of these species were imported in mass, they suffered much like the imported pumilio, histrionicus, and lehmanni of the dart frog world suffered, in that their breeding was not understood enough to breed them and keep captive populations going, for the few that survived the importation to begin with (out of a group of 8 A. spumarius males, only 3 lived over a year for me). Thus they fell out of the hobby. As far as I know, the only Atelopus currently in the hobby is A. spumarius due to recent importation, but breeding is still going to be uncommon due to so few knowing what it takes and can actually provide it, as well as the fact that their are so few females imported (1 in 60 red eye treefrogs imported are female, this ratio might be even larger for atelopus).
The glowing reference may be due to the fact that flavescens are almost flourescent orange, and under some lights may glow like a highlighter. I've never seen any of these in person.
If you haven't guessed, I work with A. spumarius and Atelopus are sort of a passion for me. I'm also working on getting a large breeding group together, and am looking for more females (they are twice the size of adult calling males) as well as a couple more males. Please let me know if you can help with that. My goal of the project is evetualy to not only get general caresheets out on at least A. spumarius, but also their breeding and raising of the young so these bold little gems won't fade out like their cousins.
