Evolutionary origin of the Zesk

A full cycle of your moon has come and gone since I last heard from Milethi, and finally she has produced new information.  I find the results of her latest research to be simultaneously surprising and not.  When her calculations of the earliest evolutionary form of the Vorox revealed a petite insect-like Rahi, I suspected that the Zesk may have had rather modest beginnings as well.  What I did not expect, was to be shown something so nearly identical in overall shape and size to the prehistoric Vorox.

From this it is clear to me, and Milethi agrees, that the Vorox and Zesk had a common evolutionary ancestor.  In simpler terms, long ago, they were one and the same.  I had actually heard long ago that this was the case, but the information was heavily disputed and speculation on the matter is widely considered taboo.  Fortunately my personal web of contacts and information spans great distances and time alike, and I have been able to assemble quite many useful pieces of this puzzle.

I need but one further bit of research from Milethi, a further confirmation of sorts, to complete this story.  She has agreed to my new request, thankfully, but unfortunately for me, this time she has requested more difficult "errands" in return. 

Now, I have a bit of travelling to do, but I will of course return at the earliest convenience...