This key is really cool, but also very technical. I think you’re going to run into problems of people who aren’t very familiar with arthropods trying to read it, encountering half a dozen words they don’t know, and getting stuck. Heck, I know a lot more about arthropods than the average person, and I still see a bunch of words in here I don’t know. It might be good to define some words, and also use simpler wording when possible; for example, “appendages frequently biramous” could instead just be “appendages frequently forking into two”. I have to imagine anyone who knows all these words already can probably tell the difference between an isopod and an Annelid worm.
Lots of useful information for telling some members of some groups apart, though, I’ll have to hold onto this. I don’t mean to sound like it isn’t useful! It just seems to me that the Venn diagram of people who recognize most of these words, and people who need help telling isopods from other creatures, probably has only a very small section in the middle.