How many ranger trainers are there?

Ranger is my secondary profession. I'm in pre-searing. I was just about to leave for post-searing when I remembered I had been told there are 4 ranger trainers. I've only found 3: Nente, Trueshot, Aidan. Are there 4? Who and where is the fourth?

There are only four if you include Artemis, whom you met first (Power Shot and Troll Unguent). It seems like you have all the available skills.

edit: Kamatsu is correct; I missed the part where you clearly specified that you are */R. My bad.

You only met Artemis if your a primary profession is Ranger, otherwise you'll only have access to three ranger trainers - Nente, Trueshot & Aidan.