Bingo.
You've got what I've always called a "green coticule."
They do look quite different from the traditional yellows.
I had one that I bought from Howard. I sold it because I got a Y/G escher that became my preferred finisher. I sort of regret it....
Keep it. They're super finishers. They are not cousins of the blue. They're their own thing. Send a thank-you letter to xxxxxx.