Baby quarks? Midget quarks? Or to be more politically correct, "Developmentally-challenged quarks"
I don't know, really. Physics is one of those subjects that I'm interested in, but haven't studied to much extent. I know enough to be satisfied, and to where I could learn more if I wanted.
From my own understanding, it's entirely possible. For the longest time, we thought atoms were the smallest particles. Then there were protons, neutrons and electrons. Now it's quarks.
Disclaimer: The ideas expressed in this post are not complete in any way, and therefore should not be taken as such. I have intentionally left out portions for the sake of brevity.