Yeah, given the application, I think Gunnar's idea of it being a stepper instead of servo is more likely, especially when I noticed the ribbon cable. Still looks to be a little planetary gearbox on the end of it though.
When digging to try to see if anyone mentioned what kind of motor it is (all I could find was "biomechatronic"), I did stumble across this:
"Eelume robot can be provided with an artificial intelligence software so that it can navigate and move even without remote control. This is an important step towards more autonomous underwater vehicles that do more than just inspection."
OK, that's a little scary... If they get the size down a little more, these things could eventually start crawling out of your toilet!
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington