Mamenchisaurus youngi

Fair warning - Mamenchisaurus has lots of fairly different species currently put into it, so it’s possible that M. youngi actually belongs in its own genus. But we don’t do any new nomenclatural acts on this website! So for now, Mamenchisaurus youngi is a member of the famously long-necked Chinese sauropod Mamenchisaurus, from the Late Jurassic. How long of a neck, you ask? Crazy-long, roughly equal to the torso and tail put together.