Kotasaurus is perhaps the earliest member of Sauropoda that we've discovered thus far, though it may be so early and primitive that it may not actually fit into Sauropoda, but be an early ancestor (or an offshoot of that ancestor). 9 meters long, close to 1000 pounds, discovered in the Kota formation in India, this guy shares a lot of features with prosauropods but one it likely did not was the ability to walk bipedaly for extended periods. Here I've drawn this dinosaur rearing to frighten away a predator, but pretty soon they'll have to come back down.

Colored sketch this time. :D