Meet Ingentia prima, a Triassic dinosaur that provides a previously-missing link between the raccoon-sized prosauropods and the Jurassic giants like Apatosaurus and Diplodocus: https://gizmodo.com/this-triassic-beast-paved-the-way-for-the-world-s-large-1827452889
"Ingentia prima", by the way, roughly means "first to get huge".
@noelle If it isn't also the name of a heavy metal cover band then there is a missed opportunity here.