Janenschia (yan-ensh-ee-ah) was a large sauropod from Late Jurassic Africa (155 million years ago), and therefore the earliest known titanosaur. Originally thought to be a species of the diplodocid Tornieria/Barosaurus (previously "Gigantosaurus"), it was later found to be a distantly related titanosaur.

Janenschia (named after Werner Janensch) was an 80 feet (24 metres) long sauropod dinosaur found in Tanzania, Africa. Only 2 forelimbs, 3 clawed hindlimbs, and back and tail vertebrae were found. This enormous, long-necked, long-tailed plant-eater was the earliest-known titanosaurid and was named by paleontologist Rupert Wild in 1991.