Scientists have announced the discovery of a 200 million year old dinosaur from South Africa that remained hidden in a fossil collection for decades.

The ancient bones were discovered in the 1930s, but was lost among the largest fossil collection in South Africa, located at the Evolutionary Studies Institute (ESI) at Wits University. While looking over the collection, paleontologist Alejandro Otero and PhD student Emil Krupandan noticed some distinctive bones. A closer look revealed these bones, which had been thought to belong to an Aardonyx, were actually from a completely new dinosaur.

"This find indicates the importance of relooking at old material that has only been cursorily studied in the past, in order to re-evaluate past preconceptions about sauropodomorph diversity in light of new data," Krupandan said.

The new dinosaur's most distinctive feature was its ankle bones, which are shaped like a cross. This inspired the researchers to name the new dinosaur Sefapanosaurus, after the Sesotho word "sefapano," meaning cross. The dinosaur is believed to have been a medium-sized sauropodomorph, which were the ancestors of long necked giants of the Mesozoic.

 "This new animal shines a spotlight on southern Africa and shows us just how much more we have to learn about the ecosystems of the past, even here in our own 'backyard'," said Jonah Choiniere, co-author and Senior Researcher in Dinosaur Palaeobiology at the ESI at Wits University. And it also gives us hope that this is the start of many such collaborative palaeo-research projects between South Africa and Argentina that could yield more such remarkable discoveries."

The findings were published in a recent edition of the Zoological Journal of the Linnaean Society.