A 3.3 million-year-old fossil of a two-and-a-half-year-old toddler found in Dikika, Ethiopia, reveals that the general structure of the modern human skeleton was already emerging millions of years ago, much earlier than previously thought, according to a new study published Tuesday in the Proceedings of the National Academy of Science.

The findings, by Carol Ward from the University of Missouri:

• The fossil, which scientists have named Selam, was discovered in 2000 and belongs to the early human species Australopithecus afarensis.
• Selam possessed "the most complete spinal column of any early fossil human relative" with 12 rib-bearing vertebrae, the same number humans have now and one fewer than most apes.
• The study said Salem represents the only known fossil with 12 rib-bearing vertebrae in early humans prior to 60,000 years ago.
• Researchers also found that Selam's joint transition from the rib cage to the lower back region followed the same distinctive pattern only seen in our early ancestors.