More than 13 million years ago in what’s now northern Kenya, an infant ape ended up dead in a lush forest, its body blanketed in ashfall from a nearby volcanic eruption.

Millions of years later, scientists uncovered the baby ape’s skull, the best-preserved of its kind ever found, and got an extraordinarily glimpse into the early stages of ape evolution.

“We’ve been looking for ape fossils for years—this is the first time we’re getting a skull that’s complete,” says Isaiah Nengo, the De Anza College anthropologist who led the discovery, supported by a National Geographic Society grant and the Stony Brook University-affiliated Turkana Basin Institute.

Roughly the size of a lemon, the skull belongs to a newly identified species of