Scientists are "very excited" to learn more about a baby tooth that only the most sophisticated DNA dating tech can analyze. Some 150,000 years ago, a young girl lost her baby tooth, and it fell into the sediment of a cave in Siberia from which the first three (and thus far only) other fossils identified in 2010 as being Denisovan were found, reports Live Science.

Before then, the hominin group that's as genetically distinct from modern humans as Neanderthals was completely unknown. This fourth fossil is the oldest, per the paper in the Science Advances journal, suggesting that the mysterious group lived in Central Asia so long ago that there was likely greater interaction with, and thus more potential to interbreed with, Neanderthals—something we humans appear to have done, too.

Five years ago, scientists would have probably had to destroy the tooth to study its genetic fingerprints, but recently Viviane Slon at the Max Planck Institute for Evolutionary Anthropology in Germany was able to scrape the tooth's surface and drill into its root to collect 10 milligrams of material that contained the DNA her team ultimately studied.

"We only have relatively little data from this archaic group, so having any additional individuals is something we're very excited about," she tells the New York Times.

The other three fossils, a finger bone and two molars, were also unearthed in the Denisova Cave in the Altai Mountains of Siberia. The baby tooth, found in deep sediment as much as 227,000 years old, is one of the oldest human specimens ever found in Central Asia.

(Dirt samples from seven caves had a lot to say about the Denisovans.)

This article originally appeared on Newser: Scientists 'Very Excited' About 150K-Year-Old Baby Tooth