LOS ANGELES — DNA from a 40,000-year-old pinkie finger, belonging to a child and found in a cave in Siberia, indicates that the bone is from a previously unknown family of human relatives who lived among Neanderthals and modern humans, German researchers reported Wednesday.

The discovery, if confirmed by research already under way, would mark the first time that an entirely new species of hominid has been identified solely on the basis of DNA sequencing, the team reported online in the journal Nature.

It also suggests that other currently unknown species could be similarly identified.

With the recent, and still controversial, discovery of the Hobbit-like species Homo floriensis that survived in Indonesia until about 13,000 years ago, the evidence now indicates that at least four species of human-like creatures walked the Earth at the same time.

The find suggests that “40,000 years ago, the planet was more crowded than we thought,” wrote evolutionary biologist Terence A. Brown of the University of Manchester in an editorial accompanying the report.

The new species shared a common ancestor with both modern humans and Neanderthals about 1 million years ago, based on the DNA sequences, according to the team led by anthropologists Johannes Krause and Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. That is about 500,000 years older than the last common ancestor shared by Neanderthals and modern humans.

“I like it because it makes us sort of a normal mammal,” said anthropologist Todd R. Disotell of New York University’s Center for the Study of Human Origins.

Until the team has a complete sequence of nuclear DNA, “we are not saying this is a new species,” Paabo said at a news conference.