Researchers discovered teeth belonging to ancient hominins at the Ledi-Gelaru archaeological site in Ethiopia.
2.6 million years ago
At the Ledi-Gelaru site in northeastern Ethiopia, researchers unearthed 13 ancient teeth. Dating the volcanic ash layers revealed that 10 of the teeth belonged to an unnamed Australopithecus species, dating to approximately 2.63 million years ago. The other three belonged to Homo, with one being as old as 2.78 million years old.
Researchers discovered ancient hominin tooth fossils at Ledi-Gelaru, Ethiopia.
This means that at that time, this grassland simultaneously housed:
- This mysterious Australopithecus (possibly a new species);
- The oldest known species of Homo (unnamed);
- The known species of Australopithecus galliformes
- These three hominin species coexisted on this land.
What was their habitat like?
Based on herbivore fossils found in the same stratum, this area was an open, arid grassland with rivers and some vegetation. Researchers say this environment, which provided water, plants, and large prey, was ideal for hominin habitation.
Thirteen fossil teeth were found at Laidi-Jelaru. Teeth LD 750 and 760 belong to an unidentified species of Australopithecus, while teeth LD 302 and AS 100 belong to an early Homo species.
However, some caution that the abundance of fossils here may be partly due to the excellent preservation conditions created by natural events such as volcanic eruptions, and does not necessarily indicate that this was an "ancient hominin concentration area."
Why is it considered a possible new species?
The teeth of this group of Australopithecus differ from those of the known species, both afarensis (the species "Lucy" refers to) and Galliformes. While there are no particularly striking features that directly confirm this as a new species, these differences have led scientists to suspect that this may be a previously undocumented member.
What implications does this have for the study of human evolution?
In the past, we often thought of human evolution as a one-way street, with one species replacing another. But growing evidence suggests that the history of the human family tree is more like a lush tree: multiple related species often coexisted and developed independently at different times and in different regions.
As one anthropologist put it, "This is a very critical time point, possibly when the earliest populations of the genus Homo emerged, and there is evidence of the coexistence of multiple hominins."
Did they interact with each other?
There is currently no direct evidence of interaction. They may even have shared areas, similar to chimpanzees and gorillas in forests today, but not often encounter each other.
However, scientists plan to analyze the chemical composition of tooth enamel to see if they ate similar foods, thereby determining whether they competed for resources.
Every tooth is a piece of the puzzle.
Researchers say every fossil they find is a piece of the puzzle of human evolution. Future excavations may yield more discoveries, perhaps even our first true glimpse of what this "cousin of Lucy" looked like.
If three species of ancient humans truly lived together on the grasslands 2.6 million years ago, do you think they avoided each other or shared water?
