Some graves contained jewelry made from shell and sea snail shells, indicating residents had developed beliefs and craftsmanship skills.
Archaeologist Jósef Szykulski concluded that the group associated with the mass grave at El Curaca won the battle, as the remains were buried in accordance with ritual.
Skeleton shows Mixodectes pungens lived in trees and primarily ate leaves during the Paleocene epoch, highlighting its unique ecological niche after the dinosaurs.
'The new date for the child is consistent with original estimates for the age of the burial, but it has changed our interpretation of the burial events themselves,' said lead author Bethan Linscott.
"Violence is a particularly common theme for later prehistoric human remains from watery places," said the head researcher.
The remains of Lucy will be presented alongside Selam, the fossil of a baby Australopithecus predating Lucy.
The discovery was made by Wolfgang Höpfner, the twin brother of Gerhard Höpfner, who led the excavation team for several years, according to N-TV.