By Elizabeth Landau, CNN
Achilles' heel was his weak spot in the Greek myth, but the heel of a newly discovered primate provides a strong connection between humans and their possible ancestors.
Scientists have discovered the oldest primate skeleton to date, from a creature that resembles humans' evolutionary line - the anthropoids - and a different primate lineage called the tarsiers. They have named this specimen Archicebus achilles, making reference to its heel bone, which resembles those of modern monkeys.
Anthropoids include humans, apes and monkeys. Tarsiers are nocturnal primates that live only in Southeast Asia today. The study is published in the journal Nature.