Final answer:
Laetoli was discovered in the 1970s by Mary Leakey, featuring a trail of hominin footprints from about 3.5 MYA, likely made by Australopithecus afarensis. These footprints are a key indicator of bipedalism in early hominids long before the famous 'Lucy' skeleton was found by Donald Johanson in 1974.
Step-by-step explanation:
The site of Laetoli was discovered in the 1970s by a team led by the English paleoanthropologist Mary Leakey. Located in East Africa, more precisely in northern Tanzania, the most significant finding at Laetoli is a 75-foot trail of hominin footprints that were preserved in wet volcanic ash about 3.5 million years ago (MYA). These footprints, which evidence bipedal locomotion, deeply suggest a modern striding gait similar to that of current humans. They are likely to have been made by the early hominin species known as Australopithecus afarensis, inferred from both the age of the footprints and associated fossil evidence.
Additional hominin fossils discovered in the region, such as those at Olduvai Gorge, support the idea that early hominid species might have inhabited East Africa for millions of years. Among these early hominid discoveries is the iconic partial skeleton named Lucy, found by American paleoanthropologist Donald Johanson in 1974, which has played a crucial role in understanding the evolution of bipedalism among hominins.