Final answer:
The footprints preserved in volcanic ash dated to 3.6 mya were made by Australopithecus afarensis, discovered in East Africa at the Laetoli site by Mary Leakey, which showed evidence of bipedalism.
Step-by-step explanation:
The specimen's footprints that were preserved in volcanic ash dated to 3.6 mya are believed to be of Australopithecus afarensis. These ancient footprints were discovered by the English paleoanthropologist Mary Leakey in the 1980s at the site of Laetoli in East Africa. The trail consisted of prints made by three bipedal hominins, providing some of the earliest evidence of hominin bipedalism. The careful analysis of these footprints revealed a modern striding gait, much like that of modern humans, indicating an advanced stage in the evolution of bipedal locomotion for the time.