A Fossil First: Scientists Find 1.5-Million-Year-Old Footprints of Two Different Species of Human Ancestors at Same Spot

More than a million years ago, on a hot savannah teeming with wildlife near the shore of what would someday become Lake Turkana in Kenya, two completely different species of hominins may have passed each other as they scavenged for food.
Scientists know this because they have examined 1.5-million-year-old fossils they unearthed and have concluded they represent the first example of two sets of hominin footprints made about the same time on an ancient lake shore. The discovery will provide more insight into human evolution and how species cooperated and competed with one another, the scientists said.

Newly discovered fossil documents small-scale evolutionary changes in an extinct human species

Males of the extinct human species Paranthropus robustus were thought to be substantially larger than females — much like the size differences seen in modern-day primates such as gorillas, orangutans and baboons. But a new fossil discovery in South Africa instead suggests that P. robustus evolved rapidly during a turbulent period of local climate change about 2 million years ago, resulting in anatomical changes that previously were attributed to sex.