(Reuters) - About 1.5 million years ago, individuals of two different species in the human evolutionary lineage trudged on a muddy lakeshore in northern Kenya, leaving behind intersecting trackways alongside the footprints of antelopes, horses, warthogs, giant storks and other animals.

Muddy footprints left on a Kenyan lakeside suggest two of our early human ancestors were neighbors some 1.5 million years ago.

Two sets of fossilized footprints from early human species were made within a few hours of each other about 1.5 million years ago, researchers suggest