A tiny trackway discovered in sedimentary rock has pushed back the date of the first organism capable of walking to 585 million years ago. This proof is 30 million years older than previously known evidence.It took two years to precisely date the trackway by radiometric dating of igneous rock that intruded into the sedimentary rock. The fossil was found in Uruguay.
The organism was about the size of a grain of rice. A trackway like this shows that it had front and back ends and was bilaterally symmetrical, with limbs that could move it forward. We could call it First Explorer.