FOSSIL tracks on the seabed could be the handiwork of oversized amoebas that roamed the ocean 1.8 billion years ago, if their modern counterparts are anything to go by.
While exploring the Bahamas, Mikhail Matz of the University of Texas at Austin discovered a new species of giant amoeba called Gromia sphaerica. As the grape-sized protozoan rolls along the ocean floor, it sucks up and spits out sediment, leaving behind long grooves and ridges.
Similar tracks preserved in ancient mud have mystified palaeontologists. They assumed that the only creatures with the physiology to make such grooves were ancestors of…
