Cloudina fossils push animal-made reefs back in time

A 548-million-year-old reef in central Namibia is the earliest known ecosystem built by hard bodied animals, according to a new study. Until now, the oldest reefs on record made of hard-bodied animals had been dated to about 530 million years of age.  The reefs were built by tiny, filter-feeding animals called Cloudina that lived on shallow equatorial seabeds during the Ediacaran Period, which ended 541 million years ago.