That distinction belongs to a coiled form of marine life known as Grypania.  The oldest fossilized relics have been recovered from an iron mine in Michigan and have an age of 2.1 billion years.  The coils fit on the side of a penny.  If the larger ones are unwound, they would stretch for about two inches.  Exactly what type of life Grypania represents is still debated—whether a colony of bacteria or of algae.  Also, no one has yet related them to anything living today, and so they may not have any living relatives.

Grypania spiralis.jpg

   Coils of Grypania