‘Wiggly’ fossils may be oldest known sign of animal life

Intricate patterns of tubular structures discovered in giant ancient reefs may be the remnants of prehistoric horny sponges and the oldest known fossils of animal life.

Researchers found the unusual features in vast reefs that were built by bacteria 890m years ago and then pushed up by geological processes to form part of the Mackenzie Mountains in north-western Canada.

Examined under a microscope, a small number of rock samples revealed tubules about half the width of a human hair that branch and reconnect to form 3D structures similar to fossils of bath sponges.

If the structures are confirmed as early sponge fossils, they would predate the next-oldest undisputed sponge fossils by about 350m years.