SCIENCE LAB SCHEMES : BURROWING IN

 

These fossils are found everywhere.  Researchers have found what made them.

If you know where to look, you can find dumbbell-shaped fossils in rock outcrops all over the world : in Brazil, the United States, Canada, India and African and European countries.

They are called Bifungites, and they are not fossilized animals but burrows left in an extinct creature's wake. Most are found in rocks from the Paleozoic era, more than 300 million years ago.

No one knows what made these burrows, which are considered trace fossils, although scientists have hypothesized what might have done so.

Daniel Sedorko, an invertebrate paleontologist in Brazil's National Museum, has studied them for more than a decade, and during an expedition in June 2022, he noticed something unusual.

The burrows are typically empty because the creatures that constructed them were soft bodied invertebrates, which often don't fossilize well. But on exposed rocks in the bed of the Sambito River in northeastern Brazil, Dr. Sedorko saw an imprint of a small worm inside one Bifungites.

Within hours, his team found seven other fossilized burrows with the same worm imprint, indicating that these organisms had produced them.

The researchers say it's the first record revealing the invertebrates that made these Bifungites. They announced the discovery in the journal  Earth History and Biodiversity. [ Priyanka Runwal ]