Scientists find tapeworms in 270 million-year-old shark poop

Scientists in Brazil have found fossilized poop from a prehistoric shark that appears to contain 93 individual tapeworm eggs.

The poop fossil is 270 million years old and was located in the municipality of São Gabriel, in southern Brazil near the border with Uruguay, say a team of scientists whose research was published in open-access online journal PLOS on Jan. 30.

Just in case you were wondering what a 270-million-year old piece of fossilized shark poop looks like, here it is:

It appeared the eggs had not yet erupted and at least one appeared to contain a developing larva.

The finding is significant as fossilized parasite eggs in such a condition are rare. As the authors write in the paper: “Helminth parasites rarely produce eggs with long-lived resistance to environmental stressors. Most of their eggs are fragile, so that they start to decompose very early outside their host.”

This finding marks the earliest known fossil record of tapeworm parasitism found in a vertebrate, the scientists say.