Science & Tech

Scientists are cutting open parasitic eggs from 200 million years ago

Scientists are cutting open parasitic eggs from 200 million years ago

The earliest predators on the planet were infested with roundworm

Nonsrirach et al

A 200 million-year-old parasite has been discovered in fossilised poo, in the latest not-at-all-scary instance of scientists unearthing a species which blighted the Earth in ancient times.

Researchers found that the earliest predators on the planet were infested with roundworm, also known as nematodes, among multiple other parasites.

The fossilised poo, which is known to palaeontologists as coprolite, is thought to belong to a type of semi-aquatic phytosaur, which was a crocodile-like predator.

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It comes weeks after another team revived a prehistoric worm – the catchily named Panagrolaimus kolymaensis – which was found dormant in the Siberian permafrost in a state of “cryptobiosis”.

The latest study saw researchers from Mahasarakham University, Thailand, analyse a three-inch-long portion of ancient poo and discover five types of parasitic remnants.

The group sliced open the parasitic egg fossils with a diamond saw using a “standard thin section method,” their report said.

The ultra-thin slices allowed the palaeontologists to look at cross-sections of the ancient infectious microbes under a microscope.

One was identified as a nematode worm egg, while the others are thought to be either more eggs, protozoan cysts or spores from moss and ferns.

While modern parasites are often an important part of ecosystems, it is usually more difficult to work out what their ancient equivalents did, because there are so few examples in the fossil record.

The creatures often inhabited the soft tissues of their hosts, but are rarely preserved as fossils, making the latest discovery all-the-more significant.

This fossilised late Triassic-era coprolite (the poo), was shielded from the elements in the Huai Hin Lat geological formation in Thailand, which is over 200 million years old.

It was found by local villagers, according to the study's lead author, paleontologist Thanit Nonsrirach.

“The peculiar appearance of these findings intrigued the villagers, who considered them potentially auspicious and capable of bestowing good luck if repurposed as talismans,” Nonsrirach told news outlet Inverse.

“In 2010, our team received word of this discovery and embarked on a field expedition, guiding the villagers to the actual fossil site.”

The discovery is the first record of parasites in a terrestrial vertebrate host from the late Triassic period in Asia, and provides a rare look at the life of an ancient creature that was infected by multiple species.

This discovery also adds to the few known examples of nematode eggs preserved within the coprolites of Mesozoic animals.

“Parasites of several species, including Ascaridida (roundworm) eggs were found in a coprolite, probably produced by a crocodile-like reptile and possibly a phytosaur,” said Nonsrirach, who works at Mahasarakham University's Palaeontological Research and Education Center.

“This is therefore the first discovery of Ascaridida eggs and evidence of multi-infection in a host assignable to the Crurotarsi from the Late Triassic of Asia.

“Coprolite is a significant palaeontological treasure trove, containing several undiscovered fossils and expanding our understanding of ancient ecosystems and food chains.

“These findings are therefore a significant contribution to scientific understanding of the distribution and ecology of parasites of the distant past.”

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