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Home > Research & Collections > News > Fossils Fresh from Antarctica

Fossils Fresh from Antarctica

Amazing animals that lived 250 million years ago

A portion of the spine of an extinct species called Thrinaxodon in a rock formation in Antarctica. Photo by Nathan Smith.


Sometimes you have to go to great lengths to get great fossils. NHMLA Dinosaur Institute Associate Curator Nathan Smith had to go all the way to Antarctica. The southernmost continent on Earth might not spring to mind when you think about fossils, but it has deposits from many periods throughout Earth’s history. On this trip, Smith and his collaborators were focusing on a site with 250-million-year-old rocks, placing them right at the start of the Triassic Period.

This was an interesting time in Earth’s history, just following the Great Permian Extinction, the biggest mass extinction event ever. Marking the end of the Permian Period 252 million years ago, a whopping 96 percent of species died out after an overwhelming series of worldwide catastrophes like volcanic eruptions, a rise in atmospheric methane, a drop in oxygen levels, and sea level fluctuations. Some speculate there might even be an asteroid impact in the mix. It was a tough time. The fossils Smith hunted for in Antarctica represent the few survivors of this cataclysm.

Taking daily helicopter flights from his camp to the dig site, over the course of six weeks Smith and his team excavated fossils of these long-extinct creatures. There are amphibians, reptiles, and relatives of early mammals. But these are not dinosaur fossils (though there are some of those elsewhere in Antarctica). These animals predate dinosaurs by many millions of years. And while they’re not the oldest fossils on the frozen continent, they are the oldest tetrapods — that is, vertebrates with four appendages (which pretty much just leaves out fish).

So what sorts of fossils did Smith bring back from Antarctica? Creatures like Thrinaxodon, Lystrosaurus, and small, yet-to-be-identified amphibians.

Illustration by Nobu Tamura.

Animals in the genus Thrinaxodon were about the size of a fox or small weasel. Relatives of early mammals, they were among the first animals to have what’s called a “semi-sprawling posture,” with their body lifted off the ground when they walked — as opposed to stomach-scraping sprawlers like lizards.

Illustration by Nobu Tamura.

Lystrosaurus had two tusks and a beak-like mouth which it may have used to chomp on plants. About the size of a Welsh corgi, it was one of the most common vertebrates on land at the beginning of the Early Triassic Period (252-247 million years ago).

a photo of a rock with small white flecks in it, those are the fossil of a long extinct amphibian
Photo by Nathan Smith.

The white bits in this rock are the fossilized remains of a small amphibian. The visible part of this fossil is about 2 inches long, and at the top, you can just make out the tiny teeth of this creature that lived 250 million years ago. The fossil is so small and delicate, Smith may opt to take a CT scan of the rock and fossil within, rather than chipping away any more of the surrounding rock to expose it.

Shipped in large wooden crates, these fossils made a long journey from rock beds in Antarctica to NHMLA, but now they are here to stay (perhaps for the next 250 million years).


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