Antarctic Trackways: Polar Sparassodonts

Publication Info:

Transcript:

H. Mansilla-Vera et al. 2026. First mammal tracks from the Eocene of Antarctica. Polar Biol 49, 101; doi: 10.1007/s00300-026-03539-1

This new, coin-sized paw print from 55 million year old deposits in Antarctica could be changing everything paleontologists know about the evolution and spread of a group of predatory marsupial relatives called sparassodonts.

Episode 337

Notes:

Do you think you recognize this little like coin-sized trackway in the middle of nowhere if you spotted it? And I mean really in the middle of nowhere, like Antarctica. And that doesn't even really help narrow it down cuz it's from an animal that until now no one would expect to find there. Cuz not only is this a group that isn't known from Antarctica, Antarctica literally has no predatory mammal trackways, or at least it didn't. This is the 50 million-year-old trackway that was just found in Antarctica and it has a hind print and a fore print. In general, paleontologists don't link a trackway to a specific animal. Ichno fossils like trackways get their own name and sometimes they don't even get a name, they just get their specific specimen name. In this case, it's T373. And even though this trackway isn't being linked to a specific species, paleontologists were able to link it to a group because it has recognizable features. The age, the size, the lack of claw marks, the triangular-shaped heel pad, even the three round toe beans, all link it to a weird group of predatory mammals called the Sparassodonts. And they are weird. They're not your normal predatory mammals. They're actually metatherians, so they're relatives of animals like marsupials without being true marsupials themselves. And up until now, they'd only been found in South America. Meaning that this tiny coin-sized trackway plenty of people probably wouldn't have even seen is going to be changing what paleontologists know about the evolution and spread of this entire group of mammals. As usual, if you want more information, here's the source.