The Pliocene Hellbender: Limnospondylus ajimuensis

Publication Info:

Transcript:

Masahiro Noda et al, A new genus of giant salamander (Urodela, Cryptobranchidae) from the Pliocene of Japan, PeerJ (2026). DOI: 10.7717/peerj.21362

Meet Limnospondylus ajimuensis, the newly named giant salamander from Pliocene Japan! These fossils, originally discovered in the 90s have turned out to be a brand new genus and species related to modern members of Cryptobranchidae like the Japanese Giant Salamander and the Hellbender. This find will be giving paleontologists amazing new insights into the evolution and survival of this rare and enigmatic group of animals.

Episode 308

Notes:

Hey, so there's a brand new giant salamander. I know a lot of the time when we talk about giant salamanders, we're talking about temnospondyls, which aren't really salamanders. They're not even a part of the same group as salamanders. They just kind of look similar. But, this isn't one of those. This is a true giant salamander, and it's not even really all that old. Meet Limnospondylus ajimuensis, the new late Pliocene giant salamander that patrolled Japan's waterways 3.5 million years ago. And it's a cryptobranchid, which means it's a member of the same group as the modern giant salamanders, like the Japanese giant salamander and the hellbender in the US. And these are the largest amphibians still alive today. Three vertebrae were discovered in the '90s, and originally identified as belonging to the genus Andrias, which is the same genus as the modern Japanese giant salamander. But, paleontologists just took a closer look and found that they really didn't quite match up with the modern giant salamander. And in fact, they're different enough that they are their own genus. Meaning that the Ajimu site is the only place on the planet that has both fossil and modern giant salamanders, which is going to provide a link to better understand the evolution of these incredibly rare and enigmatic and threatened animals. Almost forgot, it was almost 3 and 1/2 ft long. I know no one will forgive me if I left that out. As usual, if you want more information, here's the source.