Episode 365: A New Temnospondyl

Strange Animals Podcast

Let's take a look at some new findings about the temnospondyls this week! Further reading: Ancient giant amphibians swam like crocodiles 250 million years ago Fossil of Giant Triassic Amphibian Unearthed in Brazil Kwatisuchus rosai was an early amphibian [picture taken from article linked above]: Koolasuchus was a weird big-headed boi: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week we’re going to revisit an animal we talked about way back in episode 172, the temnospondyl. That’s because a new species of temnospondyl has been named that lived about 250 million years ago, and some other new information has been published about temnospondyls in general. In case you haven’t listened to episode 172 in a while, let’s brush up on some history. The temnospondyls arose about 330 million years ago during the Carboniferous period. Ocean levels were high, the continents were coming together slowly to form the supercontinent Pangaea, and much of the land was flooded with warm, shallow water that created enormous swampy areas full of plants. Naturally, a whole lot of animals evolved to live in the swamps, and the temnospondyls were especially successful. Temnospondyls were semi-aquatic animals that probably looked a lot like really big, really weird salamanders. This was before modern amphibians evolved, and scientists still aren’t sure if the temnospondyls are the direct ancestors of modern amphibians or just cousins that died out with no living descendants. Temnospondyls do share many traits with modern amphibians, but they still had a lot in common with their fish ancestors. Most temnospondyls had large heads that were broad and flattened in shape, often with a skull that was roughly triangular. Some had smooth skin but many had scales, including some species with scales that grew into armor-like plates. The earliest species had relatively small, weak legs and probably spent most of their time in the water, but it wasn’t long before species with stronger legs developed that probably lived mostly on land. Many temnospondyls were small, but some grew really big. The biggest found so far is Prionosuchus, which is only known from fragmentary specimens discovered in Brazil in South America. It had an elongated snout something like a ghavial’s, which is a type of crocodilian that mostly eats fish, and a similar body shape. That’s why its name ends in the word “suchus,” which refers to a crocodile or an animal that resembles a crocodilian. Inside, though, prionosuchus probably had more in common with its fish ancestors than with modern crocodiles, and of course it wasn’t a reptile at all. It was an amphibian, possibly the largest one that’s ever lived. The biggest specimen found so far had a skull that measured just over 5 feet long, or 1.6 meters. That was just the skull! The whole animal, tail and all, might have measured as much as 30 feet long, or about 9 meters, although most paleontologists think it was probably more like 18 feet long, or 5-1/2 meters. That’s still incredibly big, as large as the average saltwater crocodile that lives today. The resemblance of many temnospondyls to crocodilians is due to convergent evolution, since researchers think a lot of temnospondyls filled the same ecological niche as modern crocodiles. If you’re an ambush predator who spends a lot of time hiding in shallow water waiting for prey to get close enough, the best shape to have is a long body, short legs, a long tail that’s flattened side to side to help you swim, and a big mouth for grabbing, preferably with a lot of teeth. A study published in March of 2023 examined some trace fossils found in South Africa that scientists think were made about 255 million years ago by a temnospondyl. The fossils were found in what had once been a tidal flat or lagoon along the shore of the ancient Karoo Sea. You didn’t need to know it was called the Karoo Sea but I wanted to say it because it...