Episode 494: Four Water Animals

**Further reading:** New species of extinct vampire-squid-like cephalopod When teeth grow on the body Fossil shark turns into mystery pterosaur Scientists Had Never Seen This Elusive Whale Alive—Until Now **Show transcript:** Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This month I wasn’t sure what to cover in this episode, so I decided to just click on four random bookmarks of scientific articles that I’ve had waiting for attention, and we’ll discuss them. We haven’t done a four articles episode in a long time! The first article is from March 2022, and it’s about the discovery of an ancient cephalopod. Cephalopods include octopuses and squid. Octopuses famously have eight arms, while squid have eight arms and two feeding tentacles. Despite its name, the deep-sea vampire squid is actually more closely related to octopuses than to squid, and a newly discovered fossil is an ancestor to both. The fossil is 328 million years old and was discovered in Montana, in the United States, in 1988 but was only studied recently. Fossils of soft-bodied animals are incredibly rare, and this one is remarkably well-preserved. All of the animal’s arms are preserved, including the suckers, but instead of eight arms, it had ten. Scientists have long suspected that the ancestors of modern octopuses and vampire squid had ten arms. The vampire squid has eight arms and two feeding filaments that are vestigial arms. But this is the first fossil found that shows ten arms. The fossil is of an animal with a torpedo-like body shaped like a modern squid. Two of its arms appear to be elongated compared to its other arms. It’s about 4 and a half inches long including its arms, or 12 cm. That’s pretty much all we know about it now, but hopefully the fossil will reveal more information as it continues to be studied. Our next article is from October 2017 and is intriguingly titled “When teeth grow on the body.” It sounds horrific, but it’s actually a study of certain catfish that grow bony plates with tiny teeth on their bodies as defense. Catfish don’t have scales, but some species of denticulate catfish that live in South America grow bony plates that act like armor. Many of these plates are covered in thin little teeth–actual teeth, including enamel and dentin, with pulp inside. They’re called extra-oral teeth, dermal denticles, or odontodes, and the study determined that they appeared about 120 million years ago in ancient catfish that hadn’t yet evolved the bony plates. The teeth regrow when they’re lost, and in some species, males grow larger teeth than females and use them to fight other males. Imagine biting someone without needing to open your mouth. Our next article is from November 2020, about more fossils. The fossils were discovered in a collection at the Sedgwick Museum of Cambridge and the Booth Museum at Brighton in England, and were originally found in the latter half of the 19th century by miners. A PhD student at the University of Portsmouth was studying fossilized shark spines from the collection when he realized they weren’t actually shark spines. Instead, they were jaw fragments from pterosaurs. Pterosaurs were flying reptiles that filled many ecological niches that birds fill today. One of the species identified from the collection is called Ornithostoma, which means bird mouth, an animal that lived in the early Cretaceous, about 110 million years ago, in what is now Europe. We know very little about it except that it didn’t have teeth, but it probably ate fish. But there were some other jaw fragments that didn’t belong to Ornithostoma, and in fact don’t match up to any known pterosaur jaws. It may belong to a new species, but the fossils are so fragmentary that there’s no way to know for sure. The rocks that the fossils came from were completely destroyed more than a century ago during phosphate mining, so unless more fragments are found in other collections, we may never learn more about this mystery pterosaur. Our last article is from July 2022, and I have no idea why I haven’t talked about it on the podcast before now. It’s about Sato’s beaked whale, also called kurotsuchi. It’s a type of four-toothed whale with a short beak, and it’s dark gray and can grow up to 23 feet long, or 7 meters. It was only identified in 2016 as being different from the two other known species of four-toothed whales, after careful analysis, including DNA analysis, of dead individuals that had been found washed ashore. Until the summer of 2021, no one had ever seen a living Sato’s beaked whale. Then some researchers studying orcas spotted 14 of the beaked whales swimming together between Hokkaido, Japan and the Kuril Islands. The scientists recognized that these were unusual whales and they were able to get a small skin sample from one. Genetic testing confirmed that they were indeed Sato’s beaked whales. Researchers think the whales may spend at least part of the year in tropical waters, since that’s where cookie cutter sharks live and the whales show circular bite scars from cookie cutter sharks. Not much is known about most species of beaked whale, and Sato’s beaked whale is especially mysterious. But at least we know it’s alive and well right now. Thanks for your support, and thanks for listening!