The gang gets together to record their first episode back from the holidays. And what better topic to discuss than hyoliths, those strange shelly Cambrian fossils. Specifically, the gang discusses two papers that look at new discoveries of the soft tissue and the hard shells of these hylothis to try and determine the evolutionary placement of hyoliths. Are hyoliths molluscs? Are hyoliths brachiopods? Are they somewhere in between? Meanwhile, Amanda hears some good news, Curt does his best hyolith impression, and James hits some unexpected snags when he discusses the ramifications of his ideal super powers.
Up-Goer Five (Amanda Edition):
Today our friends talk about animals that are big at one end and small at another end. They might be close to things with two parts that are good to eat, or they might be close to things with two parts that are not good to eat. Some people have said not long ago that they are more close to the things with two parts that are not good to eat. Our friends look at two papers that talk about these strange animals that are big at one end and small at the other. One paper says that yes, these animals are more close to the things with two parts that are not good to eat, and says that this is shown by the fact that they have a long thing that makes them stick to the ground. Animals with two parts that are good to eat don't have this long thing that makes them stick to the ground, but animals that have two parts that don't aren't good to eat do. Our friends don't really know if this thing is actually a part that makes the strange animals that are big at one end and small at the other stick to the ground, and would like to see some cool pictures taken to help show more things. The second paper tells us that actually these strange things that are bigger at one end and smaller at another are sort of between the things with two parts that are good to eat and the things with two parts that are not good to eat. They do this by looking at the hard parts that make up the strange things that are big at one end and small at the other, and then looking at the hard parts of the animals with two parts (both good and not good to eat). They look at these hard parts very, very close up. It is very cool.
Sun, Haijing, et al. "Hyoliths with pedicles illuminate the origin of the brachiopod body plan." Proceedings of the Royal Society B: Biological Sciences 285.1887 (2018): 20181780.
Li, Luoyang, et al. "Homologous shell microstructures in Cambrian hyoliths and molluscs." Palaeontology (2018).