The gang discusses two papers that look at the ecomorphology of Mesozoic swimming reptiles. The first paper investigates swimming strategies in various marine swimming reptile groups, and the second paper looks at changes in the skull of mosasaurs compared to stem whales. Meanwhile, James has a meal, Amanda “makes” animals, and Curt needs more insight.   Up-Goer Five (Curt Edition): The friends look at two papers that look at how big angry animals that move through the water lived a long time ago. The first paper looks at how these big animals moved through the water, because there are many ways that an animal can move through water. They use numbers to look at how these animals look, and they also use some animals from today that move through water to see if the way they look is like the ones from the past. They find that there are some ways that animals look with their bodies that change how they move through the water. This shows a lot of cool things. Some groups start moving through water in one way and over time move to a different way. This shows that there was a lot of different ways these groups of big angry animals were able to move through the water. The second paper looks at the heads of one group of big angry animals from the past that move through water and also an old group of big animals with hair that move through water that are still around today. The paper wants to see if both of these groups do the same things with their heads since they are both moving into moving through water. They find that a few of the heads kind of look like each other between these two groups, which could be that they were trying to eat the same things. However, most of the time these two groups are not looking the same in the head. This is because these two groups come from different things and so they are not able to change their head in the same way.   References: Gutarra, Susana, et al. "The locomotor ecomorphology of Mesozoic marine reptiles." Palaeontology 66.2 (2023): e12645. Bennion, Rebecca F., et al. "Convergence and constraint in the cranial evolution of mosasaurid reptiles and early cetaceans." Paleobiology 49.2 (2023): 215-231.