Podcast 240 - Chibi Gar

The gang discusses two papers that look at the impact of the end Cretaceous mass extinction. The first paper looks at ecomorphospace changes in mosasaur communities prior to the extinction event, and the second paper discusses the importance of a large freshwater gar which lived through the recovery. Meanwhile, James has some new and interesting ecological theories, Curt is simpatico with his recording equipment, and Amanda acts as our resident "fish" expert.   Up-Goer Five (Curt Edition): Our friends talk about two papers that look at a time when a big rock hit us a long long time ago. The first paper looks at how big angry animals in the water that you can not drink did before the big rock hit. There is a big question about if these big angry animals that live in water you can not drink were doing well before the big rock hit, or if they were already on their way out. This paper looks at how the heads of these animals changed over space and time by looking at a large number of these from lots of different places. What they find is that there is a lot going on before the big rock hit. Some places are having their big animals look like they are having real problems, but in other places there seems to be a lot of new change in these big animals. It seems that this time before the big rock was a time when these big animals were going through a lot of changes. The big rock may have hit at a very bad time because things were not calm because of all of these changing going on. The second paper looks at animals living in water you can drink after the big rock hit. This paper finds a very large animal that breathes water head. Since this is a group of animals that are still around today, they can use the head to figure out how big the animal would have been, and they find that it would have been pretty big and also would have eaten other animals. This animal lived pretty soon after the big rock hit. This might mean that animals living on land and in the water that you can drink may have been doing a lot better than things living in the water you can not drink. If an animal was able to get that big eating other animals, it seems that these places were doing well. One of the ways animals respond when things get bad and foot is short is that they get smaller. Since we do not see that happening in this place, it could mean that places like this were not hit that bad when the rock hit.   References: MacLaren, Jamie A., et al. "Global ecomorphological restructuring of dominant marine reptiles prior to the Cretaceous–Palaeogene mass extinction." Proceedings of the Royal Society B 289.1975 (2022): 20220585. Brownstein, Chase Doran, and Tyler R. Lyson. "Giant gar from directly above the Cretaceous–Palaeogene boundary suggests healthy freshwater ecosystems existed within thousands of years of the asteroid impact." Biology Letters 18.6 (2022): 20220118.