The gang discusses two papers that look at examples of cohabitation and unique ecological interactions in the Cambrian. The first paper looks at multiple animals living together in a hemichordate living chamber, the and the second looks at a potential example of parasitism on brachiopods. Meanwhile, James flips a coin, Curt has to live with some consequences, and Amanda ranks things from meh to bad.

Up-Goer Five (Curt Edition):

Our friends talk about two papers that look at animals which are living together, sometimes not because both animals want that. The first paper looks at these long animals with no legs that live together. There are two different types of these long animals living the in the same spot, which is a home that looks like the ones built by the bigger of the two long animals, but the home seems to be a bit too big. Because the small long things do not have bits that could cut off parts of the bigger long thing, they think that these two animals would have lived in the same spot and been just fine. Since the homes are bigger than either animal, it means we still have to figure out why the homes are so big. It could be that the bigger long animals could be kids and the homes were built by the grown ups for the kids to live in.

The second paper looks at these small long round thing that was found on these animals with hard parts on either side which sit on the ground in the water and pull food out of the water. The animals with hard parts could have these small long round things on them or they could not. The animals with hard parts that had these small long round things were smaller than the ones that did not. The way the small long round things were put onto the animals with hard parts makes it look like they are homes for other small animals that would take the food out of the mouth of the animals with hard parts.

References:

Zhang, Zhifei, et al. "An encrusting kleptoparasite-host interaction from the early Cambrian." Nature communications 11.1 (2020): 1-7.

Nanglu, Karma, and Jean-Bernard Caron.  "Symbiosis in the Cambrian: enteropneust tubes from the Burgess Shale  co-inhabited by commensal polychaetes." Proceedings of the Royal Society B 288.1951 (2021): 20210061.

The gang discusses two papers that look at trackway fossils. The first paper uses a modern study to determine how many tracks are needed to get a reasonable estimate on the trace morphology, and the second paper looks at trackways from an early tetrapod and attempts to determine the likely trace maker. Meanwhile, James has thoughts on Luigi, Amanda gives the birds the bird, Curt regrets a burn, and everyone loves Christopher Walken’s line delivery in Ripper.

Up-Goer Five (Amanda Edition):

Today our friends talk about people walking on ground that is wet and animals with four legs that also had a long back end part. The first paper looks at how many people need to walk on ground that is wet before it is enough people to make the numbers good. It also looks at how different kinds of ground and different types of wet also change the way things look. There actually does not need to be too many people walking on ground that is wet before the numbers are good. That means it is easier to do this with things that are not live anymore. The second paper looks at animals with four legs that were walking around a long time ago. The paper does a good job of figuring out just what those animals with four legs probably were, and about how they walked. They also had a long back end that dragged on the ground. That also tells us about how they walked. But there needs to be more stuff done on these animals with four legs and their walking marks, as well as their legs, before we know exactly what the back end marks mean.

References:

Logghe, A., et al. "Hyloidichnus  trackways with digit and tail drag traces from the Permian of Gonfaron  (Var, France): New insights on the locomotion of captorhinomorph  eureptiles." Palaeogeography, Palaeoclimatology, Palaeoecology 573 (2021): 110436.

Belvedere, Matteo, et al. "When is enough, enough? Questions of sampling in vertebrate ichnology." Palaeontology (2021).

The gang discusses two papers with… honestly a pretty flimsy link connecting them together. The first paper looks at size shifts in the dinosaur group, Alvarezsauridae, and the other paper looks at beetle fossils preserved in a dinosauromorph coprolite deposit. Meanwhile, James finds that the third time is the charm, Curt struggles to segue, and Amanda has thoughts on ham.

Up-Goer Five (Curt Edition):

Our friends talk about two papers that are not as much the same as they had hoped. The first paper looks at a group of angry animals wear most of these animals got really big a long time ago. A few of these animals start getting small, and this paper looks at one of those groups of angry animals that gets small to try and see when and why they got small. This paper uses a study of how these different animals are sister and brother to each other and then looks at how the big these animals are and tries to see if there is a time when things start to get small. They find that these things start to get small at a time pretty late in the life of the group. This is also around the time that a lot of small animals who wear their hard parts on the outside and live in big groups first appeared. Since the angry animals have weird hands that look like they could move through the ground, it is possible that these animals got smaller and started eating these even small animals who live in big groups.

The second paper looks at a small animal that wears its hard parts on the outside that was found in shit. I have to use the word shit because it is the only word in the ten hundred most used words that can be used to tell you what this animal was found in. It was found in shit. The animal is broken up so it seems that the animal was eaten by a bigger animal who then pushed it out when that animal had a shit. This small animal is one of the best remains of one of these animals from so long ago, because the shit kept the animal parts from breaking down. Shit is a really great way to find parts of other animals because it keeps some of those parts from breaking down really well. Also, the small animals in this shit are found with other bits of green things that live in water and use sun to make food. This means that the animal which ate the small animals might have been trying to eat the green things and happened to grab a lot of those small animals who were also on the green things.

References:

Qvarnström, Martin, et al. "Exceptionally preserved beetles in a Triassic coprolite of putative dinosauriform origin." Current Biology (2021).

Qin, Zichuan, et al. "Growth and miniaturization among alvarezsauroid dinosaurs." Current Biology (2021).