Podcast 338 - Trilobite and Terror Bird

The gang discusses two papers that describe fossils which provide glimpses into the evolution and ecology of animals that were "late editions" to their clade. In other words, this podcast is focusing on fossils whose ages place them were close to the extinction of their respective groups. The first paper identifies ecological preferences in late Paleozoic trilobites, and the second paper describes a terror bird from South America that provides further evidence for a younger extinction of the group than traditionally understood. Meanwhile, Curt proposes a sitcom, Amanda has great timing, and James enjoys watching robots fail.   Up-Goer Five (James Edition): This week the group read two papers about some of the last members of some groups of animals that are now dead. The first paper looks at small animals with hard skin and lots of legs that can roll up into balls. Although these animals used to come in lots of different shapes, by this time they come in only a few different shapes and are thought to all look like each other. The animals in the paper are found toward the end of when they lived and come both rolled up, all stretched out, and broken up into little bits, showing that some of them were moved into where they are found by water. The animals found in the area are of two different kinds that are almost the same to each other but are found in different parts of the area, with one living in water that is not as deep and the other living in deeper water, showing that they were doing different things. The other paper is looking at the bone of a big angry animal that walked and had a body covered in things that are not hair but would have helped it fly if it was not so big. This one is found long after we thought these animals all died, and is also found from the bottom of the two big bits of land that got married at some point. When these bits of land got married, a lot of animals moved to the bottom bit of land and some moved to the top bit. These animals moved to the top bit and then went missing from the bottom bit, but because this animal bone was discovered we know that they actually still were in the bottom bit long after we thought they went missing.   References: Kudo, Nakuru, and Yuta Shiino. "Taphonomy and environmental distribution of Pseudophillipsia in the middle Permian Kamiyasse Formation of the Southern Kitakami Terrane, Japan." Journal of Paleontology (2026): 1-18. Machado, Victor Hugo M., et al. "A new terror bird (Cariamiformes, Phorusrhacidae) from the Late Pleistocene of Brazil: insights into the last representatives of the family." Papers in Palaeontology 12.2 (2026): e70080.

The gang discusses two papers that look at early tetrapods. The first paper investigates the transition to terrestrial environments in early tetrapods, and the second paper looks at some very small Dimetrodon. Meanwhile, Amanda has a disproportionate cat, James talks smack about a dead synapsid, and Curt gives gardening tips.   Up-Goer Five (Amanda Edition): This week our friends look at two papers on animals with hard bits in their back and four legs. The first paper asks when did animals with hard bits in their backs and four legs first start doing a big change as they grew up. Today the sort of early group of animals with hard bits in their back and four legs are really not that early and are actually really different but a lot of people use them to talk about early animals with hard bits in their backs and four legs. They do a big change as they grow up. They start out using water to breathe and then change to breathing air. Some of them grow legs when they don't start with legs. People like to say that this means early animals with hard bits in their back and four legs also must have done a big change as they grew. But actually maybe not, because old animals with hard bits in their back and four legs don't show the big change at all. So it seems like maybe the big change either came about once before a big branch between groups, and then went away in animals with hard bits in their back that live on land, or it came about twice in two different groups of animals that do a big change as they grow, one of which might have become the living group of animals with hard bits in their back and four legs that do a big change and live in both water and on land. Both of those might have been the right answer but we can't tell right now, we need more old animals to find out. The second paper is about a animal with hard bits in its back and four legs that is close to animals with hair, but probably did not have hair. Instead it has a big back with things sticking out and skin on it. These ate other animals and were really important when they lived. But the paper looks at animals in this group that are small. It's very different too because many of these animals are found in one part of the world, but one of the small ones is found far away. It's the only one not found with all the others. The other small one is found with all the others. This paper wants to find out why are they small and do they get small in the same way, so they cut up the inside hard parts and look at them really close and find that they actually get small in different ways because they can see how they grow when they look at the inside hard parts up close. They also think that the animals that lived in the far away place from the others were small for a different reason, because the place they lived was not great and they maybe didn't have a lot of food to eat. The small ones that are found with all the other animals were small because there were all those other animals with big backs with things sticking out and skin on it that would fight it. So they probably lived more in water and ate fish, maybe.   References: Pardo, Jason D., and Arjan Mann. "Direct development of stem tetrapods across the fin-to-limb transition." Science 392.6804 (2026): 1292-1296. Canoville, Aurore, et al. "Contrasting life history in the diminutive Dimetrodon species from North America and Germany." Scientific Reports 16.1 (2026): 16279.

The gang discusses two papers about jawless fishes. The first paper looks at some soft tissue preservation of early vertebrates which include preserving evidence of an ancient heart, while the second paper investigates how the fossil record of hagfish can inform the order in which characteristics evolved within the group. Meanwhile, James "solves" his problems with machines, Amanda keeps making new friends whether they like it or not, Curt claims no responsibility, and everyone loves these kawaii line drawings.   Up-Goer Five (James Edition): This week the group look at two papers that are about different animals that have no legs and live in water. The first paper is about a very strange animal that lived a very long time ago that people have thought might be an early part of the group that is made up of things with hard parts inside. The paper looks at things inside the animal and show that they are made of old blood showing the parts of the animal that carried the blood and the parts that clean it. These parts suggest that the animal is in fact an early part of the group that eventually get hard parts inside. The second paper looks at three animals that are part of the group of animals that make thick wet stuff and have a mouth that does not move. They also have small eyes under the skin and live in deep places and it has been thought they show what all animals with hard parts inside used to be like. These three old animals show how the eyes have changed over time and that these animals used to have normal eyes. One of the animals is starting to get small eyes and this shows that the eyes did not get small because they lived in the dark because this one is from water that is not deep.   References: Tian, Qingyi, et al. "Evidence for aorta and other blood vessels in fossil yunnanozoans from the Cambrian period." Royal Society Open Science 13.6 (2026): 260043. McCoy, Victoria E., et al. "Stepwise loss of complexity in hagfish eyes prior to deep sea colonization." Biology Letters 22.5 (2026): 20260127.

The gang discusses two papers that use fossil material to assess the origin of animal groups. The first paper describes a new Early Devonian fish and its implications for the evolution of jaws, and the second paper reassesses the fossil material of turtles (and possible not turtles) to determine where turtles fit on the evolutionary tree of sauropsids. Meanwhile, James invents new flavors, Curt breaks things down, and Amanda sets boundaries.   Up-Goer Five (Amanda Edition): Today our friends look at two papers that talk about things showing up for the first time. The first thing to show up for the first time are teeth. Animals with inside hard backs have teeth, but how those teeth first show up are a big question mark. Turns out that teeth first show up as not-teeth and can actually grow over each other and grow in weird ways that today's teeth can't grow in. It also turns out that these early animals with hard backs and mouths that open and close had these sort of teeth and they're pretty much from the same stuff as the teeth we have today, so these are the same thing over time. The second paper our friends look at has to do with animals with inside hard backs that also have outside hard backs. We didn't know for a long time where these animals came from. Now we know, and they look at a really old weird animal that we thought might be one of those animals with inside hard backs that also have outside hard backs. But it isn't, it is too old and has inside parts of its head that don't look right. So now we know that animals with inside hard backs that also have outside hard backs are actually closer to animals with cold blood and big long faces that sit in water all the time and attack animals that come to drink water.   References: Olive, Sébastien, et al. "A new 'acanthothoracid'placoderm from the Arctic Canada (Early Devonian) and its bearing on the evolution of jaws and teeth." Royal Society open science 12.9 (2025). Jenkins, Xavier A., et al. "The phylogenetic origin of turtles." Current Biology (2026).

The gang discusses two papers about encrusting organisms. The first paper looks at evolutionary patterns of bryozoans to infer environmental triggers for shifts in the ways bryozoans calcify. The second paper uses the distribution of encrusting organisms on spirifd brachiopods to infer the ecology of both the encrusters and the brachiopod they grew on top of. Meanwhile, James discovers new foods, Amanda constructs a worm, and Curt gets confused and makes it everyone's problem.   Up-Goer Five (Curt Edition): The friends talk about two papers that look at animals that do not move around much and live stuck to other animals. The first paper looks at a group of animals that grow together with their friends and grow really well on top of other things. This group makes hard parts out of stuff it gets from the water it lives in. When there are changes in ways big rocks move, this changes the types and number of things in the water that can be used to make hard parts, which can make one way of making hard parts easier than others. Most of these animals today make hard parts in the way that is not the way that is easy with how the water is today, but there are some groups that do use the easy way. This paper looks at how these groups changed over time using a family tree for the group, and they find that these groups that make their hard parts the easy way today may have started doing this when the water changed to the way it is today. The second paper looks at a group of animals with hard parts on the top and bottom that lives on the bottom of the water place and eats food by moving water into it to pull the food from the water. These animals do not move around much and they have big hard parts, so they are places where these animals that grow on top of other animals like to grow on top of. This paper looks at how these animals grew on top of these other animals to see if there are anythings that are the same or different between groups of animals that are growing over these animals. This is also used to see if we can learn things about how the animals with hard parts on the top and bottom which are having things grown on top of them are living, because some ways things grow over these animal could only happen if the animal with hard parts on the bottom and top are already dead. This paper shows that a lot of the ideas we had about how this animal with hard parts on the top and bottom lived are wrong. These animals did not change the way they sat at the bottom as they got bigger, and we know this because the parts of the animal that would be in the ground are not covered with animals that would grow on top. The only times we see these parts covered are when the animals that grow over would grow over the parts where the animal with hard parts on the bottom and the top would use to get water into to eat, which means that animal must already be dead.   References: Saulsbury, James G., et al. "Evolution of skeletal mineralogy in cheilostome bryozoans from calcite to aragonite seas." Geology 53.11 (2025): 914-918. Vantoorenburg, Haley N., et al. "Palaeoecology of Middle Devonian epizoans and their Paraspirifer hosts." Palaeontology 69.2 (2026): e70050.

The gang discusses two papers about fossil cephalopods. The first paper uses new methods to reassess the taxonomy of what was previously considered to be the oldest octopod, and the second paper uses preserved beaks to reconstruct large body sizes of Mesozoic octopods. Meanwhile, Amanda keeps it within Michigan, James brings up THE cephalopod talk, and Curt ascends.   Up-Goer Five (Curt Edition): Our friends talk about two papers that look at animals with many arms and a sharp mouth. The first paper looks at some parts of a very old animal with many arms. People thought that it might be an animal with many arms that does not have a hard home to live inside and carry around with it. But this paper looks over that animal and finds that the animal is an animal that lived in a hard home that it carried, but after it died it fell out of that home when it started to fall to pieces. The second paper looks at another animal with many arms and uses the size of the mouth to see how big the animal was. They find that these animals with many arms were very very big. They also say that this means they were really sharp which the friends talk about a lot.   References: Clements, Thomas, et al. "Synchrotron data reveal nautiloid characters in Pohlsepia mazonensis, refuting a Palaeozoic origin for octobrachians." Proceedings of the Royal Society B: Biological Sciences 293.2068 (2026). Ikegami, Shin, et al. "Earliest octopuses were giant top predators in Cretaceous oceans." Science 392.6796 (2026): 406-410.

The gang discusses two papers that investigate phenotypic plasticity. The first paper reviews the pathways by which phenotype can be plastic, and the second paper looks at plasticity of breeding times in urban vs rural bird populations. Meanwhile, James manages a basement, Amanda names the papers, and Curt makes allegations.   Up-Goer Five (James Edition): Today the group look at two papers that are interested in how animals change because of the type of place they live. The first paper is looking at different ways that animals can be changed, either by being changed as they grow or by changing things so that while the animal does not change right now its babies are different. The paper talks about how important the little bits that escape the brain to tell your body how to grow and what to make are and that many of the changes are caused by the different numbers of things escaping the brain because of the different places that the animal lives. The other paper is looking at small angry animals that fly and seeing when they lay small round quiet babies in different places. They look at when the small round quiet babies first appear in places that are built by people and places that are built by trees and also look at how this time has changed over several years during which it has gotten hotter. They find that most small angry animals that fly have their small round quiet babies earlier in places that are built by people, and also that as things have gotten hotter that also makes them have their small round quiet babies earlier. The further up they are though it seems like the time between having small round quiet babies in place built by people and places built by trees is not as much.   References: Seebacher, Frank, and Alexander G. Little. "Mechanisms underlying phenotypic plasticity in response to environmental change." Biological Reviews 101.2 (2026): 713-734. Cuchot, Paul, et al. "Facing rising temperatures in urban environments: the role of phenological plasticity in an urban-dwelling passerine, Parus major." Proceedings of the Royal Society B: Biological Sciences 293.2068 (2026).

The gang discusses two papers that investigate ancient bioherms. The first paper looks at the formation of early Phanerozoic reefs, and the second paper investigates patterns of reef building and collapse in the late Devonian. Meanwhile, James is being advertised to, Amanda plans unique roadtrips, and Curt solicits legal advice.   Up-Goer Five (Amanda Edition): Today our friends talk about animals that have green friends that make hard bits. These animals that make hard parts are really important today because they make good places for other animals to live. But we don't know all about them and where they first came from and how they first started making hard parts for places to live. So the first paper looks at where these animals that make hard parts for other animals to live in come from. They look at really early animals that make hard parts and show what kinds of places they live in, and also how they stick themselves to the bottom. It looks like different animals got started in different ways, then went out to all sorts of different places and got better at making hard parts for other animals to live in, until that was all they could do. The second paper talks about a bad time when everything died and how animals that make hard parts for other things to live in all died and tiny things we can't see without making them look big took over from them. At this time there were different animals that made hard parts for other animals to live in that lived together to make big areas of hard parts, but then they all died and never came back. But when we look at the rocks we find that tiny things we can't see without making them look big are all over the place while the animals that make hard bits for other animals to live in all die. This paper talks a lot about rocks, but the important thing is that they think the tiny things we can't see without making them look big might be the kind of thing that takes over all the places when times are bad and everything dies, but that might not be the case.   References: Zhuravlev, Andrey Yurevich, and Rachel Wood. "On the origin of metazoan reefs." Proceedings of the Royal Society B: Biological Sciences 293.2068 (2026). Xinsong, Zhang, et al. "How microbes replaced metazoans in reef ecosystem during the Late Devonian mass extinction: new insights from platform facies in South China." Lethaia 58.4 (2025): 1-22.

The gang discusses two papers about the functional morphology of ancient groups of animals. The first paper is a review of how the life position of rangeomorph ediacaran taxa have been reconstructed, and the second paper conducts an actualistic experiment of Oviraptor nesting strategies. Meanwhile, Curt gets activated, James doesn't die, and Amanda relishes in details.   Up-Goer Five (James Edition): The group look at two papers that focus of understanding how things are long dead lived. The first paper talks about strange things that might have either lived standing up or lying down at the bottom of the water which is big and you can not drink. It is hard to tell how these things lived because there are not any around today and so instead we need to look at their form and how they are found in the rock. Most of the things seem to have lived how we thought but one actually was lying down rather than standing up. The second paper looks at how big angry animals without hair kept their round babies and helped them grow by making a form in the ground like they used and putting round babies in it. They looked at how the round babies did by themselves and how they did with a warm bag on top like their final big form. They decide that they probably had the final big form covering the round babies when they were growing but that they did not do it the same was a things that fly and do not have hair today.   References: McIlroy, Duncan. "Determining the mode of life of Ediacaran rangeomorphs in deep marine settings of Peri-Gondwanan Avalonia." Assemblage 550.538Ma (2022). Su, Chun-Yu, et al. "Heat transfer in a realistic clutch reveals a lower efficiency in incubation of oviraptorid dinosaurs than of modern birds." Frontiers in Ecology and Evolution 14 (2026): 1351288.

The gang discusses two papers that use quantitative methods to investigate the biomechanical limitations of extinct organisms. The first paper models the range of jumping potential for a non-avian theropod dinosaur, and the other paper tests if an extinct bird could have skimmed the ocean for food. Meanwhile, James imagines a better future, Amanda is to blame, and Curt is heating up.   Up-Goer Five (Amanda Edition): Today our friends look at two papers that talk about how things do stuff. The first paper looks at how a small one of large animals with thick skin and no hair would jump. It would jump very different than living animals with not thick skin with pieces that come off and have many parts. This is because they have long back parts that would get in the way and so they have to jump different. They could probably jump well, but just very different. The paper has very funny pictures that show this. The paper also has a computer do a pretend living animal with not thick skin with pieces that come off and have many parts, but they do not look at any living animals, just what the computer does. The second paper looks at very big not living animal with not thick skin with pieces that come off and have many parts, that has not real teeth in its mouth and shows that it could not live like some living animals with not thick skin with pieces that come off and have many parts that have very long faces and the bottom part of their mouth is much longer than the top part. They go over water and use their mouth to eat things that live in water. But the not living animal with not thick skin with pieces that come off and have many parts was too big and too bad at flying to do this kind of living.   References: Hellyer-Price, Olivia, Chris Venditti, and Stuart Humphries. "The largest extinct volant bird Pelagornis could not meet the energetic demands of skimming." Royal Society Open Science 13.2 (2026). Charles, James P., Delyle T. Polet, and John R. Hutchinson. "Form–function relationships determining optimal jumping performance in an early bipedal dinosaur." Journal of The Royal Society Interface 23.235 (2026).