Palaeo After Dark

The gang discusses two papers that look at the evolutionary history of unique teeth. The first paper looks at the history of tusks and tusk-like structures in synapsids, and the second paper looks at the shape of ancient bird teeth. Meanwhile, James gets to the point, Curt is inspired, and Amanda has a drink.

 

Up-Goer Five (James Edition):

The group looks at two papers that talk about teeth in different groups of animals. The first paper is interested in big teeth that keep growing and don't have a hard cover around them. While these teeth without a hard cover that don't stop growing are usually only found in animals with hair, one group that is part of the same family but much older also has teeth that seem to get big and never stop growing. However it turns out that many of them still have the hard covering, and only some of them lose it to be like the animals with hair today that have long teeth without a cover that doesn't stop growing. The other paper is looking at animals that fly and usually don't have teeth, but that are very old and so do have teeth. They look at the types of these old teeth to see whether they can tell us what these animals ate. It turns out that it is very hard to tell what these animals ate from their teeth, and it seems that other things like the type of face they have may be more important.

 

References:

Zhou, Ya-Chun, et al. "Evolution of tooth crown shape in Mesozoic birds, and its adaptive significance with respect to diet." Palaeoworld (2021).

Whitney, M. R., et al. "The evolution of the synapsid tusk: insights from dicynodont therapsid tusk histology." Proceedings of the Royal Society B 288.1961 (2021): 20211670.

Direct download: Podcast_226_-_Insert_Fleetwood_Mac_Tusk_Joke_Here.mp3
Category:general -- posted at: 3:00am EDT

The gang discusses two papers that look at how trace fossils can give important clues to ancient ecological interactions. The first paper identifies a unique behavior using trace fossils, and the second paper uses bite marks on bone to infer ontogenetic ecological shifts in a large caiman species. Meanwhile, Curt investigates, Amanda collects, and James fixates.

 

Up-Goer Five (Amanda Edition):

This week our friends talk about animals that roll in wet tiny pieces of rock that are really very tiny tiny. We also talk about a very big very slow animal with hair that got bit by a very large animal with no hair but hard skin and lots of big teeth that has a very long face. The animal with hair that rolled in wet tiny very very tiny pieces of rock shows that these animals did this thing a very long time ago; it shows that these animals with hair and two fingers on each leg were in this place at this time, along with animals with stuff that wasn't hair but made of the same stuff as hair and could fly, too. The second paper looks at how we can talk about a hard part of a very big very slow animal with hair could have gotten grabbed by a small one of a very, very, very big animal with no hair but hard skin and lots of big teeth with a very long face. It tells us that these very big animals with no hair but hard skin and lots of big teeth ate different things when they were small than when they were very, very, very big.

 

References:

Abbassi, Nasrollah, et al. "Vertebrate  footprints and a mammal mud-bath trace fossil (Laspichnia) from the  Mukdadiya Formation (Late Miocene–Pliocene), Chamchamal Area, Kurdistan  Region, Northeast Iraq." Ichnos 28.1 (2021): 72-83.

Pujos, François, and Rodolfo  Salas-Gismondi. "Predation of the giant Miocene caiman Purussaurus on a  mylodontid ground sloth in the wetlands of proto-Amazonia." Biology Letters 16.8 (2020): 20200239.

Direct download: Podcast_225_-_Columbo_Meets_the_Caiman.mp3
Category:general -- posted at: 3:00am EDT

Random computer glitches are unable to stop the gang from delivering another podcast! This week, they focus on two papers that look at the importance history for understanding trends in our modern biosphere. The first paper discusses how speciation trends are important for planning future conservation efforts, and the second paper looks at the importance of exaptive traits (characters evolved for one purpose but used for another) in the evolutionary history of sea snakes. Meanwhile, Amanda cuts deep, Curt has done this before, and James waits for his time to tell his very good joke.

 

Up-Goer Five (Curt Edition):

Our friends talk about how the past is important. And this is funny because they already did this before but the big boxes with bits that will shock your hand if you touch them lost the talk they did about the past being important so they are doing it again. The first paper they look at is short. It is about how animals living in places that are high up but in warm places make new types of animals that stay at the same high up place, not higher or lower. This means new animals will more often be living the same types of places as the older animals they came from, and this means that as places change we need to make sure the types of places where these animals live can stay open.

The second paper looks at how long animals without legs moved into the water. There are many groups of animals without legs that moved into water, and this paper wants to know the types of places they were in before they moved into water and also if the things they all have that make it easier to be in water were things that appeared before they moved into water (letting them move in there) or after they moved into water (making it better to be in water). They find that most of these groups started in areas with trees before moving into water. They also find that the things which make it easier to be in water appeared in older groups well before these animals moved into water. This means that the things that made it easy to go in water appeared first, and then this made it so these animals could then move into water.

 

References:

Linck, Ethan B., et al. "Evolutionary conservatism will limit responses to climate change in the tropics." Biology Letters 17.10 (2021): 20210363.

Gearty, William, Elsie Carrillo, and  Jonathan L. Payne. "Ecological filtering and exaptation in the evolution  of marine snakes." The American Naturalist 198.4 (2021): 506-521.

Direct download: Podcast_224_-_Second_Times_the_Charm.mp3
Category:general -- posted at: 2:00am EDT

The gang discusses two papers that look at the impact of ecological interactions on the evolutionary history of groups. The first looks at potential competitive interactions that could control rabbit body size, and the second paper uses the fossil record to investigate potential clade interactions between two groups of bryozoans. Meanwhile, Curt researches in real time, Amanda gets to talk about a childhood favorite, and James makes future plans.

 

Up-Goer Five (Curt Edition):

Our friends talk about two papers that look at how animals trying to get food and sometimes fighting with each other can change how they live and grow and make more of themselves. The first paper looks at animals that jump and have hair and their name sounds just like hair. These things that sound like hair do not get really big in most cases, even though we know that they could get big if we try and make it happen. This paper looks for reasons why these "hairs" don't get very big. It turns out that "hairs" eat things that a lot of other animals that eat. And while there are a lot of other things in the paper here that help to build this idea, the big idea is that that how big these "hairs" get may be held back by the smallest of the other animals that eat their food. "Hairs" get about as big as the smallest of these other animals in a place.

The second paper looks at animals that grow on top of other things. There are two big groups of these animals, and when we look at how they grow, usually one group will grow over the other group. This means this one group is better at growing in a space and can push out the other group. In the past we used to have more of the group that gets pushed out, but over time we have more of the new group that is better at growing in a place. Some have thought maybe this means that what we see happening in small places may explain this larger change over time. But it is more than just that because it is not just one group going down and another going up. This paper uses a lot of number work to see how these two group may change each other. They find that it is more than just a simple one up one down thing. They find both groups change each other in a few ways. They also don't find that the things happening in the small spaces is causing these bigger changes. It could be because of the type of things we are looking at makes it harder to see these changes, but with what they have it looks like maybe this is not what is causing this change.

 

References:

Tomiya, Susumu, and Lauren K. Miller. "Why aren't rabbits and hares larger?." Evolution 75.4 (2021): 847-860.

Lidgard, Scott, et al. "When fossil clades ‘compete’: local dominance, global diversification dynamics and causation." Proceedings of the Royal Society B 288.1959 (2021): 20211632.

Direct download: Podcast_223_-_Amanda_Loves_Watership_Down.mp3
Category:general -- posted at: 3:00am EDT

The gang discusses two papers that look at evolutionary changes in animal groups after the End Cretaceous Mass Extinction. The first paper looks at morphometric changes in shark teeth, and the second paper studies the evolutionary and biogeographic patterns of snakes. Meanwhile, Amanda “fixes” her audio, Curt goes biblical, and James is missing.

 

Up-Goer Five (Curt Edition):

Our friends talk about things that lived through a real bad time when a huge rock hit the big round place where we all live. The first paper looks at large angry animals that move through water and have pointed things in their mouths and soft bits where things have hard bits. We usually just find the hard pointed bits from the mouth because the rest of the body falls to bits when they die. So this looks at how these old hard bits change from before and after the big rock hit. What they found was that changes happened within groups, where some groups were hit hard and others were not. But if you look at all of the big angry animals, it looks like very little changes. The hard bits are doing things that look the same before and after the rock hit, but its different groups doing that.

The second paper looks at animals with no legs and looked at changes in where they live and how quickly they change over time. The paper finds that after the big rock hit, one group was able to move to a new place. This move seems to happen when they also start making more of themselves. It seems that, for this big group of animals with no legs, the big rock hitting may have helped this group. It seems like a new place opened up after the big rock and the group took over and did well. There are also changes that we see when it gets colder in the time way after the rock hit.

 

References:

Klein, Catherine G., et al. "Evolution and dispersal of snakes across the Cretaceous-Paleogene mass extinction." Nature Communications 12.1 (2021): 1-9.

Bazzi, Mohamad, et al. "Tooth morphology elucidates shark evolution across the end-Cretaceous mass extinction." PLoS biology 19.8 (2021): e3001108.

Direct download: Podcast_222_-_Static_Hiss.mp3
Category:general -- posted at: 3:00am EDT

The gang discusses two papers that look at patterns of speciation and extinction and relate those patterns to shifts in climate. The first paper looks at how both plate tectonics and climatic changes have contributed to shifts in provinciality, and the second paper tests the link between dramatic temperature changes and large scale extinction events. Meanwhile, James cannot remember “that guy”, Curt does not like Oliver Cromwell, Amanda is in an abusive relationship with her cats, and we cannot stay on topic for more than 2 minutes.

 

Up-Goer Five (Amanda Edition):

Today our friends talk about how the change in hot and cold and places where rocks are over a very long time has changed the way things live. Or not lived. The first paper says that while we used to think that changes in the way the big rocks that stick out of the water that we live on is the most important thing for making different animals and green stuff live in different places. But it turns out that it may be changes in hot and cold that take a very long time to happen that is more important. Both things are important, but how it gets colder the more towards the top of the world you go is just a little more important. It really controls how things can live places. The other paper looks at changes in hot and cold and how that makes things die. It turns out that if it gets warmer faster, or colder faster, it makes things die. They have a real number of 5.2 bits, and it is at more than 10 bits every 1,000,000 years. It does not matter if it gets warmer or colder, it is the quick turn that matters, and the big jump in change. They say that we are already getting hot enough fast enough right now to cause lots of things to die, even if we were not killing them, which we are.

 

References:

Kocsis, Ádám T., et al. "Increase in  marine provinciality over the last 250 million years governed more by  climate change than plate tectonics." Proceedings of the Royal Society B 288.1957 (2021): 20211342.

Song, Haijun, et al. "Thresholds of temperature change for mass extinctions." Nature communications 12.1 (2021): 1-8.

Direct download: Podcast_221_-_Ramble_On.mp3
Category:general -- posted at: 3:11pm EDT

The gang discusses two papers that look at the fossil record of fishes. The first paper looks at the ontogeny of ancient lampreys, and the second paper investigates the impact genome duplication had on the evolutionary history of teleost fishes. Meanwhile, James finds a gnome, Curt has an adorable ghost problem, Amanda appreciates good music, and we are all back on our b#ll$h!t.

 

Up-Goer Five (Curt Edition):

Our friends talk about two papers that look at animals that live in the water and have hard parts on the inside. The first paper looks at some of these animals which have a round mouth. These animals today are very different as kids then as grown ups. As kids they live in the ground and pull food out of the water. As grown ups they move through the water and eat other animals. This paper looks at old parts of these animals from a long time ago to see if the kids always did this. They find that these very old animals did not have kids and grown ups acting so different. This means that having the kids do something different is a thing that is new, even though people have thought that these animals have always done this.

The second paper looks at the how animals with hard parts that move through the water had the bits inside them that store how to build them get a times two. When there are more bits that store how to build them, it makes the homes in the hard parts bigger. So you can use how big these homes are in the hard parts to learn something about how many bits these animals have. Using old hard parts from old animals and a tree that shows which of the animals are close brothers and sisters to each other, they look at when changes in how big these homes in the hard parts were in the past. And since how big these homes are tells us how many bits that store how to build them they have, we can also see how these bits are changing through time. People have thought that getting more of these bits may be why there are so many of these types of animals. This paper shows that it may not be that simple. The number of bits goes up first, but the number of new animals does not go up at that time. Instead, it happens after big changes in the world. It is possible that these bits may have helped in bringing the number of these animals up, but it alone does not explain it.

 

References:

Miyashita, Tetsuto, et al. "Non-ammocoete larvae of Palaeozoic stem lampreys." Nature 591.7850 (2021): 408-412.

Davesne, Donald, et al. "Fossilized cell structures identify an ancient origin for the teleost whole-genome duplication." Proceedings of the National Academy of Sciences 118.30 (2021).

Direct download: Podcast_220_-_The_Bone_Gnome.mp3
Category:general -- posted at: 3:00am EDT

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.

Direct download: Podcast_219_-_Brachiopod_Vape_Bros.mp3
Category:general -- posted at: 3:00am EDT

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).

Direct download: Podcast_218_-_Dem_Feet.mp3
Category:general -- posted at: 3:00am EDT

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).

Direct download: Podcast_217_-_In_the_Thick_of_It.mp3
Category:general -- posted at: 3:00am EDT