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.

The gang discusses two papers that study the paleoecology of the Ediacaran fauna. The first paper looks at environmental information that can be gleaned from the microbial mats these organisms lived on, and the second paper studies how different Ediacaran fossils are distributed on this microbial mat. Meanwhile, James is having a week, Curt is unsure about chips, and Amanda is comfortable being very on brand.

Up-Goer Five (Curt Edition):

The friends look at two papers that study some very old animals that lived a long long time ago and lived on these beds of tiny tiny tiny animals and not animals. In fact, these two papers are also interested in the beds these things lived on and how they lived on the bed. The first paper looks at these parts of the beds and how you can find them in different beds made of tiny tiny tiny animals and not animals. There are these lines in the beds that are found in some beds but not all of the beds. They think that the way water moves over the beds may cause these lines to form. The other cool thing they find is that the animals are found when there are these lines, and are not found when there are not these lines. This means that the way the water moves might be important for these animals to live.

The second paper looks at how these animals lived in space with each other. Did they want to live close to each other or did they want to be far from each other, or do they not really care? Some earlier papers had said they wanted to be far from each other, which is weird when we look at animals in the big blue wet thing today which want to stay close to each other. So they run a lot of studies on three different animals that can show if they are close to each other because they all need the same thing (and that thing is in small parts around the ground) or if they seem to want to be very close to each other because they either use each other or they can not move far from each other. They show that these animals all show that they are close to each other, but two of the animals are close because they all want something that is in just a few places. One animal shows a really strong need to be close, which could mean that this is something about the animal that makes new babies be closer to the father/mother. This shows we can learn things about how these animals lived and why they lived where they did, even for things that are very very very old.

References:

Boan, Phillip C., et al. "Spatial  distributions of Tribrachidium, Rugoconites, and Obamus from the  Ediacara Member (Rawnsley Quartzite), South Australia." Paleobiology (2023): 1-20.

Tarhan, Lidya G., Mary L. Droser, and  James G. Gehling. "Picking out the warp and weft of the Ediacaran  seafloor: Paleoenvironment and paleoecology of an Ediacara textured  organic surface." Precambrian Research 369 (2022): 106539.

The gang discusses two papers about inferring life habit and ecology from extinct animals. The first paper summarizes the data for ichthyosaur birth to see if they really do preferentially come out tail first, and the second paper investigates a fossil that could complicate the narrative for the origins of a European sabretooth cat group. Meanwhile, James has opinions about browsers, Amanda is camouflaged, Curt needs a drink, and everyone is surprised by a paper for the first time in a long time.

Up-Goer Five (Curt Edition):

The friends talk about two papers that looks at how animals did things and where they lived in the past. The first paper looks at a group of animals that lived in the water and had their kids inside them. This group used to be on land before they went into the water for all time. Lots of people say that when a group of animals goes from being on land to being on water, they need to change the way the babies come out of them, with the head coming out last so that they do not breathe in water. This paper looks into this to see if this is true. It turns out that lots of things today that used to be on land but are now in the water and have kids inside them usually have the kids come out with the head last. However, this is not always what happens. And, when the kids come out head first it is fine and they do not die and the mom also does not die. When we look at the parts of the dead animals from a long time ago that live in the water, we also see that, even in the groups that everyone says they go out head second, there are some that show they come out head first. It seems like, instead of being a change that is always true, these animals went from being most of the time head first, to being half and half head first, to being most of the time head second but sometimes head first.

The second paper looks at a group of angry animals with hair and long teeth. This group is found all over the world in the past and this paper is looking at one group that is most of the time found in one place but may have also had some groups close to it from other places. This paper names a new type of these animals and says that it is the first of this group, but also the study they do says that it isn't so that is weird. They also do another study to show that this group went through most of its big changes in this new place, but the study they do also seems to say that it is a third different place where a lot of important things happen but they do not talk about it. This paper is weird.

References:

Jiangzuo, Qigao, et al. "Origin of  adaptations to open environments and social behaviour in sabretoothed  cats from the northeastern border of the Tibetan Plateau." Proceedings of the Royal Society B 290.1997 (2023): 20230019.

Miedema, Feiko, et al. "Heads or tails  first? Evolution of fetal orientation in ichthyosaurs, with a scrutiny  of the prevailing hypothesis." BMC Ecology and Evolution 23.1 (2023): 1-13.

The gang discusses two papers that look at patterns of niche conservatism or niche evolution in the fossil record. The first paper looks at the pollen records of trees in Portugal to test if changing climate can explain modern tree distributions, and the second paper looks at the impact of Late Devonian extinction pulses/invasions on brachiopod communities. Meanwhile, Curt summarizes the podcast, James has brachiopod facts, and Amanda cannot control her cats.

Up-Goer Five (Curt Edition):

Our friends talk about two papers that look at where animals live and what they do in the world, and also if that stays the same or changes over time. The first paper looks at tall living things that make their own food and lose a part of themselves every fall. This looks at one place that has just a few of these types of living things but in the past there were different types there. Also, back then it was not as warm and the rain was different. This paper wants to see why the tall living things we have in this part of the world are where they are right now. What they saw was that, some of the changes in the tall things seem to be tall things following where they want to live; when things get warmer or colder they move to follow the change. But some things seem to be moving into places that are very different from where they started, so they are changing what types of places they like to live in.

The second paper looks at animals that live on the bottom of the big blue wet thing and take food out of the water and were found all over the world a long time ago. It looks at a time when a big change killed a lot of living things. This paper looks at how this changed the types of these animals over time. What they find is that, a lot of the animals that die because of the change have another animal from somewhere else doing the same thing move in and take that animal's place. The things that do not die just keep on doing their own thing. It does not look like there is much change in what the animals are doing either from the big change that happened, or from the new animals moving in.

References:

Vieira, Manuel, et al. "Niche  evolution versus niche conservatism and habitat loss determine  persistence and extirpation in late Neogene European Fagaceae." Quaternary Science Reviews 300 (2023): 107896.

Brisson, Sarah K., et al. "Niche conservatism and ecological change during the Late Devonian mass extinction." Proceedings of the Royal Society B 290.1996 (2023): 20222524.

The gang discusses two papers that look at some Cambrian problematic fossils and find new clues that allow us to determine what groups they might belong to. One paper finds new evidence that some of these tube fossils in the Cambrian may be cnidarians and the other paper identifies potential gastropod radula in Cambrian rocks with adaptations for grazing. Meanwhile, James is not at all tired, Amanda will totally clean out her garage, and Curt is in the loop about what is going on.

Up-Goer Five (Curt Edition):

The friends talk about two papers that look at some things from a long time ago that are very hard to see what is going on with them but these new finds give us a better idea of what they might be. The first paper looks at these long and soft things. We used to think they were long and soft things that live in the ground today. However, this paper finds that there are little arms on one side and that they have these parts that we see in a very different group of animals that instead has one way in that it uses to eat and shit and has lots of these small arms. They show this for one of these types of animals but it could be that a lot of the long soft animals we find that we are not sure about could all be parts of this group.

The second paper looks at these small bits that people find when they take rocks and break them down into bits. These small things look like the mouth parts of animals that are soft and some of them carry their home with them. Not just mouth parts, but mouth parts that can eat green things that make their own food. This could be the first time we see animals that just eat these kinds of green things in the past.

References:

Zhang, Guangxu, et al. "Exceptional  soft tissue preservation reveals a cnidarian affinity for a Cambrian  phosphatic tubicolous enigma." Proceedings of the Royal Society B 289.1986 (2022): 20221623.

Slater, Ben J. "Cambrian ‘sap-sucking’molluscan radulae among small carbonaceous fossils (SCFs)." Proceedings of the Royal Society B 290.1995 (2023): 20230257.

The gang discusses two papers that use morphometric studies to investigate patterns of ecomorphy in the fossil record. Specifically, they look at two papers that investigate how morphology in sloths and pterosaurs changes over time, and how well these changes map onto changes in body size and ecological shifts. Meanwhile, Amanda could be dean, Curt has opinions on figures, and James provides butchery advice.

Up-Goer Five (Curt Edition):

The friends talk about two papers that look at how things look and how that changes over time, and looks to see if these things are changing because of what they do. The first paper looks at animals with hair and long arms that move very slow. There are not a lot of these animals today, but in the past there was a lot of these animals and they did a lot of other things that we do not see them do today. These animals were also looking different as well. But it seems that the things that look different are closer to each other by being close sisters to each other. They also do find that these animals are also doing different things when they look different.

The second paper looks at angry animals who can fly but are not the animals that can fly today. These animals start small and get big over time. They actually get big a few times. This paper looks at the parts of these animals and shows the many different ways that parts can change to make these animals big or small. It also shows that, when these things get really big is when the group seems to be doing really bad.

References:

Yu, Yilun, Chi Zhang, and Xing Xu. "Complex macroevolution of pterosaurs." Current Biology 33.4 (2023): 770-779.

Casali, Daniel M., et al.  "Morphological disparity and evolutionary rates of cranial and  postcranial characters in sloths (Mammalia, Pilosa, Folivora)." Palaeontology 66.1 (2023): e12639.

The gang discusses two papers that look at the body size of ancient animals. The first paper uses new metrics to estimate the size of the ancient fish Dunkleosteus, and the second paper looks at the various ways that theropod dinosaurs can get big or small. Meanwhile, Amanda is 10 minutes away from being taken to Oz, Curt invents a new adaptation, James figures out perpetual energy, and everyone is forced to record over a conference call.

Up-Goer Five (Amanda Edition):

Today our friends talk about a large animal that lives in water with no legs but a big mouth and moving mouth pieces and a hard outer cover. This big animal was one with a hard part in its back that ate lots of things very early before many other things with hard parts in its back were around that ate other things. People used to think that it got very very very big but this study uses numbers to show that it was actually not as big as people used to think. The numbers are very good and are probably going to be very good for lots of animals that live in water with no legs.

The second paper looks at large angry animals with no hair and big teeth that lived a long time ago, but not as long ago as the large animal that lives in water with no legs and a big mouth and moving mouth pieces. It looks at how the hard pieces of these large angry animals with no hair and big teeth grew to see how they got big or small, because some got very big and some got very small. It turns out that the ones that got big did it in some different ways, and the ones that got small did it in some different ways, which is very cool.

References:

Engelman, Russell K. "A Devonian Fish  Tale: A New Method of Body Length Estimation Suggests Much Smaller Sizes  for Dunkleosteus terrelli (Placodermi: Arthrodira)." Diversity 15.3 (2023): 318.

D'Emic, Michael D., et al.  "Developmental strategies underlying gigantism and miniaturization in  non-avialan theropod dinosaurs." Science 379.6634 (2023): 811-814.

The gang celebrates their 10 year anniversary by talking about two papers on the same topic that are 10 years apart. Both papers take a critical look at how we define the “big five” mass extinctions and what this term means. Meanwhile, everyone waxes philosophical for the last 20 minutes, discussing how things have changed in our lives since we started this weird show. Thanks for listening!

Up-Goer Five (Curt Edition):

Our friends talk about two papers that were written ten years from each other. Both papers look at times when a lot of animals died. The first paper is looking at how these times changed the types of animals that were around after the big dying, and it finds that some times that didn't kill as many animals had much bigger changes in the types of animals around than times when a lot more animals died. The second paper continues this idea to ask, why do we look at the big times that we do and is there anything about these times that make the all the same. What do these times mean?

References:

Marshall, Charles R. "Forty years later: The status of the “Big Five” mass extinctions." Cambridge Prisms: Extinction 1 (2023): e5.

McGhee Jr, George R., et al. "A new ecological-severity ranking of major Phanerozoic biodiversity crises." Palaeogeography, Palaeoclimatology, Palaeoecology 370 (2013): 260-270.