Palaeo After Dark

The gang discusses two papers that look at topics in biogeography. The first paper reviews the concepts of cradles and museums (and whether we should retire those concepts), and the second paper explores traditionally defined Devonian bioregions. Also, the gang uses the broad topics from both of these papers to talk about a lot of tangentially related topics. Meanwhile, James has strong opinions about what is edible, Curt disagrees, and Amanda remains painfully neutral throughout.


Up-Goer Five (Curt Edition):

Our friends talk about two papers that look at the ways we talk about the places animals come from. The first paper is looking at two words that we use to talk about these places. The words are used to talk about places where new living things come from and places where living things can stick around for a long time. The paper talks about how those words were first used and why they came up in the first place, and then talks about how we have changed what we mean by those words in ways that maybe is not helping us better know about places. They talk a lot about how the way these words were first used has now been forgotten, and so the way we use them today makes things a little too simple. Instead of focusing on finding the simple form of these places, we should be looking at the ways the world works which can make some areas better for new living things to form or for old living things to stick around.

The second paper looks at whether or not animals that are close to each other come from the same places through time. Are there places that have their own types of animals which all come from just those places for a really long time. They look at the whole world a long time ago when people have said that they can find these groups of animals that all come from one place. They look at a lot of other studies and use those studies to run another study. They find that some of the smaller areas may show what people have said in the past, but most of the big areas do not have this long time where all the animals are from this one place. The reason why it may have looked like that in the past may be because of how we got those old animals and the types of people who were allowed to go out and get those old animals in the past.



Vasconcelos, Thais, Brian C. O’Meara, and Jeremy M. Beaulieu. "Retiring “cradles” and “museums” of biodiversity." The American Naturalist 199.2 (2022): 194-205.

Dowding, Elizabeth M., Malte C. Ebach,  and Evgeny V. Madroviev. "Validating marine Devonian biogeography: a  study in bioregionalization." Palaeontology (2021).

Direct download: Podcast_230_-_A_Rambling_Time.mp3
Category:general -- posted at: 3:00am EDT

The gang discusses two papers that explore the functional morphology of ancient groups. The first paper looks at soft tissue in ammonites which can be used to infer locomotion, and the second paper looks at how functional morphology changed as tetrapods transitioned from marine to terrestrial environments. Meanwhile, James explores the evolution of baked goods, Curt develops a new business plan, and Amanda dreams of Tiktaalik.


Up-Goer Five (Curt Edition):

Our friends talk about two papers that look into how we can learn how very old animals moved and how that moving changes over time by looking at the parts we can find in the ground. The first paper looks at animals with a lot of arms who live in a big hard round hard part. Today, while we have a lot of these animals with lots of arms, only one of those animals today lives in a big round thing. In the past, there was a big group of animals that lived in a round thing, but they did it in a different way than the one we have around today. However, because it is hard to find pieces that are not hard, we have used the animal that is around today as our best guess for how these old animals may have moved. This paper finds some soft pieces which give us a better idea of how the soft parts that allow animals to move were put together. And these old animals probably moved in a very different way from the other animal from today who lives in a round thing. In fact, the old animals that live in round parts may have moved in a way that is sort of like how the animals with many arms who do not live in round things today move (but not exactly the same).

The second paper looks at how the hard parts of animals with four legs changed when they animals moved onto land. This paper looks at these changes and also looks at how these changes make it so these animals move in different ways. They find that the animals with four legs in the water all have legs that look like we would expect for moving in water. The animals that are on land also have legs that fit the moving we would see for things that need to hold themselves up and move on land. The fun thing is that the animals who come from the animals who are not quite on land and not quite in water yet (the ones in the middle of this change) do not fit into any space where we would expect the animal to be able to move well. This could mean that these animals (which did well enough) were living in a time when it was alright to suck at moving. Also, it may be that some groups of animals that moved onto land from this group that sucks at moving might have had some of the animals in that group that came back to this sucking at moving space.



Dickson, Blake V., et al. "Functional adaptive landscapes predict terrestrial capacity at the origin of limbs." Nature 589.7841 (2021): 242-245.

Cherns, Lesley, et al. "Correlative  tomography of an exceptionally preserved Jurassic ammonite implies  hyponome-propelled swimming." Geology (2021).

Direct download: Podcast_229_-_Non-Fishable_Tetrapods.mp3
Category:general -- posted at: 3:00am EDT