Show Notes
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).
More from Palaeo After Dark
We report back with coverage of the Geological Society of America 2026 annual meeting, and only once do we completely mess up using the equipment. Progress!
The gang discusses two papers that use a lot of statistics to make their arguments. The first paper looks at the argument against the existence of megalodon nurseries, and the second paper assesses the importance of biotic vs abiotic patterns in extinction. Meanwhile, James has a new button, Amanda has school spirit, Curt tries to be civil, and we all need a drink…
The gang discusses two papers that use comparative anatomy of bone to tell some really interesting stories about fossil animals. The first paper uses the hand bones of Stegasaurus and Camarasaurus to investigate how they walked and also the evolutionary processes by which they may have developed these unique shapes. The second paper pieces together the complex taphonomy of a dead ichthyosaur. Meanwhile, Amanda fails at giving directions, James fails and following directions, and Curt fails to keep any of this on track.
The gang discusses two papers that technically involve symbiosis. The first paper looks at fossil evidence for tape worms, and the second paper is a review of the various evolutionary hypotheses of the convergent origin of viviparity (live birth). Meanwhile, Curt imagines a new theme park, James has a good night, and Amanda surprises us all.
The gang discusses two papers that use fossils to understand ecological interactions in the past. The first paper reports predation patterns on fossil blastoids, and the second paper finds brooding in the soft tissue of fossil bivalves. And then… the gang gets very much back on their bullshit… Meanwhile, James simplifies his life, Curt discusses new business ventures, and Amanda is seen.