The gang discusses two papers about skin preservation in fossil tetrapods. The first paper describes skin impressions from a Permian synapsid, and the second paper identifies feather-like structures in an early Triassic diapsid. Meanwhile, James considers the horse, Amanda shames extinct animals, and Curt quotes "philosophy".

Up-Goer Five (Amanda Edition):

Today our friends talk about things that are sort of close to things with hair but not that close to things with hair. They are closer to things with hair than to things with dry skin with no hair or long many-part skin things. Anyway for a long time we did not know what the skin of the animals that are sort of close to things with hair looked like. Did they have dry skin with no hair like the things today? Or did they maybe have hair? We didn't know, but now we have found marks in the ground that show that they had dry skin with no hair, but it looks different than the animals with dry skin and no hair today. So hair comes around after the dry skin with no hair does.

Then our friends talk about a very weird little animal that is sort of somewhere close to animals with dry skin and no hair, but it has these really weird things that come off of its back that look kind of like the many-part skin things on the most flying animals that are around today. But it's really not the same many-part skin things, because all the parts are not really same. And also there is only one of them and not one on each side. So it might be that many-part skin things come earlier than people thought they might have.

References:

Marchetti, Lorenzo, et al. "Early Permian synapsid impressions illuminate the origin of epidermal scales and aggregation behavior." Current Biology 35.11 (2025): 2752-2759.

Spiekman, Stephan NF, et al. "Triassic diapsid shows early diversification of skin appendages in reptiles." Nature (2025): 1-7.