The gang discusses two papers that deal with fossil brains. The first paper looks at a fossil arthropod from the Cambrian and uses neurological characters to determine its phylogenetic placement. The second paper looks at a synapsid braincase and tries to infer why this one species has lost its parietal eye when other members of the species have he eye. Meanwhile, Curt invents some new sponsors, Amanda has plans for James, and James discusses some personal growth.

Up-Goer Five (Curt Edition)

The friends talk about two papers that look at very old brains in animals that are long gone. The first paper is the brain of animal from a very long time ago that would grow by taking off its skin when it needs to get bigger and is made of many small bits stuck together. This animal was really weird for a long time, but the people who wrote this paper found one of them that had its brains still in it. They looked at the brains and they looked at the brains of other animals from the past and animals around today and they saw that this brain looked a lot like the brains of a group around today that some of the animals make things to catch food and live in out of their bottom. So the people who wrote the paper say this could mean that is maybe a very very very old animal from that group or close to it.

The second paper looks at the hard bits that hold the brain in for an animal that is close to the animals today that have hair and are warm. This animal may not have had hair and may not have been warm, but what the people who wrote the paper are looking at is the spaces in the hard bits that hold the brain. In animals that do not have hair and are cold, there is a space at the top of the head for an eye that can see light and dark. In animals that are warm, they lose this eye. The old animal they are looking at has some animals in the group that have that eye who live in cold places. The animal they are looking at does not have this eye, and so the question is why? They look at everything and they think that it is because the animal without the eye lives in places that are always warm and where day and night don't change that much. This would mean they would not need this light dark eye as much.

References:

Strausfeld, Nicholas J., David R. Andrew, and Frank Hirth. "Cambrian origin of the arachnid brain." Current Biology 35.15 (2025): 3777-3785.

Benoit, Julien, and Jaganmoy Jodder. "The palaeoneurology of a new specimen of the Middle Triassic dicynodont synapsid Kombuisia frerensis." Acta Palaeontologica Polonica 70.2 (2025): 369-374.