Episode 454 - Evolution‘s strange journeys in crabs, snakes and lizards

Why does nature continually evolve crabs? What is so good about crabs that nature just cannot stop inventing it? How can you trap a crab inside amber? What can a fossilized crab, capture din amber tell us about the complex history of crabs? Just when did crabs invade land and how did they get stuck in tree sap? How do you preserve  fossil as delicate as a crab? How did lizards and snakes develop their complex teeth? Mammals weren't the only ones to evolve complex teeth with cusps. Evolution isn't necessarily a one way progression, sometimes complexity can be rolled back like in lizards. Lizards developed complex teeth to eat plants, but then some went back to their old ways.
References:

1. Keiler, J., Wirkner, C., & Richter, S. (2017). One hundred years of carcinization – the evolution of the crab-like habitus in Anomura (Arthropoda: Crustacea). Biological Journal Of The Linnean Society, 121(1), 200-222. doi: 10.1093/biolinnean/blw031
2. Watson, S. (2021). Why everything eventually becomes a crab. Retrieved 23 October 2021, from https://www.popsci.com/story/animals/why-everything-becomes-crab-meme-carcinization/
3. Fabien Lafuma, Ian J. Corfe, Julien Clavel, Nicolas Di-Po�. Multiple evolutionary origins and losses of tooth complexity in squamates. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-26285-w