A fossil arthropod caught molting

[Halichoeres]

It's actually a stem-arthropod, but close enough, and it's preserved in the act of ecdysis (shedding the exoskeleton, usually to accommodate new growth). It's a known species (Alacaris mirabilis), and based on its phylogenetic position you would of course expect it to molt, but it's rare to observe it in the fossil record.

The spectacular fossil from the Cambrian Xiaoshiba Lagerstätte in China:


Paper (open access): https://www.nature.com/articles/s41598-019-41911-w

[Libraraptor]

I always find "active " fossils amazing!

[Faelrin]

I guess this poor critter didn't get to grow after all. If I had to guess its molt went unsuccessfully causing it to pass (and then lucky circumstances caused it to fossilize, preserving it in this state for an eternity)? Interesting fossil for sure though.