Sidneyia inexpectans
Middle Cambrian
Burgess Shale, Stephens Formation
Field, British Columbia
Canada

Very rare Burgess Shale predatory arthropod and one of the largest animals known from the site. Gut contents from some specimens show that they fed on hyolithids, small crustaceans and trilobites. This huge specimen is 148mm (5.8 inches) making it among the largest Sidneyia specimens known. Matrix is 185mm x 120mm slab from a collection made over 60 years ago. No restoration, no repair.

Read about the feeding habits of Sidneyia here (PDF): Zacaï, A., Vannier, J., & Lerosey-Aubril, R. (2016). Reconstructing the diet of a 505-million-year-old arthropod: Sidneyia inexpectans from the Burgess Shale fauna. Arthropod Structure & Development, 45(2), 200-220.