Sidneyia

Sidneyia
Temporal range:
Reconstruction of Sidneyia inexpectans
Fossil of S. inexpectans
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Clade: Artiopoda
(unranked): Vicissicaudata
Genus: Sidneyia
Walcott, 1911
Type species
Sidneyia inexpectans
Walcott, 1911
Species
  • S. inexpectans Walcott, 1911
  • S. minor Du et al., 2023
  • S. malongensis Zhu et al., 2023

Sidneyia is an extinct marine arthropod known from fossils found from the Early to the Mid Cambrian of China and the Mid Cambrian Burgess Shale of British Columbia, Canada. It is thought to have been a durophagous (crushing) predator that used its spine-covered leg bases (gnathobases) to feed on hard-bodied animals like trilobites and brachiopods, as well as possibly soft bodied animals. It was historically placed in the group "Xenopoda" alongside Emeraldella. It is now placed within the clade Vicissicaudata along with aglaspidids, chelonellids, as well as Emeraldella, among others. Vicissicaudata forms part of the broader group Artiopoda, which includes trilobites.