Sanctacaris is a Middle Cambrian arthropod from the Burgess shale of British Columbia. The animal is up to 10 cm in length [46 to 93mm]. Sanctacaris appears to be a primitive chelicerate arthropod.
The head of Sanctacaris bears five pairs of grasping appendages and a sixth pair of large separate appendages. The grasping appendages each bear a short antenna-like second appendage. There are 11 body segments each with a pair of walking legs and gills. There is a broad, flat paddle-like telson.
Originally Sanctacaris was called informally 'Santa Claws'. Unlike most other Burgess forms, Sanctacaris is not present in Walcott's 1909 quarry and was discovered at a different level by Desmond Collins in 1980-1981.