Sanctacaris Temporal range: Mid Cambrian | |
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An artist's illustration of Sanctacaris uncata | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Clade: | stem-group Chelicerata |
Genus: | †Sanctacaris Briggs & Collins, 1988 |
Species: | †S. uncata |
Binomial name | |
†Sanctacaris uncata Briggs & Collins, 1988 |
Sanctacaris is an extinct genus of arthropod from the Middle Cambrian period what is now in Burgess Shale of British Columbia. It was most famously regarded as a primitive chelicerate, a group which includes spiders and scorpions, although subsequent phylogenetic studies have not always supported this conclusion; it is best accommodated in the arachnate clade (i.e. as a stem-group chelicerate).
Sanctacaris specimens range from 46 to 93 mm in length. The head 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'. Its Latin name translates as "saintly crab". Unlike most other Burgess forms, Sanctacaris is not present in Charles Walcott's 1909 quarry and was discovered at a different level by Desmond Collins in 1980–1981.
Etymology[]
The generic name "Sanctacaris " is a compound of the Latin words "sanctus" (saint or sacred) and "caris" (meaning crab or shrimp, a common suffix used in aquatic arthropods).[4] The specific name of the type species "uncata " means "claws" in Latin and is named after the claw-shaped appendages on the head of this species.[4] The name "saint claws" refers to Santa Claus, which was the field name used to refer to Sanctacaris.[4]
Ecology[]
The robust gnathobases, alongside the fact that fellow sanctacaridid Wisangocaris has been found with trilobite fragments in its stomach, has led to suggestions that Sanctacaris was durophagous, feeding on hard shelled organisms.[3]