Kootenayscolex is the extinct genus of annelid resembling a bristle worm, found in Burgess Shale, British Columbia.[1] It appears to have been an aquatic worm with about 56 chaetae (bristles) on each of up to 25 segments, serving to propel it through mud or water.

Temporal range: Cambrian Stage 5
Kootenayscolex ROMIP62972.png
Paratype specimen
Scientific classification edit
Kingdom: Animalia
Phylum: Annelida
Genus: Kootenayscolex
Nanglu & Caron, 2018
K. barbarensis
Binomial name
Kootenayscolex barbarensis
Nanglu & Caron, 2018

The only one known species in the genus, Kootenayscolex barbarensis, is thought to exhibit primitive traits that show the foundation for the evolution of modern annelids, like "head" segment that still has traits of simply being another generic body segment, for example having bristles poking out of it, which no modern annelid shares.[2]


The genus name Kootenascolex, means "worm from Kootenay National Park" (in British Columbia, where its fossils were found) and species name barbarensis is from Barbara Polk Milstein, a researcher on the burgess shale fossils. Over 500 specimen are known, and length ranges 1–30 mm (0.039–1.181 in).[1] They appear to have been bottom feeders, sifting sediment from the seafloor in their mouths.[2]


  1. ^ a b Nanglu, Karma; Caron, Jean-Bernard (2018). "A New Burgess Shale Polychaete and the Origin of the Annelid Head Revisited". Current Biology. 28 (2): 319–326.e1. doi:10.1016/j.cub.2017.12.019. ISSN 0960-9822.
  2. ^ a b "New 508-million-year-old bristle worm species from British Columbia's Burgess Shale wiggles into evolutionary history". phys.org. Retrieved 2018-01-22.