Description

Middle Cambrian
Wheeler Shale
Millard County, Utah, USA
Extremely rare, 14mm worm on 91mm slab
Worm,

We think of all worms belonging to the same group but they have been quite diverse representing more than one phylum across geologic time.  Some worms had jaws or armor (composed of sclerites) but most haven’t so they appear in the fossil record only where other soft-bodied organisms are preserved.

Palaeoscolex is a worm known from isolated sclerites at some localities but from occasional body impressions  in the Wheeler Shale.