Alitta virens (right) and comparable states in the fossil, Burgessochaeta (left). A State 1-complete polychaete, entire body segment intact (ROM–64913). B State 2-damage towards the mid-section and posterior transforms into tangled remains caused by the combination of transport and decay. The body remains intact as one segment (ROM–64916). C State 3-remains of the trunk and setae. The body structure has deteriorated significantly (ROM–64914). D State 4-remains of loose setae are attached to minute segments of cuticle and jaw elements only are recovered (ROM–64915).