The re-examination of the worm fauna from Cabrières and new material from Cessenon-sur-Orb (Hérault, France) reveal an unexpected diversity of infaunal and epifaunal organisms that may have played an important role in sediment bioturbation. This ecological significance is consistent with the relatively high abundance of associated trace fossils. Although most worm body fossils are represented by incomplete trunk fragments and are often poorly preserved due to decay and coarse iron coatings, several specimens retain diagnostic features that allow identification at a relatively high taxonomic level. Two distinct forms of palaeoscolecid worms (Scalidophora) are recognized within the Cabrières biota, showing affinities with both Ordovician and Cambrian representatives of this extinct group, and co-occurring with other, yet undetermined, relatively featureless scalidophorans. The most enigmatic findings include numerous specimens, possibly lophotrochozoan worms characterized by a metameric body plan, possible paired of lateral parapodia-like appendages reminiscent of annelids, and, dorsally, chevron-like sclerites of uncertain composition. Although their precise taxonomic position within lophotrochozoans (Annelida or not) remains unresolved and premature, these worms—unlike the scalidophorans—were most likely epibenthic, as suggested by trails associated with their body fossils.
Vannier et al. (Mon,) studied this question.