Ordovician polychaeturid polychaetes: Taxonomy, distribution and palaeoecology

The fossil polychaete family Polychaeturidae is considered as monogeneric and comprises four species of the genus Pteropelta. Pteropelta, originally established on isolated scolecodonts (the carriers), is revised and the apparatus−based Polychaetura is shown to be a junior synonym of Pteropelta. In addition to Pteropelta gladiata and Pteropelta kielanae, Pteropelta huberti sp. nov., and Pteropelta sp. A are herein described from the Upper Ordovician of Estonia and Sweden. Polychaeturids include some of the most common and characteristic scolecodont−bearing polychaetes in the Ordovician of Baltoscandia. They first appeared in the early Darriwilian (Mid Ordovician), flourished in the Late Ordovician and disappeared in the early Silurian. The distribution patterns of individual polychaeturid species infer regional biostratigraphical potential. Polychaeturids were geographically widespread during the Ordovician and have been recorded from at least three palaeocontinents.