Polychaeta

Polychaetes are a class in the phylum Annelida and are divided into 24 orders with more than 80 families. The over 10,000 described species exhibit a great diversity of forms. Based on morphological and molecular biological findings, there are significant doubts that Polychaeta constitutes a monophyletic group. This means that it is likely that these species cannot be traced back to a single common ancestor.