Fossil record Stem-group polychaete fossils are known from the Sirius Passet Lagerstätte, a rich, sedimentary deposit in Greenland tentatively dated to the late Atdabanian (early Cambrian). The oldest found is Phragmochaeta canicularis. Many of the more famous Burgess Shale organisms, such as Canadia, may also have polychaete affinities. Wiwaxia, long interpreted as an annelid, is now considered to represent a mollusc. An even older fossil, Cloudina, dates to the terminal Ediacaran period; this has been interpreted as an early polychaete, although consensus is absent.
Fossil record Stem-group polychaete fossils are known from the Sirius Passet Lagerstätte, a rich, sedimentary deposit in Greenland tentatively dated to the late Atdabanian (early Cambrian). The oldest found is Phragmochaeta canicularis. Many of the more famous Burgess Shale organisms, such as Canadia may also have polychaete affinities. Wiwaxia, long interpreted as an annelid, is now considered to represent a mollusc. An even older fossil, Cloudina, dates to the terminal Ediacaran period; thi,s has been interpreted as an early polychaete, although consensus is absent.