Memoirs of Museum Victoria 71: 247–269 (2014) Published December 2014 ISSN 1447-2546 (Print) 1447-2554 (On-line) http://museumvictoria.com.au/about/books-and-journals/journals/memoirs-of-museum-victoria/ Systematics, evolution and phylogeny of Annelida – a morphological perspective GÜNTER PURSCHKE1,*, CHRISTOPH BLEIDORN2 AND TORSTEN STRUCK3 1 Zoology and Developmental Biology, Department of Biology and Chemistry, University of Osnabrück, Barbarastr. 11, 49069 Osnabrück, Germany (
[email protected]) 2 Molecular Evolution and Animal Systematics, University of Leipzig, Talstr. 33, 04103 Leipzig, Germany (bleidorn@ rz.uni-leipzig.de) 3 Zoological Research Museum Alexander König, Adenauerallee 160, 53113 Bonn, Germany (torsten.struck.zfmk@uni- bonn.de) * To whom correspondence and reprint requests should be addressed. Email:
[email protected] Abstract Purschke, G., Bleidorn, C. and Struck, T. 2014. Systematics, evolution and phylogeny of Annelida – a morphological perspective . Memoirs of Museum Victoria 71: 247–269. Annelida, traditionally divided into Polychaeta and Clitellata, is an evolutionary ancient and ecologically important group today usually considered to be monophyletic. However, there is a long debate regarding the in-group relationships as well as the direction of evolutionary changes within the group. This debate is correlated to the extraordinary evolutionary diversity of this group. Although annelids may generally be characterised as organisms with multiple repetitions of identically organised segments and usually bearing certain other characters such as a collagenous cuticle, chitinous chaetae or nuchal organs, none of these are present in every subgroup. This is even true for the annelid key character, segmentation. The first morphology-based cladistic analyses of polychaetes showed Polychaeta and Clitellata as sister groups.