SYNOPSIS. In recent years the monophyly of the Annelida and Polychaeta has been questioned, with various authors proposing that groups such as the Arthropoda, Echiura and Pogonophora render the Annelida and/ or Polychaeta paraphyletic. The Clitellata have also been proposed to be a member of the Polychaeta, potentially making this latter taxon synonymous with the Annelida. The relationships within the traditionally formulated Polychaeta have never been investigated using cladistic methodology. Recent classifications of polychaetes show a large number of “orders” with no real attempts to relate the groups in a phylogenetic sense. In this paper a number of recent studies on annelid systematics and classification are reviewed. Special emphasis is placed on the cladistic parsimony analyses of Rouse and Fauchald (1995, 1997) where a comprehensive assessment of the relationships among the various polychaete and annelid groups was attempted. A contrasting result by Westheide (1997) using a different methodology, is also outlined and discussed.

Author notes

1From the symposium Evolutionary Relationships of Metazoan Phyla: Advances, Problems, and Approaches presented at the Annual Meeting of the Society for Integrative and Comparative Biology, 3–7 January, 1998, at Boston, Massachusetts.