ABSTRACT
There are two studies providing cladistic analyses of Phyllodocida, Rouse and Fauchald (1997) and Pleijel and Dahlgren (1998), both based on morphological data. There are also other studies that include only a very limited number of Phyllodocida, but these will not be further discussed here (see Rouse and Pleijel 2001). Although both resolution and terminals within Phyllodocida differ between the results of these two studies, the inclusiveness of the group is identical in both, and both also have Eunicida as sister group. Phyllodocida and Eunicida, together with Amphinomida, make up the major clade Aciculata, by and large corresponding to what was once upon time known as 'Errantia'. One main difference between the two studies relates to the position of Pisionidae. Following Rouse and Fauchald (1997), they are situated within a large grade including e.g., chrysopetalids, syllids, nereidids, phyllodocids, nephtyids and glyceriforms, but according to Pleijel and Dahlgren (1998) they have the more traditionally (e.g. Akesson 1961) favored position as sister to the scalew orm s; the relationships of pisionids certainly warrant further studies. Another difference involves chrysopetalids, nereidids and hesionids, which in Rouse and Fauchald (1997) appear within the previously mentioned grade, but instead constitute a clade in Pleijel and Dahlgren (1998). This latter relationship was also previously suggested by Glasby (1993), as well as in a combined morphological and molecular analysis by Dahlgren et a l (2000).
