Characters of the female gonad and the phylogeny of Platyhelminthes

The female gonad of Platyhelminthes shows a wide variability in its anatomical and cellular organization and submicroscopic structure, and some characteristics may be useful for elucidating the questioned monophyly of some taxa and reconstructing the phylogenetic tree of the group. The morphological characters of the female gonad have been subdivided into three levels: macroscopic, microscopic and ultrastructural, and some examples with potential phylogenetic value are presented for each level. This revised version was published online in July 2006 with corrections to the Cover Date.