Feeding mechanisms as evidence for cyclostome monophyly



The feeding mechanisms of lampreys and hagfish, as described in the literature, are reviewed. Although current opinion generally holds that these two groups have very different feeding mechanisms, eleven synapomorphous features are recognized, and the underlying anatomical homologies are suggested. In these features, the two groups clearly share none of the anatomy of gnathostomes, and it is concluded that the cyclostomes constitute a monophyletic group, the sister-group of the gnathostomes.