We are sponges: Phylogenetic systematics is getting a tad silly

Phylogenetic systematics, as espoused in a recent book review by Harry W. Greene published in this journal, promotes the idea that paraphyly obscures the recognition of phylogenetic relationships and other aspects of organismic biology. I argue here that this viewpoint is not only without merit (what, in fact, do derived taxa tell us about paraphyletic taxa?), but that insistence on holophyly in itself may obscure ready appreciation of phylogenetic relationships. It has been recognized and accepted for the better part of this century that taxonomic groups at all levels may be derived from within other taxonomic groups, resulting in paraphyly. This phenomenon is becoming more and more evident as cladistic analyses of molecular and morphological data are more penetrating, and many well-defined taxa, including sponges, are now seen as probably paraphyletic. Computer-based cladistic analysis, integrating both molecular and morphological characters, is a powerful and increasingly essential approach for sorting out and establishing both sister-group and paraphyletic relationships. Paraphyletic taxa should be recognized as such for the fascinating perspective they provide in unraveling evolutionary patterns.