An application of dynamic homology to morphological characters: direct optimization of setae sequences and phylogeny of the family Odontellidae (Poduromorpha, Collembola).

The concept of character and the definition of the attribute are two major theoretical issues of phylogenetics. Lately, great progress has been made in the conceptual development of attributes as historical individuals undergoing series of transformations. While operational application of this ideographic concept of character has been possible since the publication of the direct optimization algorithm and POY software, it has been restricted to molecular characters only. The present paper proposes the first application of direct optimization to morphological characters, in the case study of the phylogeny of Odontellidae. This new homology regime is compared to the traditional homology scheme. The theoretical and operational limitations of the application of direct optimization to morphological characters are discussed. Some thoughts on the basics of its generalization to all morphological characters analyzed in a dynamic homology phylogenetic framework are given. © The Willi Hennig Society 2009;.