The problem of characters susceptible to parallel evolution in phylogenetic analysis: a reply to Marques and Gnaspini (2001) with emphasis on cave life phenotypic evolution

Marques and Gnaspini [Cladistics 17 (2001) 371-381] analyzed the problem-of the phylogenetic treatment of characters submitted to parallel evolution. Their proposal aimed at preserving the potential phylogenetic significance of supposedly homoplastic characters and considering them for phylogeny reconstruction. As an example, they used the troglobiomorphic features of animals restricted to caves; according to their preliminary hypothesis of homoplasy, troglobitic animals would exhibit a particular phenotype, referred to as troglobiomorphic, which they would acquire under similar selective pressures from the subterranean environment. We examined Marques and Gnaspini's approach not from the point of view of its technical flaws, but from the point of view of the authors' basic assertions on the treatment of troglobiomorphic characters and more generally the inclusion/exclusion/ transformation of characters prior to phylogenetic analysis. In the present paper, we argue that this approach is invalidated by the repeated use of ad hoc hypotheses, which are supported neither by an existing phylogenetic pattern nor by available data. We consequently contest the adequateness of this approach with a cladistic analysis of historical questions. (C) 2003 The Willi Hennig Society. Published by Elsevier Science (USA). All rights reserved.