Palaeomorphology: Fossils and the inference of cladistic relationships

Abstract

Twenty years have passed since it was empirically demonstrated that inclusion of extinct taxa could overturn a phylogenetic hypothesis formulated upon extant taxa alone, challenging Colin Patterson's bold conjecture that this phenomenon 'may be non-existent'. Suppositions and misconceptions about missing data, often couched in terms of 'wildcard taxa' and 'the missing data problem', continue to cloud the literature on the topic of fossils and phylogenetics. Comparisons of real data sets show that no a priori (or indeed a posteriori) decisions can be made about amounts of missing data and most properties of cladograms, and both simulated and real data sets demonstrate that even highly incomplete taxa can impact on relationships. The exclusion of fossils from phylogenetic analyses is neither theoretically nor empirically defensible. © 2010 The Natural History Museum.