Relative quality of different systematic datasets for cetartiodactyl mammals: assessments within a combined analysis framework

Summary

High congruence, support, stability, resolution and decisiveness are seen as positive attributes by many systematists. Within a cladistic context, the consistency index, the retention index, branch support, data decisiveness, the number of nodes resolved in a strict consensus tree and the incongruence length difference are direct measures of these qualities. Phylogenetic analyses of 29 datasets for cetartiodactyl mammals show that for a particular character partition, these indices can vary radically in separate versus combined analysis of datasets. The quality of any single dataset is of little importance in comparison to a thorough sampling of the available character space.