Wednesday, 29 October 2003 - 11:24 AM
0850

This presentation is part of : Ten-Minute Papers, Section A. Systematics, Morphology, and Evolution

The unbearable lightness of being monophyletic: clade stability and the addition of data -- a case study from erigonine spiders

Jeremy Miller, Smithsonian Institution, Systematic Biology - Entomology, National Museum of Natural History, NHB-105, P.O. Box 37012, Washington, DC and Gustavo Hormiga, George Washington University, Biological Sciences, 2023 G St. NW, Washington, DC.

We have added taxa and characters to a previous analysis of erigonine relationships. Our phylogeny differs markedly from the previous hypothesis of erigonine relationships. We investigate how the addition of characters and taxa (alone and together) has altered the original phylogeny. We conclude that topological changes from the previous study to the current one are largely the result of adding and modifying characters, not adding taxa. We also evaluate progress toward a stable phylogeny using Continuous Jackknife Function (CJF) analysis. CJF analysis uses character removal and a reference hypothesis to evaluate the stability of the hypothesis under test. The results are presented as a graph of the number of clades recovered after character removal and reanalysis against the percent probability of character removal. Stable phylogenies are expected to take the form of a decreasing asymptotic curve with a high rate of clade recovery. CJF analysis of the erigonine data set indicates that additional characters will be required before a stable phylogeny will be achieved.

Species 1: Araneae Linyphiidae
Keywords: phylogeny

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