LEGACY DATA IN PHYLOGENETICS AND A RE-ANALYSIS OF MID-PALEOZOIC PHACOPID PHYLOGENY

Phylogenetic data is often presented in published papers in a table format. This table format is not immediately useful for testing the phylogenetic hypotheses, as it cannot be directly run by a phylogenetics computer program. By imputing legacy phylogenetic matrices into an online resource like MorphoBank, old phylogenetic datasets can be made accessible for easy testing and modification. In some cases, computing power at the time of the original analyses was insufficient for a comprehensive search of treespace, and hence better results can now be obtained.

Through an initiative of importing old trilobite phylogenetic analyses into Morphobank, we reanalyzed the phylogenetic analysis of Silurian-Devonian phacopid trilobites of Ramsköld and Werdelin (1991). The hypothetical ancestor outgroup was replaced with an Ordovician pterygometopid, Calyptaulax callirachis. Several additional mid-Paleozoic phacopids were also added to the analysis. The resulting matrix was analyzed using both parsimony and Bayesian methodologies. Though the broad conclusions of the original paper remain intact, a surprising number of taxa shifted positions when compared to the original study.