Assessing phylogenetic information to reveal uncertainty in historical data: An example using Goodeinae (Teleostei: Cyprinodontiformes: Goodeidae).

A major emerging challenge to resolution of a stable phylogenetic Tree of Life has been incongruent inference among studies. Given the increasing ubiquity of incongruent studies, analyzing the predicted phylogenetic utility and quantitative evidence regarding contributions toward resolution of commonly-used markers in historical studies over the last decade represents an important, yet neglected, component of phylogenetics. Here we examine the phylogenetic utility of two sets of commonly-used legacy markers for understanding the evolutionary relationships among goodeines, a group of viviparous freshwater fishes endemic to central Mexico. Our analyses reveal that the validity of existing inferences is compromised by both lack of information and substantially biased patterns of nucleotide substitution. Our analyses demonstrate that many of the evolutionary relationships of goodeines remain uncertain - despite over a century of work. Our results provide an updated baseline of critically needed areas of investigation for the group and underscore the importance of quantifying phylogenetic information content as a fundamental step towards eroding false confidence in results based on weak and biased evidence.