Research Objectives

Various morphological data sets have been used to examine some species relationships within the family, but most of the studies have only examined a few species. Thus far, all attempts at phylogenetic reconstruction for centrarchids lack an appropriate outgroup justification, in part, because phylogenetic relationships within Perciformes remain largely unresolved. We, and others, believe that it is unlikely that the question of the sister-group to centrarchids, as well as intrafamilial relationships, will be resolved solely with morphological data. Our proposed research is the first comprehensive examination of the molecular systematics of the Centrarchidae, as well as outgroups representing potential sister-taxa, thus providing a more stable phylogenetic hypothesis than previously proposed and the necessary historical framework to reinterpret the many behavioral, biogeographic, ecological, evolutionary and developmental patterns documented by other disciplines. Specifically, in our studies we are generating a molecular data set using nuclear and mitochondrial genes and are using two existing morphological data sets from previous landmark morphological studies by Branson & Moore (1962) and Mabee (1993) to examine the monophyly of Centrarchidae, generate a phylogenetic hypothesis of centrarchid species and determine the sister-group to centrarchids.

Our first effort in this regard involves a phylogeny of the family based on cytochrome b sequences and published in Copeia 2002 (Roe, K. J., P. M. Harris, and R. L. Mayden. 2002. Phylogenetic relationships of the genera of North American sunfishes and basses (Percoidei: Centrarchidae) as evidenced by the mitochondrial Cytochrome b gene. This paper established the monophyly of the family and sister group relationships among the genera, as well as provided significant tests as to the monophyly of the genera and previous hypotheses of their relationships.

We currently have separate manuscripts submitted and in preparation on the phylogenetic relationships, speciation, and biogeographic histories of species of Lepomis, Ambloplites, and Micropterus based on cytochrome b sequence variation. We are also examining the concordance of phylogenetic signals from cytochrome b sequences and those from the nuclear gene RAG-1. Finally, these sequence data are being compared in combined and separate analyses with the morphological data that have been previously published for phylogenetic hypotheses of the family. This final analysis will be used to examine the ontogenetic transformations of morphological characters, from Paula Mabee’s studies, on these trees. We are specifically looking for the frequency of the different possible ontogenetic transformations and the likelihood of using ontogeny to provide input into character analysis.

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Fish illustrations by Joseph R. Tomelleri and used with permission.