A grant has been awarded to Drs. Henry Bart, David Hurley, and Royal Suttkus at Tulane University to study the taxonomy and evolutionary relationships of fishes in Subfamily Ictiobinae (buffalofishes and carpsuckers). As presently defined, the subfamily includes seven or eight living species, distributed throughout eastern North America and Mexico. However, there are problems with the current taxonomy. Most modern workers consider the group to be much more diverse than presently recognized. Ictiobines are an important component of large river ecosystems. They play an important role straining small invertebrates from bottom sediments and converting these organisms to fish biomass. Ictiobines (especially buffalofishes, genus Ictiobus) are also important food fishes for humans in many parts of their range. Historically, they were the dominant group of fishes in large rivers of eastern North America in terms of overall biomass. However, their numbers have been declining in recent years due to pollution, extensive modification of the large rivers they inhabit, and the success of ecologically similar, exotic carps. Human modification of large river habitats may be contributing to a problem of hybridization where closely related species occur together. It will be difficult to address conservation needs of ictiobines without a good understanding of natural diversity in the subfamily and the impact of hybridization on this diversity.
The investigators on this grant will examine morphological and genetic variation within currently recognized ictiobine species. They will formally describe any newly discovered species, and will provide characters and taxonomic keys to aid others with species identification. They will sequence portions of the mitochondrial and nuclear genomes of ictiobines to assess degrees of genetic divergence, extent and impact of interspecific hybridization, and phylogenetic relationships among species. Lastly, they will use the phylogenies to examine morphological evolution and speciation patterns within the group. The project combines the talents of a senior fish taxonomist with extensive experience in traditional methods of taxonomic revision, a more junior taxonomist/systematist familiar with modern systematic methods and data analysis, and a molecular biologist experienced with the vast array of molecular techniques, including molecular systematics.
