The use of transverse sections of sagittal otoliths has been validated for estimating the ages of largemouth bass Micropterus salmoides to age 5. However, previous research has indicated that the accuracy of this method is low for fish older than age 5. We used known-age fish of ages 0-16 to confirm that the use of otoliths is valid for estimating the ages of older largemouth bass. The estimated ages were correct for 97% of the fish. We concluded that past difficulties with using otoliths were more likely the result of preparation and reader error than of the structures depicting incorrect ages. The preparation method used in this study was simpler and faster than conventional methods of preparing thin sections and therefore should yield results that are more consistent.
The Central Texas endemic freshwater mussel, Quadrula mitchelli (Simpson in Dall, 1896), had been presumed extinct until relict populations were recently rediscovered. To help guide ongoing and future conservation efforts focused on Q. mitchelli we set out to resolve several uncertainties regarding its evolutionary history, specifically its unknown generic position and untested species boundaries. We designed a molecular matrix consisting of two loci (cytochrome c oxidase subunit I and internal transcribed spacer I) and 57 terminal taxa to test the generic position of Q. mitchelli using Bayesian inference and maximum likelihood phylogenetic reconstruction. We also employed two Bayesian species validation methods to test five a priori species models (i.e. hypotheses of species delimitation). Our study is the first to test the generic position of Q. mitchelli and we found robust support for its inclusion in the genus Fusconaia. Accordingly, we introduce the binomial, Fusconaia mitchelli comb. nov., to accurately represent the systematic position of the species. We resolved F. mitchelli individuals in two well supported and divergent clades that were generally distinguished as distinct species using Bayesian species validation methods, although alternative hypotheses of species delineation were also supported. Despite strong evidence of genetic isolation within F. mitchelli, we do not advocate for species-level status of the two clades as they are allopatrically distributed and no morphological, behavioral, or ecological characters are known to distinguish them. These results are discussed in the context of the systematics, distribution, and conservation of F. mitchelli.
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