Morphological diversification in introduced pumpkinseed (Lepomis gibbosus): assessing truss-based and geometric morphometric approaches

We examined morphological diversification in introduced pumpkinseed, Lepomis gibbosus from Iberian reservoirs using traditional morphometric (TM) and geometric morphometric (GM) approaches to assess the degree of external differentiation among pumpkinseeds occupying four habitats separated along simultaneous dimensions of flow and trophic structure. Results from both approaches showed significant differentiation among pumpkinseeds occupying these habitats. Among functional characters deemed significant in differentiating among morphs, body depth and caudal dimensions were the most consistently significant under the TM approach, whereas differences in the caudal peduncle region were more evident under the GM approach. Recent comparative studies advocate the use of GM over TM; however, our results demonstrate that TM is beneficial for quantifying differences in specific morphological characters, which is the crux of studies in functional morphology.