Dynamic Adaptive Evolution and Evolutionary Modularity and Integration in Catfishes of the Superfamily Doradoidea

Adaptation and modularity are two major features of morphological evolution that are increasingly investigated by modern macroevolutionary biologists. However, many such studies assume that adaptive processes or modularity are constant across species. Evolution of morphology and its modularity both relate to the ecological role of morphological traits. Here, we investigate whether morphological adaptation and modularity vary across families of the Neotropical superfamily Doradoidea, comprising the Aspredinidae (banjo catfishes), Auchenipteridae (driftwood catfishes), and Doradidae (thorny catfishes). We quantified morphological diversity using three-dimensional geometric morphometrics and estimated evolutionary rates, shifts between adaptive regimes, and evolutionary modularity and integration differences among families. We found that doradoids diversified into nine adaptive regimes across morphospace. We also found some significant differences in modularity and integration between families. Major morphological shifts have surprising correspondence to previously or currently recognized taxa within the Doradoidea. We found repeated, parallel evolution of body elongation across adaptive regimes, implying a role for selection in driving parallel evolution across a primary axis of shape diversification. However, modularity and integration do not necessarily shift in correspondence with shifts in morphological adaptive peaks.