Catfishes as a case study for discussions on general evolution: the importance of functional uncouplings in morphological macroevolution.

Abstract

Many evolutionary biologists have stressed that functional uncouplings play an important role in morphological macroevolution, as they facilitate diversification and speciation by increasing the number of degrees of freedom and allowing more mechanical solutions for functional problems. In the present paper, the importance of functional uncouplings in the evolution of six major catfish structural complexes is briefly discussed, namely those constituted by the mandibular barbels and associated structures, the pectoral girdle complex, the elastic spring apparatus, the suspensorium, the palatine-maxillary system, and the adductor mandibulae complex. The overview of these major structural complexes indicates that functional uncouplings did effectively play an essential role on catfish evolutionary history. The study of this cosmopolitan and particularly diverse group representing about one-third of all freshwater fishes thus supports the importance of functional uncouplings in morphological macroevolution.