Meeting Abstract

72.6  Tuesday, Jan. 6  Candiru catfish … a fish with many names and many novelties ADRIAENS, D.*; CHRISTIAENS, J.; Ghent University, Gent Belgium; Ghent University, Gent Belgium dominique.adriaens@ugent.be

Evolutionary novelties are considered as crucial step stones during adaptive evolution, triggering novel functions and allowing novel ecological landscapes to be explored. De novo formations and decouplings may arise leading to these novelties. In contrast, highly specialised body plans, as is the case for parasites, arise as the result of extensive reductions. Counter intuitively, one might wonder whether coupling events may also have allowed evolutionary specialisations. Jaw systems in teleostean fishes are one of the most illustrative cases of how different evolutionary events gave rise to a tremendous spectrum of functional systems. According to the assumption of parsimonous evolution, ancestral transformations general reflect a gradual accumulation of novelties (including simple modifications and more complex decouplings). One special case study has proven to be the blood-sucking candiru catfish, legendary for its feeding habit (and especially its mistakes during feeding). In this study, a detailed morphological study is performed on the jaw system of this Neotropical trichomycterid catfish (Vandellia spp.). By comparing its morphology with that of a more basal, but closely related trichomycterid (Trichomycterus spp.), the level of structural innovations seems to be impressively high (novel ligaments, novel muscle connections, novel dentition, novel mandibular decouplings, etc.). Compiling data on all the coupled and decoupled structural elements, together with muscular components powering the jaw system, a 3D dynamic model of biting in candiru catfish is proposed. So it seems that in this case, an evolutionary trend towards (ecto)parasitic feeding may be the result of a complex pattern of different types of evolutionary novelties.