Craniofacial diversity across Danionins and the effects of TH status on craniofacial morphology of two Danio species

Abstract

AbstractThe model zebrafish (Danio rerio) belongs to the Danioninae subfamily with a range of informative phenotypes. However, the craniofacial diversity across the subfamily is not fully described. To better understand craniofacial phenotypes across Danioninae we used microCT and 3D geometric morphometrics to capture skull shapes from nine species. TheDaniospecies examined showed largely similar skull shapes, althoughD. aesculapii, the sister species toD. rerioshowed a unique morphology. Two non-Daniospecies examined,Chela dadiburjoriandDevario aequipinnatusshowed distinct skull morphologies unique from those of other species examined. Thyroid hormone regulates skeletal development and remodeling, and we asked if changes in developmental thyroid hormone metabolism could underlie some of the craniofacial diversity across Danioninae. We reared twoDaniospecies under altered thyroid profiles, finding that hypothyroid individuals from both species showed corresponding morphological shifts in skull shape. HypothyroidDaniosshowed skull morphologies closer to that ofChelaand unlike any of the examined wild-typeDaniospecies. We provide an examination of the evolved craniofacial diversity across Danioninae, and demonstrate that alterations to thyroid hormone have the capacity to create unique skull phenotypes.