The diversity of otolith shapes: an ecomorphological study at a large phylogenetic scale

Ecomorphology is the field exploring the links between species morphology and its environment to better understand the adaptative value of a given phenotype. Different studies have now applied this discipline trying to explain intra- and interspecific variability of fishes’ otolith shape without pointing towards a consensus involving environmental influence across teleosts. The present work aims to decipher the major drivers of teleosts’ otolith diversity. Here, we will test the relationships between various ecological functional traits and otolith shape at a large taxonomic scale. We therefore gathered life history traits and functional characters for 697 fish species. Collected information included species ecology (habitat, mobility, gregariousness, feeding habits, sound production), body characteristics (body shape, mouth position, size class), swimming mode and sensory features (hearing specializations, bioluminescence, barbels). Otolith and sulcus shapes were quantified with landmark-based geometric morphometric methods. Phylogenetic information were retrieved from Betancur et al. (2017). Within the scope of this study, three main objectives were addressed: (1) to compare morphological and phylogenetic clusters and assess their discrepancies, (2) to seize the influence of fish ecology and functional traits on their otolith morphology and finally (3) to correlate functional and otolith morphological diversity of clusters and their evolution along the tree of life.