Eco-morphological traits diffusion inside fish communities of Maroni River (French Guiana and Suriname)

The Neotropical freshwater fish fauna represents 20% of the known fish species diversity. Although several historical and ecological mechanisms involved in the distribution of this diverse ichtyofauna have been explored, few studies have analyzed a complete community. Here, we report a study of the distribution and diffusion of eco-morphological traits across the phylogeny of the fish community of the Maroni Basin, located at the border between French Guiana and Suriname. We also test the eco-morphological hypothesis stating that morphology can be used as a predictor of ecology. Nuclear (five markers) and mitochondrial (one marker) sequences of 236 species were collected to reconstruct their phylogeny, morphometric measurements of 680 individuals were taken and a data table of each species’ general ecology was compiled. Multivariate analyses showed a strong structuration of morphometric data on the axes segregating the orders and successive ranks. Axis 1 (27.14%) was a component of shape, and separated compressed, deep-bodied big-eyed fishes (negative values) from depressed, long-snouted fishes with small eyes positioned upward (positive values). The second axis (25.47%) was mainly related to fin-based locomotion and showed a negative correlation between length of anal fin (negative values) and the relative area of pectoral, dorsal and caudal fins. Ecological traits showed a more diffuse pattern since some niches can be occupied by several species belonging to different orders. Co-inertia analyses showed that morphological and ecological traits were significantly linked (RV=0.23; p<0.001) but that this correlation becomes very weak once the influence of phylogeny is removed (RV=0.05; p