Body shape evolution of African/Asian minnows of the genus Labeo Cuvier 1817 (Cyprinidae, Labeonini) and variations in Labeo parvus

Abstract

Morphological variation or similarities among organisms are not only a result of common evolutionary history but can also emerge because of convergent adaptations to similar habitats. Therefore, an organism’s morphology is strongly correlated with environmental gradients and plays an important role in growth, survival, and reproduction. In aquatic habitats for instance, body shape plays a significant role in foraging, locomotion, defense, and habitat exploitation. Understanding shape variation and evolution within a group of organisms can provide insights about strategies for habitat colonization, food resource use, and even species diversity within a group. Herein, I combined geometric morphometrics, molecular phylogeny, and phylogenetic comparative methods to assess body shape variation and evolution among species of the African/Asian minnows of the genus Labeo. Additionally, I assessed species diversity and distribution patterns within Labeo parvus. I found that Labeo body shape varies significantly across species and clades. The greatest variation in body shape among Labeo species and clades occurs in body depth and width. I also found that the similarities in body shape observed between some species are not always due to common evolutionary history. Indeed, both the visual examination of the phylomorphospaces and SURFACE analyses revealed multiple instances of convergent evolution across Labeo phylogeny. Furthermore, I found that Labeo parvus is a species complex of several species and that the true Labeo parvus is endemic to the Congo basin.