Abstract

Past biogeographic events and environmental changes, along with ecological niche evolution are determining factors of species diversity and distribution. Studying species niche evolution can help improve our understanding of determining factors underpinning species evolution with regards to past biogeographic events and infer speciation processes at the origin of clades. In the present work, the ecological niche of all extant species of the echinoid Arbacia Gray, 1835 and of the related fossil species of the Pliocene, Arbacia improcera (Conrad, 1843) was characterized using Ecological Niche Modeling that enable a comprehensive representation of the species fundamental niche. Unlike many other echinoids, species of Arbacia are distributed in both tropical and temperate seas and show highly contrasting distribution patterns making the genus an interesting case study of ecological niche evolution. Comparison of ecological niches between closely related species provided insight on the importance of ecological niche evolution with regards to the genus phylogeny and the fossil record. Main results highlighted the importance of niche differentiation between species, but also between genetic units within a same species. This result holds true when comparing with their Pliocene relative and classic biogeographic scenarios.