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Influence of niche breadth and position on the historical biogeography of seafaring scincid lizards

December 5, 2020

Niche breadth and position can influence diversification among closely related species or populations, yet limited empirical data exist concerning the predictability of the outcomes. We explored the effects of these factors on the evolution of the Emoia atrocostata species group, an insular radiation of lizards in the western Pacific Ocean and Indo-Australasia composed of both endemic and widespread species that differ in niche occupancy. We used molecular data and phylogeographical diffusion models to estimate the timing and patterns of range expansion, and ancestral reconstruction methods to infer shifts in ecology. We show evidence of multidirectional spread from a centre of origin in western Micronesia, and that the phyletic diversity of the group is derived from a putative habitat specialist that survives in the littoral zone. This species is composed of paraphyletic lineages that represent stages or possible endpoints in the continuum toward speciation. Several descendant species have transitioned to either strand or interior forest habitat, but only on remote islands with depauperate terrestrial faunas. Our results suggest that the atrocostata group might be in the early phases of a Wilsonian taxon cycle and that the capacity to tolerate salt stress has promoted dispersal and colonization of remote oceanic islands. Divergence itself, however, is largely driven by geographical isolation rather than shifts in ecology.

Citation Information

Publication Year 2021
Title Influence of niche breadth and position on the historical biogeography of seafaring scincid lizards
DOI 10.1093/biolinnean/blaa172
Authors Jonathan Q. Richmond, Hidetoshi Ota, L Lee Grismer, Robert N. Fisher
Publication Type Article
Publication Subtype Journal Article
Series Title Biological Journal of the Linnean Society
Index ID 70226474
Record Source USGS Publications Warehouse
USGS Organization Western Ecological Research Center