The ecology of modern and fossil vertebrates revisited by lithium isotopes

The vertebrate fossil record documents a plethora of transitions between aquatic and terrestrial environments but their causes are still debated. Quantifying the salinity living is therefore crucial for precising sequence ecological transitions. Here, we measured lithium stable isotope composition mineralized tissues (δ7Limt) extant extinct vertebrates from various environments: seawater, freshwater/terrestrial, “transitional environments” (i.e. brackish waters, or seasonal access to freshwater seawater). We report statistically higher δ7Limt values seawater than ones, taxonomic groups considered separately. Moreover, in transitional have intermediate values. Therefore, show that both can discriminate habitat.