Geological Constraints on Evolution and Survival in Endemic Reptiles on Bermuda

—Paleontological and geological evidence suggest that the distinctive endemic skink Eumeces longirostris could potentially be as old as continuously emergent land on the Bermuda seamount (approximately . 1–2 million yr). The species has experienced sustained evolutionary stasis for at least the past 400,000 yr, during which time there has been no perceptible change in skeletal morphology. The tortoise Hesperotestudo bermudae is known from a single fossil from interglacial period marine isotope stage (MIS) 9—approximately 300,000 yr ago. A viable population of tortoise on Bermuda could be reconciled with the geological record and the lack of any other fossils of the species to date if tortoises colonized the island at or after the end of the maximal sea-level rise of interglacial MIS 11, evolved during the single glacial episode of MIS 10, and become extinct as a result of the interglacial sea-level rise of MIS 9, a period of about 100,000 yr. Such rapid evolution and extinction has a close parallel in the giant tortoises of Aldabra Island in