| Summary: | The modern Antarctic environment is typified by extremes in temperature and light. However extreme temperatures only developed within the last 35 million years. Before this Antarctic supported a temperate-climate vertebrate fauna which possessed few adaptations to extreme cold. However, dinosaurs, dicynodonts, marine reptiles and pterosaurs may have possessed adaptations for sustained darkness such as migration, hibernation and highly developed vision for remaining active in low light. After the K-T extinction event Antarctica began to cool gradually, eventually becoming too cold for its native mammals, birds and other terrestrial vertebrates which became extinct. Notothenioids thrived in the oceans and diverged significantly over a great length of time. New vertebrates have colonised Antarctica, though the extreme conditions promote bradytelic, R-selected taxa and convergent evolution. The adaptations of the modern Antarctic fauna generally can’t be attributed to Antarctica’s ancient vertebrates as conditions are too dissimilar, there is not relatedness and the modern animals are relatively ‘new’.
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