A comparison of adaptive radiations of Antarctic fish with those of nonAntarctic fish

Antarctic biologists frequently emphasize the differences between the modern Antarctic environment and its fauna, and aquatic habitats and faunas elsewhere in the world. While it is valid to portray Antarctica as remote and its fauna as endemic and cold adapted, this approach tends to obscure broad scale similarities between Antarctic and non-Antarctic faunas. For example, the Antarctic fish fauna shares an evolutionary response to its habitat with fish in some tropical, temperate and boreal lakes. In this review we compare some well studied lacustrine radiations of fish with the two radiations of marine fish in the Antarctic Region of the Southern Ocean, notothenioids and liparids. We shall first make the case that, unlike other marine habitats, the Antarctic Region fulfills most of the essential parameters of lakes containing radiations of fish and that this large component of the world ocean is equivalent to a closed basin. Therefore in spite of its vastness, the Antarctic Region provides a comparable opportunity for studying evolutionary biology within a confined area. It is likely that notothenioids, and possibly liparids, are the first known examples of species flocks or radiations of marine fish. Thus the high Antarctic shelf and upper slope is an insular evolutionary site, with endemic faunas equally as interesting, but less well known, as those in ancient lakes throughout the world.

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