Abstract

The sizes of geographic ranges of species of Australian tetrapod groups form 'hollow curve' frequency distributions, with most species having small ranges. Geometric means for range size (in 10(5) km2 units) are 1.2 for frogs and toads, 1.7 for turtles, 2.2 for lizards, 3.2 for snakes, 6.6 for birds, 2.6 for marsupials, 5.1 for bats and 2.1 for rodents. Species' densities are compared for different groups. A map of superimposed species boundaries for mammals demonstrates some relatively homogeneous faunal areas separated by distinct and narrow faunal boundaries but this is not the general pattern. The principal axes of species ranges for many groups are oriented parallel to and near coasts. Species centred on the interior tend to have larger ranges. Estimates or measurements of range size tend to be better if there are more published records, specimens, known localities of occurrence, and ecological data. Australia, in proportion to its area, has more anurans, lizards (and other reptiles), and marsupials, and it has fewer rodents and bats than North America. The ranking of groups for mean range size is the same in both continents except that Anura have smaller ranges than lizards in Australia.