Australia: The Land Where Time Began

A biography of the Australian continent 

The Peninsula Effect

Something like "the island effect", this holds true in the present and Dr Anthony Thulborne of the University of Queensland has proposed it as a possible reason Australian biota has always been "different"

It is known that present day faunas follow the basic rules of the peninsula effect, faunas being progressively impoverished from the mainland to the outer edge of the peninsula. Australia was a peninsula of Gondwana throughout the period when life was moving on to land up until it broke from Antarctica, a time span of about 1 billion years, so the present situation when Australia is biologically isolated by water, is only a continuation, though a much more severe form, of the partial isolation that had existed throughout the emergence on to land. It seems to me Dr Thulborn's suggestion makes sense.

Maybe this effect explains several observations about Australia's fossil record. For long after the dinosaurs had risen to dominance in the rest of the world, in Australia amphibians were very prominent in vertebrate fossil deposits long after their extinction elsewhere, the dinosaurs never seeming to become as dominant, or as numerous, here as they did elsewhere. There is also the early relatives of the platypus that grew to a large size and specialised to a way of life that appears to have been similar to that of the living platypus, at a time, during the Early Cretaceous, when mammals elsewhere were small and unspecialised, presumably to keep out of the way of dinosaurs, that were at their peak at that time.

Sources & Further reading