Continental Drift and the New Zealand Biota

SUMMARY Historical bio geographers have long been puzzled by the existence in the indigenous biota of New Zealand, of seemingly land tied tax a which are shared with other southern lands especially with South America. Authorities have been forced, often reluctantly, to attribute all origins to transoceanic dispersal or to envisage former land bridges. Without denying the validity of the former explanation for many tax a, there are strong biological arguments against the mechanism for some groups while land bridges have not been supported by geological evidence. The theory of continental drift has recently received strong support from a large number of earth scientists and may enable the resolution of many of the enigmas of Austral distributions. Explanations of the movements of lands of the Southern Hemisphere have been offered together with reasonably precise allocations of times at which various connections were finally severed. It appears likely that New Zealand might well have received its oldest faunal and floral components when it was part of, or immediately adjacent to, the Gondwanaland super continent. These could have included Glossopteris , Podocarps, Sphenodon, Leiopelma , and the Ratites. Nothofagus , together with a large number of other plants and invertebrates currently shared with South America, Australia and subantarctic islands, but absent from Africa and India, presumably arrived a little later. Absence of Marsupials is consistent with a severence of New Zealand prior to the overland arrival of the group in Australia. Much fossil and other evidence remains to be obtained but biologists and historical bio geographers will be happier with current explanations than they have been for more than a hundred years.