Mega-island or micro-continent? New Zealand and its fauna

The terrestrial New Zealand fauna has developed on an ancient landmass of continental origins that has had an increasingly isolated existence since the late Mesozoic. As a continental remnant, New Zealand harbours survivors of many ancient lineages many of which were once far more widely distributed. But New Zealand's fauna also resembles that of an isolated archipelago: many higher taxa are missing; some have undergone extensive radiations in situ; and levels of endemism approach 100% in many groups. Ecologically, the fauna is characterized by frequent niche shifts, gigantism, and extended life histories with low reproductive rates, factors that make many species vulnerable to human disturbance. Data continue to amass supporting the ecophysiological as well as phylogenetic distinctiveness of the fauna. Described taxonomic diversity, even of terrestrial vertebrates, continues to increase.