of the leaf-litter, and the enigmatic adzebill was a universal omnivore. The wattlebirds, Callaeidae, are a family endemic to New Zealand, but many other New Zealand birds show clear affinities to Australia, including the New Zealand pigeon and the New Zealand falcon, as well as various parrots, rails, waders, owls, and seabirds (albeit often with a New Zealand twist). Of the 245 species of birds from the greater New Zealand (the main islands along with the offshore islands, also including Norfolk Island), 174 were endemic, roughly 71%. Of these, about 32% of the genera were endemic. No agamas or iguanas are recorded from New Zealand; lizards are represented by geckos and skinks, which arrived multiple times. The fossil record shows a highly diverse herpetofauna during the Miocene, with a mekosuchine crocodile and meiolaniid and pleurodire turtles being known from the Saint Bathans Fauna. The tuatara, reaching 60 cm (23.6 inches), is New Zealand's largest living reptile, a last remnant from the once diverse clade that was Sphenodontia. Frogs, which because of their intolerance for saltwater are assumed to have descended from ancestors that broke off from Gondwana, are one of the few exceptions to the rule that amphibians are never found on oceanic islands (another being the frogs of Fiji). New Zealand's few wholly freshwater fishes are derived from diadromous species. New Zealand's terrestrial invertebrate community displays strong Gondwanan affinities, and has also diversified strongly, if unevenly. There are over a thousand species of snail, and many species of insect have become large and in many cases flightless, especially grasshoppers and beetles. There are, however, fewer than 12 species of ant. The most famous of New Zealand's insects, the wētā, are ground-living relatives of the crickets that often reach enormous proportions. Many endemic marine invertebrate species, particularly marine snails, have evolved in the seas surrounding New Zealand. Endemism New Zealand has a high number of endemic species, such as: 80% of all vascular plants 70% of all native terrestrial and freshwater birds All bats All native amphibians All reptiles 90% of freshwater fish 90% of insects and molluscs 75% of marine molluscs alone Of New Zealand's estimated 20,000 fungi species, only about 4,500 are known. New Zealand also has two subspecies of endemic cetaceans, Hector's dolphin and its close relative Maui's dolphin. Human impact The arrival of humans in New Zealand has presented a challenge for the native species, causing