The Chatham Islands beetle fauna and the age of separation of the Chatham Islands from New Zealand

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Abstract
The Chatham Islands comprise a small archipelago lying about 850 km due east of Banks Peninsula in the South Island of New Zealand, and connected to it by a shallow submarine ridge, the Chatham Rise. Current geological knowledge suggests the Chathams have not had a land connection with New Zealand since the late Cretaceous, 70 M years ago. The beetle fauna of the Chatham Islands is clearly very closely related to that of New Zealand, particularly to the extreme southern part, although other recognisable elements are present. The fauna is characterised by relatively high endemicity at the species level (25 %), low endemicity at the generic level (<2 %) and a high degree of flightlessness (90%) among its endemic species. These characteristics appear to make it unlikely that the Chatham Islands have been continuously isolated from New Zealand since the late Cretaceous.