Evidence for ghost moths and relatives as fragments of a Gondwana biota (Lepidoptera: Exoporia)
It is easy enough to understand that New Zealand is made up of geological fragments of what was formerly East Gondwana. New Zealand is a collage of different rock types. These include a western block derived from Gondwana continental rocks (mostly in Fiordland and NW Nelson) along with a series of terranes made up of material of Pacific origins that collided with coastal Gondwana between Triassic and Cretaceous times (Fig. 1). When the Tasman Sea began to open 80-55 million years ago it cut across these continental and terrane portions and isolated some within the block that included New Zealand. Originally these geological provinces formed a series of more or less parallel belts running north-south until they were displaced when the Alpine Fault became active about 23 million years ago. This fault was located at a new plate boundary between the Indo-Australian Plate and the Pacific Plate. It formed as a result of pressure from another geological structure, the Hikurangi Plateau, that moved west until obliquely colliding with the eastern edge of East Gondwana about 75 million years ago. This collision imposed a region of geological stress called the Emerald Fracture Zone which was a precursor to the Alpine Fault. It is possible that we have the Hikurangi Plateau to thank for New Zealand even existing as more than a few scattered subaerial volcanoes. Most of the remaining section of East Gondwana that was separated by the Tasman Sea became submerged due to tectonic collapse, as the original land was stretched over an ever-wider area by various sea basins (see Heads 2017 for detailed account of tectonic history of the Southwest Pacific).