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New Zealand Evolutionary Evidence

| Modern Examples | Fossil Evidence | Museum News |

New Zealand Fossil Evidence

New Zealand evolutionary evidence from the Cambrian Period: During the Cambrian, evolution was rapid and within a few million years the Earth was populated with many animal groups. Fossils found elsewhere indicate that the marine ancestors of New Zealand's ancient land dwelling caterpillar-like Peripatus were alive at that time. Cambrian deposits in the Cobb Valley, in north-west Nelson of the South Island are the oldest accurately dated geological formations in New Zealand. Some associated sequences occur in small areas in the southwest of Fiordland. The fauna typically consist of Trilobites, Brachiopods, Sponges and Ostracods. Be aware that the rocks in the Cobb Valley are protected and specimen cannot be removed.

New Zealand fossils from the Ordovician Period: During the Ordovician New Zealand was situated about 20 north of the equator. All life on Earth was still in the sea. The sediments that were to become New Zealand formed a shallow sea shelf off the coast of Gondwana. Well defined Ordovician rocks, characterised by Graptolite faunas can be found in the Nelson region and the south west of Fiordland.

New Zealand fossils from the Silurian Period: By Silurian times Gondwana had brought New Zealand into the southern Hemisphere. As marine creatures began to adapt to changing temperatures and salinity, they were preparing themselves for life on land. At Hailes Knob, to the west of Motueka a few Silurian fossils, shellfish and trilobites have been found. There is a boulder by the roadside before the entrance to the Takaka Gorge, in the Cobb Valley, Nelson, which shows folds of marble and sandstone. It is possible to see a few tiny shellfish and crinoid stems in this rock.

New Zealand fossils from the Devonian Period: Today there are only two small areas of Devonian rocks to be found in New Zealand, the Baton formation, north-west of Nelson and the Reefton Mudstones and Limestone in the South Island. Devonian corals in the region indicate that the seas were warm. Approximately 6.5 kilometres southeast of Reefton and 1.4 kilometres from Lankey Creek, the main road to Lewis Pass cuts through a dark limestone bluff beside the Inangahua River, where corals can be seen in the limestone. Some Devonian fish have been found in rocks of the Waitahu Valley, near Reefton.

New Zealand fossils from the Carboniferous Period: The Carboniferous period of Gondwana produced immense coalfields in Australia. New Zealand was back then still submarine and continued a movement to the south. The seas around New Zealand were very cold, forcing the sea life to adapt or die. The New Zealand seascape, lying off the south eastern coast of Gondwana included a chain of volcanic islands that were very active late in the period. This volcanic activity probably obscured any deposits of sediments of that time, explaining the absence of Carboniferous rocks in New Zealand.

New Zealand fossils from the Permian Period: Permian rocks are widely distributed in New Zealand's South Island and also occur in the Northland region of the North Island, where they are the oldest known rocks. In some places the deep sedimentary marine series that was laid down is up to 20 kilometres thick and one of the most complete Permian sequences preserved anywhere in the world. The biggest build up of volcanic rocks made the Takitimu Mountains near Redcliff, Waiau Valley, where the pile of tuff layers is 14 kilometres thick. Unfortunately Permian fossil outcrops are hard to find, but at Arthurton, near Gore, complete shells of Atomodesma, a bivalve, can be found. And of course a whole leaf of the Glossopteris plant has been found at Productus Creek.

New Zealand fossils from the Triassic Period: New Zealand was still mainly a marine environment, but parts began to rise out of the sea, while volcanic activity continued. Some of the ancient forms of kauri, rimu, totara and kahikatea trees colonised the land. In the rocky shore platform at Kiritehere Beach on the Waikato west coast, beds of a scallop-like bivalve, Monotis and prehistoric mussels can be found. No terrestrial vertebrates were preserved in the sediments, but Ichthyosaurus a marine reptile has been found in the Mt Potts region in the South Island. And at Nothosaur Stream, Mt Harper, Canterbury, a Nothosaur, a primitive amphibious sea lizard has been found.

New Zealand fossils from the Jurassic Period: In the Jurassic sediments that had accumulated offshore between the east of Antarctica and the west of Australia were squeezed together by several tectonic plates. They were consolidated and pressured into huge folds and uplifted and formed a New Zealand microcontinent called Tasmantis. It is likely that plants and animals travelled freely across the land and the subsequent isolation of New Zealand suggests that the archaic frogs, large land snails, tuatara and peripatus are all living fossils that stem back from those times. An ancestor to the New Zealand Weta has been found in late Jurassic rocks at Port Waikato. The first late Jurassic dinosaur was found in the Huriwai Plant Beds. The bone that is similar in shape and size to that of a Compsognathus is very rare but indicates that dinosaurs were living around New Zealand.

New Zealand fossils from the Cretaceous Period: About 120 million years ago waterways developed between the edge of Gondwana and the new uplifted Tasmantis including the piece that became New Zealand. Because of the increasing distance that separated ancestral New Zealand from Antarctica the biota it took was purely Cretaceous which subsequently experienced an evolution-in-isolation. Some of the Cretaceous concretions contain bones of marine reptiles. In inland Hawkes Bay enough bones have been collected to identify a new species of mosasaur. Also a single vertebra was found to be that of an upright carnivorous land dinosaur. At Oaro, south of Kaikoura, the sea is eroding late Cretaceous rocks just north of Amuri (or Haumuri) Bluff. They contain layers of belemnites, bones and shark teeth. Examples for K-T boundary can be seen in the rocks of the Te Uri Stream in Hawkes Bay and in Waipara, North Canterbury as well as south of Chancet Rocks at Woodside Creek. However in all those three locations the passage of time is shown by microscopic fossils, mostly Foraminifera which are intercepted by a layer of clay that contains Iridium.

New Zealand fossils from the Paleocene Epoch: During the early Palaeocene the seafloor spreading in the Tasman Sea had stopped. Much of the New Zealand landscape eroded away and sank. This happened probably because New Zealand's now separated crust was thinner (about 26 km) than that of the Gondwana landmass (about 37 km). New Zealand fossils from the Palaeocene include the marker fossil Conchorthyra, an ancestor of the ostrich foot shell which survived throughout the K-T events. Another survivor of the K-T boundary were turtles which lineage goes back 230 million years. Fossil turtles bones have been found in New Zealand from Cretaceous up until Miocene rocks.

New Zealand fossils from the Eocene Epoch: At the beginning of the Eocene, New Zealand and New Caledonia were remotely connected by a series of islands, sharing plant and animal life from their joint Gondwana heritage. New Zealand continued to erode and sink while drifting into a warmer climate. This is the time when the coalfield of Huntley and the natural gas and oil fields of southern Taranaki were formed. Leaves of pohutukawa and rata, manuka, kanuka and eucalyptus have been found in Eocene coal deposits as well as fossil pollen of Seaforthia the ancestor of the nikau palm tree. New Zealand's ancient whales such as Basilosaurus were long slender giants whose vertebrae and teeth are occasionally found in Eocene limestones of South Canterbury.

New Zealand fossils from the Oligocene Epoch: Two thirds of modern day New Zealand were submerged during the Oligocene, the movement of the tectonic plates in the north of New Zealand caused big areas of oceanic crust to be subducted, pushed into as well as over the northern and western parts of the North Island. The little land that was left during the Oligocene was home to a decreasing number of species. Many died but some snails, peripatus, frogs, tuatara and ratites survived. A similar scenario happened to the plants on land, and here the warmth loving beech trees became dominant. Large sea urchins, giant oysters, crayfish, molluscs and giant sharks (up to 13 metres) thrived in the shallow seas. The fossilised shells of giant oysters can be found in limestones on the Coromandel Peninsula at Waitete Bay in the shore platform at low tide.

New Zealand fossils from the Miocene Epoch: Around the mid-latitudes of the Southern Hemisphere prevailing westerly winds established during the Miocene. These winds, and the associated ocean currents, aided the transfer of Australian plants and animals across the Tasman Sea, and have been very important in bringing South American taxa to Australasia e.g. kowhai (Sophora) has salt-resistant seeds and colonized New Zealand from Chile. The long-tailed bat reached New Zealand from Australia in the Miocene, as did the geckos and the ancestor of the takahe, which later evolved both gigantism and flightlessness as adaptations to island life. In the seas, the giant crab Tumidocarcinus giganteus, five times the size than the modern purple rock crab, flourished. Fossilised crabs have been found near Taumaranui in the North Island and Motunau and Glenafric in the South Island.

New Zealand fossils from the Pliocene Epoch: New Zealand's geography changed rapidly during the Pliocene. There was widespread volcanic activity, particularly in the North Island (although Banks Peninsula and Port Chambers, both volcanic calderas, formed at this time), and both the Southern Alps and the Kaikoura Ranges began to form. This was important in the evolution of New Zealand's plants and animals as it split the South Island longitudinally into a wetter western side and a drier, flatter eastern side. The late Pliocene was also a period of rather high sea levels, so that NZ was divided into a series of islands. The consequent isolation of species populations that could then diverge into separate species or subspecies accounts for some of the biodiversity and also many of the distribution patterns of our modern biota. The Hebe family made its first appearance during the Pliocene while many warmth loving plants were extinct. Fossils of giant spider crabs have been found in the Wanganui River, Cape Kidnappers and in rocks of inland central Hawke's Bay. Theses animals preferred deep, cold water and are an indication that New Zealand's climate was moving towards an Ice Age.

New Zealand fossils from the Pleistocene Epoch: Throughout the Pleistocene there were about twenty cycles of cold glacial (Ice Age) and warm interglacial periods at intervals of about 100,000 years. During the Ice Ages glaciers dominated the landscape, snow and ice extended into the lowlands, transporting huge quantities of rock with them. During these periods the South Island was extensively glaciated, and there were small glaciers on the Tararua Ranges and Central Plateau. Because a lot of water was locked up in ice, the sea levels dropped during the glacials (up to 135m lower than at present). Extensive land bridges joined the main and many offshore islands, allowing the migration of plants and animals. During the warmer periods large areas became submerged again under water. These repeated episodes of environmental fragmentation drove rapid adaptive radiation in many NZ species, especially (but not exclusively) the alpine plants.

Coastal areas such as Hawke's Bay, Bay of Plenty, Wairarapa, Wanganui, Marlborough and North Canterbury have only been pushed up to become land in the last 50,000 years. Rich deposits of beautifully preserved Pleistocene sea shell fossils can be found from Te Piki (East Cape), Te Mata Peak, Cape Kidnappers and Castlecliff (Hawke's Bay), Castlepoint (Wairarapa Coast), Hawera and Wanganui, Motunau Beach (Marlborough) and at Titarangi, (Chatham Islands). They are evidence for shallow, sandy bottom seas. The cliffs of the Rangitikei River represent layers of Plio- and Pleistocene rocks, uplifted sea floors that have been eroded by the river exposing many shell and mollusc fossils.

New Zealand fossils from the Holocene Epoch: The Holocene period represents the last 8,000 years, a very short time for fossils to form. Holocene fossils are often modern species that have fallen down holes into underground caves and been preserved. Extinct species like the Moa, the giant eagle, a native goose, reptiles, frogs and bats have all been found in Holocene limestone caves. Fossil bones of the king shag, Leucocarbo carunculatus, are reported from the late Holocene dune deposits of Tokerau Beach, Doubtless Bay, Northland.


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