The otolith assemblage of the Cenozoic of New Zealand ranks as one of the largest known on a worldwide scale to date and is the richest from the southern hemisphere. A total of 426 otolith-based species have been identified from the Cenozoic marine strata of New Zealand based on about 25,000 individual specimens studied. The collections span a time interval from the Early Eocene to the Pleistocene, and a single otolith from the Paleocene. Of those, 150 species are new to science, 53 represent extant species also known from the fossil record and 74 species remain in open nomenclature. One of the main purposes of this monograph is to present a fully updated and comprehensive handbook for the fossil marine Cenozoic otoliths of New Zealand documented in instructive and clear photographs of all species recognized. Another focus is the reconstruction of past fish faunas of New Zealand. During Eocene, the fish fauna of Zealandia represented the southeasterly extension of a large former Tethyan bioprovince. Endemic elements, however, already played an important role but most of the lineages are now extinct. The first immigration from the west occurred in Late Eocene when the Tasman Gateway commenced to leak. After a gap of records over a period of 7 myr from the Early Oligocene, the Late Oligocene and Early Miocene fish fauna is the richest observed. In this period, New Zealandian endemism flourished in the southern Canterbury Basin while the Northland Basins came under the influence from the tropical Indo-West Pacific. The full opening of the Tasman and Drake Gateways facilitated an increased dispersal of temperate faunas along the proto-circum-Antarctic current, which is clearly marked in New Zealand by the arrival of new immigrants, partly originated from the northern hemisphere. The rise of a Southern Ocean temperate mesopelagic faunal component (Myctophidae) is witnessed during this time. A gradual shift to more temperate Southern Ocean-dominated fish assemblages is observed during the Late Miocene, Pliocene and Pleistocene. New Zealandian endemisms remained strong, and all lineages of that time persist until today. The Pliocene saw an increased immigration of exotic temperate water fishes from the North Atlantic, South Atlantic and South Africa along the circum-Antarctic faunal conveyor belt, probably triggered by changes of the intermediate and deep-water ocean circulation as a result of the shoaling of the Central American and Indonesian Gateways. A group of particular interest is the mesopelagic family Myctophidae which is considered useful for establishing a superregional biostratigraphic scheme based on otoliths because of their abundance and wide distribution. They dominate practically all otolith associations below 100-200 m in the Neogene where they have shown phases of rapid speciation, particularly during the times of the biogenic bloom in the world oceans in late Miocene and Pliocene. Their fossil record is rich in the Neogene of New Zealand and the data now retrieved are used to a formulate a first otolith biozonation for the southern temperate and subtropical faunal belts. |
