A comparison of Jurassic marine benthonic faunas from South America and New Zealand

Abstract

Abstract A direct comparison of Jurassic marine bivalves and brachiopods from the Murihiku terrane of New Zealand and the Argentinian-Chilean basins indicates that faunal links between equivalent facies settings of the two regions were even stronger than previously acknowledged. Some faunal elements usually regarded as Maorian endemics are also present in South America, particularly during the Early Jurassic (Aratauran and Ururoan). Middle Jurassic (Temaikan) inoceramid sequences share key elements, probably forming a latitudinally distinct stock. Two successive Retroceramus lineages that repeat general morphological trends are now recognized in South American and New Zealand Middle and Late Jurassic deposits, providing new data on correlation at the Temaikan —Heterian boundary. Since the New Zealand local stage system was based mostly on bivalves, as ammonite faunas are sparse, information from accurately dated Argentinian faunas will help improve correlation with the International Standard. From a paleogeographical point of view, the remarkable degree of faunal exchange suggests the existence of suitable neritic habitats along the margins of Gondwana and is also relevant to the issue of the provenance of New Zealand terranes.