Implications for high latitude gondwanide palaeozoogeographical studies of some new Upper Cretaceous marine ostracod
faunas from New Zealand and the Antarctic Peninsula
Sixty species of Ostracoda have been recovered from Cenomanian, Santonian and Maastrichtian strata in New Zealand, and late Campanian sediments on Snow Hill and James Ross islands in the Antarctic Peninsula. The two main New Zealand sites are in latest Maastrichtian strata, but in contrasting thermal regimes - warm, shelfal facies at Waipara, and cool, outer shelf/upper slope at Pukehou. The
palaeozoogeographical history of several important taxa across the K/T boundary in Gondwanaland is clarified by the new data: Rostrocytheridea survived at Pukehou to within a few metres of the K/T, while Majungaella was found ~0.5 m from the top of the Maastrichtian at Waipara. The previously-known retrothermal propensities of Majungaella can be traced to the Maastrichtian at Pukehou,
where a similar adaptation is observed in Rostrocytheridea, and possibly in Krithe. The first two genera became extinct across Mesozoic/ Tertiary boundary in Australasia, while in the Patagonia-Antarctic Peninsula region, Majungaella survived and colonised much of the Antarctic seaboard, but Rostrocytheridea probably did not survive into the Palaeogene. The extant genus Ameghinocythere is now
known from late Campanian of Snow Hill Island, and also occurs in the late Maastrichtian in New Zealand. The earliest record of the widely distributed Gondwanide genus Apateloschizocythere is probably from the Cenomanian at Coverham, New Zealand. Nine new species are described: Ameghinocythere lutheri, A. eagari, Apateloschizocythere? colleni, Limburgina postaurora, Majungaella wilsoni,
M. waiparaensis, Parahystricocythere ericea, Rayneria? punctata, Rostrocytheridea pukehouensis and Trachyleberis hornibrooki. The genus Parahystricocythere is new.