Extinct palynomorphs from middle and late Pleistocene terrestrial sediments, South Wanganui Basin, New Zealand

Abstract

The extinct palynomorphs, Acacia-type and. Bryosporis anisopolaris Mildenhall & Bussell n. gen. et sp., are identified and described from middle and late Pleistocene lignite samples in South Wanganui Basin marine-terrace cover beds. The upper time-stratigraphic range of Acacia-type is extended from c. 600 ka to c. 110 ka, and the youngest occurrence of B. anisopolaris is c. 90 ka. These upper ranges are calculated on the basis of ages assigned to the marine terraces and correlations of the sequences of pollen assemblages with the deep-sea oxygen isotope record. The late Pleistocene record of Acacia-type in New Zealand is discussed. These taxa are the youngeslaccepted occurrences of extinct palynomorphs from New Zealand, but neither is particularly useful in Pleistocene biostratigraphy because they occur too sporadically in the pollen record. The last appearance of Acacia-type pollen should no longer be regarded as Okehuan. The presence of these extinct palynomorphs in the middle and late Pleistocene indicates that some fossil pollen assemblages from this period do not have modem analogues in New Zealand on which paleoenvironmental interpretations may be based. Bryosporis may prove to be related to a modem bryophyte. A new combination, Bryosporis (al. Peromonolites) problematicus (Couper) Mildenhall is proposed for a Pliocene -middle Pleistocene bryophyte spore similar to B. anisopolaris.