A new early Paleocene dinoflagellate cyst species, Trithyrodinium partridgei: its biostratigraphic significance and palaeoecology

Abstract

A palynological investigation of lower Paleocene (lower Teurian) marine sediments of the Abbotsford Formation, exposed in the Fairfield Quarry, Dunedin, New Zealand, reveals a well-preserved association of dinoflagellate cysts and miospores. Thirty-six dinoflagellate species representing 26 genera were recorded, including one new peridinioid dinoflagellate species, Trithyrodinium partridgei characterized by a three-layered wall and a distinct brown, foveolate mesophragm. Trithyrodinium partridgei has a narrow range and at Fairfield Quarry co-occurs with typical New Zealand late Danian to Selandian index species such as Glaphyrocysta perforata and Alterbidinium pentaradiatum; hence it may prove an additional useful stratigraphic marker. The terrestrial palynomorph assemblage from samples within the range of Trithyrodinium partridgei includes 36 spore-pollen species dominated by the podocarp pollen Phyllocladidites mawsonii. The presence of Nothofagidites waipawaensis and Tricolpites phillipsii confirms a Paleocene age for the assemblage. The abundance of terrestrial palynomorphs and the composition of the dinocyst assemblages suggest a marine nearshore depositional environment.

Key words:

• Paleocene
• palynology
• dinoflagellate cyst
• miospores
• biostratigraphy
• palaeoecology
• New Zealand

Acknowledgements

This palynological study was part of a multidisciplinary research program supported by the New Zealand Marsden Fund and the Lund University Center for Studies of Carbon Cycle and Climate Interactions (LUCCI). Drs Poul Schiøler, Hamid Slimani and Ian Raine are thanked for constructive critiques that considerably improved this paper. Dr Graeme J. Wilson (GNS) and Dr Ian Raine (GNS) are acknowledged for sharing their extensive knowledge of Mesozoic–Cenozoic palynology. PSW thanks Dr Alan Partridge for helpful discussions. Dr S. McLoughlin is thanked for his editorial assistance. Roger Tremain (GNS) and Erica Vry are thanked for technical assistance, Dr Simon McMillan for assistance with fieldwork during the senior author's PhD project. PSW acknowledges support from the Carlsberg Fundation (grant no. 2008-01-0404) and LUCCI centre. VV acknowledges support from the Swedish Royal Academy of Sciences through the Knut and Alice Wallenberg Foundation.