A review of the Triassic pollen Staurosaccites: systematic and phytogeographical implications

Abstract

Staurosaccites, a highly distinctive pollen genus, ranges from the late Anisian (Pelsonian; Middle Triassic) to the Norian, at low to mid latitudes, globally. Here we review the systematic taxonomy and spatial and temporal ranges of Staurosaccites. We provide an emendation to S. tharipatharensis, synonymise S. minutus with the type species S. quadrifidus, and retain the species S. quadrifidus, S. tharipatharensis, S. densus and S. marginalis. Following comparison with morphologically similar pollen and environmental reconstructions of the habitat of its parent plant, we hypothesise that Staurosaccites was produced by a conifer that was likely adapted to warm and humid conditions. Based on occurrences of diagnostic taxa for the Onslow and Ipswich microfloral provinces in the Southern Hemisphere (Staurosaccites, Camerosporites, Enzonalasporites, Infernopollenites and Ovalipollis), we show that these palynofloras were established in the Middle Triassic. Our findings further suggest that, based on the presence of diagnostic taxa in western Laurasia and their absence in eastern Laurasia, western and eastern Laurasia represent different palynofloral provinces in the Middle Triassic.

Keywords:

• Onslow Microflora
• Ipswich Microflora
• palynology
• bisaccate pollen
• conifer
• phytogeography
• Anisian
• Gondwana
• Laurasia
• Xizang (Tibet) China

Acknowledgements

We thank Li Ye, Feng Limei and Zhang Xuansi (NIGPAS) for technical help in processing the samples from southern Xizang, China.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work received financial support from the National Natural Sciences Foundation of China (NSFC 42002003) and the State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS) (20182110) for JP, from the Swedish Research Council for SS (grant 2019-04524) and VV (grant 2019-04061), and from the Carl Tryggers Stiftelse för Vetenskaplig Forskning for VV and JP (CTS 19: 380).