A boreal early cradle of Angiosperms? Angiosperm-like pollen from the Middle Triassic of the Barents Sea (Norway)

Peter A. Hochuli,Susanne Feist-Burkhardt

doi:10.1144/jm.23.2.97

Peter A. Hochuli, Susanne Feist-Burkhardt

Open Access

https://doi.org/10.1144/jm.23.2.97

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Abstract

Abstract. The origin of flowering plants is still a matter of dispute. Several lines of evidence suggest that their origin may go back to the Triassic. This paper reports on pollen grains with angiosperm-like morphologies from marine Middle Triassic sediments of the Boreal Realm (Norwegian Arctic, Barents Sea area). The morphology of these pollen grains is comparable to forms recorded from the Early Cretaceous, which are generally attributed to angiosperms. The new finds of angiosperm-like pollen are the earliest in the fossil record so far and show an astonishing high diversity. In contrast to other early records, they come from high palaeolatitudes with an inferred warm-temperate climate. The new finds suggest the presence of the first angiosperms during the Middle Triassic (242–227 Ma) or, alternatively, provide evidence for an as-yet unknown group of gymnosperms, possibly an extinct sister group of the flowering plants.

Highlights

Pollen grains of angiosperm-like morphology have been found in Middle Triassic deposits from exploration wells and shallow cores from the boreal Norwegian Arctic (Fig. 1)
MATERIAL AND METHODS The described angiosperm-like pollen grains are quite rare, with about 20 specimens in glycerine jelly strew mounts available for MORPHOLOGICAL DESCRIPTION AND COMPARISON The morphological analysis shows the similarities of these pollen grains to extant and fossil angiosperm pollen
The pollen grains are characterized by a distinct reticulate sexine and an extremely thin nexine, which seems to be missing in some types

Summary

Introduction

Pollen grains of angiosperm-like morphology have been found in Middle Triassic deposits from exploration wells and shallow cores from the boreal Norwegian Arctic (Fig. 1). The pollen occur regularly, are very rare in a limited stratigraphic interval, in deposits of Anisian–Ladinian age. These pollen types were first reported within a biostratigraphic context as Retisulcites sp. A morphological study shows their similarities to angiosperm pollen and reveals an unexpected diversity. The discovery of these angiosperm-like pollen grains of Triassic age provides important fossil evidence for the yet-unsolved scientific puzzle of the origin of flowering plants

Methods

Discussion

Conclusion