DOI: 10.5061/dryad.1mn51s6
title: Data from: Lycopsid megaspores from the Upper Triassic of Svalbard and their relationship to the floras and palaeoenvironments of northern Pangaea

description: Triassic megaspore assemblages from Svalbard, Arctic Norway, are described
 for the first time based on the analysis of the Upper Triassic
 (Carnian–Norian/Rhaetian) Kapp Toscana Group on the island of Hopen. Two
 megaspore zones are described: the late Carnian ‘Dijkstraisporites
 beutleri Zone’ (undifferentiated De Geerdalen Formation), and the
 Norian/Rhaetian ‘D. beutleri – Verrutriletes preutilis Zone’ (Svenskøya
 Formation). Megaspores are attributed to heterosporous lycopsids, and
 likely correspond to the microspore Aratrisporites, which was observed in
 palynological preparations. Megaspore occurrence was highest in
 delta-plain and associated with lake-mire deposits. However, their close
 association with marine microfossils suggests episodic marine influence,
 and is consistent with previous interpretations that some Triassic
 lycopsids occupied marginal marine habitats. The absence of megaspores in
 the overlying Hopen Member and Flatsalen Formation is likely related to a
 marine transgression during the early Norian, as indicated by the recovery
 of low diversity assemblages of agglutinated foraminifera. The transition
 to ostracod-dominated microfaunas in the middle part of the formation is
 consistent with a regionally extensive maximum flooding surface, prior to
 a return to megaspore-dominated assemblages in the fluvio-deltaic deposits
 of the Svenskøya Formation. Despite the abundance of their mega- and
 microspores, lycopsid fossils are almost entirely absent within
 palaeobotanical collections from the island, which we ascribe to their
 herbaceous habit and consequent low preservation potential. The results of
 this study show lycopsids to be an important component of the local
 ecosystem and thus contribute to a more complete understanding of the Late
 Triassic floras of northern-most Pangaea.
description: Supplement 1. Binnedalen
 range chartMicropalaeontological
 and micro-biofacies distribution chart for the Binnedalen section, Hopen.
 Microfossil occurrences marked with an asterisk were previously reported
 in Paterson et al. (2016). Relative abundances of palynomorph groups are
 based on Paterson & Mangerud (2015). Sedimentary log after Mørk et al.
 (2013).Supplement 2.
 Lyngefjellet range chartMicropalaeontological
 and micro-biofacies distribution chart for the Lyngefjellet section.
 Microfossil occurrences marked with an asterisk were previously reported
 in Paterson et al. (2016). Relative abundances of palynomorph groups are
 based on Paterson & Mangerud (2015). Sedimentary log after Mørk et al.
 (2013).Supplement 3. Blåfjell
 range chartMicropalaeontological
 and micro-biofacies distribution chart for the Blåfjell section.
 Microfossil occurrences marked with an asterisk were previously reported
 in Paterson et al. (2016). Relative abundances of palynomorph groups are
 based on Paterson & Mangerud (2015). Sedimentary log after Mørk et al.
 (2013).Supplement 4. Gåskaret
 range chartMicropalaeontological
 and micro-biofacies distribution chart for the Gåskaret section.
 Microfossil occurrences marked with an asterisk were previously reported
 in Paterson et al. (2016). Relative abundances of palynomorph groups are
 based on Paterson & Mangerud (2015). Sedimentary log after Mørk et al.
 (2013).Supplement 5.
 Iversenfjellet range chartMicropalaeontological
 and micro-biofacies distribution chart for the Iversenfjellet section.
 Microfossil occurrences marked with an asterisk were previously reported
 in Paterson et al. (2016). Relative abundances of palynomorph groups are
 based on Paterson & Mangerud (2015). Sedimentary log after Mørk et al.
 (2013).Supplement 6. List of
 specimensList of figured
 megaspore and microspore specimens from Hopen with sample heights,
 localities, Palaeontological Museum Oslo numbers and England Finder slide
 coordinates.Supplement 7. SEM stub
 mapSEM stub map showing the
 position of megaspore specimens illustrated in Paterson et al. (2018, FIG.
 9). SEM stubs curated by the Natural History Museum, Oslo,
 Norway.