A palaeoenvironmental reconstruction of the Middle Jurassic of Sardinia (Italy) based on integrated palaeobotanical, palynological and lithofacies data assessment

During the Jurassic, Sardinia was close to continental Europe. Emerged lands started from a single island forming in time a progressively sinking archipelago. This complex palaeogeographic situation gave origin to a diverse landscape with a variety of habitats. Collection- and literature-based palaeobotanical, palynological and lithofacies studies were carried out on the Genna Selole Formation for palaeoenvironmental interpretations. They evidence a generally warm and humid climate, affected occasionally by drier periods. Several distinct ecosystems can be discerned in this climate, including alluvial fans with braided streams (Laconi-Gadoni lithofacies), paralic swamps and coasts (Nurri-Escalaplano lithofacies), and lagoons and shallow marine environments (Ussassai-Perdasdefogu lithofacies). The non-marine environments were covered by extensive lowland and a reduced coastal and tidally influenced environment. Both the river and the upland/hinterland environments are of limited impact for the reconstruction. The difference between the composition of the palynological and palaeobotanical associations evidence the discrepancies obtained using only one of those proxies. The macroremains reflect the local palaeoenvironments better, although subjected to a transport bias (e.g. missing upland elements and delicate organs), whereas the palynomorphs permit to reconstruct the regional palaeoclimate. Considering that the flora of Sardinia is the southernmost of all Middle Jurassic European floras, this multidisciplinary study increases our understanding of the terrestrial environments during that period of time

New ginkgophytes from the Upper Triassic–Lower Cretaceous of Spitsbergen and Edgeøya (Svalbard, Arctic Norway): The history of Ginkgoales on Svalbard.

Premise of research. During the ongoing investigation of Upper Triassic–Lower Cretaceous plant macrofossilsfrom Svalbard, Norway, some ginkgoalean leaf fossils were found from Carnian and Aptian deposits ofSpitsbergen and Edgeøya that represent newginkgophyte species. One newspecies is described as Baiera aquiloniasp. nov., and one ginkgophyte leaf is assigned to Ginkgoites sp. Along with the description of the new material,an overview of the presence and distribution of ginkgophytes in the high-latitude ecosystems of Svalbard throughtime is provided.Methodology. The plant macrofossils have been analyzed with transmitted-light and epifluorescence microscopy.Attempts to isolate cuticles were made.Pivotal results. The investigation resulted in the description of one species new to science, Baiera aquiloniasp. nov., and one specimen assigned to Ginkgoites sp. The presence of ginkgophytes on Svalbard changed significantlythrough time: periods of dominance and wide distribution interchanged with periods of very lowdiversity and abundance.Conclusions. Ginkgophytes were thriving in Svalbard, which was already located above 607N by the Carnian,from the Late Triassic to the Cenozoic in varying abundance and were finally extirpated, probably as a result ofdramatic climatic changes at the end of the Paleogene44079

An introduction to Jurassic biodiversity and terrestrial environments

This special issue of Palaeobiodiversity and Palaeoenvironments is devoted to studies of Jurassic terrestrial floras. The special issue Jurassic biodiversity and terrestrial environments includes nine contributions that investigate plant fossils and their spores and pollen from a range of localities across the globe that stratigraphically span the Jurassic (Fig. 1). These papers are a collective contribution to the IGCP project 632: Continental crises of the Jurassic: Major extinction events and environmental changes within lacustrine ecosystems