An introduction to the Rhynie chert

Abstract

The terrestrialization of life has profoundly affected the biosphere, geosphere and atmosphere, and the Geological Magazine has published key works charting the development of our understanding of this process. Integral to this understanding – and featuring in one of the Geological Magazine publications – is the Devonian Rhynie chert Konservat-Lagerstätte located in Aberdeenshire, Scotland. Here we provide a review of the work on this important early terrestrial deposit to date. We begin by highlighting contributions of note in the Geological Magazine improving understanding of terrestrialization and Palaeozoic terrestrial ecosystems. We then introduce the Rhynie chert. The review highlights its geological setting: the Caledonian context of the Rhynie Basin and its nature at the time of deposition of the cherts which host its famous fossils. There follows an introduction to the development of the half-graben in which the cherts and host sediments were deposited, the palaeoenvironment this represented and the taphonomy of the fossils themselves. We subsequently provide an overview of the mineralization and geochemistry of the deposit, and then the fossils found within the Rhynie chert. These include: six plant genera, which continue to provide significant insights into the evolution of life on land; a range of different fungi, with recent work starting to probe plant–fungus interactions; lichens, amoebae and a range of unicellular eukaryotes and prokaryotes (algae and cyanobacteria); and finally a range of both aquatic and terrestrial arthropods. Through continued study coupled with methodological advances, Rhynie fossils will continue to provide unique insights into early life on land.

Morphological diversity of fungal reproductive units in the Lower Devonian Rhynie and Windyfield cherts, Scotland: a new species of the genus Windipila

“…411.5 ± 1.3 to 407.6 ± 2.6 million years old according to Mark et al (2011Mark et al ( , 2013 and Parry et al (2011), which is in broad agreement with spore assemblages indicating that the cherts date from the middle Pragian to lower Emsian stages of the Lower Devonian according to Wellman (2006Wellman ( , 2017 and Wellman et al (2006). For details on the geology, development, and paleontology of the Rhynie chert Lagerstätte, refer to Trewin and Kerp (2017), Edwards et al (2018), and Garwood et al (2019).…”

An evidence-based 3D reconstruction of Asteroxylon mackiei the most complex plant preserved from the Rhynie chert

“…(i) The body plan of A. mackiei was similar to the cosmopolitan members of the Drepanophycales found across America, Europe and China in the Early and Middle Devonian Li and Edwards, 1995;Tomescu, 2017, 2016;Rayner, 1984;Schweitzer, 1980;Schweitzer and Giesen, 1980;Xu et al, 2013;Xue et al, 2016). This suggests that despite inhabiting the Rhynie geothermal wetland ecosystem (Edwards et al, 2018;Garwood et al, 2020;Rice et al, 2002;Strullu-Derrien et al, 2019;Wellman, 2018), mechanisms of body plan construction in A. mackiei likely also operated in other Devonian Drepanophycales. (ii) We demonstrate that rooting axes originated from root-bearing axes by dichotomy.…”

The overlooked aquatic green algal component of early terrestrial environments: Triskelia scotlandica gen. et sp. nov. from the Rhynie cherts

“…The Rhynie Basin is an outlier of Lower Old Red Sandstone situated about 50 km north‐west of Aberdeen, Scotland (see Garwood et al . (2019) for basin setting overview). It contains an estimated 1400 m of predominantly fluvial conglomerates, sandstones and shales, but the exceptionally preserved biota is mostly confined to a series of fossiliferous cherts in the 300 m thick Windyfield Shales Member of the Dryden Flag Formation (Rice & Ashcroft 2004).…”

“…2018; Garwood et al . 2019). The community of microorganisms at the Rhynie locality is varied and includes cyanobacteria (Croft & George 1959; Krings et al .…”