The Rhynie chert land plant Aglaophyton majus harbored cyanobacteria in necrotic local lesions

2021 ◽  
Vol 300 (3) ◽  
pp. 279-289
Author(s):  
Michael Krings
Keyword(s):  
Land Plant ◽  
Local Lesions ◽  
Rhynie Chert

scholarly journals History and contemporary significance of the Rhynie cherts—our earliest preserved terrestrial ecosystem

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160489 ◽  
Author(s):  
Dianne Edwards ◽  
Paul Kenrick ◽  
Liam Dolan
Keyword(s):  
Terrestrial Ecosystem ◽  
Analytical Techniques ◽  
Land Plant ◽  
Life Cycles ◽  
Systems Science ◽  
Developmental Genetics ◽  
Earth Systems ◽  
Plant Life ◽  
Rhynie Chert ◽  
Tissue Systems

The Rhynie cherts Unit is a 407 million-year old geological site in Scotland that preserves the most ancient known land plant ecosystem, including associated animals, fungi, algae and bacteria. The quality of preservation is astonishing, and the initial description of several plants 100 years ago had a huge impact on botany. Subsequent discoveries provided unparalleled insights into early life on land. These include the earliest records of plant life cycles and fungal symbioses, the nature of soil microorganisms and the diversity of arthropods. Today the Rhynie chert (here including the Rhynie and Windyfield cherts) takes on new relevance, especially in relation to advances in the fields of developmental genetics and Earth systems science. New methods and analytical techniques also contribute to a better understanding of the environment and its organisms. Key discoveries are reviewed, focusing on the geology of the site, the organisms and the palaeoenvironments. The plants and their symbionts are of particular relevance to understanding the early evolution of the plant life cycle and the origins of fundamental organs and tissue systems. The Rhynie chert provides remarkable insights into the structure and interactions of early terrestrial communities, and it has a significant role to play in developing our understanding of their broader impact on Earth systems. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals Fungi and fungal interactions in the Rhynie chert: a review of the evidence, with the description of Perexiflasca tayloriana gen. et sp. nov. †

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160500 ◽  
Author(s):  
Michael Krings ◽  
Carla J. Harper ◽  
Edith L. Taylor
Keyword(s):  
Three Dimensional ◽  
Terrestrial Ecosystem ◽  
Land Plant ◽  
Biological Degradation ◽  
Microbial Life ◽  
Plant Parts ◽  
Comprehensive Information ◽  
Rhynie Chert ◽  
Fungal Associations ◽  
Fungal Interactions

The Lower Devonian Rhynie chert is one of the most important rock deposits yielding comprehensive information on early continental plant, animal and microbial life. Fungi are especially abundant among the microbial remains, and include representatives of all major fungal lineages except Basidiomycota. This paper surveys the evidence assembled to date of fungal hyphae, mycelial cords and reproductive units (e.g. spores, sporangia, sporocarps), and presents examples of fungal associations and interactions with land plants, other fungi, algae, cyanobacteria and animals from the Rhynie chert. Moreover, a small, chytrid-like organism that occurs singly, in chain-like, linear arrangements, planar assemblages and three-dimensional aggregates of less than 10 to individuals in degrading land plant tissue in the Rhynie chert is formally described, and the name Perexiflasca tayloriana proposed for the organism. Perexiflasca tayloriana probably colonized senescent or atrophied plant parts and participated in the process of biological degradation. The fungal fossils described to date from the Rhynie chert constitute the largest body of structurally preserved evidence of fungi and fungal interactions from any rock deposit, and strongly suggest that fungi played important roles in the functioning of the Early Devonian Rhynie ecosystem. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

A review of the palaeoenvironments and biota of the Windyfield chert

2003 ◽  
Vol 94 (4) ◽  
pp. 325-339 ◽  
Author(s):  
Stephen R. Fayers ◽  
Nigel H. Trewin
Keyword(s):  
Low Temperature ◽  
Plant Species ◽  
Land Plant ◽  
The World ◽  
Arthropod Fauna ◽  
Rhynie Chert

ABSTRACTThe Windyfield chert site is located 700 m NE of the original Rhynie chert locality at Rhynie, Aberdeenshire, Scotland. Originally identified by concentrations of surface float material, a drilling and trenching programme of the area in 1997 revealed a chert ‘pod’ in situ interbedded with fluvial/lacustrine sandstones and hydrothermally altered shales. Chert morphologies identified from float blocks and trench material range from tabular beds to lenticular pods displaying massive, nodular, laminated and brecciated fabrics, and geyserite splash textures. A suite of floral and faunal associations, when combined with distinctive macro- and microscopic chert textures, has been used to interpret depositional conditions. Palaeoenvironments ranged from terrestrial laminated, brecciated and vegetated sinter sheets to low-temperature pools and marginal aquatic settings. The flora comprises six higher land plant species, nematophytes, charophytes, various fungi and probable cyanobacteria. Arthropods include branchiopod crustaceans, a euthycarcinoid, trigonotarbid arachnids, centipedes, eoarthropleurids and a possible hexapod. The biota of the Windyfield chert is closely comparable to that found in the Rhynie chert. Together, the Windyfield and Rhynie cherts contain the most diverse associated fossil arthropod fauna of terrestrial and freshwater origin from rocks of comparable age anywhere in the world.

scholarly journals Archaeosporites rhyniensis gen. et sp. nov. (Glomeromycota, Archaeosporaceae) from the Lower Devonian Rhynie chert: a fungal lineage morphologically unchanged for more than 400 million years

2020 ◽  
Vol 126 (5) ◽  
pp. 915-928 ◽  
Author(s):  
Carla J Harper ◽  
Christopher Walker ◽  
Andrew B Schwendemann ◽  
Hans Kerp ◽  
Michael Krings
Keyword(s):  
Lower Devonian ◽  
Arbuscular Mycorrhizas ◽  
Land Plant ◽  
Thin Sections ◽  
Early Devonian ◽  
Fungal Lineage ◽  
Transmitted Light Microscopy ◽  
Rhynie Chert ◽  
History Of ◽  
Early Land

Abstract Background and Aims Structurally preserved arbuscular mycorrhizas from the Lower Devonian Rhynie chert represent core fossil evidence of the evolutionary history of mycorrhizal systems. Moreover, Rhynie chert fossils of glomeromycotan propagules suggest that this lineage of arbuscular fungi was morphologically diverse by the Early Devonian; however, only a small fraction of this diversity has been formally described and critically evaluated. Methods Thin sections, previously prepared by grinding wafers of chert from the Rhynie beds, were studied by transmitted light microscopy. Fossils corresponding to the description of Archaeospora spp. occurred in 29 slides, and were measured, photographed and compared with modern-day species in that genus. Key Results Sessile propagules <85 µm in diameter, some still attached to a sporiferous saccule, were found in early land plant axes and the chert matrix; they developed, in a similar manner to extant Archaeospora, laterally or centrally within the saccule neck. Microscopic examination and comparison with extant fungi showed that, morphologically, the fossils share the characters used to circumscribe the genus Archaeospora (Glomeromycota; Archaeosporales; Archaeosporaceae). Conclusions The fossils can be assigned with confidence to the extant family Archaeosporaceae, but because molecular analysis is necessary to place organisms in these taxa to present-day genera and species, they are placed in a newly proposed fossil taxon, Archaeosporites rhyniensis.

scholarly journals Bilaterally symmetric axes with rhizoids composed the rooting structure of the common ancestor of vascular plants

2017 ◽  
Vol 373 (1739) ◽  
pp. 20170042 ◽  
Author(s):  
Alexander J. Hetherington ◽  
Liam Dolan
Keyword(s):  
Vascular Plants ◽  
Common Ancestor ◽  
Terrestrial Ecosystem ◽  
Bilateral Symmetry ◽  
Land Plant ◽  
Land Plants ◽  
Free Living ◽  
Rhynie Chert ◽  
The Common ◽  
Almost All

There are two general types of rooting systems in extant land plants: gametophyte rhizoids and sporophyte root axes. These structures carry out the rooting function in the free-living stage of almost all land plant gametophytes and sporophytes, respectively. Extant vascular plants develop a dominant, free-living sporophyte on which roots form, with the exception of a small number of taxa that have secondarily lost roots. However, fossil evidence indicates that early vascular plants did not develop sporophyte roots. We propose that the common ancestor of vascular plants developed a unique rooting system—rhizoidal sporophyte axes. Here we present a synthesis and reinterpretation of the rootless sporophytes of Horneophyton lignieri , Aglaophyton majus , Rhynia gwynne-vaughanii and Nothia aphylla preserved in the Rhynie chert. We show that the sporophyte rooting structures of all four plants comprised regions of plagiotropic (horizontal) axes that developed unicellular rhizoids on their underside. These regions of axes with rhizoids developed bilateral symmetry making them distinct from the other regions which were radially symmetrical. We hypothesize that rhizoidal sporophyte axes constituted the rooting structures in the common ancestor of vascular plants because the phylogenetic positions of these plants span the origin of the vascular lineage. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

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