The earliest records of internally stratified cyanobacterial and algal lichens from the Lower Devonian of the Welsh Borderland

Abstract

Summary Lichenization is assumed to be a very ancient mode of fungal nutrition, but fossil records are rare. Here we describe two fragments of exceptionally preserved, probably charred, lichen thalli with internal stratification. Cyanolichenomycites devonicus has a cyanobacterial and Chlorolichenomycites salopensis a unicellular, presumably green algal photobiont. Fruiting bodies are missing. Cyanolichenomycites devonicus forms asexual spores in a pycnidium. All specimens were examined with scanning electron microscopy techniques. The fossils were extracted by maceration. Extant lichens and free‐living cyanobacteria were either experimentally charcoalified for comparison or conventionally prepared. Based on their septate hyphal structure, both specimens are tentatively interpreted as representatives of the Pezizomycotina (Ascomycota). Their presence in 415 million yr (Myr) old rocks from the Welsh Borderland predates existing Late Cretaceous records of pycnidial conidiomata by some 325 Myr and Triassic records of lichens with broadly similar organization by some 195 Myr. These fossils represent the oldest known record of lichens with symbionts and anatomy as typically found in morphologically advanced taxa today. The latter does not apply to Winfrenatia reticulata, the enigmatic crustose lichen fossil from the Lower Devonian, nor to presumed lichen‐like organisms such as the Cambrian Farghera robusta or to the Lower Devonian Spongiophyton minutissimum.

Exploring functional contexts of symbiotic sustain within lichen-associated bacteria by comparative omics

“…In contrast, cyanobacterial proteins were much more abundant as expected from the contig counts; they might be more active than other phylogenetic groups. As potential carbon and nitrogen fixing organisms, they are known for a long time as substantial part of lichen symbioses (Honegger et al, 2013).…”

“…The term symbiosis was introduced by Frank (1877) in a study of lichens, which are today considered a classic example for self-sustaining partnerships of species belonging to different kingdoms of life (Nash, 2008). Lichens represent one of most diversified and oldest symbiotic lifestyles of fungi, with more than 18 000 recognized fungal species and a typical stratified morphology that evolved at least 415 million years ago (Honegger et al, 2013). The light-exposed lichen thalli are shaped by outer layers of fungal hyphae, which shelter internalized phototrophic partners.…”

Superhydrophobic hierarchically structured surfaces in biology: evolution, structural principles and biomimetic applications

“…The earliest true land plants had a close association with mycorrhizal fungi, replacing non-existing roots [141]. There is evidence that lichens [142] and ascomycetes [143] came into existence around the same time. Within the large number of extant species, the moulds such as Botrytis, Aspergillus or Penicillium show superhydrophobic surfaces resulting from minute rodlets on the vegetative hyphae, specifically conidiophores ( figure 11).…”

Acritarch Evidence for an Ediacaran Adaptive Radiation of Fungi

“…Despite claims of Butterfield (2005) and Schopf & Barghoon (1969) for evi dence of Precambrian higher fungi (Ascomycota and Basidiomycota), these clades are not convincingly re pre sen ted by Precambrian palynomorphs (Strother et al 2011), and remain unknown older than Silurian (Sherwood-Pike & Gray 1985, Taylor & Osborn 1986, Burgess & Edwards 1991, Taylor & Taylor 2000, Taylor et al 1997, 2014, Honegger et al 2013, Matsunaga et al 2013). …”