Fossil Mycelium with Clamp Connections from the Middle Pennsylvanian

Abstract

A mycelium with clamp connections and chlamydospores has been discovered within the wood of a Middle Pennsylvanian fern. This suggests that forms extant in the middle of the Pennsylvanian had life cycles conparable to some modern Basidiomnycetes.

Oldest fossil basidiomycete clamp connections

“…The hyphae and clamp connections are somewhat similar to those described by Dennis (1969Dennis ( , 1970, but are Middle Mississippian (*330 Ma) in age, and thus approximately 25 Ma older than the oldest direct fossil evidence of Basidiomycota.…”

“…However, fossil evidence for this hypothesis has been exceedingly slow to accumulate, and is largely restricted to records from the Mesozoic (Osborn et al 1989;Hibbett et al 1997;Krassilov and Makulbekov 2003;Poinar and Brown 2003;Smith et al 2004) and Cenozoic (Poinar and Singer 1990;Magallón-Puebla and Cevallos-Ferriz 1993;LePage et al 1997;Hibbett et al 2003;Fleischmann et al 2007). To date the oldest undisputed basidiomycete body fossil is Palaeancistrus martinii from the Middle Pennsylvanian (Dennis 1969(Dennis , 1970.…”

Extensive genetic divergence associated with speciation in filamentous fungi

“…(ii) These groups represent ancient lineages. The scanty fossil data for the Basidiomycotina places them back to the Pennsylvanian, 300 million years before present (25). The complex mating relationships and range of DNA hybridization values observed in our study suggest that there are several species in the C. dryophila group.…”

First record of fossil basidiomycete clamp connections in cordaitalean stems from the Asselian–Sakmarian (lower Permian) of Shanxi Province, North China

“…According to the presence of callosities in some host cells in the cortical tissues of Botryopteris antiqua, Krings et al (2011a) suggested that the plant was alive at the time the Visean basidiomycetous fungi invaded the tissues, and the fungi could have been biotrophic or saprotrophic. Dennis (1969Dennis ( , 1970 documented a well-preserved basidiomycete in a fern (Zygopteris illinoiensis) rhizome from the Middle Pennsylvanian of North America, and formally described it as Palaeancistrus martinii. Individual hyphae are conspicuously elongate and bear well-defined clamp connections.…”

“…In these cases, the disease symptoms, rather than evidence from the actual fungi, have been used to interpret their systematic affinities of the hyphae (Krings et al, 2011a). There are only three records of basidiomycetous fungi associated with the late Palaeozoic plants, which are surprisingly all from ferns (Dennis, 1969(Dennis, , 1970Barthel et al, 2010;Krings et al, 2011a).…”