Amber fossils of sooty moulds

Sooty moulds are saprophytic ascomycetes with brown hyphae, often forming extensive subicula on living plant surfaces. These fungi grow on plant exudates and honeydew secreted by sap sucking insects and are ubiquitous in many humid terrestrial ecosystems. Here, we review previously published specimens of sooty moulds and provide new fossil evidence that traces the fossil record of these fungi for about 100 million years, from the early Miocene (17 million years) to the Early Cretaceous (Albian, about 100 to 113 million years). Investigation of Mesozoic and Cenozoic ambers from different parts of the world revealed sooty moulds from eight northern hemisphere amber deposits. Fragments of superficial subicula composed of smooth brown moniliform hyphae with tapering distal ends identical to those produced by extant species in the family Metacapnodiaceae (Capnodiales) are recorded since the Albian. The fossil fungi originate from tropical to temperate coastal forests where they grew on leaves and bark of different conifer and angiosperm trees. This indicates that capnodialean sooty moulds have occupied their specialized niche since at least from when early angiosperms appeared in the fossil record.