The diversity and interactions of fungi from the Paleozoic and Mesozoic of Antarctica

Abstract

Fungi are ubiquitous in all ecosystems and are the driving force in many types of interactions, such as mutualists, saprotrophs, parasites, and necrotrophs. Fungi are equally as integral in extant ecosystems as they certainly were in paleoecosystems. Paleomycology, the study of fossil fungi, is an emerging field of paleontology. Most fossil fungi are found in or in close association with plants and thus, paleomycology is also considered a sub-discipline of paleobotany. Therefore when plants are well preserved there is the increase potential to examine their fungal associates. Permineralized material is a preservation type that offers the opportunity to study plants, fungi, and other microorganisms anatomically and morphologically. Prior research suggested that fungi were too fragile and delicate to be structurally preserved in the fossil record; however, fungi have been described in some early paleobotanical studies as dispersed fragments, spores, and other remnants. The taxonomic and ecological affinities of many of these fungi, however, were not described in great detail. The objective of this study is to investigate the fungal components and plant-fungal associations of the Permian, Triassic, and Jurassic of Antarctica. The Paleobotanical Collections at the University of Kansas (KU) house the largest collection of Antarctic permineralized peat deposits in the world. To date, the majority of reports on Antarctic fossil fungi are found in Triassic peat material, with fewer reports on Permian fungi, and are most sparse on Jurassic fungi. These contributions utilized the acetate peel technique, a traditional method of studying permineralized material in paleobotany, and provided a platform for the investigation of microorganisms in ancient Antarctic environments. It has been demonstrated that paleontological thin sections of permineralized peat yields more information on fossil microbes because the fine details of the microorganisms are not etched away as they would be in the acetate peel technique. This study will fully exploit the use of paleontological thin section techniques, as well as preliminary studies using analytical techniques, to discover and describe new fossil fungi and plant-fungal interactions from the Antarctic paleobotanical collections at KU. Despite the large number of fungal remains in the fossil record, including those that provide direct or indirect evidence of an association or interaction with land plants, the discipline of paleomycology is at a relatively early stage of development. As more information is obtained about fossil fungi, including those from Antarctic permineralized peat deports, it will be increasingly possible to present more detailed hypotheses that can be used in association with those described from modern communities, to more accurately depict the role of these organisms in the functioning of early continental ecosystems. Therefore, this study adds new information to our understanding of the diversity of fungi in the Permian, Triassic, and Jurassic of Antarctica, and thus contributes to a more focused concept of the complexity of late Paleozoic and Mesozoic ecosystems.