Structurally preserved polypores from the Neogene of North Africa: Ganodermites libycus gen. et sp. nov. (Polyporales, Ganodermataceae)

A new fossil polypore, Ganodermites libycus (Polyporales, Ganodermataceae), occurs in the form of a structurally preserved (permineralized) basidiocarp from the Lower Miocene (Neogene) of Jebel Zelten in the northern part of the Libyan Sahara, North Africa. The basidiocarp is characterized by distinct growth increments, a stratified hymenium, and equidistantly arranged pores. The trimitic hyphal system consists of generative, skeletal, and binding hyphae; clavate pilocystidia regularly occur among the tramal hyphae. The basidia are clavate and (2-)4-sterigmate. They produce ellipsoid, apically truncate basidiospores, which display a two-layered ganodermatoid spore wall. Ganodermites libycus represents the earliest persuasive fossil evidence for polypores closely related to the extant genus Ganoderma, and displays a mosaic of characters seen in modern Ganoderma species. Coprolite-filled tunnels in the basidiocarp indicate that G. libycus was utilized as a food source by fungivorous arthropods or arthropod larvae.