Margaretbarromyces dictyosporus gen. sp. nov.: a permineralized corticolous ascomycete from the Eocene of Vancouver Island, British Columbia.

A single, permineralized ascoma resembling a pseudothecium assignable to the Pleosporales is described from the Eocene Appian Way fossil locality on Vancouver Island, British Columbia. The ascoma is globose, ostiolate, and erumpent on a fragment of the bark from an unidentified seed plant. Basally arranged asci contain large, multicelled, obovate ascospores within a single cavity or locule enclosed by a two-layered pseudoparenchymatous tissue that ostensibly represents ascostroma. Given this interpretation of the specimen's morphological features, Margaretbarromyces dictyosporus gen. sp. nov. represents the first report of a corticolous pleosporalean ascoma in the fossil record.