to be known from the New Jersey amber. Three species, Aureofungus yaniguaensis, Coprinites dominicana and Protomycena electra, have been described from the Miocene Dominican amber found in the Dominican Republic. The extinct Agaricomycetes species Quatsinoporites cranhamii, found in marine calcareous concretions on Vancouver Island, Canada, and dating to about 130–125 Mya, is probably in the Hymenochaetales or the Polyporales. In 2007, another agaric was reported, Palaeoagaracites antiquus, found in Early Cretaceous Burmese amber (about 100 Mya). Description The holotypes of Archaeomarasmius consist of mushrooms and associated basidiospores. Specimen AMNH NJ-90Y is a nearly complete mushroom, broken off near the base of the stipe (stem). The pileus (cap) is up to in diameter and has a convex shape sporting an umbo (a broad raised central region). The mushroom is a medium-dark brown color with thin, minutely textured flesh and an incurved margin. The lamellae or gills are distantly spaced, with 12 gills extending fully from the cap edge to the stipe, and lack lamellulae (short gills which do not reach the stipe from the edge of the pileus). The pileus is centered on the stipe, which is long and is broken off above the base. The stipe lacks a veil and is smooth and cylindrical. The top of the pileus is exposed on a fracture plain, and to prevent oxidation, the area was coated in a fine layer of synthetic resin, which also resulted in slightly improved visibility of the mushroom. Specimen AMNH NJ-90Z is a small wedge-shaped fragment of pileus which was accidentally fractured during preparation for study, splitting it in half. Though the researchers had not intended to perform destructive analysis on the sample, this fracturing warranted the sacrifice of some parts of the specimen for structural and molecular study. Small pieces of the specimen were mounted directly on scanning electron microscopy (SEM) stubs and sputter coated with a gold/palladium alloy. The resulting images showed that little intact tissue remained, and only fragmented and crushed basidiospores were seen. Another sample of the specimen was mounted in spurr's resin (an embedding medium used in electron microscopy) and sectioned with a diamond knife; the resulting sections were examined with transmission electron microscopy (TEM). The lack of discernible biological material from the mushroom seen in the SEM study was confirmed in the TEM analysis. A final section of the fossil was selected to attempt DNA sequencing. A small sample of the fossil