was extracted at the AMNH and sent to the Peabody Museum of Archaeology and Ethnology for DNA amplification. None of the three selected extracts showed any results after the amplification was attempted. It is possible that the fractures and flowlines which split AMNH NJ-90Z during initial preparation had already penetrated into the fossil and destroyed the hermetic seal which would have been needed for preserving the organic matter of the mushroom. The basidiospores recovered with the fruiting body were examined during the SEM study. The spores showed considerable damage from both the fossilization process and the subsequent weathering and specimen collection. They also displayed distinct halos in the amber, possibly from gas or liquid leaching out, or a reaction in the spores that prevented the resin from turning to amber. Even so, enough remained to make some observations about spore morphology. The basidiospores are broadly elliptic to oval, measuring approximately 7.3 by 4.7 μm, and each shows a distinct hilar appendage. The combined characters of Archaeomarasmius indicate a relation to the modern family Tricholomataceae, with a close similarity to the genera Marasmius and Marasmiellus. Both genera are noted for marcescence, toughening and drying, rather than putrifying. This property would increase the chances of a mushroom becoming entombed in amber. However, a number of other species are also possible close relatives of Archaeomarasmius, mostly in Tricholomataceae, although some species in the family Strophariaceae are also marasmioid. The authors suggest it may also be appropriate to classify Archaeomarasmius more conservatively as incertae sedis (of uncertain placement) within the Tricholomatoceae, Agaricales, or Homobasidiomycetes. Associated inclusions The amber specimen "AMNH NJ-90", which preserved the two holotypes, also preserved a number of other inclusions that give indications as to what the ecology of Archaeomarasmius may have been. Of the approximately forty insect inclusions present, flies in the families Ceratopogonidae and Chironomidae, together with caddisflies of the order Trichoptera, suggest that the mushroom was growing near fresh water. Beetles from the family Elateridae, a termite and a pseudoscorpion, in addition to the mushroom, are indicators of rotting wood, probably from a tree in the family Cupressaceae. Modern Marasmiaceae members are saprobic—obtaining nutrients by breaking down organic matter—and specimens included with Archaeomarasmius indicate a similar habit for the mushroom. See also List of Tricholomataceae genera References Archaeomarasmius †Archaeomarasmius Prehistoric fungi Fossil taxa described in 1997 Cretaceous fungi Monotypic Agaricales genera New Jersey amber