Millifrumaceae

Millifrumaceae is a proposed family of fossil fungi. Its placement within fungal phylogeny is uncertain, as it is known only from the fossil record. The type genus, Millifruma, is characterized by spherical to subspherical fruiting bodies, known as apothecia, which are typically less than a millimeter in diameter. These apothecia contain asci, the spore-bearing cells, which are often clavate and contain ascospores. The ascospores themselves are usually hyaline and filamentous or thread-like, giving the genus its name.

Fossils attributed to Millifrumaceae have been found in various geological formations, often associated with amber inclusions. These discoveries suggest that the fungi existed during the Mesozoic and possibly earlier periods. The ecological role of Millifrumaceae is not well understood, but their presence in fossilized plant material, particularly wood, hints at a saprotrophic lifestyle, decomposing organic matter.

The taxonomic classification of Millifrumaceae has been debated. Some researchers have suggested affinities with certain extant orders of Ascomycota, based on morphological similarities of the fruiting bodies and spores. However, the lack of molecular data from these ancient fossils makes definitive phylogenetic placement challenging. Continued paleontological research and advancements in fossil analysis may provide further insights into the evolutionary history and relationships of this extinct fungal group.