Fungal sporocarps from the Carboniferous: An unusual specimen of Traquairia

Small spherical structures commonly termed sporocarps are widespread elements in Carboniferous permineralized peat. While sporocarps today are generally interpreted as fungal, their precise systematic affinities largely remain unknown. A specimen of the sporocarp-type Traquairia from the Lower Coal Measures (Lower Pennsylvanian) of Great Britain demonstrates a heretofore unknown feature in the form of a preformed aperture from which emerges a fascicle of radially oriented structures that are constricted sub-distally; transverse septa are present in the constricted areas of some of the structures. The outgrowths are morphologically similar to conidiophores bearing terminal conidia of certain extant fungi in the order Entomophthorales, and thus might suggest affinities of Traquairia with the Zygomycota. Alternatively, the outgrowths might represent sporulating hyphae of a parasitic or saprotrophic blastocladalean fungus or a peronosporomycete that used Traquairia as a nutrient source.

► A heretofore unknown feature of the enigmatic Carboniferous microfossil Traquairia.
► A fascicle of sub-distally constricted structures emerges from a preformed aperture.
► The specimen may be germinating, or the outgrowths were produced by a parasite or saprotroph.
► Structural differences in these microfossils can be recognized and may be significant.
► Usage of the term sporocarp for these fossils might be inaccurate.