Fungalpedia – Note 163 Chaetosphaerites
Citation when using this data: Saxena RK & Hyde KD in prep – Fungalpedia, Fossil Fungi. Mycosphere.
Classification: Fossil Ascomycota
Felix (1894) instituted Chaetosphaerites from the Eocene sediments (56–34 mya) of Perekeschkul, near Baku, Azerbaijan. Felix (1894) stated that “Some of the silicified spores are characterized particularly by the two middle cells being dark brown, the two end cells pale brown. Since the boundaries of the respective colours coincide exactly with the sharp delimitations of the individual segments, it is probably not justified to assume that the differences in shade only resulted from the state of preservation. It is unlikely, particularly in view of the minute size of the objects, for differences to occur in the state of preservation of the individual parts”. The spores are is strongly obtuse spindle-shaped, almost like that of a cylinder with rounded ends. They probably are 4-celled, but the central septum is not clearly visible due to the dark colouration. Spores are 23.8 μm x 8.5 μm. The two median, darker cells are larger, with a combined length of 14.8 μm.
Spores like these are found in many modern ascomycete genera in Sordariomycetes (e.g., Ascotaiwania, Chaetosphaeria, Savoryella, Jones et al. 2019) and Dothideomycetes (e.g. Paucispora, Thambugala et al. 2015) and some asexual genera (Versicolorisporium, Wijayawardene et al. 2016).
Synonym: Cannanorosporonites Ramanujam & Rao
Type species: Chaetosphaerites bilychnis Felix.
Figure 1 – Chaetosphaerites bilychnis. Scale bar = 5 μm (redrawn from Felix 1894)
Felix J. 1894 – Studien über fossile Pilze. Zeitschrift der Deutschen Geologischen Gesellschaft 46, 269–280.
Ramanujam CGK, Rao. KP. 1978 – Fungal spores from the Neogene strata of Kerala in South India, 291–304. In: Bharadwaj D.C. et al. (Editors) – Proceedings of the 4th International Palynological Conference, Lucknow 1976–77, Volume 1, Birbal Sahni Institute of Palaeobotany, Lucknow.
Ramesh K. Saxena, Birbal Sahni Institute of Palaeosciences, Lucknow, India
Edited by Kevin D. Hyde