Fungalpedia – Note 255, Involutisporonites (Fossil Fungi)


Involutisporonites R.T. Clarke. 

Citation when using this entry: Saxena RK & Hyde KD. 2024 (in prep) – Fungalpedia, Fossil Fungi. 

Index Fungorum, Facesoffungi, MycoBankGenBank, Fig. 1

Classification: Fossil Fungi, Incertae sedis

The monotypic fossil genus Involutisporonites was instituted by Clarke (1965) from the Late Cretaceous (100–66 mya) sediments of Canon City Coalfield, Fremont County, Colorado, USA. The genus accommodates planispiral fungal spores having lobate individual cells and simple septa with an opening through each septum. Elsik (1968) emended the generic diagnosis to include monoporate, psilate, multiseptate, coiled fungal spores. Kalgutkar & Jansonius (2000) proposed an elaborated emended diagnosis to include coiled, transversely septate and multicellate, fungal spores. Individual cells (8-10 µm in diameter) are of variable shapes. Septal pores may or may not be present. Terminal cell, if present, may have a single pore. Spore wall generally psilate to variously ornamented. The epithet foraminus is derived from its resemblance of the species to planispiral foraminifera.

Type species: Involutisporonites foraminus Clarke 1965.

Figure 1 – Involutisporonites foraminus. Scale bar = 10 μm. Redrawn from Clarke (1965)



Clarke RT. 1965 – Fungal spores from Vermejo Formation coal beds (Upper Cretaceous) of Central Colorado. Mountain Geologist 2, 85–93.

Elsik WC. 1968 – Palynology of a Palaeocene Rockdale lignite, Milam County, Texas. 1. Morphology and taxonomy. Pollen et Spores 10(2), 263–314. 

Kalgutkar RM, Jansonius J. 2000 – Synopsis of fungal spores, mycelia and fructifications. AASP Contribution Series 39, 1–423.


Entry by

Ramesh K. Saxena, Birbal Sahni Institute of Palaeosciences, Lucknow, India


(Edited by Kevin D. Hyde, Samaneh Chaharmiri-Dokhaharani, & Achala R. Rathnayaka)


Published online 21 May 2024