Fungalpedia – Note 159 Callimothallus  (Fossil Fungi)


Callimothallus Dilcher ex Janson. & L.V. Hills.

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

Index Fungorum, Facesoffungi, MycoBank ,GenBank, Fig. 1

Classification: Microthyriaceae, Microthyriales, Fossil Ascomycota, Fungi

Callimothallus was proposed by Dilcher (1965) from the Early Eocene (56–48 mya) sediments of western Tennessee, USA, with the following diagnosis: “No free hyphae. Stroma round, radiate, astomate, no central dehiscence, individual cells may possess single pore. Spores undetermined”. According to Dilcher (1965), Sapindus sp. leaves host this fungus, most frequently on the upper surface and occasionally on the lower surface. Since Dilcher (1965) did not designate a holotype, Jansonius & Hills (1976) selected a lectotype from the syntypes (all resulting from a single collection).

Callimothallus lacks any central dehiscence and is characterized by numerous pores. It is the only genus in the Microthyriaceae that is multiporate. The only report of such pores in modern fungal material was made by Stevens (1925) for Microthyriella (Micropeltaceae), in which he described “secondary ostioles.” Elsik (1978) pointed out that the porate condition in Callimothallus requires at least a number of the cells to separate it from Phragmothyrites and that if the porate nature is well represented, even fragments of the fructification are recognizable.

Synonyms: Pseudosphaerialites Venkatach. & R.K. Kar, Siwalikiathyrites R.K. Saxena & H.P. 

Type species: Callimothallus pertusus Dilcher (lectotype, selected by Jansonius & Hills 1976, card no. 356).



Figure 1 – Callimothallus pertusus Scale bar = 50 μm. Redrawn from Dilcher (1965).



Dilcher DL. 1965 – Epiphyllous fungi from Eocene deposits in western Tennessee, U.S.A. Palaeontographica Abt. B. Palaephytol. 116, 1–54.

Elsik WC. 1978 – Classification and geologic history of the Microthyriaceous fungi. Proceedings of the IV International Palynological Conference, Lucknow (1976–77), Vol. 1, 331–342.

Jansonius J, Hills LV. 1976 – Genera file of fossil spores. Spec. Pub., Dept. Geology, Univ. Calgary, Canada, 1–3287.

Stevens FL. 1925 – Hawaiian fungi. Bernice P. Bishop Museum Bulletin 19, 1–189.


Entry by

Ramesh K. SaxenaBirbal Sahni Institute of Palaeosciences, Lucknow, India


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