Fungalpedia – Note 159 Callimothallus
Callimothallus Dilcher ex Janson. & L.V. Hills
Citation when using this data: Saxena RK & Hyde KD in prep – Fungalpedia, Fossil Fungi. Mycosphere.
Classification: Microthyriaceae, Microthyriales, Ascomycota.
The genus 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 are the host for this fungus, most frequently on upper surface, occasionally on lower surface. Since Dilcher (1965) did not designate a holotype, Jansonius and 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) for which he described “secondary ostioles”. Elsik (1978) pointed out that the porate condition in Callimothallus is required for 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. Singh
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)
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.
Saxena RK, Singh HP. 1982 – Palynological investigation of the Upper Siwalik sediments exposed along Hoshiarpur–Una Road Section in Punjab and Himachal Pradesh. Geophytology 12(2), 287–306.
Stevens FL. 1925 – Hawaiian fungi. Bernice P. Bishop Museum Bulletin 19, 1–189.
Ramesh K. Saxena, Birbal Sahni Institute of Palaeosciences, Lucknow, India
Edited by Kevin D. Hyde