Examples of fossil fungal parasites: Chytridiomycota and zygomycetous fungi. A. Portion of charophyte Palaeonitella cranii showing normal cell size from Lower Devonian Rhynie chert; colour version of fig. 1 in Taylor et al. (1992a); bar 100 μm. B. Hypertrophied cells of P. cranii from Lower Devonian Rhynie chert; colour version of fig. 26 in Taylor et al. (1992c); bar 200 μm. C. Partially degraded sporangia of Horneophyton lignieri colonized by Rhizophydites matryoshkae (arrows) from Lower Devonian Rhynie chert; fig. 1E in Krings et al. (2021); bar 100 μm. D. Rhizophydites matryoshkae with four generations of zoosporangia occurring one inside another from Lower Devonian Rhynie chert; fig. 5A in Krings et al. (2021); bar 10 μm. E. Fungal intruders of enigmatic propagule clusters in microbial mats from Lower Devonian Rhynie chert; fig. 2a in Krings and Harper (2019); bar 10 μm. F. Illmanomyces corniger zoosporangium on host spore from Lower Devonian Rhynie chert; fig. 2a in Krings and Taylor (2014); bar 50 μm. G. Globicultrix nugax in glomeromycotan spore from Lower Devonian Rhynie chert; fig. 2.2 in Krings et al. (2009b); bar 20 μm. H. Thalli of Brijax amictus in ephemeral outer wall component of glomeromycotan acaulospore from Lower Devonian Rhynie chert; pl. III, fig. 8 in Krings and Harper (2020); bar 25 μm. I. Callosity (white arrows) in glomeromycotan spore; note sporangium of parasite on host spore surface (black arrow) from Lower Devonian Rhynie chert; fig. 31 in Krings (2022); bar 10 μm. J. Callosities in lycophyte periderm from Visean (Mississippian) chert deposits in France; pl. II, fig. 12 in Krings et al. (2009a); bar 20 μm. K. Chytrid-like inclusions in gymnosperm pollen grain from Upper Permian of India; fig. 2C in Aggarwal et al. (2015); bar 20 μm. L. Developing spore of a fungal pathogen inside a nematode from Miocene Mexican amber; fig. 2A in Jansson and Poinar (1986); bar 10 μm. M. Termite bearing white colonies of an entomophthoralean fungus (arrow) from Miocene Dominicam amber; colour version of fig. 1 in Poinar and Thomas (1982); bar 1.0 mm. A, B. Courtesy of Hagen Hass and Hans Kerp, University of Münster. L, M. Courtesy of George O. Poinar, Oregon State University.