Abstract:
Over the past two decades, numerous Geosmithia fungi have been isolated from the bodies and galleries of
wood–boring beetles. However, this genus of asexual Sordariomycetes remains taxonomically and ecologically
understudied, especially in the Southern Hemisphere. In South Africa, two prior surveys reported Geosmithia
species from bark beetles, but neither thoroughly investigated species identities. In this study, we collected bark
beetles from native trees in the Western Cape Province of South Africa and isolated, identified and described
their associated Geosmithia species. Geosmithia spp. previously collected in South Africa were also re-examined.
The ITS sequences of Geosmithia isolates from 13 beetle taxa infesting 10 host species were considered. Addi
tional gene regions, BT, EF1a and RPB2, were sequenced for a subset of isolates. Four previously described
species, G. flava, G. langdonii, G. omnicola and G. pumila were identified by phylogenetic analyses. Additionally,
four novel taxa were identified and are here described as G. capensis, G. multisociorum, G. oroboidis and G. stel
lenboschiana. Geosmithia multisociorum appears to be a generalist associated with multiple beetle–host combi
nations in the Northern and Southern Hemisphere, whereas G. oroboidis is currently known only from a single
beetle and tree host in South Africa. South African isolates of G. capensis and G. stellenboschiana appeared to be
restricted to Lanurgus spp. and Hypothenemus sp. beetles, respectively, but both species are also known from
beetles and hosts in other countries.
