Abstract
Geosmithia is a genus of mitosporic filamentous fungi typically associated with phloeophagous bark beetles worldwide. During this study, the fungal associates of ambrosia beetles Cnesinus lecontei, Eupagiocerus dentipes and Microcorthylus sp. from Costa Rica, were studied using morphology and DNA sequences.
Fungal associates belonged to four undescribed Geosmithia species. Geosmithia eupagioceri sp. nov. and G. microcorthyli sp. nov. are evidently primary ambrosia fungi of their respective vectors E. dentipes and Microcorthylus species.
They both have convergently evolved distinct morphological adaptations. The primary ambrosia fungi described here are derived from phloem-associated ancestors, and represent two independent lineages of ambrosia fungi in the Hypocreales and a new ecological strategy within Geosmithia.