Original Paper

Antonie van Leeuwenhoek

, Volume 101, Issue 2, pp 403-421

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Rasamsonia, a new genus comprising thermotolerant and thermophilic Talaromyces and Geosmithia species

  • J. HoubrakenAffiliated withDepartment of Applied and Industrial Mycology, CBS-KNAW Fungal Biodiversity Centre Email author 
  • , H. SpierenburgAffiliated withDepartment of Applied and Industrial Mycology, CBS-KNAW Fungal Biodiversity Centre
  • , J. C. FrisvadAffiliated withDepartment of Systems Biology, Technical University of Denmark


The phylogenetic relationship among Geosmithia argillacea, Talaromyces emersonii, Talaromyces byssochlamydoides and other members of the Trichocomaceae was studied using partial RPB2 (RNA polymerase II gene, encoding the second largest protein subunit), Tsr1 (putative ribosome biogenesis protein) and Cct8 (putative chaperonin complex component TCP-1) gene sequences. The results showed that these species form a distinct clade within the Trichocomaceae and Trichocoma paradoxa is phylogenetically most closely related. Based on phenotypic and physiological characters and molecular data, we propose Rasamsonia gen. nov. to accommodate these species. This new genus is distinct from other genera of the Trichocomaceae in being thermotolerant or thermophilic and having conidiophores with distinctly rough walled stipes, olive-brown conidia and ascomata, if present, with a scanty covering. Species within the genus Rasamsonia were distinguished using a combination of phenotypic characters, extrolite patterns, ITS and partial calmodulin and β-tubulin sequences. Rasamsonia brevistipitata sp. nov. is described and five new combinations are proposed.


Emersonii Argillacea Taxonomy Extrolites Phylogeny Trichocomaceae