The rise and fall of Sarawakus (Hypocreaceae, Ascomycota)

Abstract

Species of Sarawakus are rarely encountered. Their teleomorphs resemble sexual stages of Trichoderma, formerly called Hypocrea, but differ from that genus by unicellular ascospores. The two green-spored species S. britannicus and the type species of Sarawakus, S. lycogaloides, recently were collected, compared with their types and cultured. We redescribe and illustrate these species and transfer them to Trichoderma, based on phylogenetic analysis of the translation elongation factor 1-alpha encoding gene (tef1), containing the two last introns and exon, and a part of the rpb2 gene, encoding the second largest RNA polymerase subunit. Trichoderma lycogaloides, was found to cluster with Hypocrea sulawesensis, an unusual species of Trichoderma, while T. britannicum is closely related to T. aerugineum of the Spinulosa clade. The anamorphs of the two examined species are characterized by (odd) verticillium-like conidiophores, large cylindrical phialides and conidia, which belong to the largest of those species forming green conidia, oval to subglobose in T. lycogaloides and oblong in T. britannicum. All species currently recognized in Sarawakus are transferred to Trichoderma, introducing the new combinations T. fragile, T. hexasporum, T. izawae, T. sordidum, T. subtrachycarpum, T. succisum and T. trachycarpum and the new name T. rosellum. Trichoderma trachycarpum is redescribed and illustrated from an isotype.

• Ascomycota
• Hypocrea
• Hypocreaceae
• Hypocreales
• pyrenomycetes
• rpb2
• tef1
• Thuemenella
• Trichoderma

Acknowledgments

We thank Begoña Aguirre-Hudson of the fungarium Kew and Walter Till at WU for sending and managing collections, Jesko Kleine for sending a fresh collection and images of Sarawakus britannicus, Trix Merkx and Gerard Verkley (CBS) for patience with our cultures, Anton Hausknecht for insertion of specimens into WU and Thomas Læssøe for specimen information.

The financial support by the Austrian Science Fund (FWF; project P22081-B17) is gratefully acknowledged.