Auriculibuller fuscus gen. nov., sp. nov. and Bullera japonica sp. nov., novel taxa in the Tremellales Jose ´ Paulo Sampaio, 1 Joa ˜o Ina ´ cio, 1 A ´ lvaro Fonseca, 1 Ma ´ rio Gadanho, 1 Isabel Spencer-Martins, 1 Gloria Scorzetti 2 and Jack W. Fell 2 Correspondence Jose ´ Paulo Sampaio jss@fct.unl.pt 1 Centro de Recursos Microbiolo ´ gicos, Secc ¸a ˜o Auto ´ noma de Biotecnologia, Faculdade de Cie ˆ ncias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal 2 Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Key Biscayne, FL 33419, USA Seven phylloplane yeast strains that were collected in the Arra ´ bida Natural Park, Portugal, and identified preliminarily as Bullera alba, the anamorphic stage of Bulleromyces albus, were investigated. In contrast to Bulleromyces albus, these isolates produced a brownish pigment when grown on potato dextrose agar. The pigment caused darkening of the cultures and diffused into the culture medium. Mating studies revealed that the Arra ´ bida isolates did not react with the different mating types of Bulleromyces albus, but were sexually compatible with them and produced mycelium with clamp connections, haustoria and transversally septate basidia that ejected the basidiospores. Various taxonomic criteria that were evaluated during the present study and comparison with other sexual taxa of the Tremellales indicated that this teleomorph should be classified in a novel genus. Therefore, Auriculibuller fuscus gen. nov., sp. nov. (type strain, PYCC 5690 T =CBS 9648 T ) is proposed. In addition, during the course of this investigation, a member of a novel Bullera species, Bullera japonica sp. nov. (type strain, PYCC 4534 T =CBS 2013 T ), was found among collection isolates that were identified formerly as Bullera alba. In molecular phylogenetic analysis of the D1/D2 domains of the 26S rDNA and the internal transcribed spacer region, the two taxa were found to be closely related, but distinct at the species level. INTRODUCTION The phenotypic circumscription of the basidiomycetous anamorphic genus Bullera Derx is based on the production of rotationally symmetrical ballistoconidia, absence of bud-forming stalks, white to cream or yellowish cultures, inositol assimilation, production of starch-like compounds (a few exceptions are known for the two latter tests), CoQ10 as the major ubiquinone system and the presence of xylose in whole-cell hydrolysates (Boekhout & Nakase, 1998). Presently, the genus Bullera comprises approxi- mately 30 species that belong to the Tremellales, based on various molecular phylogenetic analyses (Fell et al., 2000; Nakase, 2000; Bai et al., 2001; Scorzetti et al., 2002). Until now, two teleomorphic genera, Bulleromyces Boekhout and Fonseca (Boekhout et al., 1991) and Bulleribasidium Sampaio, Weiss and Bauer (Sampaio et al., 2002) have had their anamorphic counterparts in Bullera. However, no teleomorph is known for most Bullera species. Implement- ation of molecular phylogenetic analyses based on DNA sequence data has emphasized the need to integrate mito- sporic taxa, such as Bullera, into the classification system that was originally built exclusively for sexual fungi. Ballistoconidia-producing yeasts are found frequently in the phylloplane. Forceful liberation of propagules seems to constitute an ecological advantage for colonization and dissemination in the plant leaf environment (Nakase, 2000). A 2 year survey (1997–1998) of the phylloplane yeast communities that are found on selected plants from two study sites in the Arra ´bida Natural Park, Portugal, was carried out by Ina ´cio et al. (2002). This natural park encompasses different microclimatic areas with specific formations of typically Mediterranean vegetation. Among a vast majority of isolates of basidiomycetous affinity, seven yeast strains were identified preliminarily as Bullera alba Hanna, the anamorphic stage of Bulleromyces albus Boekhout and A ´ . Fonseca. In contrast to Bulleromyces albus, these isolates produced a brownish pigment when Abbreviations: ITS, internal transcribed spacer; MCMC, Markov chain Monte Carlo. The GenBank/EMBL/DDBJ accession numbers for the sequences determined in this study are shown in Table 1. 02970 G 2004 IUMS Printed in Great Britain 987 International Journal of Systematic and Evolutionary Microbiology (2004), 54, 987–993 DOI 10.1099/ijs.0.02970-0