Multi-locus phylogeny reveals two new species of Exidia (Auriculariales, Basidiomycota) from China

Taxonomy and Phylogeny of Corticioid Fungi in Auriculariaceae (Auriculariales, Basidiomycota): A New Genus, Five New Species and Four New Combinations

The Auriculariaceae accounts for most of the species in the Auriculariales, and all species in the family are wood-decaying fungi with gelatinous, crustaceous, or woody basidiomes. Many new taxa were published recently, but the taxonomy and phylogeny of the corticioid species in the Auriculariaceae are far from resolved. We undertook a comprehensive taxonomic and phylogenetic study of the family with emphasis on corticioid specimens collected from East and Southeast Asia. Phylogenetic analyses on concatenated ITS and 28S rDNA sequences of representative taxa of the Auriculariaceae and the genera Eichleriella and Heteroradulum were carried out that resolved five new lineages. Heterocorticium gen. nov. is established for two species with resupinate coriaceous basidiomes with smooth, pigmented hymenophores. Five new species, H. bambusicola (generic type), H. latisporum, Eichleriella alpina, E. bambusicola, and Heteroradulum maolanense, are described and illustrated. In addition, Heterochaete delicata, H. discolor, and H. sinensis are transferred to Eichleriella, whereas H. roseola is regarded as a synonym of Kneiffia discolor (= H. discolor). Eichleriella aculeobasidiata is treated as a synonym of Heterochaete sinensis (= E. sinensis). Heterochaete mussooriensis is transferred to Heteroradulum with Heteroradulum semis as a heterotypic synonym. The present study contributes to the understanding of species diversity, taxonomy, and phylogeny of corticioid fungi in Asia.

Two new species of Exidia sensu lato (Auriculariales, Basidiomycota) based on morphology and DNA sequences

In the present study, fourteen Exidia-like specimens were collected from China, France, and Australia. Based on morphological characteristics and phylogenetic analyses using the internal transcribed spacer regions (ITS) and the large subunit of nuclear ribosomal RNA gene (nLSU), four species in Exidia sensu lato, including Exidia saccharina and Tremellochaete atlantica, and two new species, Exidia subsaccharina and Tremellochaete australiensis, were identified. The four species are described and illustrated in detail. E. saccharina and T. atlantica, two known species from China are reported for the first time. E. subsaccharina and T. australiensis, two new species from France and Australia, respectively are also described. E. subsaccharina is characterized by its reddish brown to vinaceous brown basidiomata, slightly papillate hymenial surface, and narrowly allantoid basidiospores without oil drop measuring 12.5-17.5 × 4.2-5.5 μm. It differs from the similar species, E. saccharina, by distinctly larger basidiospores (12.5-17.5 × 4.2-5.5 vs. 10-14.2 × 3.2-4.5 μm). Tremellochaete australiensis is characterized by its white to grayish blue basidiomata, obviously and densely papillate hymenial surface, and allantoid basidiospores with oil drop measuring 13.8-16.2 × 4.8-6.5 μm. It also can be distinguished from the similar species, T. atlantica and T. japonica, by its distinctly larger basidiospores (13.5-17.8 × 4-5.2 vs. 10-11.8 × 4-4.8 μm in T. atlantica; 9.4-11.8 × 3.5-4.2 μm in T. japonica).

Alloexidiopsis gen. nov., A Revision of Generic Delimitation in Auriculariales (Basidiomycota)

Auriculariales is a fungal order with highly diverse morphological traits of basidiomes, which partially leads to a poor understanding of its taxonomic system at the generic level. To identify our recently collected specimens of Auriculariales to a species level, we perform a comprehensive phylogenetic analysis of the generic relationships in Auriculariales. In association with morphological characteristics, a new genus Alloexidiopsis belonging to Auriculariaceae is erected with two new species, namely, A. australiensis and A. schistacea. Moreover, Exidiopsis calcea separated from the generic type E. effusa and Heteroradulum niveum and H. yunnanense recently inaccurately described as members of Heteroradulum are recovered in the clade of Alloexidiopsis. These three species are thus transferred to this new genus. One collection of Exidiopsis grisea also falls in the clade of Alloexidiopsis, whereas another collection of this species is separated far from Alloexidiopsis and E. effusa. Since we have no collection to confirm the species identity of E. grisea, its generic position is uncertain. The main taxonomic morphological differences among Alloexidiopsis and related corticioid genera in Auriculariales are summarized. A key to all the five accepted species of Alloexidiopsis is provided. As two unnamed lineages exist in Alloexidiopsis besides the abovementioned five species, it is assumed that more new species will be revealed from this genus under its current circumscription.

Redelimitation of Heteroradulum (Auriculariales, Basidiomycota) with H.australiense sp. nov

Auriculariales accommodates species with diverse basidiomes and hymenophores. From morphological and phylogenetic perspectives, we perform a taxonomic study on Heteroradulum, a recently validated genus within the Auriculariales. The genus Grammatus is merged into Heteroradulum, and thus its generic type G.labyrinthinus is combined with Heteroradulum and G.semis is reaccepted as a member of Heteroradulum. Heteroradulumaustraliense is newly described on the basis of three Australian specimens. Heteroradulumyunnanense is excluded from this genus and its taxonomic position at the generic level is considered uncertain. Accordingly, the circumscription of Heteroradulum is re-delimited and the concept of this genus is adjusted by including irpicoid to poroid hymenophores and a hyphal system with clamp connections or simple septa. A key to all nine accepted species of Heteroradulum is presented.

Exidia qinghaiensis, a new species from China

A novel, wood-inhabiting jelly fungus from China is described as a new species, Exidia qinghaiensis (Basidiomycota: Auriculariaceae). Phylogenetic analyses were based on sequences of the nuclear ribosomal DNA internal transcribed spacer (nrITS) and large subunit (nrLSU), RNA polymerase II second largest subunit (RPB2), and translation elongation factor 1-α (Tef1) regions. Sequences of the new taxon formed a sister group to Exidia thuretiana, a species known from Europe and Asia, and distant to sequences of Exidia repanda from Europe. Fruiting bodies are cushion-shaped to irregularly lobed and yellowish brown, basidiospores are hyaline, allantoid (averaging 12.7 × 3.4 μm; average length/width is 3.7), and the host is Betula. The new species also can be distinguished by nrITS, nrLSU, RPB2, and Tef1 sequences. Our multigene phylogeny supports an Exidia including Exidia japonica, type species of Tremellochaete, but defining generic limits in Auriculariaceae will require more extensive taxon sampling.