Haploanthostomella Konta & K.D. Hyde, in Konta, Hyde, Eungwanichayapant, Karunarathna, Samarakoon, Xu, Dauner, Aluthwattha, Lumyong & Tibpromma, Life 11(no. 486): 10 (2021)

Index Fungorum number: IF 557876; Facesoffungi number: FoF 09173

Etymology:haplos” (απλóς) in Greek means single; Anthostomella refers to its morphological similarity to Anthostomella.

Saprobic on dead leaves and rachis in terrestrial habitats. Sexual morph: Ascomata immersed in the host epidermis, beneath a clypeus, visible as slightly raised blackened areas, dark brown to black, coriaceous, solitary or aggregated into clusters, scattered, with an ostiolar canal. Peridium wall thick, comprised of several layers of cells, outwardly comprising dark brown cells of textura prismatica and inwardly comprising hyaline cells of textura angularis. Paraphyses septate, tapering hyphae-like, hyaline. Asci eight-spored, unitunicate, clavate to cylindric, short pedicellate, with J-, apical ring. Ascospores uni to biseriate into the asci, unicellular, obovoid, fusoid, hyaline or brown to dark brown, verrucose with a mucilaginous cap at the apex. Germ slit straight, less than spore length. Asexual morph: Not observed.

Type speciesHaploanthostomella elaeidis Konta & K.D. Hyde.

Notes –  Anthostomella species were proven to be polyphyletic, and it is no surprise that a new genus with anthostomella-like characteristics was discovered in this study. Phylogenetic analyses based on a single dataset of ITS and combined sequence data indicated that Haploanthostomella belongs to the Xylariales genera incertae sedis, separating well from other genera but with low bootstrap values. According to the phylogenetic tree, seven genera (Ceratocladium, Circinotrichum, Gyrothrix, Idriella, Neoanthostomella, Virgaria and Xenoanthostomella) are closely related to our new genus, but the morphological characteristics of these genera are different. The genera Neoanthostomella, Virgaria, and Xenoanthostomella were compared morphologically since they are similar to our new taxon. Haploanthostomella differs from Virgaria, Neoanthostomella, and Xenoanthostomella in having a J- apical ring, fusoid-obovoid ascospores, and verrucose with a mucilaginous cap at the apex, while Virgaria has asci with a J+ apical ring and smooth-walled elliposidal ascospores lacking a mucilaginous sheath; Neoanthostomella smooth-walled ellipsoidal ascospores surrounded by a thick mucilaginous sheath; Xenoanthostomella has unilocular ascoma and ascospores lacking germ slits and mucilaginous sheaths. Therefore, Haploanthostomella is described here as a new genus based on phylogeny coupled with morphology. In addition, we provide a key to genera with Anthostomella-like characteristics.

Figure 1. Maximum likelihood majority rule consensus tree for the analyses of selected Xylariomycetidae isolates based on a dataset of combined ITS, LSU, rpb2, and tub2 nucleotide sequence. Bootstrap support values for maximum likelihood (ML) equal to or higher than 50% are given above each branch. Bayesian posterior probabilities (BYPP) equal to or greater than 0.90 are given at the nodes. Novel taxa are in blue bold and ex-type strains are in black bold. The tree is rooted to Delonicicolaceae and Leptosilliaceae (Delonicicolales). The asterisks represent unstable species.