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

MycoBank number: MB 557877; Index Fungorum number: IF 557877; Facesoffungi number: FoF 09174

Etymology: Referring to the genus of palm trees, Elaeis Jacq.

Holotype – MFLU 20-0522.

Saprobic on dead leaves and rachis of Elaeis guineensis. Sexual morph: Ascomata 160–280 × 130–350 µm (x̄ = 220 × 240 µm, n = 20), 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 13–45 µm wide, thick, comprising several layers of cells, outwardly comprising dark brown cells of textura irregularis and inwardly comprising hyaline cells of textura prismatica, 7–20 µm wide. Paraphyses 1.5–4.5 µm wide, septate, hyphae-like, hyaline. Asci 50–90 × 10–15 µm (x̄ = 70 × 12 µm, n = 40), 8-spored, unitunicate, clavate to cylindric, short pedicellate, with J- apical ring. Ascospores 10–18 × 5–8 µm (x̄ = 14 × 6 µm, n = 100), uni-biseriate into the asci, unicellular, obovoid, fusoid, hyaline to light brown when immature and brown to dark brown when mature, mostly one, rarely two-guttulate, cell wall verrucose, with a mucilaginous cap at the apex. Germ slit 3–6 µm length (x̄ = 5 µm, n = 50), straight, less than spore length. Asexual morph: Not observed.

Material examined – THAILAND, Surat Thani Province, on dead leaves and rachis of Elaeis guineensis Jacq. (Arecaceae) on the ground, 21 July 2017, Sirinapa Konta, SRWD12 (MFLU 20-0522, holotype).

Notes – A BLAST search of H. elaeidis ITS sequence shows 83.87% similarity with Gyrothrix oleae (CPC 37069); LSU sequence shows 95.95% similarity with Gyrothrix eucalypti (CPC 36066); and rpb2 sequence shows 80.95% similarity with Lopadostoma meridionale (LG). Only the sexual morph of H. elaeidis was found in nature, and we could not obtain a pure culture from fresh samples. Therefore, the morphological characteristics of H. elaeidis were not compared with those of Ceratocladium, Circinotrichum, Gyrothrix, and Idriella, as they only had asexual morphs found in nature. Hence, the morphological features of H. elaeidis were only compared with Neoanthostomella, Virgaria, and Xenoanthostomella, as they have sexual morphs.

Figure 1. Haploanthostomella elaeidis (MFLU 20-0522, holotype). A Substrate. B, C Appearance of ascomata on the host surface. D Sections of ascomata. E Peridium. F Hamathecium. G Septa of paraphyses shown in red arrows. H, I–K Asci. L J- apical ring in Melzer’s reagent. M, N, P–R Ascospores with a mucilaginous cap (red arrows in M, Q, R) and germ slit (red arrows in P). O An ascospore with verrucose wall. Scale bars: B = 1000 µm, C = 200 µm, D = 500 µm, E, G, L = 20 µm, F, H–K = 50 µm, M–P = 10 µm, Q–R = 5 µm.