Aquasubmersa

Aquasubmersa K.D. Hyde & Huang Zhang, Cryptog. Mycol. 33(3): 340 (2012)

Citation when using this entry, Chen C. et al. in prep. – An updated monograph of Coelomycetes, Mycosphere

Index Fungorum, Facesoffungi number, MycoBank, GenBank        

Classification: Aquasubmersaceae, Pleosporales, Dothideomycetes, Ascomycota, Fungi

Saprobic on submerged wood in freshwater habit. The sexual morph is characterised by ascomata which are immersed to semi-immersed, separate to aggregated, unilocular, short papillate, glabrous, subglobose, dark brown to black and ostiolate. The peridium is constituted by dark brown to pale brown, thick-walled cells of textura angularis. The hamathecium is composed of hyaline, septate, subcylindrical and branched pseudoparaphyses and asci. Asci are 8-spored, bitunicate, pedicellate, cylindrical, apex rounded, with an ocular chamber. Ascospores are hyaline, constricted at the septum, 1-septate, broadly fusiform, straight or slightly curved, base rounded, with gelatinous sheath (Ariyawansa et al. 2015). The asexual morph is characterised by the semi-immersed pycnidial conidiomata, which are unilocular, glabrous, dark brown to black, subglobose to ellipsoidal, separate, thick-walled and ostiolate. The conidiomatal wall is comprised of textura angularis to textura prismatica, thick-walled and dark brown to pale brown cells. Conidiophores are formed from the inner cells of the conidiomata wall, which are subcylindrical to doliiform, septate and unbranched when present. Conidiogenous cells are holoblastic, separate or aggregated, determinate, thick and smooth-walled, subcylindrical to lageniform and hyaline. Conidia are hyaline, thick and smooth-walled, guttulate, ellipsoidal, rounded at both ends, or sometimes bases papillate, with or without gelatinous sheath (Zhang et al. 2012, Li et al. 2020).

Type species: Aquasubmersa mircensis Huang Zhang & K.D. Hyde, Cryptog. Mycol. 33(3): 340 (2012)

Notes: Aquasubmersa was introduced by Zhang et al. (2012) with A. mircensis as the type species, which was isolated from submerged wood in a freshwater stream. At the same time, Zhang et al. (2012) placed A. mircensis in Pleosporales based on SSU and LSU sequence data, without assigning it to a family (Zhang et al. 2012). The second species, A. japonica, was introduced by Ariyawansa et al. (2015) including both the sexual and asexual morph, which was the first reported sexual morph of Aquasubmersa. Hashimoto et al. (2017) re-evaluated Aquasubmersa and introduced it to a new family Aquasubmersaceae (Pleosporales) based on SSU, ITS, LSU, tef1, and rpb2 sequence data. Species Fungorum (September 2024) lists two species in Aquasubmersa. There are 34 sequence data available for Aquasubmersa in GenBank (September 2024). The updated taxonomic treatment of this genus is Aquasubmersaceae, in Pleosporales (Dothideomycetes) (Wijayawardene et al. 2022).

For all accepted species: see Species Fungorum, search Aquasubmersa.