Aquasubmersaceae A. Hashim. & Kaz. Tanaka, in Hashimoto et al., Persoonia 39: 56 (2017).
MycoBank number: MB 819235; Index Fungorum number: IF 819235; Facesoffungi number: FoF 08160, 2 species.
Saprobic on woody plants, submerged plant substrate. Sexual morph: Ascomata scattered or grouped, semi-immersed, subglobose, with a papillate ostiolar neck. Peridium comrpises flattened, thin-walled, polygonal cells. Hamathecium comprising septate, branched, pseudoparaphyses. Asci 8-spored, bitunicate, cylindrical, with a short pedicel. Ascospores broadly fusiform with rounded ends, hyaline, septate. Asexual morph: Coelomycetous. Conidiomata pycnidial, globose to ellipsoidal, solitary or scattered, semi-immersed to superficial, dark brown to black, ostiolate. Conidiophores reduced. Conidiogenous cells holoblastic, lageniform, hyaline, smooth, formed from the inner cells of the pycnidial wall. Conidia holoblastic, ellipsoidal, hyaline, aseptate, thin- and smooth-walled, or guttulate (adapted from Zhang et al. 2012a, Hashimoto et al. 2017b)
Type – Aquasubmersa K.D. Hyde & Huang Zhang.
Notes – The family was established by Hashimoto et al. (2017b), with the generic type Aquasubmersa. Based on the description of Aquasubmersa japonica provided by Ariyawansa et al. (2015a), it has 2–4.5 μm pseudoparaphyses. However, we could not see clearly from the photoplate whether it is cellular or trabeculate pseudoparaphyses. Molecular studies using LSU and SSU sequence data placed Aquasubmersa in Pleosporales (Zhang et al. 2012a, Ariyawansa et al. 2015a). Hashimoto et al. (2017b) indicated that Aquasubmersa formed a sister clade to the clade containing Lophiotremataceae Tanaka and Cryptocoryneaceae. Morphologically, Lophiotremataceae is similar to Aquasubmersaceae in having ascomata with papillate ostiolar neck and pycnidial conidiomata. However, Lophiotremataceae differs from Aquasubmersaceae in having ascomata with a compressed, slit-like ostiole. Cryptocoryneaceae and Hermatomycetaceae have sporodochial conidiomata and cheiroid or lenticular conidia, while Aquasubmersaceae has ellipsoidal conidia. Therefore, Hashimoto et al. (2017b) introduced Aquasubmersaceae to accommodate Aquasubmersa.