Pleosporales » Morosphaeriaceae » Aquihelicascus

Aquihelicascus thalassioideus

Aquihelicascus thalassioideus (K.D. Hyde & Aptroot) W. Dong & H. Zhang

Index Fungorum number: IF557920; Facesoffungi number: FoF09262

Basionym: Massarina thalassioidea K.D. Hyde & Aptroot, Nova Hedwigia 66(3–4): 498 (1998)

Synonymy: Helicascus thalassioideus (K.D. Hyde & Aptroot) H. Zhang & K.D. Hyde, Sydowia 65(1): 159 (2013)

 

Saprobic on decaying wood submerged in freshwater. Sexual morph: Pseudostromata clustered, immersed, visible on the host surface as blackened ostiolar dots. Pseudoparaphyses 1–3 μm diam., abundant, cellular, hypha-like, hyaline, septate, embedded in a gelatinous matrix. Asci 150–190 × 14.5–23 μm (x̄ = 175 × 17.5 μm, n = 5), 8-spored, bitunicate, fissitunicate, clavate, long pedicellate, up to 90 μm long. Ascospores 24–28 × 7–10 μm (x̄ = 25.5 × 8.5 μm, n = 25), overlapping uni- to bi-seriate, sometimes overlapping tri-seriate, ellipsoidal, hyaline, 1-septate, constricted at septum, curved, thin-walled, smooth. Asexual morph: Undetermined (detailed description see Hyde and Aptroot (1998) and Zhang et al. (2013).

 

Material examined: THAILAND, Chiang Rai Province, on submerged wood in a stream, 1 July 2018, W. Dong, CR134-1 (MFLU 18-1705), living culture KUMCC 19-0094; ibid., CR134-2 (HKAS 105076).

 

Notes: The new collection KUMCC 19-0094 is identified as Aquihelicascus thalassioideus based on multigene phylogenetic analysis. The morphological feature of KUMCC 19-0094 also fits well with A. thalassioideus except for the long pedicel, which is probably because of the pedicel spreading in water. Most publications do not report an ascospore sheath for A. thalassioideus except Zhang et al. (2015) who noted some fugacious mucilaginous remnants visible in Indian Ink when ascospores were just released from the asci. This character was not observed in our collection. (Notes from Dong et al. 2020)

 

Freshwater distribution: Australia (Hyde and Aptroot 1998), Brunei (Hyde and Aptroot 1998), China (Tsui et al. 2000; Ho et al. 2001; Luo et al. 2004), French West Indies, Martinique (Zhang et al. 2015), Peru (Shearer et al. 2015), Japan (Tanaka et al. 2015), Philippines (Hyde and Aptroot 1998b), Thailand (Kurniawati et al. 2010; Zhang et al. 2013; Dong et al. 2020)

 

Fig 1. Aquihelicascus thalassioideus (MFLU 18-1705). a, b Immersed pseudostromata with blackened ostiolar dots, c Ascus embedded in pseudoparaphyses, d, e Bitunicate asci, f, g Ascospores. Scale bars: c–e = 50 μm, f, g = 20 μm (Dong et al. 2020)

 

References

Dong W, Wang B, Hyde KD, McKenzie EHC, Raja HA, Tanaka K, Abdel-Wahab MA, Abdel-Aziz FA, Doilom M, Phookamsak R, Hongsanan S, Wanasinghe DN, Yu XD, Wang GN, Yang H, Yang J, Thambugala KM, Tian Q, Luo ZL, Yang JB, Miller AN, Fournier J, Boonmee S, Hu DM, Nalumpang S, Zhang H (2020) Freshwater Dothideomycetes. Fungal Divers 105:319–575. https://doi.org/10.1007/s13225-020-00463-5

Ho WH, Hyde KD, Hodgkiss JI, Yanna (2001) Fungal communities on submerged wood from streams in Brunei, Hong Kong, and Malaysia. Mycol Res 105:1492–1501

Hyde KD, Aptroot A (1998b) Tropical freshwater species of the genera Massarina and Lophiostoma (ascomycetes). Nova Hedwigia 66:489–502

Kurniawati E, Zhang H, Chukeatirote E, Sulistyowati L, Moslem MA, Hyde KD (2010) Diversity of freshwater ascomycetes in freshwater bodies at Amphoe Mae Chan, Chiang Rai. Cryptogam Mycol 31:323–331

Luo J, Yin J, Cai L, Zhang KQ, Hyde KD (2004) Freshwater fungi in Lake Dianchi, a heavily polluted lake in Yunnan, China. Fungal Divers 16:93–112

Shearer CA, Zelski SE, Raja HA, Schmit JP, Miller AN, Janovec JP (2015) Distributional patterns of freshwater ascomycetes communities along an Andes to Amazon elevational gradient in Peru. Biodivers Conserv 24:1877–1897

Tanaka K, Hirayama K, Yonezawa H, Sato G, Toriyabe A, Kudo H, Hashimoto A, Matsumura M, Harada Y, Kurihara Y (2015) Revision of the Massarineae (Pleosporales, Dothideomycetes). Stud Mycol 82:75–136

Tsui KM, Hyde KD, Hodgkiss IJ (2000) Biodiversity of fungi on submerged wood in Hong Kong streams. Aquat Microb Ecol 21:289–298

Zhang H, Hyde KD, Abdel-Wahab MA, Abdel-Aziz FA, Ariyawansa HA, Ko TWK, Zhao RL, Alias SA, Bahkali AH, Zhou D (2013) A modern concept for Helicascus with a Pleurophomopsis-like asexual state. Sydowia 65:147–166

Zhang JQ, Zhou YP, Dou ZP, Fournier J, Zhang Y (2015) Helicascus unilocularis sp. nov., a new freshwater pleosporalean ascomycete from the Caribbean area. Mycol Prog 14:1–8

 

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