Pleosporales » Morosphaeriaceae

Neohelicascus

Neohelicascus W. Dong, H. Zhang, K.D. Hyde & Doilom

Index Fungorum number: IF557807; Facesoffungi number: FoF08722

Etymology: referring to its morphological similarity to Helicascus

 

Saprobic on submerged wood. Sexual morph: Pseudostromata scattered, comprising brown to black fungal material growing in cortex of host, unil- or multi-loculate, flattened at the basal region, horizontally arranged under the pseudostroma, visible on the host surface as blackened ostiolar dots. Locules immersed, lenticular to ampulliform, ostiolate. Ostiole converging at the center, uniting into one common, central pore, periphysate. Peridium of locules comprising several layers of brown, thin-walled angular cells, paler inwardly, fusing with the host cells. Pseudoparaphyses numerous, cellular, hypha-like, hyaline, septate, embedded in a gelatinous matrix. Asci 8-spored, bitunicate, fissitunicate, clavate, long pedicellate, base of endoascus long, narrow and coiled within ectoascus, ectoascus uncoiling to form a long tail-like extension, apically rounded with a cylindrical ocular chamber. Ascospores mostly biseriate, straight or slightly curved, ellipsoidal to broadly fusiform, with rounded ends, 1–(2–3)-septate, apical cell slightly larger than basal cell, brown, thin-walled, smooth- or rough-walled, with or without a deliquescing sheath (Zhang et al. 2013). Asexual morph: Coelomycetous. Pycnidia solitary, superficial, with the base immersed, uniloculate, globose to subglobose, brown, coriaceous, central ostiolate, with minute papilla. Peridium composed of brown, thin-walled cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells holoblastic, determinate, cylindrical to subcylindrical, hyaline, smooth. Conidia ellipsoid to obovoid, hyaline, aseptate, occasionally two-celled, smooth, thin-walled, without sheath or appendage (Zhang et al. 2013).

 

Type species: Neohelicascus aquaticus (H. Zhang & K. D. Hyde) W. Dong & H. Zhang

 

Notes: Neohelicascus is introduced to accommodate the new species N. submersus H. Yang et al. and another seven new combinations as listed below. Neohelicascus is distinguished from Aquihelicascus in producing brown ascospores and the base of endoascus is long, narrow, and coiled within ectoascus which uncoils to form a long tail-like extension. In contrast, Aquihelicascus possesses hyaline ascospores and an uncoiled endoascus. Phylogenetic analysis supports two genera, Aquihelicascus and Neohelicascus.

 

The ascospores of Neohelicascus egyptiacus and N. elaterascus are surrounded by a defined gelatinous sheath, which is absent in N. unilocularis (Zhang et al. 2013, 2015). Neohelicascus gallicus is surrounded by some fugacious mucilaginous remnants, but only seen in ascospores that are just released from the asci (Zhang et al. 2014). Neohelicascus aquaticus was characterized by 1–(2– or 3–) -septate ascospores with a deliquescing sheath (Zhang et al. 2013), although Tanaka et al. (2015) observed only 1-septate ascospores without a sheath from a Japanese collection. Neohelicascus aquaticus is the only species producing asexual morph in culture (Zhang et al. 2013).

 

List of freshwater Neohelicascus species

Neohelicascus aquaticus (H. Zhang & K. D. Hyde) W. Dong, K.D. Hyde & H. Zhang

Basionym: Helicascus aquaticus H. Zhang & K.D. Hyde, Sydowia 65(1): 155 (2013)

Synonymy: Helicascus alatus M. Zeng, S.K. Huang, Q. Zhao & K.D. Hyde, Phytotaxa 351(3): 215 (2018)

Freshwater distribution: China (Zeng et al. 2018; Dong et al. 2020), Japan (Tanaka et al. 2015), Thailand (Zhang et al. 2013)

 

Neohelicascus chiangraiensis (Z.L. Luo, J.K Liu, H.Y. Su & K.D. Hyde) W. Dong, K.D. Hyde & H. Zhang

Basionym: Helicascus chiangraiensis Z.L. Luo, H.Y. Su & K.D. Hyde, Phytotaxa 270(3): 185 (2016)

Freshwater distribution: Thailand (Luo et al. 2016)

 

Neohelicascus egyptiacus (Abdel-Wahab & Abdel-Aziz) W. Dong, K.D. Hyde & H. Zhang

Basionym: Helicascus egyptiacus Abdel-Wahab & AbdelAziz [as ‘aegyptiacus’], Sydowia 65(1): 153 (2013)

Freshwater distribution: Egypt (Zhang et al. 2013)

 

Neohelicascus elaterascus (Shearer) W. Dong, K.D. Hyde & H. Zhang

Basionym: Kirschsteiniothelia elaterascus Shearer, Mycologia 85:963 (1993).

Synonymy: Morosphaeria elaterascus (Shearer) S. Boonmee & K.D. Hyde, Mycologia 103: 705 (2012), Helicascus elaterascus (Shearer) H. Zhang & K.D. Hyde, Sydowia 65: 158 (2013)

Freshwater distribution: Brunei (Ho et al. 2001), Chile (Shearer 1993), China (Tsui et al. 2000; Luo et al. 2004), Japan (Tanaka et al. 2015), Peru (Shearer et al. 2015), South Africa (Hyde et al. 1998), Thailand (Hyde et al. 2020; Dong et al. 2020), USA (Shearer 1993; Raja et al. 2009)

 

Neohelicascus gallicus (Y. Zhang ter & J. Fourn) W. Dong, K.D. Hyde & H. Zhang

Basionym: Helicascus gallicus Y. Zhang ter & J. Fourn., Phytotaxa 183: 185 (2014)

Freshwater distribution: France (Zhang et al. 2014)

 

Neohelicascus submersus H. Yang, W. Dong, K.D. Hyde & H. Zhang

Freshwater distribution: China (Dong et al. 2020)

 

Neohelicascus unilocularis (J. Fourn. & Y. Zhang ter) W. Dong, K.D. Hyde & H. Zhang

Basionym: Helicascus unilocularis J. Fourn. & Y. Zhangter, Mycol. Progr. 14(7/47): 3 (2015)

Freshwater distribution: French West Indies, Martinique (Zhang et al. 2015)

 

Neohelicascus uniseptatus (J. Yang, J.K. Liu & K.D. Hyde) W. Dong, K.D. Hyde & H. Zhang

Basionym: Helicascus uniseptatus J. Yang, J.K. Liu & K.D. Hyde, Phytotaxa 270(3): 187 (2016)

Freshwater distribution: Thailand (Luo et al. 2016)

 

Key to freshwater Neohelicascus species

1. Pseudostromata uni-loculate........................................................................ 2

1. Pseudostromata mostly multi-loculate........................................................... 6

2. Ascospores rough-walled.............................................................................. 3

2. Ascospores smooth-walled........................................................................... 4

3. Peridium 60–70 μm, ascospores 1–(2–3)-septate........................ N. elaterascus

3. Peridium 30–50 μm, ascospores 1-septate............................. N. chiangraiensis

4. Ascospores with sheath............................................................. N. submersus

4. Ascospores lacking sheath or with deliquescing sheath.................................. 5

5. Peridium 50–65 μm, ascospores (21.6–)23–25.8(–27.3) × (9.2–)10.2–11.4(–11.7) μm                                N. unilocularis

5. Peridium 40–48 μm, ascospores 25–32 × 9–13 μm..................... N. uniseptatus

6. Ascospores rough-walled.......................................................... N. aegyptiacus

6. Ascospores smooth-walled........................................................................... 7

7. Ascospores (24.2–)25.1–31.3(–33) × (8.8–)9.3–12.1(– 12.6) μm......... N. gallicus

7. Ascospores 19−26 × 8−11 μm...................................................... N. aquaticus

 

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, de Silva NI, Jeewon R, Bhat DJ, Phookamsak R, Doilom M, Boonmee S, Jayawardena RS, Maharachchikumbura SSN, Senanayake IC, Manawasinghe IS, Liu NG, Abeywickrama PD, Chaiwan N, Karunarathna A, Pem D, Lin CG, Sysouphanthong P, Luo ZL, Wei DP, Wanasinghe DN, Norphanphoun C, Tennakoon DS, Samarakoon MC, Jayasiri SC, Jiang HB, Zeng XY, Li JF, Wijesinghe SN, Devadatha B, Goonasekara ID, Brahmanage RS, Yang EF, Aluthmuhandiram JVS, Dayarathne MC, Marasinghe DS, Li WJ, Dissanayake LS, Dong W, Huanraluek N, Lumyong S, Liu JK, Karunarathna SC, Jones EBG, Al-Sadi AM, Xu JC, Harishchandra D, Sarma VV (2020) AJOM new records and collections of fungi: 1–100. Asian Journal of Mycology 3:22–294

Hyde KD, Goh TK, Steinke TD (1998) Fungi on submerged wood in the Palmiet River, Durban, South Africa. S Afr J Bot 64:151–162

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

Luo ZL, Yang J, Liu JK, Su HY, Bahkali AH, Hyde KD (2016) Two new species of Helicascus (Morosphaeriaceae) from submerged wood in northern Thailand. Phytotaxa 270:182–190

Raja HA, Schmit JP, Shearer CA (2009) Latitudinal, habitat and substrate distribution patterns of freshwater ascomycetes in the Florida Peninsula. Biodivers Conserv 18:419–455

Shearer CA (1993) A new species of Kirschsteiniothelia (Pleosporales) with an unusual fissitunicate ascus. Mycologia 85:963–969

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

Zeng M, Huang SK, Hyde KD, Zhao Q (2018) Helicascus alatus (Morosphaeriaceae), a new freshwater species from southwestern China. Phytotaxa 351:210–218

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

Zhang Y, Liu YJ, Zhou YP, Zhang XD, Cui BK, He SH, Fournier J (2014) Helicascus gallicus sp. nov., a new freshwater pleosporalean ascomycete from France. Phytotaxa 183:183–192

 

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