Tubeufiales » Tubeufiaceae

Pseudohelicoon

Pseudohelicoon Y.Z. Lu & K.D. Hyde

Index Fungorum number: IF 554919; Facesoffungi number: FoF 04748

 

Saprobic on submerged decaying woody substrate. Sexual morph: Undetermined. Asexual morph: Hyphomycetous, helicosporous. Colonies on natural substratum dark-brown, somewhat glistening, effuse. Mycelium partly immersed but mostly superficial, consisting of branched hyphae and short conidiophores bearing conidia, pale yellowish-brown, smooth, branched, closely septate, slightly constricted at the septa. Conidiophores macronematous, mononematous, cylindrical, erect, straight, arising as short branches more or less at right angles to the subtending hyphae, yellowish-brown or somewhat darker than the subtending hyphae, unbranched, aseptate, smoothwalled. Conidiogenous cells monoblastic, integrated, terminal, determinate. Conidia solitary, dry, acrogenous, medium brown, helicoid, smooth, distinct multiseptate, slightly constricted at the septa, tightly coiled 7-13 times in a clockwise direction to form a subglobose or broadly elliptical body, usually incorporated with mucilaginous substances such that no gaps are visible between adjacent coils, non-hygroscopic; conidial secession schizolytic at the delimitating septum of the conidiogenous cell, giving rise to a short pedicel at the base. (Description from Lu et al. 2018).

 

Type species: Pseudohelicoon subglobosum (Goh & C.H.Kuo) Y.Z. Lu & K.D. Hyde

Basionym: Helicoon subglobosum Goh & C.H. Kuo [as‘Helicoön], Phytotaxa 346(2): 145 (2018)

 

Notes: Pseudohelicoon is characterized by dark brown, glistening colonies, short, branched conidiophores, determinate conidiogenous cells and helicoid conidia that are tightly coiled 7–13 times to form a subglobose or broadly elliptical body, usually incorporating with mucilaginous substances (Lu et al. 2018). The type species P. subglobosum was transferred from Helicoon to avoid further taxonomic confusion as the polyphyletic nature of Helicoon (Tsui and Berbee 2006; Goh and Kuo 2018; Lu et al. 2018). Two freshwater species are accepted in Pseudohelicoon and formed a well-supported clade in Tubeufiaceae (Lu et al. 2018). They can be separated by the conidial shape and length (Goh and Kuo 2018). (Notes from Dong et al. 2020)

 

List of freshwater Pseudohelicoon species

Pseudohelicoon gigantisporum (Goh & K.D. Hyde) Y.Z. Lu & J.K. Liu, Fungal Diversity 92: 254 (2018)

Basionym: Helicoon gigantisporum Goh & K.D. Hyde, Mycol. Res. 100(12): 1487 (1996)

Freshwater distribution: Australia (Goh and Hyde 1996)

*Pseudohelicoon subglobosum (Goh & C.H. Kuo) Y.Z. Lu & K.D. Hyde, Fungal Diversity 92: 255 (2018)

Basionym: Helicoon subglobosum Goh & C.H. Kuo [as ‘Helicoön], Phytotaxa 346(2): 145 (2018)

Freshwater distribution: Taiwan, China (Goh and Kuo 2018)

 

Key to freshwater Pseudohelicoon species

1. Conidia broadly ellipsoidal, 78−123 μm long…………………… P. gigantisporum

1. Conidia subglobose, 66−78 μm long………………………………P. subglobosum

 

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 X-D, Wang G-N, Yang H, Yang J, Thambugala KM, Tian Q, Luo Z-L, Yang J-B, Miller AN, Fournier J, Boonmee S, Hu D-M, Nalumpang S, Zhang H (2020) Freshwater Dothideomycetes. Fungal Divers 105:319–575. https://doi.org/10.1007/s13225-020-00463-5

Goh TK, Hyde KD (1996) Helicoon gigantisporum sp. nov., and an amended key to the genus. Mycol Res 100:1485–1488. https://doi.org/10.1016/S0953-7562(96)80083-9

Goh TK, Kuo CH (2018) A new species of Helicoön from Taiwan. Phytotaxa 346:141–156. https://doi.org/10.11646/phytotaxa.346.2.2

Lu YZ, Liu JK (Jack), Hyde KD, Jeewon R, Kang JC, Fan C, Boonmee S, Bhat DJ, Luo ZL, Lin CG, Eungwanichayapant PD (2018) A taxonomic reassessment of Tubeufiales based on multi-locus phylogeny and morphology. Fungal Divers 92:131–344. https://doi.org/10.1007/s13225-018-0411-y

Tsui CKM, Berbee ML (2006) Phylogenetic relationships and convergence of helicosporous fungi inferred from ribosomal DNA sequences. Mol Phylogenet Evol 39:587–597. https://doi.org/10.1016/j.ympev.2006.01.025

 

Recent Genus

1
Neochlamydotubeufia
Neohelicomyces

Recent Species

Neohelicomyces submersus
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