Pseudohelicoon gigantisporum (Goh & K.D. Hyde) Y.Z. Lu & J.K. Liu
Basionym: Helicoon gigantisporum Goh & K.D. Hyde, Mycol. Res. 100(12): 1487 (1996)
Index Fungorum number: IF 554920; Facesoffungi number: FoF 04815
Holotype: BRIP 23200
Etymology: Greek gigas, giant + spora; referring to the large size of the conidia.
Asexual morph: Colony on natural substratum dark-brown, somewhat glistening, effuse. Mycelium partly immersed but mostly superficial, consisting of branched hyphae and short conidiophores bearing conidia; superficial hyphae ca 2.5–4 μm wide, pale yellowish-brown, smooth, branched, closely septate, slightly constricted at the septa which are 11–16 μm apart. Conidiophores macronematous, mononematous, cylindrical, erect, straight, arising as short branches more or less at right angles to the subtending hyphae, mid yellowish-brown or somewhat darker than the subtending hyphae, unbranched, non-septate, smooth, 6.5–14 μm long, 3–4.5 μm wide. Conidiogenous cells monoblastic, integrated, terminal, determinate. Conidia solitary, dry, acrogenous, yellowish-brown to dark-brown, helicoid, filament 6.5–10 μm wide, smooth, distantly septate, slightly constricted at septa, tightly coiled (12–)13 times in a counter-clockwise direction to form a broadly ellipsoidal or doliiform body, 78–120 μm long, 48–90 μm wide, usually incorporated with mucilaginous substances such that no gaps are visible between adjacent coils; conidial secession presumably schizolytic at the deliminating septum of the conidiogenous cell, giving rise to a short hilar projection ca 4–9 × 3–4.5 μm at the base. Sexual morph: Undetermined. (Description from Goh and Hyde 1996)
Material examined: AUSTRALIA, north Queensland, Mt Lewis, on submerged wood in small stream, May 1995, K.D. Hyde & T.M. Hyde, BRIP 23200.
Notes: This taxon was introduced as Helicoon gigantisporum by Goh and Hyde (1996). We synonymize it under Pseudohelicoon gigantisporum based on phylogenetic evidence. Pseudohelicoon gigantisporum shares a sister relationship to H. subglobosum with good bootstrap support within the family Tubeufiaceae. (Notes from Lu et al. 2018)
Freshwater distribution: Australia (Goh and Hyde 1996)
Fig. 1. Pseudohelicoon gigantisporum (BRIP 23200, holotype). 1. Squash mount illustrating several conidia. 2–4. Conidia on short conidiophores. 5. Glistening conidia on substratum surface. Scale bars 1–4 = 50 μm, 5 = 1 mm. (Goh and Hyde 1996)
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
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
Recent SpeciesNeohelicomyces submersus