Tubeufiales » Tubeufiaceae » Berkleasmium

Berkleasmium aquaticum

Berkleasmium aquaticum (Y.Z. Lu, Boonmee & K.D. Hyde) Y.Z. Lu

Basionym: Neoacanthostigma aquaticum Y.Z. Lu, Boonmee & K.D. Hyde, Cryptog. Mycol. 38(2): 176 (2017)

Index Fungorum number: IF 553170; Facesoffungi number: FoF 03239

Etymology: ‘aquaticum’ referring to aquatic habitats of this fungus

Holotype: HKAS 97431


Saprobic on decaying wood in a freshwater stream. Sexual morph: Ascomata 235–290 μm high × 180–225 μm diam., superficial, seated on a subiculum, solitary, scattered, subglobose, ellipsoidal-ovate, dark brown to black, with a central ostiolate. Setae 35–65 μm long, 3.5–6 μm wide in the middle, one-celled, thick-walled, brown to black, straight to slightly curved, covered with the whole ascomata. Peridium 25–34 μm wide, composed of cells of textura angularis, with inner cells brown and outer cells dark brown. Hamathecium comprising numerous, filiform, septate, branched, hyaline pseudoparaphyses. Asci 115–175 × (11–)12.5-16(–17.5) μm ( = 140 × 14 μm, n=20), 8-spored, bitunicate, cylindrical, short-pedicellate, apically rounded. Ascospores (45–)50.5–60 × 4.5–6.5 μm ( = 54 × 5.5 μm, n=50), overlapping 2–3-seriate, fusiform, tapering towards rounded ends, slightly curved, guttulate, 7-septate, not constricted at septa, hyaline, smooth-walled. Asexual morph: hyphomycetous, helicosporous. Conidiophores (13–)18–45.5(–54) × 3.5–6 μm, pale brown, macronematous, erect, short, cylindrical, septate, smooth-walled. Conidiogenous cells 6–24 μm long, 3–5 μm wide, holoblastic, mono- to polyblastic, integrated, terminal, cylindrical, truncate at apex after conidial secession, hyaline to pale brown, smooth-walled. Conidia 100–150 μm diam. and conidial filament 8–12(–13.5) μm wide ( = 125 × 9.5 μm, n = 50), 500–1070 μm long, coiled 2½–3 times when tightly coiled, becoming loosely coiled in the water, with elongated basal cell, rounded at the tip, multi-septate, up to 93-septate, slightly constricted at septa, pale brown, smooth-walled. (Descriptions from Lu et al. 2017)


Material examined: CHINA, Guangxi Province, Fang Cheng Gang, on decaying wood in a freshwater stream, 15 May 2016, Yong-Zhong Lu, JHC23-3 (HKAS 97431, holotype; GZAAS 16-0069, isotype); ex-type living culture, MFLUCC 17-0049 = GZCC 16-0057; Ibid., 15 May 2016, Yong-Zhong Lu, JHC02-1 (HKAS 97421, paratype; GZAAS 16-0105), living culture, MFLUCC 17-0039 = GZCC 16-0093; Ibid., JHC05-1 (GZAAS 16-0046, paratype), living culture, GZCC 16-0034; Ibid., JHC08-1 (GZAAS 16-0051, paratype), living culture, GZCC 16- 0039; Ibid., JHC12-3 (GZAAS 16-0056, paratype), living culture, GZCC 16-0044; Ibid., JHC23-1 (GZAAS 16-0067, paratype), living culture, GZCC 16-0055; Ibid., JHC23-2 (GZAAS 16-0068, paratype), living culture, GZCC 16-0056.


Notes: Berkleasmium aquaticum was collected from a freshwater stream in Guangxi Province, southern China. Morphologically, the sexual morph of B. aquaticum is similar to B. septoconstrictum (ANM 536.1) in that ascomata are covered with one-celled setae, asci bitunicate and cylindrical, ascospores fusiform (Promputtha & Miller 2010). However, B. aquaticum differs from B.septoconstrictum in having narrower asci (115-175 × 12.5-16 μm vs 110-140 × 17-22 μm). The asexual morph of B. aquaticum resembles B. guangxiense in having macronematous, erect, short conidiophores, terminal conidiogenous cells and helicoid conidia. However, B. aquaticum differs from B. guangxiense in having different number of septa (up to 93-septate vs up to 62-septate). Phylogenetically, B. aquaticum forms a sister clade to B. guangxiense with high support, but the phylogenetic tree clearly showed that they are phylogenetically distinct species. Further, we also compared B. aquaticum with B. guangxiense by using single gene data, and there are 44 bp (base pair), 3 bp and 37 bp differences in ITS, LSU and TEF1α respectively, which also confirmed that they are phylogenetically distinct species. (Notes from Lu et al. 2017)


Fig 1. Berkleasmium aquaticum (HKAS 97421, GZAAS 16-0046, GZAAS 16-0051, GZAAS 16- 0056, GZAAS 16-0067 and GZAAS 16-0068, paratypes). a-c Colony on decaying wood. d-g, j Conidiophores with attached conidia. h-i Conidiophores with conidiogenous cells. k-m Conidia. n Germinating conidium. o-p Colony on PDA from above and below. Scale bars: d = 100 µm, e, j-n = 50 µm, f-i = 20 µm, o-p = 20 mm. (Lu et al. 2017)



Lu YZ, Boonmee S, Liu JK, Hyde KD, Bhat DJ, Eungwanichayapant PD, Kang JC (2017) Novel Neoacanthostigma species from aquatic habitats. Cryptogam Mycol 38:169–191

Promputtha I, Anmiller AN (2010) Three new species of Acanthostigma (Tubeufiaceae, Dothideomycetes) from Great Smoky Mountains National Park. Mycologia 102(3): 574–587


About Freshwater Fungi

The webpage Freshwater Fungi provides an up-to-date classification and account of all genera of freshwater fungi.


Published by the Mushroom Research Foundation 
Copyright © The copyright belongs to the Mushroom Research Foundation. All Rights Reserved.