Arachnomyces jinanicus B.D. Sun Y.G. Zhou & A.J. Chen, 2019

Sun, Bing-Da, Zhou, Yu-Guang, Chen, Amanda-Juan & Houbraken, Jos, 2019, Phylogeny and a new species of the genus Arachnomyces (Arachnomycetaceae), Phytotaxa 394 (1), pp. 89-97 : 93-94

Arachnomyces jinanicus B.D. Sun Y.G. Zhou & A.J. Chen , sp. nov. Fig. 2–3

MycoBank: MB821133

Etymology: The specific epithet “jinanicus ” referring to the place where the fungus was first isolated.

Diagnosis. Colonies 25 oC 21 d on OAT 10–13 mm diam, PDA 11–15 mm diam, SAB 10–14 mm diam ( Fig. 2 ). Aerial mycelium on OAT sparsely developed and colonies were flat and white; on PDA and SAB sparse or produced moderately, gradually increasing in height and becoming wrinkled, reaching heights of 3–5 mm, colonies yellowishwhite or yellowish-grey, reverse dark brown or olive-brown and without any diffusing pigment.

Sporulation occurred slowly, poor on OAT and SAB, moderate on PDA. Vegetative hyphae hyaline, 1.0–2.5 μm wide, septate, smooth or finely verrucose, anastomosis was common, usually by direct fusion of adjacent hyphae or by producing thin lateral hyphal pegs ( Fig. 3L ). Fertile hyphae scarcely differentiated, initially septate without constriction at the septa, with individual cells swelling and becoming constricted at the septa. Arthroconidia formed randomly in intercalary positions or in basipetal order on lateral branches; broadly ellipsoidal, cylindrical, nearly spherical or irregularly shaped, 0–1 septate, often persisted in branched or unbranched chains, smooth to minutely-warty, hyaline to pale-yellow, (2.3–) 3.0–4.5 (–6.0) × 2.0–3.5 μm (0-septate), (4.5–) 5.0–7.0 (–8.5) × 2.5–3.5 μm (1-septate). Setae (brown hyphae) developed after 12 weeks’ incubation, 2.0–5.0 μm in width, bearing irregular, raised, darker brown knobs ( Fig. 3A–D ), with the apical regions straight. Sclerotia absent.

Holotype: — CHINA. Shandong province: Jinan city, 36°32’15” N 116°44’38” E, pig farm soil, 12 July 2011, B.D. Sun (HMAS 247193, holotype); ex-type living culture CGMCC 3.14173. GenBank accession numbers ITS: KY440749; 28S: KY440752.

Habitat. pig farm soil.

Known distribution. China.

Notes: The three A. jinanicus strains were crossed in all possible combinations and these crossings didn’t result in ascomata. Phylogenetically, A. jinanicus and A. nodosetosus clustered together and are sister species. The two species have a similar micromorphology, both of them have well developed anamorphic stages and chained arthroconidia, produce strongly nodose setae in cultures after prolonged incubation (12 weeks). The difference was that the setal tips of A. jinanicus were straight while those of A. nodosetosus were circinate or loosely coiled ( Sigler & Congly 1990, Gibas et al. 2002a). In addition, the arthroconidia of A. nodosetosus are larger, up to 17 μm in length and 6.5 μm in width ( Sigler & Congly 1990).

Figures

FIGURE 2. Colonies of Arachnomyces jinanicus (ex-type CGMCC 3.14173).A–B, on PDA; C–D, on SAB; E–F, on OAT.

FIGURE 3. Arachnomyces jinanicus (ex-type CGMCC 3.14173).A–B, Setae with dark brown knobs; C–D, Setal tips; E–K,Arthroconidia in persistent chains; L, Hyphal fusions. Scale bars: A = 10 μm (apply to B–D); E = 20 μm; F = 10 μm (apply to G–H); I, J, K, L = 10 μm.