Neospadicoides amphibia R.J. Xu, Boonmee & Q. Zhao, 2023

Xu, Rong-Ju, Zhu, Ying-An, Li, Lu, Yu, Feng-Ming, Boonmee, Saranyaphat & Zhao, Qi, 2023, A new lignicolous hyphomycete species of Neospadicoides in Xenospadicoidaceae (Xenospadicoidales) from Thailand, Phytotaxa 619 (2), pp. 161-172 : 165-169

Neospadicoides amphibia R.J. Xu, Boonmee & Q. Zhao , sp. nov. ( FIGURES 2–3 )

Index Fungorum number: IF558744, Facesoffungi number: FoF 10322

Etymology:—“ amphibia ” meaning amphibious; referring to freshwater and terrestrial habitats where the specimens were collected.

Holotype:— MFLU 21-0108

Saprobic on submerged decaying wood in a freshwater stream. Sexual morph: Undetermined. Asexual morph: Colonies superficial, effuse, dark brown. Mycelium mostly superficial, partly immersed in the substrate, consisting of branched, septate, smooth, hyaline to pale brown hyphae. Conidiophores 150–411 × 5–9 μm (x = 282 × 7 μm, n = 20). macronematous, mononematous, unbranched, single or in groups, erect, cylindrical, straight or slightly flexuous, brown, 6–10-septate, smooth, slightly tapering towards the apex, truncate at the apex. Conidiogenous cells 5–14 × 2–5 μm (x = 9 × 3 μm, n = 50), monoblastic, integrated or discrete, terminal and intercalary, obclavate, sometimes cylindrical chain, pale brown to brown, darkened at the terminal, paler towards the truncate apex, usually percurrently proliferating. Conidia 14–33 × 7–17 μm (x = 23 × 11 μm, n = 90), acrogenous or acropleurogenous, obovoid, wider and rounded at the apex, narrow towards truncate at the base, hyaline to pale brown, becoming brown at maturity, 3- euseptate, guttulate, smooth-walled.

Culture characteristics:— Conidium germinated on PDA media within 24 hours and germ tubes arising from terminal end of conidium. Colony reached 5 cm at 28°C in the incubator for 3 weeks on PDA media. Circular, flat, sparse, dark brown mycelium, with radial margin; sporulation in culture. Conidiophores 257–400 × 3–6 μm (x = 312 × 4 μm, n = 15), often reduced to conidiogenous cells, macronematous, mononematous, erect, cylindrical, straight or slightly flexuous, unbranched, sometimes branched, brown, sometimes rhizoid at the base ( FIGURE 3 , f). Conidiogenous cells 4–8 × 2–4 μm (x = 6 × 3 μm, n = 27), monoblastic, integrated, terminal and intercalary, pale brown to brown, darkened at the terminal, paler towards the truncate apex. Conidia 8–20 × 6–12 μm (x = 14 × 8 μm, n = 27), acrogenous or acropleurogenous, obovoid, wider and rounded at the apex, narrow towards truncate at the base, brown, 3-euseptate, smooth-walled.

Material examined:— THAILAND, Chiang Rai Province, Mueang, Nang Lae , saprobic on submerged decaying wood in a freshwater stream, 560 msl., 99°52′52.93″E, 20°3′2.52″N, 18 July 2020, R . J Xu , MD-98, ( MFLU 21- 0108 , holotype), ex-type living culture, MFLUCC 21-0167 ; THAILAND, Chiang Mai Province, Mushroom Research Center ( MRC), 675m msl., 98°46′44.28″E, 19°7′7.62″N, decaying wood in terrestrial habitat, 13 July 2020, Song Wang, SW369 ( MFUL 21-0109 , paratype), living culture, MFLUCC 21-0168 .

Notes: — Morphologically, Neospadicoides amphibia shares common characteristics with N. aquatica , N. bambusicola , N. lignicola , and N. yunnanensis such as macro-mononematous, solitary or in groups, erect, straight or flexuous, pigmented conidiophores, integrated conidiogenous cells, and obovoid or fusiform, septate, pale brown, conidia ( Luo et al. 2019, Hyde et al. 2021). However, N. amphibia differs from N. lignicola in conidiogenous cell characteristics with obclavate, successive proliferations from lateral and percurrent and paler towards the truncate apex ( Luo et al. 2019). Neospadicoides yunnanensis distinguished from N. amphibia in having polytretic, integrated conidiogenous cells and smaller conidia (7.5–10.5 μm vs 14–33 μm, Luo et al. 2019). Whereas, N. aquatica differs from N. amphibia in having percurrent proliferation of conidiophores, narrower fusiform to cylindrical (7–9 μm vs 7–17 μm) with 2-septate conidia ( Luo et al. 2019). For N. bambusicola differs from N. amphibia in having smaller sized conidia (15.5–22 × 5–7.5 μm vs 14–33 × 7–17 μm) and longer sized conidiophores [(781–)1027–1296 μm vs 150–411 μm)] ( Hyde et al. 2021). Comparison with other related species of Neospadicoides is shown in ( TABLE 2 ).

Phylogenetic analyses showed that we collections formed a distinct in Neospadicoides , and sister group with N. thailandica (100% ML, 1.00 BIPP) ( FIGURE 1 ). However, N. amphibia differs from N. thailandica in having 2–4- branches conidiophores, with gelatinous sheath and larger sized conidia (29–35 × 15–20 µm vs 14–33 µm × 7–17 μm) ( Bao et al. 2021).

Figures

FIGURE 1. RAxML tree based on analysis of a combined ITS, LSU, SSU and RPB2 sequences for Xenospadicoidaceae. Bootstrap support values for maximum likelihood (ML) equal to or greater than 75% were given above the nodes (left). Bayesian posterior probability (BIPP) equal to or greater than 0.95 were given above the nodes (right) and hyphen (-) were marked as values below 0.95. The tree was rooted to Ceratostomella cuspidata (ICMP 17629) and C. pyrenaica (CBS 129343) (Réblová et al. 2018). Two new isolates were shown in red.

FIGURE 2. Neospadicoides amphibia (MFLU 21-0108, holotype). a Colonies on substrate. b–d Conidiophores with conidiogenous cells and conidia. e Successive proliferations conidiogenous cells at the apex. f–m Immature and mature conidia. Scale bars: b = 100 μm, c–e = 20 μm, f–m =10 μm.

FIGURE 3. Neospadicoides amphibia sporulation in PDAculture (MFLUCC 21-0167,ex-type). a Germinated conidium.b Colony culture on PDA from surface at 2 weeks. c–e Development of mycelium and conidia in culture. f Conidiophores with conidia. g Conidiogenous cells with sometimes branched conidiophores. h–j Conidia. Scale bars: a, h–j = 10 μm, d, f = 50 μm, e, g = 20 μm.