Triadelphia fusiformis Y.Z. Lu, J.K. Liu & K.D. Hyde, 2018

Lu, Yong-Zhong, Fan, Cui, Kang, Ji-Chuan, Hyde, Kevin D., Boonmee, Saranyaphat & Eungwanichayapant, Prapassorn Damrongkool, 2018, Triadelphia fusiformis sp. nov. from a freshwater habitat in Thailand, Phytotaxa 374 (3), pp. 231-240 : 234

Triadelphia fusiformis Y.Z. Lu, J.K. Liu & K.D. Hyde , sp. nov. FIGURE 2

Index Fungorum : IF 555344; Facesoffungi number: FoF 04874

Etymology: ‘ fusiformis ’ referring to the fusiform conidia of this fungus.

Holotype: MFLU 18–1436

Saprobic on submerged decaying wood. Sexual morph: undetermined. Asexual morph: hyphomycetous, phragmosporous. Colonies on the substratum superficial, effuse, gregarious, black. Mycelium composed of partly immersed, partly superficial, hyaline, septate, branched hyphae. Conidiophores lacking. Conidiogenous cells holoblastic, monoblastic, integrated, borne directly on the mycelium, hyaline, smooth-walled. Conidia: this species develops one conidial form: form (d), fusiform, straight or sometimes curved, rounded at the tip, guttulate, 4–6-septate, rarely slightly constricted at septa, 25–30 × 11–13 μm (x = 27 × 12 μm, n = 50), end cells pale brown, central cells brown to dark brown, dark band covering over the central septum.

Culture characteristics: Conidia germinating on water agar and producing germ tubes within 24 hours. Colonies growing on MEA, circular, umbonate, surface rough, edge undulate, reaching 9 mm in 2 weeks at 28 °C, pale brown to brown. Mycelium superficial and partially immersed, branched, septate, hyaline to pale brown, smooth.

Material examined: THAILAND, Krabi, Plai Praya, Khao To, Ban Bang Thao Mae , on decaying wood in a freshwater stream, 17 December 2015, Saranyaphat Boonmee , BTM05–2 ( MFLU 18–1436 , holotype; HKAS 102206 , isotype) ; ex-type living culture, MFLUCC 16–0231 . GenBank numbers: ITS: MH777097 , LSU: MH777098 , TEF1 -α: MH763011 .

Notes: Morphologically, Triadelphia fusiformis ( FIGURE 2 ) is similar to T. alabamensis and T. queenslandica in having fusiform conidia which are multiseptate, the end cells pale brown, central cells brown to dark brown, and dark band covering over the central septum. However, Triadelphia fusiformis can be distinguished from T. alabamensis by fewer conidial septa (4–6-septate vs 6–8-septate) and only one conidial form, while T. alabamensis has two forms of conidia ( Li & Ye 2018). Triadelphia queenslandica has three forms of conidia, but T. fusiformis lacks these characters ( Matsushima 1989). Phylogenetically, Triadelphia fusiformis formed a distinct clade within the genus Triadelphia with good bootstrap support ( FIGURE 1 ), and the phylogenetic analysis indicates that T. fusiformis is distinct species from other Triadelphia species.

Figures

FIGURE 1. Phylogenetic tree based on analysis of a combined ITS and LSU dataset. Bootstrap support values for RAxML and maximum parsimony (MP) greater than 75 % and Bayesian posterior probability greater than 0.95 (PP) are indicated above the branches as MLBS/ MPBS/PP. The tree is rooted with Colletotrichum neosansevieriae CBS 139918 (Glomerellaceae). The new isolate is in red and ex-type strains are in black bold.

FIGURE 2. Triadelphia fusiformis (MFLU 18–1436, holotype). a Colony on decaying wood. b–f Conidia. g Germinating conidium. h–i Colony on MEA from above and below. Scale bars: a = 100 μm, b–g = 20 μm.