Canalisporium aquaticium
Canalisporium aquaticium J. Yang & K.D. Hyde, in Hyde et al., Fungal Diversity 100: 209 (2020)
Index Fungorum number: IF556631 Facesofungi number: FoF 06276
Etymology: Referring to the aquatic habitat.
Holotype: MFLU 18-1504
Saprobic on twigs from freshwater habitats. Sexual morph: Undetermined. Asexual morph: Colonies sporodochial, scattered, punctiform, pulvinate, dark brown to black, glistening. Mycelium immersed, consisting of branched, septate, smooth, thin-walled, pale to brown hyphae. Conidiophores micronematous or semi-macronematous, subhyaline or lightly pigmented, smooth, thin-walled, septate, simple or sparsely branched, loosely fasciculate, becoming vesiculate and disintegrating as conidia mature, up to 66 μm long, 3.5–6 μm wide. Conidiogenous cells monoblastic, integrated, terminal, determinate, hyaline or pale brown, cylindrical to ellipsoidal, giving rise to a single crop of conidia which mature synchronously. Conidia acrogenous, holoblastic, solitary, yellowish brown to mid brown, guttulate, muriform, with ordered arrangement of vertical and transverse septa, slightly constricted at the septa, complanate, smooth-walled, consisting of three vertical columns and 7–8 transverse rows of cells with a single cuneiform basal cell, 45–58 × 21–25.5 μm (x̄ =51 × 23 μm, n=30), thickened at the septa of middle column.
Culture characteristics: Conidia germinating on PDA within 24 h and germ tubes produced from several cells. Colonies on PDA slow-growing, reaching 5–10 mm diam. at a month at 25 °C, in natural light, circular, with sparse dark brown mycelium on the surface with entire margin, in reverse dark brown to black.
Material examined: THAILAND, Phang Nga Province, Bann Tom Thong Khang, on decaying wood submerged in a freshwater stream, 17 December 2015, J. Yang, Site 7-12-1 (MFLU 18-1504, holotype; KUN-HKAS 102159, isotype), ex-type living culture MFLUCC 16-0862.
GenBank numbers: ITS=MN061351, LSU=MN061365, SSU=MN061353.
Notes: Canalisporium aquaticium, C. kenyense Goh, W.H. Ho & K.D. Hyde and C. pulchrum (Hol.-Jech. & Mercado) Nawawi & Kuthub. have three columns of conidial cells, C. variabile Goh & K.D. Hyde rarely has three columns and mostly has two columns of conidial cells, while the remaining species produce conidia with two columns (Nawawi and Kuthubutheen 1989; Goh and Hyde 2000; Phookamsak et al. 2019). Canalisporium aquaticium difers from C. kenyense in having yellowish brown conidia with a single basal cell, while C. kenyense has reddish brown to dark brown conidia often with three basal cells (Goh et al. 1998; Phookamsak et al. 2019). Canalisporium aquaticiumis distinguished from C. variabile in having regular muriform conidia which are slightly constricted at the septa, while C. variabile has variable-shaped conidia which are strongly constricted at the septa (Goh and Hyde 2000). In addition, conidia in C. aquaticium (45–58×21–25.5 μm) are wider than those in C. kenyense (34–56×24–34 μm) and larger than those in C. variabile (22–35×15–23 μm).
Canalisporium aquaticium mostly resembles C. pulchrum in having regular muriform conidia of a similar size with a single cuneiform basal cell. However, conidia of C. aquaticium (45–58 × 21–25.5 μm) often comprise 7–8 transverse rows of cells, while conidia of C. pulchrum (36–55 × 22 27 μm) have 5–7 rows (Nawawi andKuthubutheen 1989). Conidiophores in C. aquaticium are hyaline and up to 66 μm long but those in C. pulchrum are mostly pale brown and up to 20 μm long. The combined four-gene phylogenetic analyses (Fig. 135) showed that C. aquaticium clustered close to C. elegans Nawawi & Kuthub., C. jinghongense L. Cai, K.D. Hyde & McKenzie and C. pulchrum with signifcant support (79% ML, 95% MP, 1.00 BYPP). Sequence data of C. pulchrum generated in Sriindrasutdhi et al. (2010) with only one conidial photo which matches the conidial characters in the original diagnosis. However, sequence data for its ex-type is unavailable. Canalisporium pulchrum has a worldwide in distribution (Goh et al. 1998; Ferrer and Shearer 2005; Damyanti et al. 2015). Goh et al. (1998) showed several collections of the species but one collection from Brunei (HKU(M) 2911) shares the same conidial characters with C. aquaticium. We therefore assume that the previous collections of C. pulchrum may not be correctly identifed for all collections. Thus, the epitypifcation of C. pulchrum is necessary to resolve the taxonomic problem (Hyde and Zhang 2008).
Figure X. Canalisporium aquaticium (MFLU 18-1504, holotype). a Colonies on woody substrate. b, c Conidiophores and conidia. d–h Conidia. i Germinated conidium. j, k Culture on WEA (j=from above, k=from below). Scale bars: a=500 μm, b–d=30 μm, e–i=20 μm
Reference: Hyde KD, Dong Y, Phookamsak R, Jeewon R, Bhat DJ, Jones EB, Liu NG, Abeywickrama PD, Mapook A, Wei D, Perera RH. Fungal diversity notes 1151–1276: taxonomic and phylogenetic contributions on genera and species of fungal taxa.
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