Dictyosporium tratense J. Yang & K.D. Hyde
Index Fungorum number: IF554772; Facesoffungi number: FoF04678
Etymology: Referring to the collecting site in Trat province, Thailand.
Saprobic on decaying plant substrates. Sexual morph: Undetermined. Asexual morph: Colonies punctiform, sporodochial, scattered, black, glistening. Mycelium mostly immersed, composed of smooth, septate, branched, hyaline to pale brown hyphae. Conidiophores micronematous, mononematous, septate, cylindrical, hyaline to pale brown, smooth-walled, sometimes reduced to conidiogenous cells. Conidiogenous cells monoblastic, integrated, terminal, determinate, hyaline to pale brown. Conidia (40–)43–54(–57) × (20–)23–32(–36) μm (x̄ = 49.5 × 26 μm, n = 40), acrogenous, solitary, cheiroid, smooth-walled, complanate, yellowish-brown to light brown, consisting of 39–68 cells arranged in 4–6 (mostly 5) closely compact columns, 9–11-euseptate in each column, guttulate; the inner columns nested within the outer columns, the outer columns derived from the basal cell of the conidium; the intermediate columns are derived from the first or second cell of the outer columns; the inner columns derived from the first or second cell of the intermediate columns; usually with 2–3 central columns longest and of equal length, 2–3 peripheral columns shorter and of equal length; sometimes with hyaline globose appendages at the apical cells of outer columns with hyaline cloud-shaped mucilaginous sheath.
Cultural characteristics: Conidia germinating on PDA within 24 h and germ tubes produced from basal cell. Colonies on MEA reaching 5–10 mm diam. in a week at 25 °C, in natural light, circular, with fluffy, dense, pale yellow mycelium in the middle and sparse mycelium in the outer ring on the surface with irregular margin; in reverse, dark yellow to brown in the middle and pale yellow at the margin.
Material examined: THAILAND. Trat Province, Amphoe Ko Chang, 12°08'N, 102°38'E, on decaying wood submerged in a freshwater stream, 27 April 2017, Y.Z. Lu, YJT 6-2 (MFLU 18-1042 holotype, HKAS 102133 isotype), ex-type living culture MFLUCC 17-2052 (Additional SSU sequence GenBank MH381761).
Notes: Phylogenetic analyses indicated Dictyosporium tratense nested within Dictyosporium and close to D. wuyiense. It is distinguished from the other species in the genus in having a mucilaginous sheath. Morphologically, D. tratense is most comparable to D. elegans in conidial colour and shape, but conidia of the new taxon (40-57 × 20-36 μm) are smaller than those of D. elegans (40-80 × 24-36 μm) (Goh et al. 1999).
Freshwater distribution: Thailand (Yang et al. 2018)
Yang J, Liu JK, Hyde KD, Jones EBG, Liu ZY (2018) New species in Dictyosporium, new combinations in Dictyocheirospora and an updated backbone tree for Dictyosporiaceae. Mycokeys 36:83–105