14/06/2014

Chi và loài nấm mới Braunomyces dictyosporus ở Cát Tiên

Loài Braunomyces-dictyosporus (Theo IMa Fungus) ·
(biodivn.blogspot.com) Abstract: The generic name Braunomyces (ascomycetes, asexual morph), with B. dictyosporus as type species, is described, illustrated and discussed, based on material collected in Vietnam on leaf debris of an unidentified broadleaved tree. The new genus is well characterised and quite distinct from other synnematous and non-synnematous dematiaceous hyphomycete genera by its unique combination of traits, viz. determinate synnematous conidiomata, integrated, terminal and intercalary conidiogenous cells with one to several conidiogenous vesicles becoming cupulate with age, tretic conidiogenesis, and mostly cruciately septate, solitary dictyoconidia.
Braunomyces Melnik & Crous, gen. nov. MycoBank MB807593: 
Braunomyces dictyosporus Melnik & Crous, sp. nov. MycoBank MB807594 
Etymology: Epithet derived from the dictyoseptate conidia.
Diagnosis: Synnemata determinate, 400–650 µm long, consisting of brown, apically splaying conidiophores. Conidiogenous cells terminal and intercalary, 6–20 × 2–7 µm, with a single or several aggregated swellings, 1.5–3.5 µm diam, subcircular to somewhat oblong in outline, later often collapsing, becoming cupulate, mono- to polytretic, loci about 0.8–1.5 µm diam. Conidia solitary, dictyosporous, globose, subglobose, (4–)5–8(–9) µm diam, 2- to 4-celled, cruciately to obliquely septate, pale to medium dark olivaceous brown, verruculose to verrucose. 
Type: vietnam: Dong Nai Prov.: Cat Tien National Park, Nam Cat Tien Sector, polydominant monsoon tropical forest, on dry leaves of an unidentified broadleaved tree, 16 Nov. 2011, Yu. Novozhilov (HAL 2606 F – holotype; LE 263985, CBS H-21489 – isotypes).
Description: Conidiomata synnematous, scattered, dark brown to blackish. Synnemata determinate, erect, straight, 400–650 µm long, composed of tightly appressed filaments, forming a firm subcylindrical, dark brown stipe, 20–40(–50) µm wide, widened and foot-like at the very base, to 130 µm diam, with a loose capitulum of apically divergent conidiophores, free terminal portions of the filaments 80–300 µm long. Conidiophores individually filiform, simple or occasionally branched, 1.5–3 µm wide, pluriseptate, brown, wall thin to slightly thickened, smooth. Conidiogenous cells integrated, terminal and intercalary, about 6–20 × 2–7 µm, irregularly shaped due to vesicular conidiogenous loci, pale to medium brown, thin-walled, smooth, with a single or several aggregated swellings (“conidiogenous vesicles”), 1.5–3.5 µm diam, subcircular to somewhat oblong in outline, later often collapsing, becoming cupulate, loci about 0.8–1.5 µm diam, with minute pore surrounded by a slightly darkened refractive halo or halo sometimes lacking, conidiogenesis tretic (mono- to mostly polytretic). Conidia solitary, conidium initials globose, colourless or very pale, aseptate, in this stage rough wall ornamentation already evident, at first forming a single median septum, followed by one or mostly two additional oblique to perpendicular septa, pigmentation setting in with septation and gradually proceeding, mature conidia dictyosporous, globose, subglobose to slightly angular in outline, (4–)5–8(–9) µm diam, 2- to 4-celled, cruciately to obliquely septate, occasionally slightly constricted at the septa, wall relatively thin (up to 0.8 µm), pale to medium dark olivaceous-brown, verruculose to verrucose. (biodivn.blogspot.com) 
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