Mycotribulus Nag Raj & W.B. Kendr., Can. J. Bot. 48(12): 2219 (1970)
Facesoffungi number: FoF 07459
Agaricomycetes, Agaricomycetidae, Agaricales, Physalacriaceae
Saprobic on dead leaves of plant host. Sexual morph: undetermined. Asexual morph: Conidiomata dark brown to black, pycnidial, solitary to gregarious, immersed to semi-immersed, conical to subglobose, unilocular, thick-walled, glabrous, ostiolate. Ostiole cylindrical, single, centrally located. Conidiomata wall composed of thick-walled, hyaline to brown cells of textura angularis. Conidiophores hyaline, unbranched or sparsely branched, intermingled with paraphyses formed from the inner layers of the conidiomata. Paraphyses hyaline, filamentous, branched or unbranched, septate, narrowed at the base, broad and lobed or irregular at the apices. Conidiogenous cells hyaline, holoblastic, subcylindrical, to obclavate, discrete, smooth. Conidia hyaline, fusiform to navicular, pointed at apex, narrowed and somewhat truncated at base, aseptate, smooth, guttulate, bearing filiform, tubular, flexuous appendages at both ends, apical appendage single, polar, unbranched, straight or slightly curved, basal appendages mostly 2–3, invested laterally slightly above the truncate base, unbranched, divergent, straight or often curved.
Notes: Few coelomycetous genera viz. Cenangiomyces, Chaetospermum, Ellula, Fibulocoela, Giulia, Mycotribulus and Pycnovellomyces have been reported as asexual morphs of Basidiomycota (Dyko and Sutton 1979, Nag Raj 1979,1980, 1993, Rungjindamai 2008). Only Chaetospermum, Giulia and Mycotribulus are confirmed by molecular sequences (Rungjindamai 2008, Crous et al. 2014a, Tangthirasunun et al. 2014a). Mycotribulus was introduced by Nag Raj and Kendrick (1970) to accommodate M. mirabilis collected from rotting leaves of Eucalyptus sp. This species is probably cosmopolitan (China, India, Venezuela and South Africa and Thailand) and associated with several host plants namely, Apodytes abbottii Potg. & A. E.van Wyk, Eucalyptus camaldulensis Dehnh., Mangifera indica L. and Syzygium cordatum Hochst. ex Krauss (Nag Raj 1993, Crous 1993, Marincowitz et al. 2010). Rungjindamai et al. 2008) located Mycotribulus in Physalacriaceae (Agaricales) on the basis of SSU and LSU sequence data. Crous et al. (2014a) epitypified this genus and confirmed the result of Rungjindamai et al. (2008), and introduced the second species, M. indonesiae Crous.
Mycotribulus can be confused with Ajrekarella, Dinemasporium and Polynema because of the conidia being hyaline, fusiform to navicular or ellipsoid with appendages at each end. However, Mycotribulus and Ajrekarella have pycnidial conidiomata, which are distinct from the cupulate conidiomata in Dinemasporium and Polynema. Mycotribulus differs from Ajrekarella by its paraphyses.
Distribution: China, India and Venezuela (Crous et al. 2014).
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.