Dinemasporium Lév., Annls Sci. Nat., Bot., sér. 3 5: 274 (1846)
Facesoffungi number: FoF 01763
Sordariomycetes, Sordariomycetidae, Chaetosphaeriales, Chaetosphaeriaceae
Saprobic on various herbaceous and woody substrata. Sexual morph: Ascomata subepidermal, on leaf sheaths and stems, immersed to semi-immersed, solitary to gregarious, globose to elongated, unilocular, glabrous, thick-walled composed of brown elongate polygonal cells. Asci 4–8-spored, unitunicate, cylindrical to subcylindrical, pedicellate, rounded above. Ascospores hyaline, uniseriate, rarely sub-biseriate, narrowly elliptical to spindle-shaped or slightly inequilateral, smooth-walled, biguttulate. Paraphyses absent (Webster 1955). Asexual morph: Conidiomata black, stromatic, cupulate, pulvinate in surface view, initially closed, ultimately becoming erumpent and often covered with a mass of conidia that is glutinous and pale pink when moist, but waxy yellowish brown and crustose when dry, solitary to gregarious, superficial to semi-immersed, oval to rounded or irregular in outline, unilocular, setose. Conidomatal setae composed of two types, a) arising from basal stroma, conspicuous, subcylindrical, unbranched, septate, dark brown to black, blunt at the base, pale brown, tapered towards the apex, rigid, thick- and smooth-walled; b) arising from excipular elements, pale brown to brown, inconspicuous, subulate, flexuous, unbranched, aseptate, smooth-walled. Conidiomatal wall composed of a thin hypostroma and well-developed excipulum. Conidiophores lining the cavity of the conidiomata, hyaline, cylindrical to subcylindrical, branched, smooth-walled, invested in mucus. Conidiogenous cells hyaline, phialidic, cylindrical to subcylindrical or lageniform, discrete or integrated, indeterminate, smooth-walled. Conidia hyaline, ellipsoid, allantoid to naviculate or fusiform, unicellular, bearing branched or unbranched, single or multiple, bipolar or lateral appendages.
Types species: Dinemasporium strigosum (Pers.) Sacc., Michelia 2(7): 281 (1881)
= Dinemasporium graminum (Lib.) Lév., Annls Sci. Nat., Bot., sér. 3 5: 274 (1846)
Notes: Léveillé (1846) introduced Dinemasporium with D. graminum (Lib.) Lév. (= D. strigosum (Pers.) Sacc.) as type species. The genus is characterized by superficial, cupulate, setose conidiomata which are initially closed, becoming erumpent, and unicellular conidia with bipolar appendages (Léveillé 1846). Two additional species were added, D. platense Speg. and D. cruciferum Ellis, and the generic concept was expanded to accommodate species with both bipolar and lateral conidial appendages (Spegazzini 1880, Ellis 1882). Conidial appendages are seen as taxonomically informative in separating species and genera (Sydow et al. 1916, Kalani 1964, Nag Raj 1993, Duan et al. 2007). Saccardo (1884a) established the subgenus Stauronema to accommodate taxa with conidia bearing apical, basal and lateral appendages. Stauronema was elevated to generic level by Sydow et al. (1916) on the basis of insertion of conidial appendages. Sutton (1980) accepted this proposal and narrowed circumscription of Dinemasporium to include only species with aseptate conidia. Crous (2012a) reduced Stauronema to a synonym of Dinemasporium based on molecular data (LSU, ITS), and concluded that appendage morphology alone cannot be a defining feature at generic level. Hashimoto et al. (2015a) confirmed this conclusion and added Diarimella Sutton as a synonym because diarimella-like species nested within Dinemasporium. Therefore, the generic concept of Dinemasporium is expanded to accommodate species having conidia with unicellular, unbranched or branched, single or multiple, bipolar and lateral appendages at each end.
Culture studies showed that Dinemasporium strigosum was associated with Phomatospora dinemasporium J. Webster, a species having 4–8-spored, unitunicate, cylindrical, pedicellate, asci with rounded apex and hyaline, uniseriate, narrowly elliptical to spindle-shaped conidia (Webster 1995). However, Rappaz (1992) excluded P. dinemasporium from Phomatospora Sacc. because it lacked ornamented ascospores and an ascus apical ring. He also connected P. berkeleyi Sacc. (generic type of Phomatospora) and P. arenaria Sacc., E. Bommer & M. Rousseau to Sporothrix Hektoen & C.F. Perkins asexual morph (hyphomycetes), which is in conflict with coelomycetous asexual morph of P. dinemasporium (Fallah and Shearer 1998, Senanayake et al. 2016). The sexual morph of Dinemasporium has not been subsequently reported. More collections of Phomatospora-like taxa are needed to confirm the connection with Dinemasporium species.
We re-examined the type species of Dinemasporium strigosum, D. cruciferum Ellis (= Stauronema cruciferum) and D. setulosa (= Diarimella setulosa B. Sutton) and provide a detailed description and photo plates. Four collections from Italy are also identified as conspecific with D. pseudostrigosum, D. pseudodecipiens and D. morbidum. Dinemasporium pseudodecipiens is considered to be a complex species, because of its varied conidiomatal setae morphology and conidial dimensions. Additional fresh collections are needed to confirm this.
Distribution: Argentina, Canada, China, Commonwealth of Independent States (Former U.S.S.R.), Cuba, Czech Republic, France, Ghana, India, Italy, Japan, Netherlands, Nigeria, Sierra Leone, USA, (Nag Raj 1993, Duan et al. 2007, Crous et al. 2012b, 2014b, Hashimoto et al. 2015, this study).
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.