Heteromicrosphaeropsis ononidicola (Thambug., Camporesi & K.D. Hyde) M. Mehrabi, K.D. Hyde & Jayaward., in Artand, Mehrabi-Koushki, Tabein, Hyde & Jayawardena, Mycosphere 43(7): 164 (2022)

Index Fungorum number: IF 841491; MycoBank number: MB 841491; Facesoffungi number: FoF 15900

Etymology – The species epithet “ononidicola” refers to the host genus Ononis on which the holotype occurs

Holotype – MFLU 16–2601

Saprobic on stems of Ononis spinosa L. Sexual morph: Undetermined. Asexual morph: Conidiomata 100–190 μm high × 100–230 μm diam. (x̄ = 135 × 155 μm, n = 10), pycnidial, scattered, solitary, aggregated or gregarious, immersed, slightly erumpent, black, globose to subglobose, uni- to bi-loculate, ostiolate. Conidiomatal wall 12–24 μm wide, consisting of light to dark brown, thick-walled cells of textura angularis, becoming hyaline to lightly pigmented towards the conidiogenous region. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 2.5–4.2 × 3.5–4 μm (x̄ = 3.5 × 3.8 μm, n = 15), enteroblastic, phialidic, hyaline, cylindrical, discrete or integrated, smooth.
Conidia 4–6 ×2–2.8 μm (x̄ = 5 × 2.3 μm, n = 50), hyaline to yellowish brown, aseptate, obovoid to ellipsoidal, straight, smooth-walled, sometimes minutely guttulate.

Culture characteristics – Colonies growing on PDA, reaching a diameter of 30 mm after 10 d at 25 °C, circular to irregular, flat to slightly raised, moderately dense, surface initially white, becoming pale saffron to pale white; saffron to dark brown, smooth surface with entire to slightly filamentous edge.

Material examined – ITALY, Province of Forlì-Cesena [FC], Valbura – Premilcuore, dead aerial stems of Ononis spinosa L. (Fabaceae), 13 June 2014, Erio Camporesi IT 1237 (MFLU 16–2601, holotype), ibid. (GZAAS 16–0129, isotype), ex-type living culture MFLUCC 15–0459, ICMP 21575

Notes – Microsphaeropsis ononidicola was introduced with the description of a saprobic strain (MFLUCC 15-0459) isolated from dead aerial stems of Ononis spinosa L. (Fabaceae) in Italy (Thambugala et al. 2018). In the phylogenetic analyses of the present study, this species is distant from the Microsphaeropsis lineage and other genera in the Microsphaeropsis complex. Therefore, a new genus, Heteromicrosphaeropsis, is introduced to accommodate this species. Nucleotide comparison of Heteromicrosphaeropsis M. Mehrabi-Koushki, K.D. Hyde & Jayaward., gen. nov. with Microsphaeropsis species revealed a difference of 0.6% (3/521 bp) in the LSU region, 2.6% (11/431 bp) in the ITS and 11% (22/198 bp) in the tub2. However, this new genus is morphologically similar to Microsphaeropsis but phylogenetically different. (Refer Thambugala et al. 2018)

Figure 1 – Heteromicrosphaeropsis ononidicola (holotype). a Appearance of conidiomata on host surface. b-d Vertical sections through conidiomata. e Conidiogenous cells and developing conidia. f conidia. Scale bars = b-d = 50 μm; e, f =10 μm.