Neomicrosphaeropsis Thambugala, Camporesi & K.D. Hyde, gen. nov. Index Fungorum number: IF552089
Etymology: The generic epithet, neo (Lat., new), refers to the similarity to Microsphaeropsis
Saprobic or weak pathogens on branches of Tamarix species. Sexual morph: Ascomata solitary, scattered, immersed, slightly erumpent, dark brown to black, ostiolate. Peridium comprising 6–8 layers, outer layers heavily pigmented, thick-walled, comprising blackish to dark brown cells of textura angularis, inner layers composed of lightly pigmented to hyaline, thin-walled cells of textura angularis. Hamathecium comprising numerous, filamentous, branched, septate, pseudoparaphyses. Asci 8-spored, bitunicate, fissitunicate, cylindrical to cylindric-clavate, pedicellate, apically rounded, with an ocular chamber. Ascospores 1–2-seriate, partially overlapping, muriform, ellipsoidal, 4–6 transversely septate, with 3–4 vertical septa, constricted at the central septum, yellowish brown, conical and narrowly rounded at the ends, smooth-walled, with out a mucilaginous sheath (description modified from Crous et al. 2014). Asexual morph: Conidiomata pycnidial, scattered or solitary, immersed, slightly erumpent, black, globose to subglobose, uni- to multi-loculate, ostiolate. Conidiomatal wall consisting of light to dark brown, thick-walled cells of textura angularis, becoming hyaline towards the conidiogenous region. Conidiogenous cells enteroblastic, phialidic, hyaline, cylindrical, discrete or integrated, smooth. Conidia hyaline to light brown, aseptate, obovoid to ellipsoidal, smooth-walled.
Notes: Microsphaeropsis was established by Von Höhnel (1917), and placed in the family Montagnulaceae. Microsphaeropsis is morphologically similar to some species in the genus Coniothyrium and is characterized by phialidic conidiogenous cells with a periclinal thickening, and pale greenish brown, 0–1 septate conidia (De Gruyter et al. 2013; Chen et al. 2015). Barr (1987) classified Microsphaeropsis as an asexual morph of Phaeosphaeriaceae, while some Microsphaeropsis species have been reported in Montagnulaceae (= Didymosphaeriaceae) (Someya et al. 1997; Zhang et al. 2012; Verkley et al. 2014). Recent studies (De Gruyter et al. 2009, 2013; Aveskamp et al. 2010; Hyde et al. 2013) however, treated this genus in Didymellaceae based on the sequences of the type species M. olivacea (Bonord.) Höhn. Chen et al. (2015) showed in their phylogenetic analysis based on LSU, ITS, β-tubulin and RPB2 sequence data, that Microsphaeropsis grouped basal to the Didymellaceae and introduced a new family Microsphaeropsidaceae considering both morphological traits and phylogeny. Neomicrosphaeropsis represents a species complex which includes morphologically similar but phylogenetically different species. Recollecting and sequencing of more coniothyrium like species would be helpful to classify their placement in the genera Microsphaeropsis and Neomicrosphaeropsis.
Type species: Neomicrosphaeropsis italica Thambugala, Camporesi & K.D. Hyde