Pleurophragmium Costantin

Réblová, Martina, Nekvindová, Jana, Bauchová, Lucie & Hernández-Restrepo, Margarita, 2025, Pleurophragmium parvisporum (Ascomycota): One name, seven stories – a case highlighting the need for verification of strains from public culture collections, IMA Fungus 16, pp. e 173033-e 173033 : e173033-

Pleurophragmium Costantin , Les mucédinées simples: 100. 1888.

Synonyms.

Dactylaria sect. Pleurophragmium (Costantin) de Hoog , Stud. Mycol. 26: 36. 1985.

Neomyrmecridium Crous , Persoonia 41: 287. 2018.

Type species.

Pleurophragmium parvisporum (Preuss) Hol. - Jech.

Description.

Sexual morph. Not observed. Asexual morph. Colonies effuse, hairy, brown to black, subhyaline, beige to pale brown when sporulating; vegetative hyphae immersed or semi-immersed. Conidiophores macronematous, mononematous, solitary or in small groups, erect, straight or slightly flexuous, unbranched or rarely branched, sometimes elongating percurrently, brown, septate. Conidiogenous cells integrated, terminal and / or intercalary resulting from the formation of a septum within the original cell during sympodial elongation, polyblastic, occasionally monoblastic, sympodially proliferating, bearing one to several denticles or forming a rachis with minute, pimple-like denticles or protrusions scattered over the surface; conidiogenesis holoblastic-denticulate. Conidia solitary, dry, acropleurogenous, obovoid or subclavate, fusiform, ellipsoidal, usually tapering towards the base, with a distinct hilum, hyaline, subhyaline or pale brown, sometimes with paler end cells, aseptate or transversely septate, wall smooth or finely ornamented, with an ephemeral mucoid sheath; conidial secession schizolytic.

Notes.

Morphological comparisons together with phylogenetic analyses of P. parvisporum CBS 770.83 support the view that genera Neomyrmecridium and Pleurophragmium are congeneric, leading to the proposal of 11 new combinations and the introduction of two new names.

Given the substantial morphological variability among species currently placed in Pleurophragmium , the genus is unlikely to represent a single evolutionary lineage, rendering the traditional generic concept untenable. Accordingly, the present generic description is based on the morphological variability of species whose placement is supported by molecular data and refers to Pleurophragmium s. str. The following list of species is organised into three categories: (i) species accepted in Pleurophragmium s. str.; (ii) species of uncertain status that remain in Pleurophragmium s. lat.; and (iii) species excluded from Pleurophragmium and transferred to other genera. Names in bold indicate the currently accepted classification, accompanied by full synonymy and, where appropriate, brief explanatory notes. The interspecific variability of species listed in the first two categories is summarised in the synopsis table (Table 3 ). Key to species of Pleurophragmium was provided by D’Souza and Bhat (2012).

Aquapteridospora ( Distoseptisporales , Sordariomycetes) ( Yang et al. 2015), is a dematiaceous hyphomycete genus that warrants comparison with Pleurophragmium . Both genera share rigid, erect, darkly pigmented, simple conidiophores on the natural substrate that bear terminal and frequently intercalary holoblastic-denticulate conidiogenous cells that proliferate sympodially, as well as septate conidia that may be surrounded by a mucoid sheath. However, they differ primarily in conidial pigmentation. In Pleurophragmium s. str., conidia are typically hyaline to subhyaline, becoming pale brown at maturity or when in mass, occasionally showing paler end cells, seldom with a mucoid sheath, and have thin-walled septa. Pleurophragmium fusiforme is an exception in having pale brown conidia with paler ends. However, in Aquapteridospora conidia are primarily pigmented, continuously brown or dark brown, often with paler end cells, with thick-walled septa and are often embedded in a mucoid sheath. The exception is A. hyalina described with hyaline conidia that become subhyaline to pale brown at maturity ( Ma et al. 2022). Based on molecular evidence, Pleurophragmium bambusinum ( Dai et al. 2016) has been transferred to Aquapteridospora by Bao et al. (2021). In addition, several other Pleurophragmium species of uncertain status (see below) and which lack molecular data, show close morphological similarity with members of this genus.

Pleurotheciella (Réblová et al. 2012) is another genus warranting comparison with Pleurophragmium . Despite their close morphological resemblance in asexual characteristics, which makes them difficult to distinguish, the two genera are clearly separated phylogenetically. Pleurotheciella belongs to the Pleurotheciales , where it forms a robust and species-rich lineage.