Morphological Variety in Distoseptispora and Introduction of Six Novel Species

Abstract

Distoseptispora is one of the sporidesmium-like taxa with great variation in asexual morphology and delineation of species. Phylogenetic analyses of four gene regions LSU, ITS, TEF1α, and RPB2 revealed the placement of several sporidesmium-like species in Distoseptispora (Distoseptisporaceae, Distoseptisporales, Sordariomycetes), collected on submerged decaying twigs from streams in China and Thailand. Based on morphological examination and molecular DNA data, six new species, Distoseptispora amniculi, D. atroviridis, D. effusa, D. fusiformis, D. hyalina, and D. verrucosa, are proposed. Among them, D. hyalina is the first sexual morph confirmed in the genus. A new geographical record is reported for D. lignicola in China. Conidial length proved to be of less taxonomic significance for some Distoseptispora species, whereas the type of conidial septa is informative at species level.

Polyphasic Identification of Distoseptispora with Six New Species from Fresh Water

“…To date, a total of 54 Distoseptispora species have been reported. They have been found to cluster into three well-supported clades, which is in agreement with all previous studies on Distoseptispora [ 5 , 8 , 9 , 23 , 24 , 25 ]. The morphologies of Distoseptispora species are similar, and taxonomic identifications mainly rely on phylogeny.…”

“…Morphologically, D . aqualignicola possesses smooth-walled conidia, which are distinct from the verrucose conidia of D. aquamyces, D. suoluoensis and D. verrucosa [ 5 , 24 ]. Distoseptispora aqualignicola differs from D. meilingensis in having euseptate, thin-walled conidia as compared with the distoseptate, thick-walled conidia of D. MEILINGENSIS [ 43 ].…”

“…Notes : In our phylogenetic analyses, Distoseptispora nonrostrata cluster with D. effusa . Morphologically, D. nonrostrata possesses oblong, obclavate or narrowly obpyriform, mostly non-rostrate, pale-olivaceous or pale-brown conidia, while D. effusa is clearly different in having obclavate, rostrate, olivaceous-brown to dark-brown, longer conidia (35.5–113 μm vs. 22–51 μm) [ 24 ]. Comparisons of sequence data between these two species showed differences of 27 (4.9%, four gaps) and 34 (3.8%, no gaps) noticeable nucleotides in ITS and TEF gene regions, respectively.…”

“…Subsequently, the generic concept of Distoseptispora was emended to include percurrently elongating conidiogenous cells and euseptate, verrucose conidia with percurrent proliferation, based on the newly introduced species D. guttulata and D. suoluoensis [ 5 ]. In the past five years, more than 40 new species (excluding D. submersa ) were successively reported in Thailand and China [ 3 , 5 , 7 , 8 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. Distoseptispora submersa , found on submerged wood in China, was introduced by Luo et al [ 17 ].…”

“…Recently, Yang et al [ 24 ] used multi-locus analysis and reported, for the first time, a sexual morph in Distoseptispora , namely, D. hyalina , which was characterized by an immersed to semi-immersed, subglobose to ellipsoidal, dark-brown perithecial with a short neck; a relatively thick peridium; sparse, persistent, hyaline paraphyses; cylindrical asci with non-amyloid apical annuli; and hyaline, filiform, 0–3-septate ascospores with mucilaginous sheaths. To date, it is the only known sexual morph in Distoseptispora .…”