Stromatolinea K. Habib & Q. R. Li, 2024

Habib, Kamran, Zhou, Xin, Zeng, Wenyu, Zhang, Xu, Hu, Hongmin, Wu, Qianzhen, Liu, Lili, Lin, Yan, Shen, Xiangchun, Kang, Jichuan & Li, Qirui, 2024, Stromatolinea, a new diatrypaceous fungal genus (Ascomycota, Sordariomycetes, Xylariales, Diatrypaceae) from China, MycoKeys 108, pp. 197-225 : 197-225

Stromatolinea K. Habib & Q. R. Li gen. nov.

Etymology.

Referring to linear characteristics of the stromata.

Type species.

Stromatolinea hydei K. Habib & Q. R. Li , sp. nov.

Description.

Saprobic on dead bamboo culms, forming black parallel elongate ascostromata on the host, surrounded by grey or black patches like pseudostromata. Pseudostromata grey or black, spreading between stromata and across the host surface. Sexual morph: Stromata parallel elongate, linear, consistent to inconsistent in thickness, fusiform, high, solitary to confluent, slit to non-slit, black or grey on its sides, exposing black ostioles. Upper cells of stromata near the perithecial ostiole black, thick-walled. Stromatic tissue completely yellow or yellow above and white between / below perithecia, compact. Ascomata perithecial, few to frequent, immersed in stromata, globose to subglobose, ostiolate centrally, with a neck, opening to outer surface, slight erumpent over stromata, appearing as black shinny spots. Peridium composed of elongate cell, texture angularis, outer thick layer, dark brown, inner hyaline, surrounded by yellow or white and yellow stromatic tissue. Hamathecium paraphyses, filiform, hyaline, long. Asci 8 - spored, clavate, with a long and thin pedicel, apically rounded to truncate, J- apical ring. Ascospores allantoid, aseptate, straight to slightly curved, rounded at both ends, subhyaline, with oil droplets in both ends. Asexual morph: undetermined.

Notes.

Phylogenetically, Eutypa is polyphyletic (Fig. 1 ), a species distributed in different clades. Ma et al. (2023) proposed a new genus, Alloeutypa , which exhibits close affinity to Eutypa . However, based on the presence of Diatrype - like discrete stromata with yellowish-green interior tissue characteristics and forming separate monophyletic clades, they proposed Alloeutypa as a new genus to accommodate Alloeutypa milinensis and A. flavovirens ( Ma et al. 2023) .

Morphologically, Stromatolinea is similar to Alloeutypa , as both possess yellowish-green interior tissue. However, the new genus is distinguished from Alloeutypa by its linear stromata and phylogenetically, they are clustered very distantly. The strains of Stromatolinea form a monophyletic clade representing its distinct position. Thus, based on morphological evidence and phylogenetic analyses, we accommodate Stromatolinea as a new genus with Stromatolinea hydei designated as the type species.

Figures

Figure 1. A – C. Phylogenetic tree generated from maximum likelihood analysis (RAxML) based on combined ITS and TUB 2 sequences data. Bootstrap support values for maximum likelihood (ML) greater than 70 % and Bayesian posterior probabilities (BPP) greater than 0.90 are displayed above or below the respective branches (ML / BPP). The species obtained in this study are in red and ex-type taxa are in bold.