Biatriosporaceae K.D. Hyde,  in Hyde et al., Fungal Diversity 63: 50 (2013)

Index Fungorum Number: IF803357

Saprobic on decaying submerged intertidal mangrove wood. Sexual state: Ascomata relatively large, solitary to gregarious, pyreniform, immersed, lying horizontal to the host surface, ostiolate, periphysate, black, coriaceous, with ostiole recurving upwards to pierce the host surface. Peridium thin, composed of brown pseudoparenchymatous cells. Hamathecium of dense, thin (ca 1μm diam) anastomosing, branching, trabeculate pseudoparaphyses embedded in a gelatinous matrix. Asci 8-spored, bitunicate, fissitunicate, cylindrical, with a relatively long pedicel, with a large, distinct ocular chamber. Ascospores overlapping uni-seriate, fusiform, dark brown, with hyaline swollen rounded ends, with 1–4 septa towards the ends, lacking septa in the centre part, smooth-walled, releasing mucilage from the ends. Asexual state: Unknown.

Typus : Biatriospora K.D. Hyde & Borse

Notes: This remarkable genus was introduced by Hyde and Borse (1986) for a mangrove inhabiting species and has since been collected many times and shown to have a wide-ranging distribution and to occur on a wide range of hosts. The dark brown ascospores are unusual in that they are fusiform with hyaline, rounded swollen ends which release mucilage (Hyde and Jones 1989) and 1–4 septa are situated near the ends. In previous classifications, this genus would have sat nicely in Melanommataceae, as it has trabeculate pseudoparaphyses. However, Liew et al. (2000) show this character to be unreliable in predicting family placement of genera in Dothideomycetes. In the phylogenetic tree, this genus sits independently with Roussoella and Roussoellopsis strains with strong support (92 %). A new family, Biatriosporaceae in the Pleosporales is therefore introduced to accommodate this monotypic genus.

Species

  • Biatriospora

Fig. Biatriospora marina (Material examined: SEYCHELLES, on submerged wood of Rhizophora, 2 January 1985, K.D. Hyde, IMI 297768, holotype). a Ascomata semi-immersed on host. b Vertical section of ascoma. c Peridium. d Pseudoparaphyses stained with lactophenol cotton blue. e–f Bitunicate asci. h–i Ascospores. g Pedicle. Scale bars: b, c =100μm. e =50μm. d, f–i =20μm