Neoaquastroma bauhiniae C. Phukhams. & K.D. Hyde

Phukhamsakda, Chayanard, Bhat, Darbhe J., Hongsanan, Sinang, Xu, Jian-Chu, Stadler, Marc & Hyde, Kevin D., 2018, Two novel species of Neoaquastroma (Parabambusicolaceae, Pleosporales) with their phoma-like asexual morphs, MycoKeys 34, pp. 47-62 : 47

Neoaquastroma bauhiniae C. Phukhams. & K.D. Hyde sp. nov. Figure 2

Etymology.

Name refers the host from which this fungus was isolated.

Type material.

THAILAND. Phrae Province: Song District, on dead twigs of Bauhinia variegata L. ( Fabaceae ), 25 July 2015, C. Phukhamsakda, S1-11, MFLU 17-0002 (holotype), MFLUCC 16-0398 = ICMP 21572 (ex-type living culture).

Description.

Saprobic on dead twigs of Bauhinia variegata L. Sexual morph. Ascomata 113-190 μm high × 170-307 μm diam. (x̄ = 160 × 260 μm, n = 10), semi-immersed to immersed, solitary, scattered, subglobose to compressed, coriaceous, brown to dark brown, rough-walled, with short hyphae projecting from peridium, ostiolate. Ostiole 33 × 85 μm diam., centrally located, papillate, periphysoid. Peridium 8-25 μm wide (x̄ = 17, n = 30), with cells 3-8 μm wide, composed of 3 layers of reddish-brown to dark brown, cells of textura angularis, inner layer composed of hyaline gelatinous cells. Hamathecium composed of numerous, dense, long, 1-2.4 μm (x̄ = 1.7 μm, n = 50), narrow, filiform, transversely septate, branched, anastomosing, cellular psedoparaphyses. Asci 53-116 × 26-43 μm (x̄ = 98 × 37 μm, n = 30), 8-spored, bitunicate, fissitunicate, oboviod to oblong, with furcate pedicel, with ocular chamber visible when immature. Ascospores 37-46 × 9-16 μm (x̄ = 43 × 13 μm, n = 50), bi-seriate or overlapping, broad fusiform, narrow towards the apex, initially hyaline, becoming brown to dark brown at maturity, 4-7-transversely euseptate, constricted at the septa, with cell above central septum wider, rough-walled, indentations present, surrounded by 7-12 μm wide, mucilaginous sheath. Asexual morph coelomycetous. Pycnidia produced on mycelium in water agar. Conidiomata 33−49 μm high × 92-108 μm wide diam., pycnidial, dark brown to black, covered by dense vegetative hyphae, globose, in agar immersed to superficial, uniloculate, solitary to scattered, ostiolate. Conidiomatal wall thin, brown to black-walled with cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 3−4 × 2−3.5 μm, enteroblastic, phialidic, integrated, oblong, hyaline, formed from the inner layer of pycnidium wall. Conidia 2-4 × 1.5-2 μm (x̄ = 3 × 1.7 μm, n = 100), broad-oblong to oval, hyaline, aseptate, smooth-walled.

Culture characteristics.

Colonies on MEA, reaching 50 mm diam. after 4 weeks at 25 °C. Culture dark olive-green with black centre, with dense mycelia, circular, flat, umbonate, rough surface, dull, fimbriate, radially furrowed, covered with white aerial mycelium; mycelium strongly radiating into agar, yellow pigment diffusing in the agar; reverse black with radiating brown mycelium. Sexual and asexual morphs formed in culture. Morphology of sexual phase similar to those on substrate.

Additional material examined.

THAILAND, Phrae Province, Song District, on dead twigs of Bauhinia variegata L. ( Fabaceae ), 25 July 2015, C Phukhamsakda, S1-11 (isotype in HKAS, under the code of HKAS 99513); ibid., on dead twigs of Bauhinia purpurea L. ( Fabaceae ), 5 May 2016, C Phukhamsakda, S1_03_16, ex-paratype living culture, MFLUCC 17-2205.

Distribution.

Phrae Province, Thailand.

Notes.

Neoaquastroma bauhiniae is similar to N. krabiense , but the ascomata, asci and ascospores are smaller and the species also has a thinner peridium with 4−7 septate hyaline ascospores. Thus, Neoaquastroma bauhiniae is introduced as a second species in Neoaquastroma based on its unique morphology coupled with high support values from the phylogenetic analysis (100% ML/1.00 PP, Fig. 1). Tanaka et al. (2015) only described the asexual morph in Parabambusicola to produce spermatia. We now obtained a single spore isolate which produces both sexual and asexual morphs in culture. The asexual morph of Neoaquastroma bauhiniae produced pycnidial conidiomata with hyaline conidia (Fig. 2, u–z).