Neoaquastroma krabiense 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 krabiense C. Phukhams. & K.D. Hyde sp. nov. Figure 3

Etymology.

Name refers the location where this fungus was collected.

Type material.

THAILAND, Krabi Province: Meuang district, on dead twigs of Barringtonia acutangula ( Lecythidaceae ), 16 December 2015, C. Phukhamsakda, Kr015, MFLU 17-0003 (holotype), MFLUCC 16-0419 = ICMP 21572 (ex-type living culture).

Description.

Saprobic on dead twigs of Barringtonia acutangula (L.) Gaertn. Sexual morph. Ascomata 404-498 μm high × 290-319 μm diam. (x̄ = 426 × 300 μm, n = 10), immersed in bark, solitary, scattered or sometimes gregarious, compressed globose, with a flattened base, coriaceous, black to dark brown, smooth, papillate, ostiolate. Ostiole 137-146 μm high × 117-154 μm diam. (x̄ = 143 × 137 μm, n = 10), centrally located, oblong, filled with hyaline periphysoid. Peridium 45-73 μm wide (x̄ = 56, n = 30), cell width 3-12 (x̄ = 8 μm, n = 40) composed of 6 –10(– 13 at base) layers of blackish-brown to dark brown, with cells of textura angularis, outer layer heavily pigmented, inner layer composed of hyaline gelatinous cells. Hamathecium composed of numerous, dense, long, 1.6-2.4 μm (x̄ = 2 μm, n = 50), broad, filiform, transversely septate, branched, anastomosing, cellular pseudoparaphyses. Asci 95-169 × 29-45 μm (x̄ = 135 × 35 μm, n = 25), 8-spored, bitunicate, fisitunicate, oboviod to clavate, with furcate pedicel, ocular chamber clearly visible when immature. Ascospores 50-64 × 9-18 μm (x̄ = 57 × 13 μm, n = 50), bi-seriate or overlapping, fusiform, narrow towards the apex, hyaline, 5-8-transversely septate, constricted at the septa, cell above central septum slightly wider, rough-walled, indentations present when mature, granulate when stained with India ink, surrounded by 3-9 μm wide, mucilaginous sheath. Asexual morph coelomycetous, formed on rice straw agar. Conidiomata 84−90 μm high × 73-89 μm wide., pycnidial, uniloculate, confluent or scattered, superficial, covered with dense vegetative hyphae, globose, dark brown to black. Conidiomatal wall thin, brown to black-walled cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 3−5 × 1.5−4 μm, enteroblastic, phialidic, integrated, broad-cylindrical to oblong, hyaline, formed from the inner layer of pycnidium wall. Conidia 2-4 × 1.5-2.5 μm (x̄ = 3 × 2 μm, n = 60), ellipsoidal to oblong, hyaline, aseptate, smooth-walled.

Culture characteristics.

Colonies on MEA, reaching 50 mm diam. after four weeks at 25 °C. Culture grey, becoming dark-olive brown after four weeks, of dense mycelia, colonies circular, flat, umbonate, raised from the agar in the centre, surface rough, dull, covered with aerial mycelium, white mycelium radiating into the agar, pale orange pigment diffusing in the agar; reverse black, dense, circular, with irregular, fimbriate margin. Sexual and asexual morphs formed in culture. Morphology of sexual phase similar to those on the substrates.

Additional material examined.

THAILAND, Krabi Province, Meuang district, on dead twigs of Barringtonia acutangula ( Lecythidaceae ), 16 December 2015, C. Phukhamsakda, Kr015, (isotype in HKAS, under the code of HKAS 99512).

Distribution.

Krabi Province, Thailand

Notes.

Neoaquastroma krabiense was collected in the southern part of Thailand on dead twigs of Barringtonia acutangula . It is placed in Neoaquastroma based on its morphology of both sexual and asexual morph and close phylogenetic affinity to other species of Neoaquastroma . Neoaquastroma krabiense is distinct in that it has a flattened ascomata base and larger and more slender asci and ascospores than N. guttulatum and N. bauhiniae . The species formed an asexual morph in culture (Fig. 3, m) as pycnidial conidiomata with hyaline conidia (Fig. 3, x-ae).