Pseudoastrosphaeriella africana
Pseudoastrosphaeriella africana (D. Hawksw.) Phook. & K.D. Hyde
Basionym: Astrosphaeriella africana D. Hawksw., Sydowia 38: 116 (1986) [1985]
Index Fungorum number: IF551643, Facesoffungi number: FoF 01235
Holotype: IMI 105924
Saprobic on submerged bamboo, visible as raised, brown to dark brown, hemispherical regions with short papilla on the host surface. Sexual morph: Ascostromata 200–330 μm high, 520–750 μm diam., dark brown, scattered, solitary, immersed beneath host epidermis, erumpent through host surface by papilla, hemisphaerical to lenticular, with flattened base, wedge-shaped at the rim, uni-loculate, glabrous, coriaceous, ostiole central, with short papilla, internally periphysate, brittle, carbonaceous. Peridium 25–110 μm wide, of unequal thickness, thicker at the sides, especially towards the apex, composed of dark brown to black, pseudoparenchymatous cells, comprising host cells plus fungal tissue at outside, arranged vertically in a textura angularis to textura prismatica, poorly developed at the base, (20–30 μm wide). Hamathecium composed of dense, 0.8–1.8 μm wide, filiform, trabeculate pseudoparaphyses, anastomosing at the apex, embedded in a hyaline gelatinous matrix. Asci (104–)110–130(–135) × (12–)13–15(–17) μm (x̄ =122.4 × 14.4 μm, n = 30), 8-spored, bitunicate, clavate to cylindric-clavate, with slightly long furcate or knob-like pedicel, apically rounded, with an indistinct ocular chamber. Ascospores (39–)40–48(–50) × 5–7 μm (x̄ = 44.8 × 6.1 μm, n = 30), overlapping uni-seriate at the base, bi- to tri-seriate at the apex, initially hyaline to pale brown, becoming brown to dark brown at maturity, fusiform, with acute ends, 1(–3)-septate, constricted at the septum, swollen immediately above central septum, lower cell longer than upper cell, rough-walled with distinc longitudinal ridges towards the ends. Asexual morph: Undetermined. (Description from Phookamsak et al. 2015)
Material examined: THAILAND, Chiang Rai Province, Mae Jun District, Huai Kang Pla Waterfall, on dead stems of bamboo, 25 October 2010, R. Phookamsak, RP0092 (MFLU 11-0212, reference specimen designated here), living culture, MFLUCC 11-0176.
Notes: Pseudoastrosphaeriella africana was introduced as Astrosphaeriella africana in Hawksworth and Boise (1985). The species is characterized by coriaceous, hemisphaerical ascostromata, with short necks and fusiform, reddish brown ascospores, with longitudinal ridges (Hawksworth and Boise 1985; Hyde and Fröhlich 1998; Chen and Hsieh 2004; Liu et al. 2011). Hawksworth and Boise (1985) and Liu et al. (2011) mentioned that A. striaspora was similar in its striate, but shorter ascospores. Chen and Hsieh (2004) introduced A. macrospora and A. pallidipolaris also with striate ascospores. Astrosphaeriella macrospora differs from A. africana in having significantly larger ascospores with five septa, whereas in A. pallidipolaris ascospores are 5(–6)-septate with paler end cells (Chen and Hsieh 2004; Liu et al. 2011). Pseudoastrosphaeriella africana is most similar to P. bambusae, P. thailandensis and Astrosphaeriella macrospora in having reddish brown to dark brown ascospores with 1(–3)-septate, with longitudinal ridges and enlarged above the central septum. However, P. africana differs from P. thailandensis and P. bambusae and the differences are discussed under those species. Pseudoastrosphaeriella africana was first reported on Poaceae (possibly Phragmites australis (Cav.) Trin. ex Steud.) from Tanzania, Africa (Hawksworth and Boise 1985; Liu et al. 2011). Later, Hyde and Fröhlich (1998) reported the species on various hosts: Arenga, bamboo, Calamus, Daemonorops, Phragmites and palms from tropical parts of Australia, Brunei, Malaysia, Philippines, and Tanzania, while Chen and Hsieh (2004) found the species on bamboo in Taiwan. Liu et al. (2011) also reported P. africana on bamboo in Thailand. These reports need to be verified against the reference specimens. (Notes from Phookamsak et al. 2015)
Freshwater distribution: Thailand (Phookamsak et al. 2015)
Fig. 1. Pseudoastrosphaeriella africana (MFLU 11-0212, reference specimen). a Ascostromata immersed in host. b Section through ascostroma. c Section through upper part of peridium d Section through side part of peridium. e Asci embedded in trabeculate pseudoparaphyses stained in Indian ink. f Young ascus. g–i Asci. j Young ascospore. k–o Ascospores. Scale bars: b = 200 μm, c–e = 50 μm, f–i = 20 μm, j–o = 10 μm. (Phookamsak et al. 2015)
References
Hyde KD, Fröhlich J (1998) Fungi from palms XXXVII. The genus Astrosphaeriella, including ten new species. Sydowia 50(1):81–132
Liu JK, Phookamsak R, Jones EBG, Zhang Y, Ko-Ko TW, Hu HL, Boonmee S, Doilom M, Chukeatirote E, Bahkali AH, Wang Y, Hyde KD (2011) Astrosphaeriella is polyphyletic, with species in Fissuroma gen. nov., and Neoastrosphaeriella gen. nov. Fungal Divers 51:135–154
Phookamsak R, Norphanphoun C, Tanaka K, Dai DQ, Luo ZL, Liu JK, Su HY, Bhat DJ, Bahkali AH, Mortimer PE (2015) Towards a natural classification of Astrosphaeriella-like species; introducing Astrosphaeriellaceae and Pseudoastrosphaeriellaceae fam. nov. and Astrosphaeriellopsis, gen. nov. Fungal Divers 74:143–197
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