Kretzschmaria shiwandashanensis C.T. Lu & Q.R. Li., 2024

Lu, Changtao, Hu, Hongmin, Habib, Kamran, Ren, Yulin, Kang, Yingqian, Shen, Xiangchun, Li, Qirui & Long, Qingde, 2024, A new Trunk Rot species in the genus Kretzschmaria (Xylariaceae) from Guangxi, China, Phytotaxa 675 (1), pp. 34-42 : 39

Kretzschmaria shiwandashanensis C.T. Lu & Q.R. Li. sp. nov. Fig. 2

Mycobank number: MB 854919

Etymology: —The specific epithet “shiwandashanensis ” refers to its collection location, Shiwandashan National Nature Reserve.

Description: —Saprobic on the bark surface of unknown dead wood. Sexual morph: Stromata 1.8‒2.6 cm long × 1.7‒2.3 cm wide × 0.1‒0.2 cm thick, (x̅ = 2.2 × 2.0 × 0.16 cm, n = 5) cushion-like protuberances, serrated edges, steeply sloping, sessile, slightly narrowed where in contact with dead wood, with distinctive cracks on the surface, containing several perithecia, greyish-brown to brownish-brown surfaces, carbonized, inter-perithecial tissues charcoal, black, solitary or clustered, pore. Ostioles papillate. Perithecia 390‒1000 µm wide, 860‒1200 µm high (x̅ = 680 × 1000 µm, n = 10), obovoid to cylindrical, ostioles coarsely papillate. Asci 236.7‒393.4 × 10.5‒26.5 µm (x̅ = 303.8 × 15.0 µm, n = 20), 8-spore, unitunicate, cylindrical, long-stalked, spore-bearing part 158.7‒218.4 µm (x̅ = 196.3 µm, n = 20) long, apically rounded, with a J+, urn-shaped apical ring, bluing in Melzer’s iodine reagent, 7.0‒9.7 µm high, 3.7‒6.0 µm wide. Ascospores 28.4‒36.2 × 10.3‒14.3 µm (x̅ = 32.5 × 12.4 µm, n = 30), overlapping uniseriate, unicellular, inequilateral ellipsoid, smooth, hyaline when immature, slight brown to dark brown at maturity, with rounded ends, with a straight germ slit, slightly shorter than spore-length; Asexual morph: Undetermined.

Material examined: — CHINA, Guangxi Zhuang Autonomous Region, Fangchenggang City, Shiwandashan National Nature Reserve (21°41′51.44″N, 107°33′51.75″E), elevation: 518 m, on dead tree trunk, 16 August 2023, Changtao Lu, 2023 SWDS21 (GMB4901 Holotype; KUN-HKAS 136274 Isotype; GMBC4901 ex-type, Genbank accession number: ITS: PQ456124; ACT: PQ463993; TUB2 : PQ463991; rpb2: PQ463989) .

Additional material examined (paratype): — CHINA, Guangxi Zhuang Autonomous Region, Fangchenggang City, Shiwandashan National Nature Reserve (21°43′56.25″N, 107°37′26.79″E), elevation: 485 m, on dead tree trunk, 16 August 2023, Changtao Lu, 2023 SWDS26 (GMB4906; GMBC4906 ; Genbank accession number: ITS: PQ456125; ACT: PQ463994; TUB2 : PQ463992; rpb2: PQ463990) .

Notes: —In the phylogram ( Fig. 1 ), K. shiwandashanensis and K. sandvicensis formed a sister clade with a 100% MLB/1.00 BYPP support value. Morphologically, both of them show similar stromal features that attach to the substrate by narrow connective tissues and have steep, thick crenellated margins (Herrera and Maldonado 2014). However, the new species can be distinguished by its smaller perithecia (1.3‒1.8 mm high, 0.6‒1.5 mm wide vs. 0.86‒1.20 mm high, 0.39‒1.00 mm wide), and the smaller ascospores (28.4‒36.2 × 10.3‒14.3 µm vs. 33‒46 × 8.5‒11.5 µm). Their ITS and β-tubulin sequences show significant differences, with 91.90% and 95.69% similarity, respectively.

Morphologically, Kretzschmaria shiwandashanensis is similar to the recently described new species from China, K. landingshanensis S.H. Long & Q.R. Li. However , the K. landingshanensis differ from K. shiwandashanensis by having shorter ascospores (7.5‒9.5 µm in vs. 10.3‒14.3 µm) and a smaller apical apparatus (5‒6.5 × 3‒4 µm vs. 7‒9.7 × 3.7‒6 µm) ( Li et al. 2024). Morphologically, it is also close to the K. quercicola J. H. Yun & D. H. Kim. However , K. quercicola has larger and broader ascospores (35‒46 × 10.5‒17 µm vs. 28.4‒36.2 × 10.3‒14.3 µm) and a larger apical apparatus (6.5‒10.5 × 4‒5.5 µm vs. 7.0‒9.7 × 3.7‒6.0 µm) ( Yun et al. 2016).

Figures

FIGURE 1. RAxML tree of Kretzschmaria and its related taxa based on a combined ITS, ACT, β-tubulin and rpb2 sequences dataset. Bootstrap support values for maximum likelihood (MLB) greater than 75% and Bayesian posterior probabilities (BYPP) greater than 0.90 are displayed above the respective branches (ML/BI). The newly described species were marked in red. Type specimens or cultures were marked in bold.

FIGURE 2. Kretzschmaria shiwandashanensis (GMB4901, holotype). A Substrate; B, C Surface of stromata; D Vertical section of stroma; E Longitudinal section of stroma; F‒H Asci; I Ascus apical apparatus (stained in Melzer’s Reagent); J‒M Ascospores; Scale bars: 200 μm (B‒C); 100 μm (D, E); 10 μm (F‒M)