Xiuguozhangia sahyadriensis Rajeshk., O.P. Sruthi, Réblová & R.F. Castañeda, 2025

Paraparath, Sruthi O., Rajeshkumar, Kunhiraman C., Réblová, Martina, Jeewon, Rajesh, Lad, Sneha S., Karunarathna, Samantha C., Tibpromma, Saowaluck & Castañeda-Ruiz, Rafael F., 2025, Morphological characterization and phylogenetic placement of Xiuguozhangia sahyadriensis (Pseudoberkleasmiaceae, Pleosporales), a new species from the Western Ghats, India, Phytotaxa 711 (3), pp. 263-280 : 270-272

Xiuguozhangia sahyadriensis Rajeshk., O.P. Sruthi, Réblová & R.F. Castañeda sp. nov. ( Figures 2 , 3 )

Index Fungorum number: IF903708

Etymology:—The specific epithet sahyadriensis is derived from the Sanskrit name for the Western Ghats, “Sahyadri” where the fungus was collected. Sahyadri means ‘benevolent mountain range in Sanskrit’, reflecting its resilience to change.

Holotype:— INDIA. Kerala, Pokalappara, Vazhachal Forest Division, 10.2997° N, 76.6575° E, on decaying twig of Ochlandra sp. , 22 October 2023, O. P. Sruthi & K. C. Rajeshkumar, holotype — AMH 10786 , ex-type living culture NFCCI 6029 .

Description on natural substrate (fresh material): Mycelium partly superficial, partly immersed in the substratum, composed of septate, branched, smooth hyphae initially white, turning mature pale brown to brown with age. Conidiophores macronematous, mononematous, unbranched or rarely branched, erect, straight or flexuous, smooth, 8–12-septate, dark brown at the base, and paler towards the apex, 270–930 μm long (x̄ = 500 μm, n = 25), 12–22 μm wide (x̄ = 15 μm, n = 25) at the base, 8–12 μm wide (x̄ = 10 μm, n = 25) in the middle, tapering to 3.5–10 μm wide (x̄ = 6 μm, n = 25) at the apex. Conidiogenous cells monoblastic, integrated, terminal, and discrete, lateral, 7.5–10.5 × 6.5–8 μm, elongating percurrently, with 1–4 supporting cells as a result of elongation resembling branches, 7.5–38 × 6.5–9 μm, flat at the conidiogenous locus; Conidia holoblastic, produced terminally, solitary, dry, pale brown to dark brown, cheiroid, fan-shaped or variable in shape, lenticular in edge view, 1–4-lobed, dictyoseptate, with smooth conidial body and roughened basal cell, and rows of cells radiating from a protuberant cell at the base, 6–10 vertical rows of cells, 24–62 × 30–60 μm (x̄ = 40 × 30 μm, n = 30), with 1–3 appendages arising from outermost cells or middle of the conidial body. Appendages pale brown to brown, becoming hyaline and rounded at the tips, consisting of 1–2- septa, 12.5–32 × 2.5–10 μm (x̄ = 22.5 × 5 μm, n = 30).

Culture characteristics: Colonies on MEA at 25 ± 2 °C after 20d reaching 22–25 mm diam., initially white (1A1), becoming grey (6F1), brownish grey (6E2) to greyish brown (6E3) with age, reverse brownish grey (7F2). Colonies circular, flat, velvety, with irregularly lobate margin that are umbonate at the centre. Sporulation was observed after one-year incubation on MEA. Germination of conidia after 24 Hrs of incubation in MEA at 25 ± 2 °C.

Description in culture: Mycelium composed of septate, branched, smooth, hyphae that are initially white and become pale brown to brown with age. Conidiophores 85–280 × 5.5–6.5 μm, with a bulbous base. Conidia 40–65 × 24–60 μm (x̄ = 54 × 40 μm, n = 15), with 2–8 appendages.

Additional collection examined: INDIA. Kerala, Pokalappara, Vazhachal Forest Division, 10.2997° N, 76.6575° E, on decaying twig of Ochlandra sp. , 22 October 2023, O.P. Sruthi & K.C. Rajeshkumar, isotype —AMH 10787, living culture NFCCI 6030.

Notes: Xiuguozhangia sahyadriensis is characterised by the longest conidiophores (270–930 μm long) among all known species of Xiuguozhangia , which are rarely branched, similar to X. broussonetiae . Conidiogenous cells with up to four successive percurrent extensions were comparable to those observed in the morphologically similar species X. broussonetiae and X. indica . Conidia of X. sahyadriensis (24–62 × 30–60 μm) show close morphological overlap with those of X. indica (34–44 × 39–52 μm). However, X. sahyadriensis can be distinguished, by having fewer vertical rows of cells arising from the protuberant basal cell (6–10 in X. sahyadriensis vs. up to 15 in X. indica ) and fewer appendages (1–3 in X. sahyadriensis vs. 2–4 in X. indica ). Additionally, X. sahyadriensis possess appendages (12.5–32 × 2.5–10 μm) that are rounded at the tip, in contrast to the tapering appendages of X. indica (15–30 × 3–4.4 μm).

Similarly, conidia and appendages of X. sahyadriensis and X. broussonetiae exhibit overlapping characters. While the conidia of X. sahyadriensis (24–62 × 30–60 μm) and X. broussonetiae (25–40 × 30–60 μm) are comparable in size, X. broussonetiae , like X. indica , has up to 15 vertical rows of cells, distinguishing it from X. sahyadriensis . Both X. sahyadriensis and X. broussonetiae have untapered appendages, but appendages are sometimes absent in X. broussonetiae .

A detailed morphological comparison of all species under Xiuguozhangia is provided in Table 2.

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Figures

FIGURE 2. Xiuguozhangia sahyadriensis (AMH 10786, Holotype). A Colonies on natural substrate. B Conidium attached to terminal conidiogenous cell. C Terminal and lateral conidiogenous cells with percurrent extension. D Conidium attached to lateral conidigenous cell. E–H Developing conidia. I–L Matured conidia displaying variable shape. M–Q Conidia and conidiophores in vitro. M Conidia attached to conidiophores in vitro. N Conidiophore with bulbous base and lateral conidiogenous cell. Q Conidia with conidiophores. P, Q Mature conidia. R Colonies on MEA obverse. S Colonies on MEA reverse. Scale bars: A = 200 μm. B = 20 μm. C = 10 μm. D = 20 μm. E–L = 10 μm. M–Q = 20 μm.

FIGURE 3. Xiuguozhangia sahyadriensis (AMH 10786, Holotype). A–C Conida attached to conidiophores. D Conidiogenous cell with percurrent extension. E Conidium in lenticular view. F Conidium attached to conidiogenous cell. G–H Base of conidia. I–K Mature conidia. Scale bars: A–B = 20 μm. C–K = 2 μm.