Arthrobotrys angiopteridis J. Y. Zhang, Y. Z. Lu & K. D. Hyde, 2025

Arthrobotrys angiopteridis J. Y. Zhang, Y. Z. Lu & K. D. Hyde sp. nov.

Fig. 2 View Figure 2

Etymology.

Named after the fungal host genus Angiopteris.

Holotype.

HKAS 129855 View Materials .

Description.

Saprobic on dead rachis of Angiopteris fokiensis in terrestrial habitats. Sexual morph Undetermined. Asexual morph Colonies on natural substrate superficial, effuse, hyaline, with white and glistening masses of conidia on the apex of conidiophores. Mycelium partly superficial, partly immersed, composed of septate, branched, smooth hyphae. Conidiophores 345–502 µm long, 6–8.5 µm wide at the base (x ̄ = 418 × 6.9 µm, n = 20), macronematous, mononematous, solitary, erect, straight or slightly flexuous, unbranched, cylindrical, septate, smooth-walled, hyaline. Conidiogenous cells 95–176 × 2–4.5 µm (x ̄ = 129 × 3.5 µm, n = 20), polyblastic, producing 1–5 separate nodes by the repeated elongation, with multi polyblastic denticles at each node, hyaline. Conidia 25–35 × 8–11 µm (x ̄ = 28.8 × 9 µm, n = 25), aseptate, or 1 - septate at the median to submedian, not constricted or slightly constricted at the septum, clavate to elongate pyriform, broadly rounded at apex, pointed or sometimes truncate at the base, sometimes with a bud-like projection at base, straight or slightly curved, smooth-walled or rough walled, guttulate, hyaline.

Culture characteristics.

Conidia germinating on WA within 15 h and germ tube produced from conidia. Colonies growing on PDA, reaching 60 mm diameter in 10 days at 26 ° C, circular, cottony, white, and not producing pigmentation in culture.

Material examined.

China • Guizhou Province, Zunyi City , Xishui County (28°22'19"N, 106°0'35"E), on dead rachis of Angiopteris fokiensis ( Marattiaceae ) in a disturbed forest nearby the roadside, 13 April 2023, J. Y. Zhang, ZY 06 ( HKAS 129855 , holotype; GZAAS 23–0758 , isotype), ex-type living culture, KUNCC 23–14121 ; GoogleMaps • ibid., ZY 02 ( HKAS 129854 , paratype), ex-paratype living culture, KUNCC 23–14119 GoogleMaps . Additional sequence: KUNCC 23–14121 : PQ 346313 ( SSU) and PQ 346310 (LSU); KUNCC 23–14119 : PQ 346312 ( SSU) and PQ 346309 (LSU).

Notes.

Phylogenetically, the new isolates KUNCC 23–14121 and KUNCC 23–14119 of Arthrobotrys angiopteridis clustered together formed a separate clade with 100 % ML / 1.00 PP bootstrap support and are sister to A. pyriformis (Fig. 1 View Figure 1 ). A comparison of nucleotide base pairs between them reveals differences of 30 / 459 (6.5 %, including 15 gaps) and 82 / 730 bp (11 %, no gap) in the ITS and rpb 2 sequences, respectively. This indicates that they are distinct species. Morphologically, A. angiopteridis aligns well with the generic concept and resembles A. oligospora in having hyaline conidiophores with the successive production of additional denticle nodes ( Yu et al. 2014). However, A. angiopteridis can be easily distinguished from A. oligospora by its longer conidiophores (345–502 µm vs. 110–440 μm) and clavate to elongate pyriform conidia, with 0–1 septate near the middle, whereas A. oligospora has pyriform or obovoid conidia with 1 - septate near the base. Therefore, we introduce A. angiopteridis as a novel species based on its distinct morphological and phylogenetic evidence following the guidelines of Maharachchikumbura et al. (2021).