Hirsutella flava X. Zou, J.J. Qu, Z.A. Chen & Z.Q. Liang, 2021

Qu, Jiaojiao, Zou, Xiao, Cao, Wei, Xu, Zhongshun & Liang, Zongqi, 2021, Two new species of Hirsutella (Ophiocordycipitaceae, Sordariomycetes) that are parasitic on lepidopteran insects from China, MycoKeys 82, pp. 81-96 : 81

Hirsutella flava X. Zou, J.J. Qu, Z.A. Chen & Z.Q. Liang sp. nov.

Fig. 2

Diagnosis.

Characterised by phialides slender awl-shaped and tapered; a width of base 24-40.8 × 2.2-2.5 μm; tapering to narrow neck, 7.2-9 μm long × 0.5 μm wide. Conidia narrow cymbiform, long fusoid or limoniform, 6.5-10 × 2.1-4.3 μm.

Type.

China, Zhejiang Province, Tianmu Mountain National Nature Reserve (30°18'N, 119°28'E, approximately 600-1200 m a.s.l.), 27 June 2010, presented by Prof. Zhuan Chen. The holotype has been deposited at KIB (HKAS112884). Sequences from isolated strains (GZUIFR-hir100627-1, GZUIFR-hir100627-2 and GZUIFR-hir100627-3) have been deposited in GenBank .

Description.

Synnemata extending from the head of insect, 3-10 cm × 0.5-1 mm, simple or irregularly branched, dark brown and changing to faint yellow toward the apex; no conidiation was observed (Fig. 2A ). The fungus grows slowly at 22 ± 1 °C on Czapek-Dox agar medium to a diam. of 8-12 mm; the colony surface was flat and flocculent with white aerial hyphae. On PDA agar, fungal colonies grew quickly to a diam. of 15-23 mm after 20 d at 22 ± 1 °C, when the colonies were blanket-like with rough mycelia, radiating beam-like from the centre; centre lunate concave, pale yellow; colony surface with yellowish liquid exudation (Fig. 2B, C ). Mycelium hyaline, smooth, septate, 3.6-4.5 μm wide. Conidiogenous cells form directly from the mycelial end, monophialidic or polyphialidic, and borne perpendicular or at acute angles (80°-85°) to the subtending hyphae. Phialides slender awl-shaped and tapered, width of the base 24-40.8 × 2.2-2.5 μm, tapering to a narrow neck, 7.2-9 μm long × 0.5 μm wide. Conidia narrow cymbiform, long fusoid or limoniform, 6.5-10 × 2.1-4.3 μm; single- or double-enveloped in a hyaline mucus, thickness 2.0-3.0 μm (Fig. 2D-K ).

Host.

Larva of a species of Lepidoptera .

Habitat and distribution.

On decaying leaves in broadleaved forests, Zhejiang Province, China.

Etymology.

Refers to the yellow colour (Lat. ' Hirsutella flava ') of the holotype and colony.

Teleomorph.

Unknown.

Remarks.

This species is allied with the H. sinensis and H. strigosa clade. The phialides of H. flava are subulate, and the necks are slenderer. In particular, the colony morphology of this fungus is unique among the Hirsutella species. The colony surface appears very rough, and the hyphae are gathered into outwardly radiating filamentous bundles of varying sizes.

Figures

Figure 2. Morphological characteristics of Hirsutella flava A the infected insect specimens with a long and single synnemata (HKAS 112884) B, C colonial morphology on PDA agar media for 20 d B shows the front of the colony and C shows the back of the colony D-G LM images of the general morphology of conidiogenous cells and conidia H-K SEM images showing conidiogenous cells and conidial structure; Scale bars: 1 cm (A); 5 cm (B, C), 10 μm (D-G); the rest of the bars are shown in the figure. LM, light microscopy; PDA, potato dextrose agar; SEM, scanning electron microscopy.