Trimmatothelopsis knudsenii J. X. Wang & L. Hu, 2025

Trimmatothelopsis knudsenii J. X. Wang & L. Hu sp. nov.

Fig. 3 View Figure 3

Diagnosis.

Similar to Trimmatothelopsis montana but differing in having wider thallus (up to 9 cm vs. up to 4 cm), in having completely immersed apothecia, and in having hymenial gel IKI + blue turning red, hemiamyloid (vs. IKI + blue-black amyloid).

Type.

China • Fujian Province: Quanzhou City, Fengze District, Qingyuan Mountain, Quankuguanpu , 24°56'49.14"N, 118°36'0.86"E, alt. 121 m, on non-calcareous rock, 1 Mar. 2025, J. X. Wang 20250049 ( SDNU, holotype) GoogleMaps .

Etymology.

The species is named in honor of lichenologist and taxonomist Kerry Knudsen from the Czech Republic for his excellent revision of the genus Trimmatothelopsis and continuing work on the Acarosporaceae of California and southwestern North America, USA.

Description.

Hypothallus usually distinct, thick, grayish to greenish, irregular in outline. Thallus epilithic, continuous and rimose, to 9 cm wide, ca. 150 μm thick, pale greyish green, pale green, yellowish brown to brown, sparingly to richly rimose with cracks, somewhat pulpy when wetted, sometimes easily entirely peeling from rock. Epicortex absent. Cortex (5 –) 20–40 μm thick. Algal layer (25 –) 30–35 (– 75) μm thick, continuous, rarely interrupted by hyphal bundles, algal cells 5–9 μm wide. Medulla ca. 75 μm thick, obscured, sometimes interspersed with a few algal cells. Apothecia rather numerous, scattered, immersed, mostly solitary, sometimes with compound apothecia, disc up to 0.45 mm wide, usually level with the thallus, slightly convex or flat, rough or smooth, reddish brown or whitish with a brown circle at center, sometimes with slightly elevated brown apothecial crown, usually with a reddish brown ring around the base of mature apothecia. Parathecium 10–60 μm wide, merging with cortex, sometimes with an inter IKI + blue, ca. 8–25 μm wide. Hymenium 150–230 μm high, paraphyses 1.5–2 μm wide, apices slightly widened in terminal brown gel cap, hymenial gel IKI + blue turning red, hemiamyloid. Asci clavate, 90–100 × 20–30 μm, ascus stain IKI + light blue tholus and space between the outer and inner wall of the ascus before ascospores fill the asci, ascospore several hundred per asci, ellipsoid to narrowly ellipsoid, 4–5 (– 6) × (1.5 –) 2–3 μm. Subhymenium obscure, 20–75 μm thick, IKI + blue or sometimes light blue, with much oil drops. Hypothecium 20–25 μm thick, IKI-. Hymenium indistinct. Pycnidia immersed with dark ostioles, ca. 90 × 60 μm, with conidiogenous cells 22–28 × 1.5–2 μm, conidia rhabditiform, 5–6 × 1 μm. Not producing secondary metabolites.

Habitat and distribution.

This new species is so far only known from Qingyuan Mountain, growing on non-calcareous rock at 121–263 m from low hillsides. It commonly occurs in the type, living in full sun or in deeply shaded forest habitats.

Notes.

Trimmatothelopsis knudsenii has a rimose thallus which is an uncommon trait in the genus. Before this study, only one species was described with rimose thallus, T. montana . It can be distinguished from T. knudsenii by greenish black apothecia which look like perithecia and IKI + blue-black hymenial gel ( McCarthy 2008).

The morphological traits of this new species exhibit significant changes in response to habitat variation. Specimens from sun-exposed habitats usually have yellowish-brown to brown thallus with densely rimose surfaces. In contrast, specimens from shaded habitats usually have pale grayish-green to pale green thallus (rarely brown), with only sparse rimose cracking. Acarosporaceae usually occurs in fully sunny locations. When growing in shaded areas, they still receive sunlight for the majority of the day. In the family, only T. montana and T. knudsenii can tolerate deep shade.

Additional specimens examined.

China • Fujian Province: Quanzhou City, Fengze District, Qingyuan Mountain, Jianlongtai to Nanshanyan , 24°57'10.44"N, 118°35'47.04"E, alt. 263 m, on non-calcareous rock, 28 Feb. 2025, J. X. Wang 20250014, 20250015, 20250016, 20250017, 20250020, 20250021, 20250022, 20250023, 20250024, 20250025, 20250026, 20250027, 20250028, 20250029 ( SDNU) GoogleMaps ; • Quanzhou City, Fengze District, Qingyuan Mountain, Dafozi , 24°56'51.25"N, 118°36'2.36"E, alt. 175 m, on non-calcareous rock, 28 Feb. 2025, J. X. Wang 20250031, 20250032, 20250033, 20250034, 20250035, 20250036, 20250037, 20250038 ( SDNU) GoogleMaps ; • Quanzhou City, Fengze District, Qingyuan Mountain, Quankuguanpu , 24°56'49.14"N, 118°36'0.86"E, alt. 121 m, on non-calcareous rock, 1 Mar. 2025, J. X. Wang 20250039, 20250040, 20250041, 20250043, 20250044, 20250045, 20250046, 20250047, 20250048 ( SDNU) GoogleMaps .