Sarcogyne xizangensis F. H. Liang & L. Hu sp. nov.

Figs 5, 6

Type.

China • Xizang Autonomous Region: Nagarze County, Yamdrok Yumtso scenic area, 28°44'08"N, 91°02'19"E, alt. 4546 m, on siliceous rock, 9 Jun. 2025, Li. L. 20250906 - BH 118-2 A (KUN, holotype).

Diagnosis.

Similar to Acarospora privigna (Kantvilas 1998; Knudsen et al. 2021 b), but differs in having lower hymenium (60–95 μm vs. 90–130 μm), wider paraphyses (2.5–4 μm vs. 1–1.5 μm), and ellipsoid to broadly ellipsoid ascospores (vs. bacilliform to narrowly ellipsoidal).

Etymology.

The specific epithet is derived from the type locality, Xizang Autonomous Region (Tibet), where this species was collected.

Description.

Thallus endolithic, algae usually in clusters in substrate or at base of apothecium, algae cells 6–12 μm wide. Apothecia black, light shiny, 0.1–0.75 mm wide, 250–300 μm thick, dispersed or forming conspicuous clusters through replication, becoming compound apothecia, young apothecia usually round, without carbonized epihymenium accretions, and usually becoming rough with gobs of melanin build-up on the disc, but sometimes just smooth and only the margin carbonized. Disc dark reddish brown to black, red when wetted, epruinose, flat and below the margin, sometimes on an equal level with margin, rarely convex. Margin carbonized, 150 μm thick when young, 50 μm thick when mature, usually raised above the disc, partly knobby or crenulate, sometimes entire, not becoming segmented. Parathecium 20–60 μm thick, out layer black, 10–35 μm thick, inner brown, 10–25 μm thick. Hymenium 60–95 μm tall, epihymenium reddish – brown, 10–30 μm tall, occasionally with brown or black carbonized accretions, sometimes lack accretions, paraphyses 2.5–4 μm wide, infrequent branch, light expand to 5 μm wide in pigment caps, hymenial gel IKI + red or blue turning red, hemiamyloid. Asci 50–70 × 12–20 μm, hundreds of ascospores, 4–6 × 2–3 μm wide, ellipsoid to broadly ellipsoid, simple and hyaline, usually with two oil drops. Subhymenium 25–50 μm thick, IKI + blue. Hypothecium indistinct to 10 μm thick. Pycnidia not observed. Not producing secondary metabolites.

Habitat and distribution.

This species is only found in the high-altitude areas of the Qinghai-Xizang Plateau in western China, growing on calcareous or siliceous rocks.

Additional specimens examined.

China • Xizang Autonomous Region: Nagarze County, Yamdrok Yumtso scenic area, 28°44'08"N, 91°02'19"E, alt. 4546 m, on siliceous rock, 9 Jun. 2025, Li. L. 20250906 - BH 118-2 A, 20250906 - BH 118-2 B (KUN); • Nagarze County, Yamdrok Yumtso scenic area, 28°44'57"N, 90°53'18"E, alt. 4545 m, on siliceous rock, 9 Jun. 2025, Li. L. 20250906 - BH 115-3 (KUN); • Nagarze County, Yamdrok Yumtso scenic area, 28°44'08"N, 91°02'19"E, alt. 4547 m, on calcareous rock, 9 Jun. 2025, Li. L. 20250906 - BH 118-5 (KUN).

Note.

This new species has wider paraphyses 2.5–4 μm, which can easily distinguish from other Sarcogyne species. In addition, the new species has variable morphological characteristics. The specimen (20250906 - BH 118-2 A KUN) has obviously segmented margin, and discs with carbonized epihymenial acceretions, while the other specimens have entire and smooth margin, rarely becoming segmented, and discs usually observe no carbonized epihymenial accretions.

Sarcogyne xizangensis is similar to S. albothallina by its carbonized apothecia, but it differs from S. albothallina by endolithic thallus (vs. epilithic thallus), wider paraphyses 2.5–4 μm (vs. 1.5–2.5 μm), smaller ascospores 4–6 × 2–3 μm (vs. 6.0–7.5 × 3–4 μm), and not producing secondary metabolites (vs. producing 4 - O-methylhiascic acid) (Knudsen et al. 2016). Sarcogyne xizangensis differs from S. pakistanensis in wider paraphyses 2.5–4 μm (vs. 2–3 μm), larger ascospores 4–6 × 2–3 μm (vs. 3–4 × 1–2 μm), hymenial gel IKI + red or blue turning red (vs. IKI + dark blue), in not producing secondary metabolites (vs. 2 ' - O-demethylpsoromic acid, psoromic acid detected), and in producing carbonized epihymenial accretions (vs. without carbonized epihymenial accretions) (Fayyaz et al. 2023).