Acarospora austrooccidentalis K. Knudsen, Kocourk. & Kondrysová, 2025

Acarospora austrooccidentalis K. Knudsen, Kocourk. & Kondrysová sp. nov.

Fig. 4 View Figure 4

Type.

U. S. A. • New Mexico, Lincoln Co., Tularosa Basin, Oscura, Road 54 , 33.4863, -106.0928, alt. 1475 m, SW-NE crest above the valley, southernmost hill, on soft acid sandstone, 14 March 2022, J. Kocourková 10842 (PRM-holotype, Hb. K & K-isotype) GoogleMaps .

Diagnosis.

Similar to A. oscurensis but differs especially in not producing initially apothecia with a smooth margin and without epihymenial accretions and in not forming white stromata with pycnidia, in having ellipsoid ascospores (1.5 –) 4.0–4.6 (– 5.1) × (1.0 –) 2.0 (– 2.8) µm vs. globose to broadly ellipsoid ascospores (1 –) 2–3 (– 6) × 1.0–3.4 µm, and in having thinner paraphyses 1.0–1.5 (– 2.8) µm vs. (1.5 –) 2–2.5 (– 3.5) µm.

Etymology.

Named for its southwestern distribution in North America.

Description.

Endolithic base or white ecorticate chasmolithic thallus in large-grained sandstone or with small white mycelial base, algal cells, 5–10 µm wide, scattered deep in substrate or sometimes below apothecia, sometimes forming a continuous algal layer between apothecia. Apothecia 0.5–1.6 mm wide, 0.3–0.4 mm tall, convex or not, sometimes compound with two hymenia, dispersed or occasionally forming clusters of apothecia with a mycelial base through replication by division. Margin segmented, usually in long linear sections at joints, 90–120 µm wide, outer layer carbonized, inner area hyaline, width variable, margin sometimes excluded. Disc black, usually gyrose with dense carbonized epihymenial accretions, often higher than margin. Hymenium (100 –) 120–150 µm tall, paraphyses 1.0–1.5 (– 2.5) µm wide, simple or slightly branched, non-anastomosed, apices unexpanded, hymenial gel IKI + dark blue, euamyloid, or turning pale blue and fading to pale green, or blue turning red in squash, hemiamyloid, not of diagnostic value. Asci variable from 100 × 10–40 to 40 × 15 µm in same hymenium, ellipsoid ascospores (1.5 –) 4.0–4.6 (– 5.1) × (1.0 –) 2.0 (– 2.8) µm (n = 40). Subhymenium 40–50 µm tall, IKI + dark blue, euamyloid. Hypothecium 20–100 µm tall, hyphae 1–2 µm wide or gelatinized and filled with substrate crystals, continuous with margin and endolithic thallus. No pycnidia observed. Not producing secondary metabolites.

Habitat and distribution.

Currently known from California, Nevada, New Mexico, and Utah, on non-calcareous sandstone, occasionally calciferous sandstone. One specimen was collected on cracked granite. Several specimens were collected on calciferous volcanic tuff. It can occur with A. oscurensis , as it does at its type locality in New Mexico.

Additional specimens examined.

U. S. A. • Arizona, Yavapai Co., Coconino National Forest, Red Rock Ranger District, Transept Trail, southwest-facing cliff , 34.7907, -111.7894, alt. 1298 m, no date, G. Neil 609 a ( ASU) GoogleMaps ; • California, Tuolumne Co., edge of Emigrant Wilderness, Huckelberry Trail through Kennedy Meadow, white pine, incense cedar , 38.2916, -119.333, alt. 1950–2025 m, on a cracked granite rock, 14 Aug. 1989, B. Ryan 24540 - b ( ASU) GoogleMaps ; • Nevada, Lincoln Co. Antelope Canyon , 37.637, -114.535, alt. 1500 m, on vertical quartzite outcrop, 30 Mar. 2016, J. Hollinger 11033 & N. Noell ( BRY-L-0049263 ) GoogleMaps ; • Clover Mountain, Tepee Rocks, base of loose ash-tuff cliff , 37.5958, -114.4407, alt. 1690 m, on ash-tuff, 31 May 2018, J. Hollinger 21365 (hb. H & N) GoogleMaps ; • Jumbled Hills, at base of east-facing ash-tuff cliff , 37.3070, -115.6142, alt. 1514 m, on calciferous ash-tuff, 28 May 2018, N. Noell 3909, 3917 & J. Hollinger, J. Hollinger 21350 & N. Noel (hb. H & N) GoogleMaps ; • New Mexico, Lincoln Co., Tularosa Basin, Oscura, Road 54 , 33.4863, -106.0928, alt. 1475 m, SW-NE crest above the valley, southernmost hill, on soft acid sandstone, 14 March 2022, J. Kocourková 10902, 11003 (hb. K & K) GoogleMaps ; • Utah, Emery Co., San Rafael Desert, vicinity of Three Canyons overlook, on sandstone on rim west of the Green River , 38.7087, -110.1245, alt. 1320 m, 15 Apr. 2023, S. Leavitt et al. 23067, 23092 ( BRY-C) GoogleMaps ; • Kane Co., Glen Canyon Recreational Area, in Navajo sandstone canyon , 37.311, -110.977, alt. 1160 m, on sandstone, 17 May 2019, S. Leavitt s. n. ( BRY-L-0050518 ) GoogleMaps ; • San Juan Co., Bears Ears National Monument, between the UT 211 Rd. and sandstone crest , 37.9836, -109.5003, alt. 1869 m, thin juniper and shrubby pine vegetation on gently sloping terrain, on sandstone rocks, 22 Sept. 2024, J. Kocourková 11559 & K. Knudsen (hb. K & K) GoogleMaps ; • La Sal Mountains, La Sal Loop Rd, top of small SW oriented crest , 38.4532, -109.3750, alt. 1866 m, on HCl – sandstone, 21 Sept. 2024, J. Kocourková 11554 & K. Knudsen (hb. K & K) GoogleMaps ; • Wayne Co., Capital Reef National Park, Cassidy Arch Trail , 38.2637, -111.2159, no alt., on Navajo sandstone, 12 June 1992, Larry St. Clair 14030 ( BRY-L-0030684 ) GoogleMaps ; • ca. 2 miles from entrance to Maze District of Canyonlands National Park , 38.2212, -110.2130, alt. 1948 m, on exposed sandstone bedrock, 9 April 2014, J. Hollinger 6321 & N. Noell (hb. H & N) GoogleMaps • Highway 95 , on sandstone, 3 Oct., 1986, J. W. Thomson ( ASU) .

Notes.

High hymenium, thin paraphyses, and ellipsoid ascospores distinguish Acarospora austrooccidentalis . Acarospora oscurensis also has a high hymenium but differs in having globose to broadly ellipsoid ascospores and thicker paraphyses. Unfortunately, the ascospore size of the two species can overlap, with A. oscurensis sometimes having some ascospores that are not broadly ellipsoid but ellipsoid. Paraphyses width can also be a difficult character, as occasional specimens of both species can have a predominance of paraphyses 2 µm wide. Lichens did not evolve for lichenologists. Acarospora oscurensis also differs in having young apothecia with a smooth margin and a disc without carbonized epihymenial accretions as well as occasionally white stromata.

The specimens from the Jumbled Hills in Lincoln County, Nevada, on eroding calcareous tuff had the lowest hymenia at 100 µm high and formed a chasmolithic thallus from substrate erosion and were not as robust as specimens on large-grained HCl – sandstone (Noell 3909, 3917).