Thallus fulvus vel pallide spadiceus, tenuis, rimosoareolatus, sine prothallo. Lirellae simplices aut semel ramosae, atrae, 0·15–1 × 0·08–0·2 mm, apicibus acutis, disco vulgo expanso, margine tenui (c. 30–70 µm lato). Hymenium 50–62 µm altum, epithecio distincto, paraphysibus non-moniliformibus. Ascosporae simplices, (7–)9–11 × 4–6 µm.
Typus: Falkland Islands, East Falklands, Stanley, outcrops along Goat Ridge, 600 ft, 30 January 1968, H. Imshaug & R. C. Harris [Imshaug 41510B] (MSC— holotypus; BCRU—isotypus).
Thallus forming small rounded patches to 2 cm diam. or more wide-spreading, not sharply delimited, rimose-areolate, with angular areoles c. 0·15–0·5 mm wide, buff to pale tan-brown, matt; prothallus not evident. In sections: thallus to c. 100 µm thick, ecorticate but with a hyaline, c. 5–8 µm thick epinecral layer; medulla thin, but thicker where the thallus crosses microfissures in the substratum, containing large amounts of mineral fragments, patchily I+ blue. Photobiont cells ±globose, 7–12 µm diam.
Apothecia lirelliform, essentially fusiform in outline with acute apices, straight to slightly curved, simple or once branched, innate in the thallus or margin becoming raised above the surface level of the thallus, but then the apices remain embedded in the areoles, 0·15–1 × 0·08–0·2 mm, black; disc slit-like at first but usually expanding, epruinose; margin raised, c. 0·03–0·07 mm wide, when dry an adhering ‘skin’ of thallus tissue can give the appearance of a thalline margin. Exciple cupulate, reddish brown, K–, N–, c. 25–50 µm thick at base, 17–37 µm thick laterally, sometimes widening to 70 µm at the apex [margin, or ‘labium’]. Hymenium 52–62 µm tall, hyaline or dilute reddish brown, I+ blue; epithecium usually well defined, c. 7 µm tall, dark reddish brown. Hypothecium c. 12–25 µm tall, mottled reddish brown. Paraphyses rather sparse, sparingly branched or anastomosing, distinctly septate but not moniliform, 1–1·7 µm wide in mid-hymenium, up to 3 µm wide at the clavate apices; apices embedded in pigmented matrix and some are provided with a thin, dark brown ‘hood’. Asci clavate, 41– 49 × 12–18 µm, 8-spored; in K/I with amyloid outer wall, and tholus with a thin amyloid apical cap and amyloid flanks (Trapelia-type). Ascospores (7–)9–11 × 4– 6 µm, ellipsoid, simple, hyaline, without a distinct perispore.
Pycnidia immersed, black, c. 50–60 µm diam.; wall reddish brown. Conidia narrowly bacilliform, but sometimes wider at the proximal end, 6–8 × c. 0·8 µm.
Chemistry. Thallus K–, C–, KC–, P–, UV–; small quantities of atranorin, zeorin and protocetraric acid detected by TLC, but this should be confirmed as these may be the result of contamination.
Ecology and distribution. Known only from the type locality on the Falkland Islands, where it grew on a siliceous rock outcrop on a ridge at c. 180 m altitude.
Lithographa opegraphoides is only known from one location and its total Area of Occupancy is 4 km2. Livestock grazing and/or climatic changes could quickly lead to the decline and extirpation of thisspecies. Therefore, it is listed as Vulnerable under criterion D2.
Assessor/s: Fryday, A.; Reviewer/s: Lendemer, J.; Contributor(s): Allen, J. & Scott, T.Facilitators(s) and Compiler(s): Allen, J. & Scott, T.
Bachman, S., Moat, J., Hill, A.W., de la Torre, J. & Scott, B. (2011) Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool. In: V. Smith & L. Penev (eds) e-Infrastructures for data publishing in biodiversity science. Zookeys150: 117–126.
Coppins, B. J. & Fryday, A. M. (2006) New or previously misunderstood species of Lithographa and Rimularia (Agyriaceae) from the southern subpolar region and western Canada. Lichenologist38: 93-107.
Fryday, A. M. & Prather, L. A. 2001. The lichen collection of Henry Imshaug at the Michigan StateUniversity Herbarium (MSC). The Bryologist104: 464-467.
Fryday, A. M., Orange, A., Ahti, T., Øvstedal, D. O. & Crabtree, D. E. (2019) Checklist of lichenized andlichenicolous fungi reported from the Falkland Islands. GLALIA8(1): 1-100.
IUCN (2020) The IUCN Red List of Threatened Species. Version 2020-3. Available at: www.iucnredlist.org. (Accessed: 10 December 2020).
McAdam, J. (2013) The impact of the Falklands War (1982) on the peatland ecosystem of the islands. Landscape Archaeology and Ecology10: 143-162.
Stenroos, S. & Ahti, T. (1992) The lichen family Cladoniaceae in the Falkland Islands. Annales Botanici Fennici 29(1): 67-73.
Find out more about the IUCN Red List Categories and Criteriahere.