Diagnosis. A saxicolous species with blackened, cryptolecanorine to ± aspicilioid apothecia on a brownish olive, distinctly areolate thallus; possibly related to the corticolous C. floridana, which also lacks secondary metabolites, but has sessile, black, biatorine-lecideine apothecia on a dark gray, rimose thallus.
Type. Ecuador, Galápagos: San Cristóbal, hills S of Punta Pit at the NE-coast of the island, 0°43′16″S, 89°14′40″W, 63 m alt., coastal zone, SSE-exposed ridge of basalt cliff, on rock, 21-Apr-2007, Bungartz, F. 6170 A (CDS 34382‒holotype).
Description. Thallus distinctly areolate, not delimited by a prothallus, effuse, but individual areoles in part occasionally eroded, especially around their margin, then as if delimited by a whitish border; surface dark brownish olive, smooth, ± shiny, epruinose, lacking vegetative propagules. Apothecia sparse to abundant, dispersed, ± aspicilioid, i.e., initially immersed and ± cryptolecanorine, their margin barely distinct from the thallus, eventually becoming adnate and then lecanorine; thalline margin thick, circular, dark brownish olive, concolorous with the thallus, epruinose; proper margin absent; disc plane to very slightly convex, black, epruinose, C–, K–; epihymenium brownish olive, pigmentation diffuse, C–, K–, ± contiguous with the outer exciple; hymenium hyaline, not inspersed; proper exciple absent (completely reduced); thalline exciple pronounced, differentiated into a central part abundantly filled with trebouxioid photobionts, lacking crystals, followed by a hyaline layer that becomes increasingly pigmented towards the outside, pigmentation brownish olive, diffuse, C–, K–; subhymenium and hypothecium not differentiated, hyaline, not inspersed; asci broadly clavate, Teloschistes-type; ascospores 8/ascus, polaribilocular, ellipsoid to broadly ellipsoid, (9.0–)10.0–11.3(–12.5) × (4.5–)5.8–7.8(–11.0) μm, with a moderately broadened, (2.0–)3.0–4.1(–4.5) μm wide septum (n = 42). Pycnidia unknown.
Chemistry. Thallus and apothecia P–, K–, C–, KC–, UV– (dull); no secondary metabolites detected.
Etymology. Named for its black apothecial discs.
Ecology and distribution. Known only from the Galapagos where it grows from the coast into the lower transition zone, on sunny, wind- and rain-exposed rock.