Lichenologist 24, 3: 223 (1992).

Basionym: Thyrea divergens Henssen, Mycotaxon 25, 2: 497 (1986).

Protolog: Diagnosis. Thallus rosulatus, fruticulosus, nigricans, isidiosus, usque ad 10 mm latus, umbilico affixus. Lobi erecti, applanati, ramosi, 3-5 mm longi et 0.5-0.8 mm lati, apice divergenti, isidia globosa, usque ad 0.3 mm lata. Hyphae ordinatae longitudinaliter in centro thalli et perpendiculariter versus marginem, cortex deest, cellulae algarum ad zonam marginale restrictae. Alga verosimiliter ad ordinem Pleurocapsales pertinens, cellulae (4.5-)6-12 µm latae. Apothecia marginalia, adnata, usque ad 1 mm lata. Hymenium 70-100 µm altum, in iodo vinosum, hypothecium 25-35 µm altum excipulum proprium 45-50 µm crassum, ad basi restrictum et in stipite elongatum. Asci cylindracei, 6-8-spori, 60-80 x 10-12 µm. Sporae eseptatae, incolores, ellipsoideae, 12-14 x 8 µm. Pycnidia marginalia, c. 0.15 mm lata, conidia fusiformia, 2.5-4 x 1 µm.

Protolog type data: Typus: Kenya, Eastern Province, Distr. Marsabit, Lake Turkana, Koobi Fora, 3°55'N 36°12'E, on rocks, c. 1800 m, 1983, Hindmarsh 58 (MB-holotypus; BM, EA-isotypi).

Type locality: Kenya, Eastern Province, District Marsabit, Lake Turkana, Koobi Fora, on rocks, c. 1800 m, 1983, Hindmarsh 58 (MB - holotype; BM, EA - isotypes).

Type locality coordinates: 3°55'N 36°12'E.

Molecular barcode: Data lacking.

Thallus: blackish, to 10 mm large, rosette-shaped, fruticose, isidiate, attached by central umbilicus. Lobes more or less erect, 3-5 mm long, 0.5-0.8 mm wide and c. 0.06-0.8 mm thick, flattened, plane or furrowed on the underside, richly branched, the side branches divergent; isidia globular, to 0.3 mm wide. Thallus heteromerous, ....

Photobiont: Data lacking.

Chemistry: No lichen substances.

Ecology: On calcareous rock.

Distribution type: Cape Verde Islands, Kenya, Yemen, Yemen: Socotra Island, SW North America.