Criterion A is not applicable as there is no information about the trends of population size over long time periods.
Criterion B: using GeoCat tool, EOO was assessed 8,821 km². The species has been recorded only in 3 mountain tips in Papua New Guinea and is definitely absent from some relatively often visited mountains in between these three localities. It might extend also to the mountains in Papua province, Indonesia (earlier Irian Jaya). Even so, the whole mountain range would be less than 20,000 sq km. Lichen population in mountain tips is clearly fragmented within this range, and the population reduction is inferred because of possible fires and mining activities in the species habitat. Cetreliopsis papuae is assessed EN.
Criterion C is not applicable as there is no information about the number of mature individuals.
Criterion D: AOO was assessed 12 sq km; no of known localities is 3
The species occurs only in one island and in one country – Papua New Guinea.
1. Papua New Guinea, [Western province,] Star Mountains, Mt. Scorpion, 3600 m, open herbfield, leg. Hope 1975 (US, holotype).
2. Papua New Guinea, Central distr., Tapini subdistr., Mt. Strong, 3450 m, shrublet communities, leg. Coode 03.05.1971 (Herb. Aptroot).
3. Papua New Guinea, Southern Highlands, Mt. Giluwe, 4140 m, leg. D. McVean 1967 (BM).
Cetreliopsis papuae is an extremely rare species with very restricted distribution area in New Guinea. Only three localities are known till now (collections made in 1967, 1971 and 1975), all from high altitudes (over 3400 m) in montane areas of Papua New Guinea.
Population Trend: unknown
No conservation plan is available; the known localities are not situated in protected areas, according to the present knowledge. There is an urgent need for a detailed assessment of the current extent of occurrence, population size and trend.The first concern is whether Cetreliopsis papuae is still growing in the area where it has been recorded in 1960-70s; any further data about its ecology, biology and population trends are required as well.