This is shrubby species growing saxicolous on volcanic rocks. It stands up to 5 cm high, and it adheres to the substrate surface through a holdfast 2-4 mm diam. It is richly branched. Branches are solid, subterete to somewhat complanate, 0-8-1-2(-2) mm wide, often with shortly linear pseudocyphellae, especially near the base, apices with several branching points close together. Soredia absent. Cortex c. 25 um thick, chondroid tissue forming a discontinuous cylinder with a few chondroid strands interconnected across the medulla. Apothecia numerous, lateral, up to 3 mm diam.; spores (few seen) bilocular,
13-14x6 um. Chemistry: Divaricatic acid, triterpenoids, usnic acid. The species belongs to the Ramalina decipiens group (Krog & Osthagen 1980), a group of Macaronesian endemic species.
The species is very morphologically very similar to the also endemic R. jamesii. Main differences are anatomical and chemical. Chondroid tissue is discontinous in R. timdaliana and continuous in R. jamesii filling most of the branches. Further, different terpenoid patterns are found in both species and salazinic acid is only found in R. jamesii.
Source: Krog, H 1990: New ramalina species from porto santo, Madeira. - Lichenologist 22(3): 241-247
There only exists a single small population on one volcano in the world. It is threatened by accidental extinction by trampling, grazing and possibly collecting.
Criterion A: There is not current information about the trends of population size over long time periods, so it is not possible to apply this criterium.
Criterion B: Both B1 and B2 subcriteria could be applied as the extent of occurrence is smaller than 100 km2 and the area of occupancy is likely smaller than 10 km2. However, the species does not fit the two necessary conditions for this criterium. It only satisfy subcriterion B1a (or B2a) as it occurs in a single population worldwide. However no available information support the application of subcriteria a or b.
Criterion C. No information is available about the total number of individuals of this species. Thus, subcriteria C1 or C2 are not applicable.
Criterion D. The total number of individuals is unknown, considering 1m2= 1 ind, it is likely the number of individuals is less than 250. D1= Endangered. The Area Of Occupancy is smaller than 20 km2 and the number of locations is 1 which fits subcriterion D2 (Vulnerable).
Criterion E. No quantitave analyses have been carried out.
The species has been assessed as Vu (D2) until more research on the actual number of individuals and population size is carried out.
Assessment: Endangered under criterion D1.
The species is known from a single peak -old volcano- Pico do Castello on the small Island of Porto Santo in the Madeira Archipelago (Portugal). This peak also hosts other endemic Ramalina species also assesed as R. erosa, R. confertula, R. jamesii and the recently IUCN red listed species Anzia centrifuga.
The species is restricted to one locality on a volcano. Population size was not assessed. Population size is, considering 1 individual =1 m2, likely less than <250
Population Trend: Uncertain
Saxicolous, on volcanic acidic rocks.
The most important threats are related to its small population size, and its single island endemic character. Due to the small population size thre is a high risk of extinction due to single catastrophic event (fire?).
It is very likely that the species may be grazed by goats during dry periods as it occurs with other Ramalina species in the Macaronesia.
There is also a high risk of population reduction due to collection by lichenologists.
Finally, trampling by turistic activities may represent a risk for this species.
The most important action to be taken is the whole protection of the area where this and other threated species occur.
Urgent need of establish the actual population size as well as population dynamics. Research on the biology of the species (reproduction, generation time,...) is also needed. Phylogenetic studies to infer its phylogenetic affinities are being carried out.
Krog, H 1990 New ramalina species from porto santo, Madeira. - Lichenologist 22(3): 241-247
krog, H & Østhagen, H 1980 The genus Ramalina in the canary Islands. - Norwegian Journal of Botany 27: 255-296.