Taxonomic Notes & Identification Information: 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 strandsinterconnected across the medulla. Apothecia numerous, lateral, up to 3 mm diam.; spores (few seen)bilocular,13-14x6 um.
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 areanatomical 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.
There only exists a single small population on one volcano mountain in the world. It is threatened by accidental extinction by trampling, grazing and possibly collecting. Criterion A: There is no current information about the trends of population size over long time periods, so it is not possible to apply this criterion. Criterion B: Both B1 and B2 subcriteria could be applied as the extent of occurrence is smaller than 100km² 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. Criterion D: The total number of individuals is unknown, considering 1m²= 1 ind, it is likely the number of individuals is less than 250. Actually 250 m² is occupied by the species, which is known from a single mountain top.
Assessor/s: Perez-Ortega, S.; Reviewer/s: Scheidegger, C.; Contributor(s): Weerakoon, G., Spribille, T. & Aptroot, A.
Bibliography:
Aptroot, A. & Schumm., F. (2008) Key to Ramalina species known from Atlantic islands, with two newspecies from the Azores. Sauteria15:21-57.
IUCN (2017) The IUCN Red List of Threatened Species. Version 2017-3. Available at: www.iucnredlist.org. (Accessed: 7 December 2017).
Krog, H. (1990) New Ramalina species from Porto Santo, Madeira. Lichenologist22(3): 241-247.
Krog, H & Østhagen, H. (1980) The genus Ramalina in the Canary Islands. Norwegian Journal of Botany27: 255-296.
Sparrius, L.B. et al. (2017) Estimating the population size of the endemic lichens Anzia centrifuga (Parmeliaceae) and Ramalina species (Ramalinaceae) on Porto Santo (Madeira archipelago). The Bryologist120(3): 293-301.
Find out more about the IUCN Red List Categories and Criteriahere.