This is a very characteristic umbilicate stiped lichen that belongs to the genus Sticta but replaces the genus Umbilicaria. which is not known from all of New Guinea, on this mountain.
Upper surface dark chocolate to blackish brown, glossy; often, but not on every lobe, with shallow reticulations and foveae. Lower surface black, mostly covered with a short felty layer of rhizinae, always with cyphellae. Rhizines 50–150 μm long, simple or usually
dichotomously branched, consisting of one row of isodiametrical, thick-walled cells,
which are c. 10 μm diam., brown below, and tapering to c. 5 μm diam., hyaline for the upper 2–4 cells, which are markedly
rounded and catenulate. Cyphellae ochraceous inside, 0·2–0·4 mm deep, 0·2–0·8 mm wide, margin slightly raised (thelotrematoid),
glossy dark brown to black, 0·1 mm wide. Cortex identical on upper and lower surface, isidia and apothecium margin, paraplectenchymatous,
cell walls thickened, dark
brown, 5–10 μm diam. Medulla ochraceous, unchanged in KOH. Photobiont nostocoid, cells in clusters, c. 4–7 μm diam., often
compressed sideways. Lobes irregularly branched, concave or somewhat saddle-like contorted, flat, mostly 0·7–2·4 mm wide,
0·1–0·3 mm thick. Lobe margins much incised, always with pockets of isidia projecting upwards and sideways. Isidia simple to
branched, knobbly to finger-like, often bent, glossy chocolate brown, 0·1–0·2 mm wide,
up to 1·0 mm long, becoming detached leaving ochraceous scars. Soredia absent. Cilia
absent. Apothecia occasionally present, sessile on a small stipe at the tips of lobes, 0·5–5·0 mm wide, 0·3–1·7 mm high. Disc concave, shiny, chocolate brown. Apothecium margin rough,
dull, dark brown, c. 0·2–0·4 mm thick. Excipulum hyaline inside, brown in a small cortical zone, consisting of radially arranged,
thickened cells 5–8 x 7–12 μm. Epihymenium fuscous brown, c. 50 μm high. Hymenium hyaline, not inspersed. Hypothecium
ochraceous, c. 50 μm high. Paraphyses simple, hyaline, c. 2 μm wide, tip clavate, formed by 2–4 cells, tapering gradually up to
4 μm wide, fuscous brown, with a truncate tip. Ascospores 4/ascus, fusiform with lower end tapering into a tail, hyaline, 3-septate,
40–55 x 7–10 μm. Pycnidia occasionally present, hemispherical, concolorous with thallus, 0·1–0·2 mm diam. Conidia not observed. Chemistry. No lichen substances detected, but with strong fishy smell.
This species grows only in the summit area of a very high isolated mountain in the tropics. If the area would become subject to global warming, its natural niche (an oro-alpine situation) would vanish and the species would have no place to retreat to, and will be soon replaced by species that are adepted to milder climate in the unlikely case that it manages to adept to a milder climate.
Criterion A does not apply.
Criterion B does not apply.
Criterion C does not apply.
Criterion D: Estimated population size acccording to the area occupied area is <250 individuals. So it can be assesed as Endangered under criterion D1. AOO is z 20km2 and number of populati According to criterion D2 the species would be Vulnerable.
So, the final assesment for this species is Endangered under criterion D1.
Summit area of Mount Wilhelm, an isolated high mountain almost on the equator in Papua New Guinea.
It grows at an altitude of c. 4200-4300 m.
It occurs in loose and dispersed stands, the total Area of Occupancy of the population is less than a few dozen square meters.
Population Trend: Uncertain
On bare rock, an unusual substrate for this genus. The species here fills the empty niche of the family Umbilicariaceae, which is absent from the region.
Global warming. This species grows only in the summit area of a very high isolated mountain in the tropics. If the area would become subject to global warming, its natural niche (an oro-alpine situation) would vanish and the species would have no place to retreat to, and will be soon replaced by species that are adepted to milder climate in the unlikely case that it manages to adept to a milder climate.
Reduce man’s impact on the climate that leads to global warming.
Aptroot, A. 2008. Sticta alpinotropica, a new saxicolous lichen species from the alpine zone of Mt Wilhelm, Papua New Guinea. Lichenologist 40: 419-422.