Biatora aureolepra is a species of lichen in the family Ramalinaceae,[1] first found in inland rainforests of British Columbia. This lichen forms thin, powdery crusts that are bright yellow-green when fresh but fade to golden tones over time, and it has never been observed producing fruiting bodies. It grows on the bark and decaying wood of conifers in very humid, old-growth forests and has a scattered distribution in northwestern North America and central Norway.
The species was described in 2009 by Toby Spribille and Tor Tønsberg during a survey of inland rainforest lichens; the holotype, collected from soft conifer wood beside the Roaring River arm of Quesnel Lake, British Columbia (716 m a.s.l.), is lodged in the Canadian Museum of Nature herbarium, with duplicates in Bergen and other collections. Its name combines the Latinaureolus (“golden-yellow”) with lepra ('scurf' or 'leprosy'), a nod to the species' golden hue in dried material and its powdery habit.[2]
Because B.aureolepra has never been seen with apothecia, its placement in Biatora is provisional. Morphological and chemical traits—especially the leprose crust and the C+ (rose) reaction—suggest affinity with Biatora chrysantha and B.chrysanthoides, yet the new species lacks the small corticate areoles typical of those taxa and it contains far more 5-O-methylhiascic acid. That depside is known as a major compound in only two leprose crusts worldwide (B.aureolepra and Micarea coppinsii), allowing the new species to be distinguished readily from superficially similar yellow-green crusts of Lecanora expallens, Cliostomum spp., or Lepraria spp., which possess other chemistries and usually inhabit drier bark.[2]
Description
Biatora aureolepra forms a thin, leprose crust that is bright yellow-green when fresh but often fades to straw-coloured or golden tones in older herbarium specimens. The thallus lacks any layered (stratified) structure; instead, the fungal filaments grow partly within the outer bark or sapwood ( endosubstratal ), while a single surface layer of powdery soredia builds a patchy film several centimetres across. Individual soredia are usually 18–21μm in diameter (occasionally as small as 13μm or as large as 30μm) and frequently clump into consoredia up to 70μm wide; viewed under polarised light these granules glitter with minute crystals. A slender, whitish prothallus may outline young colonies. The green-algal partner (a chlorococcoid photobiont) consists of jelly-sheathed cells 6.5–14μm wide that tend to cluster together.[2]
No sexual fruit-bodies (apothecia) or asexual pycnidia have yet been observed, so the species is known only from its vegetative crust. Chemical tests reveal 5-O-methylhiascic acid as the dominant secondary metabolite, accompanied by traces of gyrophoric and lecanoric acids; a quick rose-violet flash on the thallus with bleach (C+) is characteristic, while reactions with potassium hydroxide solution (K) and para-phenylenediamine (Pd) are negative.[2]
Habitat and distribution
In North America the lichen is confined to interior wet-belt forests of British Columbia and neighbouring Montana, where it colonises bark or decaying wood of western redcedar (Thuja plicata) and western hemlock (Tsuga heterophylla) within humid, old-growth stands that are mostly more than three centuries old. Sites range from about 525 to 930m (1,722 to 3,051ft) elevation and share a microclimate of persistent ground-level moisture under closed canopies.[2]
Across the North Atlantic, three collections from central Norway place B.aureolepra on bark and dead wood of Norway spruce (Picea abies) in cool, rain-drenched boreal spruce forests, again of late-successional age. These records point to a disjunct north-western North America–north-western Europe distribution pattern that mirrors several other moisture-dependent lichens of the inland rainforest biome. Given its minute, sterile thallus and the limited number of targeted surveys, the species is likely under-recorded; nevertheless, its reliance on long-undisturbed, humid conifer forests suggests that ongoing logging of such habitats could threaten its continuity.[2]
1 2 3 4 5 6 Spribille, Toby; Björk, Curtis R.; Ekman, Stefan; Elix, John A.; Goward, Trevor; Printzen, Christian; Tønsberg, Tor; Wheeler, Tim (2009). "Contributions to an epiphytic lichen flora of northwest North America: I. Eight new species from British Columbia inland rain forests". The Bryologist. 112 (1): 109–137. doi:10.1639/0007-2745-112.1.109.
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