Hypotrachyna neosingularis

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Hypotrachyna neosingularis is a bark-dwelling, leafy lichen in the Parmeliaceae family. It was described as a new species in 2001 by Pradeep Divakar, Dalip Upreti, and John Elix. It is found in India and is endemic to the Eastern Himalaya. The type specimen was collected in Gangtok, Sikkim, on tree bark in July 1959 by K. P. Srivastava and is kept at the LWG herbarium in Lucknow.

The name neosingularis reflects its close relationship to Hypotrachyna singularis from South America, but it differs in lobule shape, smaller spores, and medulla chemistry. The thallus is foliose (leafy) and can reach up to about 8 cm wide, loosely attached with a leathery texture. The lobes are 3–5 mm wide, imbricate (overlapping), and rounded, with lobules scattered along the margins and surface. The upper surface is grey to grey-brown, smooth and shiny, and the lichen lacks isidia, soredia, and pustules, indicating it mainly reproduces by spores. The white medulla sits beneath a grey to black upper surface, and the lower surface is black at the margin with dark rhizines.

Apothecia (fruiting bodies) are common, 1–2.5 mm wide, pale brown to black, and shallow. The ascospores are ellipsoid and about 8–9 by 4.5–5.5 μm. Pycnidia are black and immersed in the thallus, and the conidia measure about 6–8 by 1 μm.

Chemically, the cortex reacts K+ yellow, while the medulla shows no reaction to K, C, KC, or P tests. major secondary metabolites include atranorin and lichesterinic acid, with minor chloroatranorin and trace protolichesterinic acid, plus an unknown fatty acid. This chemical profile helps distinguish H. neosingularis from the similar H. singularis, which has a different mix of acids.

Originally known only from its type locality in Sikkim, it was also reported from Mizoram in 2020. Hypotrachyna neosingularis is considered endemic to the Eastern Himalaya.