Montanelia
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| Montanelia | |
|---|---|
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| Montanelia panniformis | |
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Lecanorales |
| Family: | Parmeliaceae |
| Genus: | Montanelia Divakar, A.Crespo, Wedin & Essl. (2012) |
| Type species | |
| Montanelia panniformis (Nyl.) Divakar, A.Crespo, Wedin & Essl. (2012) | |
Montanelia is a genus of lichen-forming fungi belonging to the large family Parmeliaceae.[1] The genus comprises foliose lichens recognised by its short, narrow lobes with flat to slightly convex edges; a smooth, unperforated outer skin (epicortex); shallow, irregular pseudocyphellae—tiny pores—on the upper surface; slender, cylindrical to spindle-shaped asexual spores (conidia); and a white medulla that contains orcinol depsides.
Montanelia was circumscribed in 2012 by Pradeep K. Divakar, Ana Crespo, Mats Wedin, and Ted Esslinger in 2012 to accommodate a group of five species previously assigned to the genus Melanelia. The genus name combines "montane", referring to its montane distribution, with -elia alluding to the genus Melanelia.[2]
Molecular phylogenetics work that sampled all recognised species showed that Montanelia predisjuncta nests firmly inside the M. disjuncta clade. Because no genetic discontinuity was detected between them, the authors concluded that M. predisjuncta is best treated as a synonym of M. disjuncta.[3]
A rate-calibrated species tree based on six nuclear and mitochondrial loci dates the origin of the genus to about 23 million years ago (early Miocene). Most diversification occurred through the Miocene and Pliocene, with a more recent burst of speciation during the Pleistocene that is especially evident in the M. tominii complex.[3]
A follow-up revision in 2016 formally recognised three of those cryptic lineages—Montanelia occultipanniformis sp. nov., M. secwepemc sp. nov. and M. saximontana (raised from variety to species rank)—and treated M. predisjuncta as a possible synonym of M. disjuncta, basing the decision on six-locus coalescent species-delimitation analyses and diagnostic ITS barcodes.[4]
Description
The foliose thallus forms mats that sit loosely to moderately tight against the substrate, occasionally bulging into a low cushion. Lobes are narrow and more or less linear, only 0.4–3 mm wide; their tips lie flat to gently rounded and never develop the long marginal hairs (cilia) seen in some other brown Parmeliaceae. The upper surface varies from tan to dark brown-black, with a texture that is smooth near the tips but often finely wrinkled toward the centre. It lacks spots or stains and is commonly broken by tiny, pale pores (pseudocyphellae), except in M. sorediata (where they are absent) and only occasionally in M. panniformis. These pores are flush with the surface and have no fixed outline. A non-pored epicortex overlies the cellular upper cortex. Beneath, the medulla is white, while the lower surface is black—grading to dark brown at the margin—and bears short, unbranched rhizines of the same colour that anchor the thallus.[2]
The genus reproduces sexually through laminal apothecia that are usually stalkless but may be very shortly pedicellate. Their discs start concave, become flat or slightly convex with age, and remain solid (imperforate); a ring of pseudocyphellae often rims the margin. The hymenium is 40–70 μm tall and contains eight spores per Lecanora-type ascus. These ascospores are simple, colourless, mostly ellipsoid (occasionally ovoid), and measure 8–12 × 4–7 μm, with walls up to 1 μm thick. Asexual propagation occurs in immersed, surface-level pycnidia that release cylindrical to spindle-shaped conidia 4–7.5 × 1 μm. Chemically the medulla produces orcinol depsides—especially perlatolic, stenosporic, or gyrophoric acid—which help to distinguish species within the genus.[2]