A new lichen species from the Heritage Range , Ellsworth Mountains , Antarctica

(A new lichen species from the Heritage Range, Ellsworth Mountains, Antarctica). Opegrapha edsonii, with soralia and norstictic acid is described.


Introduction
The terrestrial biota of the Antarctica comprises almost exclusively lower organism, and among these, lichens are by far the most dominant.New knowledge has revealed a higher diversity of lichen species than previously known (Ruprecht et al. 2012), and the total number for the Antarctic and South Georgia now well exceeds 500 (Øvstedal & Lewis Smith 2011, Øvstedal unpublished data).
A soil and permafrost field study in the Ellsworth Mountains in the summer 2012 included the collection of some lichens growing on cryoturbic soils from ice free areas of the Union Glacier Region in the southern Heritage Range.The Heritage Range forms the southern part of the Ellsworth Mountain system, consisting of scattered ridges and peaks of moderate height, escarpments, hills and nunataks, the various units of relief set off by numerous intervening glaciers, such as the Union Glacier (figure 1).Lichens were sampled on two polygonal soils, both on felsenmeer of Crashsite quartzite, one at 754 m and one at 785 m altitude.
The collection comprises both saxicolous and terricolous lichens.Only the saxicolous ones are treated here.Among these was an undescribed species, which is described below.

Material and methods
The specimens are deposited in BG.Anatomy and morphology were studied using a Zeiss Stemi 2000C microscope, and a Zeiss Axiolab compound microscope.Chemical constituents were identified by thin layer chromatography (Elix & Ernst-Russell 1993).
The specimen is similar to Opegrapha gyrocarpa Flotow, found in Europe, Asia, Macaronesia and North America (Smith et al. 2009), but differs in chemistry, having smaller soredia and distinct different ecology.Opegrapha gyrocarpa grows mainly under rock overhangs, but also rarely on bark (Tønsberg 1992).It has discrete soredia, but the soralia are larger, 24.5 ± 2.04 µm (several Norwegian specimens in BG studied).In addition, O. gyrocarpa contains gyrophoric and ± schizopeltic acids.Generally the thallus is smooth and thin, not rough and thick as in the present species.Norstictic acid is found in the paleotropic species O. semiatra Müll.Arg. and O. mozambica Vain.(Ertz 2009), both of which are non-sorediate species and very different from O. edsonii.Other taxa with Trentepohlia as photobiont recorded from the Antarctic include Cystocoleus aff.ebeneus (Dillw.)Twaites (Øvstedal & Lewis Smith 2001) and Porina aenea (Wallr.)Zahlbr.(Øvstedal & Lewis Smith 2004).A number of Opegrapha species are known from Argentina (Redinger 1940) The soils had permafrost at between 10-15 cm depth, and showed cryoturbic features, though not very well developed.Lichens were found growing on sheltered, loose fragments of rock and on soil in the middle of the sorted polygons of north-western facing slopes.Liquid water was present within the polygons.
The climate in the Heritage range is typical of the low Plateau of continental Antarctica (e.g.Byrd Station), and average air temperature at the Union Glacier is around -12 to -35 ºC.
Surface temperatures above zero last for a few hours a day, and during for less than 30 days during the summer.It is very cold year-round, with approx.
-12 to -35 ºC monthly averages, with decreasing temperatures decreasing with altitude.In the summer, clear skies, calm air and little precipitation is common; other phenomena are the strong karabatics, occasional fogs and low clouds from the Ronne ice shelf (King & Turner 1997).
Based on soil characterization, all sites have alkaline pHs and salt accumulation on the lee side of rock fragments; salts are usually gypsum (CaSO 4 .nH 2 O) and typical of Ellsworth Polar desert soils; the amounts of available P is surprisingly high by polar desert standards, and with very low amounts of organic carbon (table 1), corroborating the extremely low  biomass.The amount of selected heavy metals (Pb and, Cu) are within the range of polar desert soils.The relative concentration of exchangeable cations (Ca, Na, Mg and, K) in nutrient-poor quartzites can be attributed to salt sprays from distant marine sources, concentrated by long term deposition and the absence of leaching.
These extremophilous lichens are present on nutrient-poor substrates (quartzites) and associated with salt-affected soils from the Antarctic Polar deserts.They have only been observed on sheltered sites where liquid water was apparent, and mostly on northern or north-western facing slopes.

Figure 1 .
Figure 1.Map of Antarctic peninsula with location of Ellsworth Mountains marked.

Table 1 .
Characterization of soils at the sites investigated.