Xanthoparmelia tehuelchorum Elvebakk, 2014

Elvebakk, A., Bjerke, J. W. & Støvern, L. E., 2014, Parmelioid lichens (Parmeliaceae) in southernmost South America, Phytotaxa 173 (1), pp. 1-30 : 19-21

Xanthoparmelia tehuelchorum Elvebakk , spec. nov.

Xanthoparmeliae hypomelaenae similis, sed thallo minus adnato, ascosporis latioribus acidoque protocetrarico in medulla praesenti differt.

MycoBank # 808979.

Type:— CHILE: XII Regiòn de Magallanes y de la Antártica Chilena: Provincia Magallanes, Morro Chico , 52 ° 03’S, 71 ° 28’W, 200 m, on northwest-facing volcanic rocks, 28 Nov 1999, Elvebakk, A. 99:811 (holotype SGO, isotypes TROM, NY, S, BM, MAF) .

Figs. 6, 11, 12.

FIGURE. Xanthoparmelia tehuelchorum , HOLOTYPE. Scale bar = 1 cm.

Thallus 3−20 cm large, foliose and adnate to loosely attached to acidic rock surfaces; lobes elongate and irregularly and densely branched, becoming contiguous and areolate in central parts of the thalli, glossy in younger parts, 0.5−1 mm wide, 250−300 µm thick, weakly convex, lobe tips rounded to truncate, margins smooth and eciliate; upper surface yellowish green, emaculate, black-rimmed of a peripheral 0.2−0.3 mm wide marginal zone of young lobe tips being black-pigmented, soon fading to dark brown, whereas the whole thallus is normally dark grey in central parts due to a cover of filaments of a lichenicolous fungus becoming gradually dominant towards the centre; lower surface dark brown near lobe apices, otherwise black, rhizines common, 0.3−0.5 mm long, black, stout and simple, in some cases tufted when in contact with the substrate, absent only from a narrow, 0.3−0.7 mm broad marginal zone; upper cortex 20−25 µm thick, paraplectenchymatic, yellowish from usnic acid; medulla white, lax, 150−250 µm thick, upper 25−35 µm composed of a photobiont layer of globose to subglobose trebuxioid cells 7−12 µm diam.; lower cortex compact, paraplectenchymatic, blackish, c. 10 µm thick.

Apothecia common, substipitate, 1−4 mm broad, disc dark chestnut brown, concave, thalline excipulum persistent and concolorous with thallus; epithecium dark brown, 10−15 µm thick, hymenium colourless, 30−40 µm thick, asci clavate, 8-spored, 15 × 35 µm; paraphyses septate, sparingly branched, apices swollen; hypothecium colourless, 50−60 µm thick, photobiont layer present below the hypothecium; ascospores 6−8 × 10−12 µm, simple, short-ellipsoid, smooth, perispore lacking; conidiomata pycnidia, common and laminal, immersed in thallus, ostiole black, conidia bifusiform, 1.5 × 5.5 µm, few seen.

Chemistry; usnic acid and protocetraric acids (majors).

Etymology: Named after the indigeneous people Tehuelches, now known as Aonikenk, who used to live in the distribution area of this species in Chile, but who are now only present on the Argentinian side.

Additional examined specimens (paratypes): ARGENTINA. PROVINCIA DE SANTA CRUZ: Río Gallegos, Estancia Güer- Aike, on basaltic rocks at the edge of the meseta just above the valley of Río Gallegos , 18 Jan 1940, Santesson, R . 302 (S) .

CHILE. XII REGIÒN DE MAGALLANES Y DE LA ANTARTICA CHILENA: Sierra Baguales, 1.3 km S of the junction between the roads leading to Las Chinas and Las Cumbres , 50 ° 53’S, 72 ° 23’W, 250 m, on erratic, granitic boulders, 5 Dec 1999, Elvebakk, A. 99:1132 ( TROM) ; 99:1142 ( LE); 99:1143 ( TROM); 3-4 km S of Estancia Tres Erres , 50 ° 47’30.5”S, 72 ° 24’43.2”W, 300 m, on exposed, very soft sandstones, 5 Dec 1999, Elvebakk, A. 99:1163 ( TROM) ; 99:1164 ( TROM); Parque Nacional Torres del Paine , 700 m SE of Laguna de los Cisnes , 51 ° 02’30”, 72 ° 51’W, 200 m, on rocks, 3 Dec 1999, Elvebakk, A. 99:1041 ( TROM) ; 3−400 m SE of Laguna Los Flamencos , 51 ° 02’S, 72 ° 48’W, 250 m, on lower parts of boulders, 3 Dec 1999, Elvebakk, A. 99:1014 ( TROM) ; 2.5 km NE of N end of Lago Sarmento Chico , 51 ° 02’30”S, 72 ° 55’W, 200 m, on rocks, 18 Dec 1997, Elvebakk, A. 97:424 ( TROM) ; Refugio Pudeto, on the E side of the northernmost bay, 51 ° 04’S, 73 ° 01’W, 80 m, on rocks, 11 Dec 1999, Elvebakk, A. 99:1294 ( TROM) ; 500 m E of Lagunas Las Mellizas , 51 ° 03’30”S, 72 ° 58’W, 150 m, on rocks on a ridge, 3 Dec 1999, Elvebakk, A. 99:1037 ( TROM) ; 14:008 TROM); at eastern Lagunas Mellizas , 51 ° 04’30”S, 72 ° 58’W, 100 m, on exposed rock, 1 Dec 2000, Elvebakk, A. 00:880A ( TROM) ; Lago Pehoe , NW, 3–500 m SE of Refugio Pehoe , 51 ° 04’30”S, 73 ° 07’W, 70 m, on rocks on an exposed ridge, 11 Dec 1999, Elvebakk, A. 99:1245 ( TROM) ; c. 2 km SW of Guardería Laguna Amarga , 51 ° 00’S, 72 ° 50’W, 80 m, on rocks, 12 Dec 1995, Elvebakk, A. 95:570 ( LE) ; 1.5 km SW of Guardería Laguna Amarga , 150 m, 50 ° 59’30”S, 72 ° 48’W, on exposed rocks, 4 Jan 1998, Elvebakk, A. 98:025 ( TROM) ; 2 km NW of Guardería Laguna Amarga , 50 ° 59’30”S, 72 ° 49’W, 150 m, on sun-exposed rocks, Nov. 1995, Elvebakk, A. 95:456 ( TROM) ; Morro Chico , 52 ° 03’S, 71 ° 28’W, 200 m, on rocks in a SW-facing slope, 28 Nov 1999, Elvebakk, A 99:790 ( TROM) ; 99:810 ( TROM); 99:812 ( TROM); on N-facing rocky slopes, Elvebakk , A 99:821 ( TROM) ; 99:825 ( TROM); 99:827 ( TROM); 99:834 ( TROM); 99: 855B ( TROM); 13:082 ( MAF; TROM); 13:086 ( TROM); 13:087 ( TROM); on exposed rocks on the southern summit, Elvebakk , A. 99:882 ( TROM) ; Parque Nacional Pali-Aike , 0.5 km E of Laguna Ana, 51 ° 04’35.2”S, 69 ° 46’44.6”W, 130 m, in steppe, 26 Nov 2000, Elvebakk, A. 00:816 ( TROM) .

Xanthoparmelia tehuelchorum is very common along the whole eastern sector of Magallanes from Pali-Aike northwards to Sierra Baguales, as indicated by the 31 herbarium samples reported here. It is probably also a very common species in the lichenologically poorly investigated province of Santa Cruz in Argentina, although only one herbarium specimen has been seen from this area. This is the only known fertile yellow-green Xanthoparmelia in the study area. The species grows with X. austrosorediata and Flavoparmelia gerlachei on exposed siliceous rocks in the Patagonian steppes and in neighbouring more or less unforested areas. The species is a fertile counterpart of the sorediate X. austrosorediata , which it grows together with. Morphologically, it is most similar to the more northern and fertile species X. hypomelaena (Hale) Hale , which is more adnate, has more narrow ascospores and fumarprotocetraric acid as its diagnostic secondary compound. Apart from X. austrosorediata only two other yellow Xanthoparmelia species from South America contain protocetraric acid, one is isidiate and one is subcrustose and sorediate ( Nash et al. 1995), and no other species elsewhere have been found to be conspecific with the present species, a conclusion agreed to by J.A. Elix after examining one specimen (pers. comm., 2008).

FIGURE. Xanthoparmelia tehuelchorum (Elvebakk 13:086) photographed at Morro Chico.