Xanthoparmelia austrosorediata Elvebakk, 2014

Elvebakk, A., Bjerke, J. W. & Støvern, L. E., 2014, Parmelioid lichens (Parmeliaceae) in southernmost South America, Phytotaxa 173 (1), pp. 1-30 : 12-14

Xanthoparmelia austrosorediata Elvebakk , spec. nov.

Xanthoparmeliae tehuelcorum similis, sed capitatis soraliis, rarissime apotheciis minutis, plerumque marginibus sorediatis instructa.

MycoBank # 808978

(Figs. 3, 6−7)

Type:— CHILE: XII Región de Magallanes y de la Antártica Chilena: Provincia Magallanes, Morro Chico, SW part, 52 ° 03’S, 71 ° 28’W, 200 m, on exposed basaltic rocks in a W-facing boulder slope, 28 Nov 1999, Elvebakk, A . 99:780 (holotype SGO, isotypes BM, NY, S, TROM) .

Morphologically, anatomically and chemically identical to X. tehuelchorum except in the following characters:

Soralia common, capitate, 2−8 mm diam., composed of single soredia 0.1−0.2 mm diam, fluffy and partly conglutinated.

Apothecia very rare, 0.5−1 mm diam, thalline excipulum margin often sorediate, ascospores short-ellipsoid and 5−7 × 8−12 µm diam.

Etymology: Named after its conspicuous soralia and its distinctly southern distribution.

Additional specimens examined: ARGENTINA. PROVINCIA DE TIERRA DEL FUEGO: Ushuaia, on a small island in the Beagle Channel off the town, on rocks near the sea-shore, 30 Jan 1940, Santesson, R . 534 ( S) ; PROVINCIA DE SANTA CRUZ: Puerto Deseado, on exposed rocks near the sea-shore, 12 Jan 1940, Santesson, R . 238 ( S) .

FIGURE. Xanthoparmelia austropatagonica (Elvebakk 13:083) to the right together with X. tehuelchorum (Elvebakk 13:082), photographed at Morro Chico.

CHILE. XII REGIÓN DE MAGALLANES: Sierra Baguales, 1.3 km S of the junction between the roads towards Las Chinas and Las Cumbres , 50 ° 52’40”S, 72 ° 23’06”W, 2−300 m, on the vertical surface of an erratic boulder, 5 Dec 1999, Elvebakk, A . 99:1137 ( TROM); Parque Nacional Torres del Paine , 200 m S of Salto Grande , W of the Pudeto inlet, 51 ° 03’30”S, 73 ° 01’W, 70 m, on exposed rocks, 5 Dec 2000, Elvebakk, A . 00:922 ( TROM); Refugio Pudeto, E side of the northernmost bay, 51 ° 04’S, 73 ° 01’W, 70 m, on rocks, 11 Dec 1999, Elvebakk, A . 99:1274 ( TROM); 4 km ENE of Salto Grande , 4−500 m W of ‘altitude 222’, 51 ° 03’30”S, 72 ° 57’W, 100 m, on rocks, 11 Dec 1999, Elvebakk, A . 99:993 B ( TROM); 100 m N of Salto Grande , 51 ° 03’57.3”S, 73 ° 00’25.7”W, 80 m, on a light-exposed rock, 3 Dec 1999, Elvebakk, A . 99:1023 ( LE); 1.5 km N of N end of Lago Sarmiento Chico, 51 ° 03’S, 72 ° 56’W, 150 m, on rocks, Nov 1995, Elvebakk, A . 95:424 ( LE); Lago Grey S , 1 km N of Guardería Lago Grey , 51 ° 07’30”S, 73 ° 10’30”W, 70 m, on a vertical, N-facing cliff wall, 8 Dec 2000, Elvebakk, A . 00:946 ( 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 . 99:1239 ( TROM); Lagunas Mellizas E , 51 ° 04’30”S, 72 ° 58’W, 100 m, on exposed rock, 1 Dec 2000, Elvebakk, A . 00:879 ( TROM); 1.5 km SW of Guardería Laguna Amarga , 50 ° 59’30”S, 72 ° 48’W, 80 m, on an exposed gravelly ridge, 24 Jan 1996, Elvebakk, A . 96:111 A ( TROM); Lago Sarmiento E , Baño Viejo, 50 ° 56’S, 72 ° 34’W, 70 m, sun-exposed rock in the steppe, 7 Dec 2000, Elvebakk, A . 00:934 ( TROM); Lago del Toro ( L. Maravilla), Estancia Río Paine , on exposed rocks, 14 Mar 1941, Santesson, R . 6495 ( S); Seno Skyring, Ea. Río Verde , 3 km W of Maria Felicinda, 52 ° 26’S, 71 ° 22’W, 2 m, on the E side of supralittoral rocks, 30 Nov 1999, Elvebakk, A . 99:944 ( TROM); Seno Otway area , 2 km NE of Punta Espolón, 52 ° 47’S, 71 ° 12’W, 5 m, on an erratic rock of andesite, 30 Nov 1999, Elvebakk, A . 99:907 ( TROM); Elvebakk , A . 99:911 ( CANB); 20 m, on erratic rocks in heathlands, Elvebakk, A . 99:928 ( TROM); 1 km S of Carpa Manzana , 50 ° 36’40”S, 71 ° 09’07”W, 50 m, on a small erratic boulder, 6 Dec 1999, Elvebakk, A . 99:110 ( TROM); Morro Chico , 52 ° 03’S, 71 ° 28’ W, common on wind-exposed basaltic rocks, 28 Nov 1999, Elvebakk, A . 99:822 C; 99:835; 99:840; 99:835; 99:880; 99:881 ( TROM); 30 Dec 2013 Elvebakk, A . 13:075 ( TROM); 13:077 ( TROM); 13:083 ( MAF; TROM); Kampen-Aike , 1 km NW of E end of Laguna Cabeza del Mar , 52 ° 42’S, 70 ° 53’W, 30 m, on a single granitic erratic boulder, 25 Nov 1999, Elvebakk, A . 99:722 ( TROM); Parque Nacional Pali-Aike , 2−3 km E of Laguna Ana, 52 ° 04’S, 69 ° 44’W, 250 m, on rocks, 16 Oct 2000, Elvebakk, A . 00:815 ( TROM); 00:992 ( TROM); Tierra del Fuego , Porvenir , in dry Empetrum rubrum heath, 27 Dec 1940, Santesson, R . 6901 ( S) .

This species is common all along the eastern and dry part of the Chilean region of Magallanes, as indicated by the 31 collections from Magallanes cited here. It is probably also common in adjacent parts of Argentina, although only two collections have been available for this study. The species grows together with its fertile counterpart, X. tehuelchorum , and is associated also with Flavoparmelia gerlachei , although the latter occupy the most exposed parts of rock outcrops and boulders. It is astonishing that these two large Xanthoparmelia species have not been described previously, and the only explanation is that their distribution is distinctly southern. The Argentinian province of Santa Cruz is almost unknown lichenologically, and further to the south, lichenologists have focused on the humid coastal forests, and neglected the southernmost steppes.

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

Xanthoparmelia austrosorediatum can be mistaken for Flavoparmelia gerlachei . However, their lobe margins and outlines are different as shown below F. gerlachei , and in Fig. 3. The chemistry is constant, and the 24 specimens which have been studied by TLC all have protocetraric and usnic acids as major compounds.

Apothecia are very rare, and were present only in two of the studied collections (Elvebakk 99:881 and 99:907). They are 1−1.5 mm wide, and many of the apothecia have sorediate thalline excipulae. The ascospores are of a typical Xanthoparmelia type, short-ellipsoid and only 5−7 × 8−12 µm in size, and shorter than those of F.lgerlachei which measure 6−8.5 × 12.5−14 µm, with a thin perispore in addition. Their few apothecia available for study probably explains the slight deviation in spore size as compared with X. tehuelchorum .

In their Xanthoparmelia monograph, Nash et al. (1995) stated that quite a number of the species ‘become darker (to almost blackish) in the older central parts with age’. In species such as X. mougeotii , skottsbergiana and X. submougeotii this is apparently due to pigmentation patterns. However, in X. tehuelchorum and X. austrosorediata a similar decoloration in practically all specimens is instead caused by a network of strange hyphae of conidia-like cells on the surface of the lichen. These hyphae belong to a lichenicolous fungus now under study by Zhurbenko (2013, pers. comm.).