Thelocarpon andicola Flakus & Kukwa, 2014

Flakus, Adam & Kukwa, Martin, 2014, The first squamulose Thelocarpon species (Thelocarpaceae, Ascomycota) discovered in the biological soil crusts in the Bolivian Andes, Phytotaxa 175 (5), pp. 281-286 : 282-283

Thelocarpon andicola Flakus & Kukwa sp. nov. ( Figs. 1A–D , 2A–G ) Mycobank MB 809675

Diagnosis: Differs from other Thelocarpon species by the following combination of characters: distinctly squamulose to placodioid and yellow pruinose thallus with numerous ascomata, non-amyloid hyemnial gel, branched paraphyses, amyloid asci without mass axial and broadly ellipsoid ascospores.

Type: — BOLIVIA. DEPT. COCHABAMBA: Prov. Carrasco, Parque Nacional Carrasco, Koricaza , 17°33’21”S, 65°16’29”W, 2950 m, Páramo Yungueño, on soil rich in organic humus, 18 Aug. 2012, A. Flakus 24628 (holotype KRAM!; isotypes LPB!, UGDA!, herb. Flakus!) .

Thallus lichenized, 0.4–6.0 mm in diam., 0.1–0.3 mm thick, yellow pruinose, distinctly squamulose to placodioid, faintly lobed at the margins (lobes 0.2–0.5 × 0.2–0.3 mm) with (1–)6–30 (or more) immersed perithecia when mature, in young stage only surrounding the ascomata and forming a hemispherical verrucae (0.2–0.4 mm in diam.); upper cortical layer 10–15 µm wide, composed of several layers of cells (3–4 µm in diam.), with surface covered by yellow crystals; photobiont layer continuous, 40–60 µm thick; medulla often present, white, 40–100 µm thick; lower cortical layer usually absent, 5–10 µm wide, composed of several layers of strongly gelatinized hyphae; photobiont chlorococcoid, globose, cells 7–12 um in diam.; ascomata perithecioid, globose to slightly flattened at the top, 200–400 µm wide and 200–350 µm high; exciple prosoplectenchymatous, hyaline, 10–20 µm wide; outer wall (thalline layer) 70–100 µm wide, composed of loosely arranged hyphae (2–3 µm thick) mixed with photobiont cells (7–12 µm in diam.) and covered by cortical layer; surface pruinose by yellow crystals; hamathecium with non-amyloid gel (I–, K/I–), 110–160 µm high, composed of sparsely branched and anastomosing, 1–1.5 µm wide paraphyses, and c. 15 µm long, septate, strongly branched and anastomosing periphysoids; asci flask-shaped, (70–)110–160 × (10–)25–35 µm, apex nonamyloid and without visible mass axial, walls I+ pale blue, K/I+ dark blue, endospore I+ orange, multispored (>100 ascospores); ascospores simple, hyaline, broadly ellipsoidal, 4–5.5 × 2.5–3 µm, with 1(–2) oil droplets; conidiomata pycnidial, immersed in thallus, pyriform, 80–140 µm tall, 70–120 µm wide; pycnidial wall indistinct, 4–6 µm thick, hyaline, composed of loosely arranged hyphae (textura intricata); conidiophores regularly branched with one main axis and several lateral branches; conidiogenous cells terminal, simple, elongated, 12–15 × 1.5–2 µm; conidia acrogenous, hyaline, simple, broadly ellipsoid to oblong and slightly attenuated at the base (lacriform), rarely constricted in the middle, 4–5(–6.5) × 2–3 µm, with 1(–2) oil droplets.

Chemistry: Vulpinic acid (major) and pulvinic acid (trace).

Notes: Thelocarpon andicola clearly differs from all known species of the genus by its yellow pruinose, distinctly squamulose to placodioid, thick thallus with numerous ascomata (usually 6–30). The new species most resembles T. laureri ( Flotow 1847: 65) Nylander (1855: 191) by having yellow pruinose lichenized thallus and branched paraphysoids. The later however differs in thallus composed only of verrucae containing a single ascomata ( Salisbury 1966; Kocourková-Horáková 1998; Orange et al. 2009).

Thelocarpon albidum Nylander (1853: 317) and T. robustum auct. brit. non Eitner (1901: 13) ( Vondrák et al. 2010: 25–26) are two other species developing thalli of crowded or plane verrucae with irregular margins, however they never form squamulose to placodioid thalli. Furthermore, the first one differs in its epruinose thallus, simple paraphyses and larger ascospores (11–17 × 5.5–9 µm), and the latter by its greyish thallus with yellow pruina only present at the apex of ascomata, and narrowly ellipsoid ascospores (2.5–5 × 1.2–2 µm) ( Orange et al. 2009; Vondrák et al. 2010).

Five further species, i.e. T. olivaceum Bouly de Lesdain (1914: 149) , T. magnussonii Salisbury (1953: 74) , T. nigrum Aptroot & K.H. Moon in Moon & Aptroot (2009: 309), T. pallidum Salisbury (1953: 75) and T. palniense Awasthi & Singh (1975: 39) , are also known as distinctly lichenized, but differ from T. andicola in several respects. Thelocarpon olivaceum and T. pallidum lack paraphyses and additionally T. pallidum is only sometimes pruinose at the ascomatal apex ( Salisbury 1966). Thelocarpon magnussonii , T. nigrum and T. palniense have black or almost black (at least when dry) and epruinose fertile verrucae. Thelocarpon magnussoni lacks paraphyses and has narrowly oblong ascospores (3.5–5 × 1.2–1.8 µm), T. nigrum produces larger ascospores (9–12 × 5–6 µm) and the ascospores of T. palniense are broadly ellipsoidal to subglobose (3.8 × 2.8–3.8 µm) ( Salisbury 1966; Awasthi & Singh 1975; Awasthi 1991; Moon & Aptroot 2009).

Lichenization is one of the highly successful nutritional strategies in fungi and many major evolutionary lineages of Ascomycota are derived from lichens ( Lutzoni et al. 2001). We could assume that also non-lichenized species of Thelocarpon have secondarily lost the ability to form lichen symbiosis. Thus, T. andicola , the typically lichen-forming fungus due to its fully-developed heteromerous and suqamulose thallus, can possibly bear the most ancestral features within the genus. At present, however, there is little information to support this hypothesis which certainly requires further study using molecular framework.

Distribution and habitat: So far the new species is known only from the type locality in Bolivian Andes. Its population grows in open places in the biological soil crusts where it is a dominant lichen growing together with Arthrorhaphis alpina , Baeomyces rufus and Placynthiella icmalea . We have noticed two different strategies to colonize the substrate by Thelocarpon andicola . In the first strategy, initially single, dispersed verrucae of young ascomata start to form squamules , later individual ascomata surrounded by squamules are joined and fused together leading to establish large mature thalli. In, the second observed strategy, Thelocarpon andicola produces sterile thalli, which develop numerous immersed ascomata during growth, later that fertile thalli could also fuse together to form large mature thalli.

Additional specimens examined (paratypes). BOLIVIA. DEPT. COCHABAMBA: Prov. Carrasco, Parque Nacional Carrasco, Koricaza , 17°33’21”S, 65°16’29”W, 2950 m, Páramo Yungueño, on soil rich in organic humus, 18 August 2012, M. Kukwa 11698 & 11717 ( LPB, UGDA) .

Figures

FIGURE 1. Thelocarpon andicola (holotype). A, initial subglobose perithecioid ascomata, forming a single thalline warts surrounding by thalline squamules. B, young squamulose thallus with six ascomata. C, mature large thallus with numerous ascomata. D, cross section of thalline wart with ascoma showing surrounding algal sheath, thin cortical layer and yellow-pruinose outer layer. Scales: A–C—500 µm, D—50 µm.

FIGURE 2. Thelocarpon andicola (holotype). A, cross section of thalline wart showing colourless paraplectenchymatous exciple and thalline layer composed of loosely arranged hyphae and photobiont cells (mounted in LPCB). B, flask-shaped ascus (mounted in Lugol’s solusion). C, ascus apex (mounted in Lugol’s solusion). D, cross section of conidiomata immersed in thallus (mounted in LPCB). E, conidiophores with elongated conidiogenous cells and acrogenous conidia (upper mounted in LPCB; lower in tap water). F, ascospores with 1–2 oil droplets (in tap water). G, conidia with 1–2 oil droplets (upper mounted in LPCB; lower in tap water). Scales: A—50 µm, B—20 µm, C—10 µm, D—25 µm, E–G—10 µm.