Introduction
The genus Pertusaria DC. has a worldwide distribution with over 350 species, being particularly common in subtropical and temperate regions (Lumbsch & Nash Reference Lumbsch, Nash, Nash, Ryan, Gries and Bungartz2002). The genus is characterized by a crustose thallus, hemiangiocarpous apothecia often sunken in verrucae, the presence of a cupulate exciple, primary paraphysoids present in the hamathecium of mature ascomata, thick-walled asci with bivalve dehiscence, and one-celled, often thick-walled, hyaline to brownish ascospores (Lumbsch & Schmitt Reference Lumbsch and Schmitt2001). The morphological characters show a remarkable variability and, in addition, the chemistry of the genus is very complex.
The genus has received considerable attention during the past few decades, which has resulted in numerous revisions and the description of many new species (Dibben Reference Dibben1980; Hanko Reference Hanko1983; Kantvilas Reference Kantvillas1990; Archer Reference Archer1995, Reference Archer1997, Reference Archer2004; Lumbsch et al. Reference Lumbsch, Nash and Messuti1999; Zhao et al. Reference Zhao, Ren and Aptroot2004; Messuti Reference Messuti2005; Sipman Reference Sipman2006; Messuti et al. Reference Messuti, Becker and Archer2007; Zhurbenko & Lumbsch Reference Zhurbenko and Lumbsch2006; Lendemer et al. Reference Lendemer, Harris and Elix2008; Archer & Elix Reference Archer and Elix2009). Molecular studies have shown that Pertusaria is a polyphyletic genus and could be divided into three monophyletic groups (Lumbsch & Schmitt Reference Lumbsch and Schmitt2001; Schmitt & Lumbsch Reference Schmitt and Lumbsch2004).
The Macaronesian Islands form part of one of the 25 World Biodiversity Hotspots (Myers et al. Reference Myers, Mittermeier, Mittermeier, da Fonseca and Kent2000), and the Canary Islands play a key role within this region (Médail & Quézel Reference Médail and Quézel1997, Reference Médail and Quézel1999). The lichen biota of the Canary Islands is rich, with c. 1500 species listed for an area of just 7447 km2 (Hernández Padrón Reference Hernández Padrón, Izquierdo, Martìn, Zurita and Arechavaleta2004). Nevertheless, new records arise and new species continue to be described from the islands with some frequency (Giralt et al. Reference Giralt, Etayo and van den Boom2002; Etayo & Marbach Reference Etayo and Marbach2003; Elix & SchummReference Elix and Schumm2003; Hernández Padrón et al. Reference Hernández Padrón, Sicilia Martìn, Pérez-Vargas, Pérez de Paz, Etayo and Beltrán Tejera2004; van den Boom & Vězda Reference van den Boom and Vĕzda2005; van den Boom & Etayo Reference van den Boom and Etayo2006; Pérez-Vargas et al. Reference Pérez-Vargas, Hernández-Padrón and Elix2007; Giralt & van den Boom Reference Giralt and van den Boom2009; Pérez-Vargas & Pérez de Paz Reference Pérez-Vargas and Pérez de Paz2009), confirming that the lichen biota in this region with its many ecosystems, is insufficiently known. In the present paper we describe two new species of Pertusaria from La Calderade Taburiente National Park, La Palma.
Material and Methods
The specimens were collected from conifers in the high mountains of La Caldera de Taburiente National Park (La Palma) and deposited in CANB, TFC, and the private herbarium of J. Etayo. The morphology of the lichen specimens was examined using a Leica ZOOM 2000 or a Zeiss Stemi 2000C stereo-microscope. Sections for anatomical examination were cut by hand and examined with an Olympus CH compound microscope. Measurements of well-developed ascospores lying outside the asci were made in water at a magnification of ×1000. Colour reactions (spot tests) were made using standard methods (Orange et al. Reference Orange, James and White2001). Chemical constituents were identified by thin-layer chromatography using solvent systems A, B' and C (Culberson Reference Culberson1972; Culberson et al. Reference Culberson, Culberson and Johnson1981; Culberson & Johnson Reference Culberson and Johnson1982; Elix & Ernst-Russell Reference Elix and Ernst-Russell1993), high performance liquid chromatography (Elix et al. Reference Elix, Giralt and Wardlaw2003) and by comparison with authentic samples.
The New Species
Pertusaria aceroae Hern.-Padr., Etayo, I. Pérez-Vargas & Elix sp. nov
Thallus corticola, crustaceus, flavido-olivaceus, verrucosus; soredia vel isidia nulla. Verrucae fertiles thallo concolores, numerosae. Apothecia disciformia, numerosa, conspicua; disci nigri, plani vel concavi, epruinosi. Epithecium brunneum, K+ violaceum. Hymenium hyalinum. Paraphyses c. 2·5 μm crassae. Asci cylindrici, 2-spori. Ascosporae hyalinae, non-septatae, ellipsoideae, 125–182 × 53–75 μm. Paries 10–19 μm crassus; thallus acidum thiophanicum, 2,4-dichloro-3-O-methylnorlichexanthonum et 2-chloro-6-O-methylnorlichexanthonum continens.
Typus: Spain, Canary Islands, La Palma, La Caldera de Taburiente National Park, Barranco Los Guanche, por Tres Venas, UTM: 221900/ 318305, 1930–2000 m alt., on Juniperus cedrus Webb & Berthel. in Pinus canariensis C. Sm. ex DC. in Buch forest, November 2000, A. Palomares 5321 (TFC Lich—holotypus; CANB, hb. Etayo—isotypi).
(Fig. 1)
Pertusaria aceroae (part of the holotype). A, habit, showing thallus and apothecia; B, hymenium; C, ascus with spores. Scales: A = 0·5 mm; B = 150 μm; C = 100 μm.
Thallus crustose, epiphloeodal, rimose to verrucose, moderately thick, greenish yellow, lacking isidia and soredia.
Apothecia numerous, rounded to rather irregular, verruciform at first, becoming disciform at maturity, concolorous with the thallus, up to 1 mm diam; disc at first immersed finally exposed, concave to flat, black, glossy, not pruinose. Epithecium olivaceous, K+ violet. Hymenium colourless, 350–400 μm thick. Paraphysoids branched and anastomosed, 2–2·5 μm diam., with small oil drops. Asci cylindrical, 275–320 × 70–90 μm. Ascospores 2 per ascus, hyaline, ellipsoid, 125–182 × 53–75 μm; spore walls thick, 10–19 μm, not or slightly ornamented.
Pycnidia not seen.
Chemistry. K− or yellowish, C+, KC+ and UV+ vivid orange, P−; containing thiophaninic acid (major), 2,4-dichloro-3-O-methylnorlichexanthone (minor) and 2-chloro-6-O-methylnorlichexanthone (minor).
Etymology. The specific epithet aceroae is derived from the native pre-hispanic name of the area where the new species occurs.
Notes. This new species is characterized by its verrucose thallus with exposed, epruinose apothecia, asci with two ascospores with thick walls and the presence of thiophaninic acid in addition to several minor chlorinated norlichexanthones. It superficially resembles the corticolous Pertusaria paramerae Crespo & Vĕzda, an epiphytic species that grows on Juniperus thurifera L., in the open juniper woods of the Iberian high plateau (parameras) on the Spainish mainland (Crespo & Vĕzda Reference Crespo and Vězda1985). That species, however, has a whitish-grey thallus with the apothecia immersed in fertile soralium-like warts, the 2-spored morphotype has smaller ascospores (95–96 × 53 μm) and it contains the planaic acid chemosyndrome in addition to the thiophaninic acid chemosyndrome.
This new species also resembles Pertusaria stenhammarii Hellb., a 2-spored species with disciform apothecia and K+ violet epithecia that grows on bark of conifers at high elevations in Europe and western North America (Dibben Reference Dibben1980; Lumbsch et al. Reference Lumbsch, Nash and Messuti1999), but that species is sometimes sorediate, has shiny-pruinose discs, smaller spores (60–120 × 30–65 μm) and lacks secondary metabolites (Table 1).
See also Notes under P. calderae.
Habitat and distribution. Pertusaria aceroae occurs on lignum of Juniperus cedrus and more rarely Pinus canariensis, two endemic conifers present in the highest areas of La Palma. This Canarian pine and cedar forest (Loto hillebrandii-Pinetum canariensis A.Santos 1983 + Juniperus cedrus), which occurs between 1900–2100 m, is characterized by low forest density and harsh climatic conditions.
Selected specimens examined. Spain: Canary Islands: La Palma, La Caldera de Taburiente National Park: Los Andenes, UTM: 2100 m alt., on J. cedrus, July 1999, A. Rebolé (TFC Lich: 2485); ibid., Sendero desde el Roque de Los Muchachos, UTM: 218500/ 318393, 2150 m alt., on J. cedrus, July 1999, A. Rebolé (TFC Lich: 2497); ibid., Barranco Los Guanches, por Tres Venas, UTM: 221900/ 318305, 1930–2000 m alt., on J. cedrus, November 2000, A. Palomares (TFC Lich: 6009, 6010, 6012): ibid., Punta de los Roques, near mountain hut, 2084 m alt., on J. cedrus, December 1999, J. Etayo s.n. & M. Martìn (hb. Etayo).
Pertusaria calderae Hern.-Padr., Etayo, I. Pérez-Vargas & Elix sp. nov
Thallus corticola, crustaceus, flavidus vel olivaceus, rimosus vel verrucoso-areolatus; isidiis et sorediis destitutis. Verrucae fertiles thallo concolores, numerosae. Apothecia disciformia, numerosa, conspicua; disci nigri, albopruinosi. Hymenium hyalinum, epithecium brunneum, K+ violaceum. Paraphyses c. 3 μm crassae. Asci cylindrici. Sporae singulae, ellipsoideae, laeves, 142–187 μm longae, 52–98 μm latae, parietibus (5–)7–9(–12) μm crassis. Thallus acidum thiophanicum, 2,4-dichloro-3-O-methylnorlichexanthonum et 2-chloro-6-O-methylnorlichexanthonum continens.
Typus: Spain, Canary Islands, La Palma, La Caldera de Taburiente National Park, Barranco Los Guanche, por Tres Venas, UTM: 221900/ 318305, 1930–2000 m alt., on Juniperus cedrus in Pinus canariensis forest, November 2000, A. Palomares 4080 (TFC Lich –holotypus; CANB, hb. Etayo—isotypi).
(Fig. 2)
Pertusaria calderae (part of holotype). A, habit, showing thallus and apothecia; B, hymenium; C, ascus with spores. Scales: A = 1 mm; B = 150 μm; C = 100 μm.
Thallus corticolous, crustose, epiphloeodal, rimose, thin or somewhat thickened, greenish yellow, lacking isidia and soredia.
Apothecia conspicuous, numerous and crowded, concolorous with the thallus, 0·75–1·2 mm diam., verruciform at first, becoming disciform at maturity; disc concave to flat, black, white pruinose. Epithecium olivaceous, K+ violet. Hymenium colourless, 200–300 μm thick. Paraphysoids branched and anastomosed, up to 3 μm diam., with oil droplets. Asci cylindrical, 190–225 × 55–75 μm; ascospores 1 per ascus, hyaline, ellipsoid, 142–187 × 52–98 μm; walls (5–) 7–9 (–12) μm thick, not ornamented.
Pycnidia not seen.
Chemistry. K− or yellowish, C±, KC±orange and UV± pinkish orange, P−; containing thiophaninic acid (major), 2,4-dichloro-3-O-methylnorlichexanthone (minor) and 2-chloro-6-O-methylnorlichexanthone (minor).
Etymology. In 1815 the German geologist Leopold von Buch visited La Caldera de Taburiente (La Palma) and other islands in the Canary Archipelago. When he published his memoirs, he introduced the term “caldera” into the geological vocabulary. The specific epithet calderae derived from the name of the spectacular orographic feature where this species occurs.
Notes. This new species is characterized by its rimose thallus with exposed, pruinose apothecia, single spored asci and the presence of thiophaninic acid and several minor chlorinated norlichexanthones.
Pertusaria calderae resembles the corticolous P. hymenea (Ach.) Schaer. present in temperate Europe and western North America, with its apothecioid ascomata, black, pruinose exposed discs and dark K+ violet epithecium but the latter differs in having a greyish, often continuous thallus, 8-spored asci, smaller spores (60–130 × 25–50 μm) and contains gyrophoric acid in additon to thiophaninic acid.
This new species also resembles the 1-spored morphotype of P. paramerae. Pertusaria calderae, however, is distinguished by having apothecia that are never soralium-like, a greenish yellow rather than whitish grey thallus and by its chemical composition. A further similar corticolous species is the Mediterranean P. caesioalba (Flot.) Nyl., but the latter has a white thallus, larger ascospores (180–220 × 75–100 μm) and a different chemistry (thiophaninic and 2-O-methylperlatolic acids).
The new species is chemically identical to P. aceroae described above. Although these two species appear to be very closely related, they are morphologically different. In particular P. calderae is a monospored species, and P. aceroae has 2-spored asci. That, in itself, might not constitute sufficient reason to regard them as separate (e.g., P. paramerae has one- and two-spore morphotypes), but in the case of P. aceroae and P. calderae, there are many correlated morphological differences. Pertusaria aceroae has a moderately thick and verrucose thallus whereas the thallus of P. calderae is thin and rimose. In both species the ascomata are finally apothecioid with exposed disc, but in P. aceroae, they are sessile to slightly emergent and verrucose, and in P. calderae they are almost immersed, barely emerging from the thallus. The apothecial disc in P. calderae is always pruinose; in P. aceroae it is epruinose, black and shiny. Pertusaria aceroae has a higher hymenium than P. calderae (350–400 μm vs 200–300 μm). The asci are larger in P. aceroae: 275–350 μm tall compared to 190–225 μm in P. calderae (Table 1). Although the spore size is similar, the spore walls are thicker in P. calderae than in P. aceroae. No intermediate morphotypes were found.
Habitat and distribution. Pertusaria calderae occurs on lignum of Juniperus cedrus in the highest zones of La Caldera de Taburiente National Park (La Palma), between 1700–2400 m, with similar ecology to P. aceroae described above.
Selected specimens examined. Spain: Canary Islands: La Palma, La Caldera de Taburiente National Park: Veta los Pinos, 1700 m alt., on J. cedrus, July 1999, A. Rebolé (TFC Lich: 4085); ibid., Inmediaciones Pico de la Cruz, 2050 m alt, on J. cedrus, July, 1999, A. Rebolé (TFC Lich: 2665); ibid., Barranco Los Guanche, por Tres Venas, UTM: 221900/ 318305, 1930–2000 m alt., J. cedrus, November 2000, A. Palomares (TFC Lich: 4084, 6011); ibid., Bajo el Espigón del Roque, UTM: 218570 318384, 2400 m alt., on J. cedrus, January 2004, C. Hernández & P.L. Pérez de Paz (TFC Lich: 5347, 6016); ibid., Punta de los Roques, near mountain hut, 2084 m alt., on J. cedrus, December 1999, J. Etayo 17555 & M.Martìn (hb. Etayo).
This work was supported by Organismo Autónomo de Parques Nacionales (Spanish Ministerio de Medio Ambiente), project: TEC 000376. We are indebted to members of Caldera de Taburiente National Park, especially to A. Rebolé who collected several specimens of the two species. We also thank D. Sicilia for her collaboration, H. T. Lumbsch for his help and comments and I. R. Brodo for critically reviewing the paper and for most helpful suggestions for its improvement.
