Introduction
The North-eastern Region of Brazil is rich in crustose lichens, including many endemic species (Cáceres Reference Cáceres2007). The vegetation is mainly Caatinga, dry open forest, with some dense rainforest enclaves at higher altitudes. During ecological studies by the first author in the Vale do Catimbau National Park (a conservation unit of Caatinga vegetation in Pernambuco State, NE Brazil), two undescribed species of Pyrenula were found and are described here.
The Vale do Catimbau National Park is one of the most important conservation areas of the Caatinga biome (IBAMA 2002), with a surface area of 62300 hectares, and altitude range of 900–1000 m. The Vale do Catimbau comprises not only a typical hyperxerophytic Caatinga vegetation but also shows influences of other Brazilian ecosystems such as the Atlantic rainforest, Restinga, Cerrado and rocky fields (Siqueira Reference Siqueira2006; Ferreira Reference Ferreira2009).
The genus Pyrenula comprises at least 169 species worldwide (Aptroot Reference Aptroot2012). The present species both differ from all species known so far in the genus by the combination of a red or orange-brown thallus with anthraquinones, inspersed hamathecium and relatively small ascospores. They differ from each other in many characters, for example ascoma aggregation, thallus colour, ascospore size and arrangement of the ascospores within the ascus.
Material and Methods
Identification and descriptive work were carried out in Itabaiana, Universidade Federal de Sergipe, using a Leica EZ4 stereomicroscope and a Leica DM500 compound microscope, and also in Soest using an Olympus SZX7 stereomicroscope and an Olympus BX50 compound microscope with interference contrast, connected to a Nikon Coolpix digital camera. Sections were mounted in tap water, in which all measurements were taken. The chemistry of the type specimens was investigated by thin-layer chromatography (TLC) using solvent A (Orange et al. Reference Orange, James and White2001). The specimens from this study are preserved in URM and ISE.
The Species
Pyrenula reginae E. L. Lima, Aptroot & M. Cáceres sp. nov.
MycoBank No.: MB 801058
Pyrenula with dark carmine red thallus, aggregated ascomata with fused walls but separate ostioles, inspersed hymenium, and biseriate ascospores 12–15×6–8 µm.
Type: Brazil, Pernambuco, Buíque, Vale do Catimbau National Park, on bark of tree, c. 885 m alt., 7 August 2011, E. L. Lima 0010 (URM—holotype; ISE—isotype).
A–F, Pyrenula reginae (holotype); A & B, habitus; C, section through thallus showing distribution of pigment; D & E, asci; F, ascospores. G–K, Pyrenula rubromamillana; G & H, habitus (holotype); I, habitus (right), with P. mamillana (left) (Cáceres 6958); J, hamathecium (holotype); K, ascospores (holotype). Scales: A & B, G–I=1 mm; C–E=10 μm, F, J & K=5 μm.
Thallus corticate, dull, rough, continuous, thin, dark carmine red, without pseudocyphellae, without prothallus; algae trentepohlioid.
Ascomata perithecioid, associated in groups of 2–20 with partly fused walls but with separate ostioles, hemispherical, emergent, 0·2–0·4 mm diam., tops glossy black, edges with thallus covering; often only the ostioles black. Wall only carbonized above, extending sideways as a clypeus, without crystals, KOH−, c. 70 µm thick. Ostioles black, apical. Hamathecium hyaline, densely inspersed with oil droplets. Asci cylindrico-clavate, IKI−, with 8 biseriate ascospores. Ascospores brown, IKI−, 3-septate, fusiform, without constrictions at the septa, 12–15×6–8 µm, ends rounded, middle lumina broadly diamond-shaped, end lumina triangular, separated from the wall by thick endospore layer.
Pycnidia not observed.
Chemistry
Thallus UV−, KOH+ purple. TLC: anthraquinone.
Ecology and distribution
On smooth bark of trees in primary forest. Known only from Brazil. The type specimen grows together with Protoparmelia multifera (Nyl.) Kantvilas et al.
Discussion
This species is close in many characters to P. rubroanomala Aptroot & Lücking (Aptroot et al. Reference Aptroot, Lücking, Sipman, Umaña and Chaves2008). The main differences are the smaller ascospores and the inspersed hamathecium. It would key out at B67 in the world key to the species of the genus Pyrenula (Aptroot Reference Aptroot2012).
Additional specimens seen. Brazil: same as the type, July 2012 (ISE—3 topotypes).
Pyrenula rubromamillana E. L. Lima, Aptroot & M. Cáceres sp. nov.
MycoBank No.: MB 801059
Pyrenula with orange-brown thallus, dispersed ascomata, inspersed hamathecium, and uniseriate ascospores (15–)17–20×5·5–7·0 µm.
Type: Brazil, Pernambuco, Buíque, Vale do Catimbau National Park, on bark of tree, c. 880 m alt., 7 August 2011, E. L. Lima 367 (ISE—holotype).
Thallus corticate, smooth, continuous, thin, orange-brown, without pseudocyphellae, surrounded by a black prothallus line; algae trentepohlioid.
Ascomata perithecioid, simple, dispersed, hemispherical, emergent, 0·5–0·9 mm diam., black, edges with thallus covering. Wall only carbonized above, extending sideways as a clypeus, without crystals, KOH−, c. 150 µm thick. Ostioles black, apical. Hamathecium hyaline, densely inspersed with oil droplets. Asci cylindrico-clavate, IKI−, with 8 uniseriate ascospores. Ascospores brown, IKI−, 3-septate, fusiform, often with constrictions at the septa, (15–)17–20×5·5–7·0 µm, ends rounded, middle lumina broadly diamond-shaped, end lumina triangular, separated from the wall by thick endospore layer.
Pycnidia not observed.
Chemistry
Thallus UV−, KOH+ purple. TLC: anthraquinone.
Ecology and distribution
On smooth bark of trees in primary forest. Known only from Brazil. The specimens grow together with Fissurina dumastii Fée, Pyrenula anomala (Ach.) Vain., and Pyrenula mamillana (Ach.) Trevis.
Discussion
This species is close in many characters to P. mamillana, with which it co-occurs. The main difference is the orange-brown thallus colour due to the presence of an anthraquinone. It would key out in B67 in the world key to the species of the genus Pyrenula (Aptroot Reference Aptroot2012).
Additional specimens seen. Brazil: Sergipe: Areia Branca, Serra de Itabaiana National Park, on bark of tree, c. 350 m alt., 1 May 2010, M. E. S. Cáceres 6958 (ISE).
The CNPq – Conselho Nacional de Desenvolvimento Científico e Tecnológico is thanked for a research grant to MESC (Processo 501633/2009-0) and for financial support for the collecting trips (CNPq-Protax Processo 562.330/2010-0 and INCT-Herbário Virtual Processo 573.883/2008-4). The Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco – FACEPE is also thanked for a Master's scholarship to ELL. Leo Spier is thanked for performing thin-layer chromatography. AA is grateful to the Stichting Hugo de Vries-Fonds for a travel grant.
