Introduction
Calopadia Vězda, a genus with a pantropical distribution, comprises more than 25 species that grow on leaves, bark and rocks (Vězda Reference Vězda1986; Kalb & Vězda Reference Kalb and Vězda1987; Lücking Reference Lücking2008; Lücking et al. Reference Lücking, Seavey, Common, Beeching, Breuss, Buck, Crane, Hodges, Hodkinson and Lay2011; Lumbsch et al. Reference Lumbsch, Ahti, Altermann, Amo De Paz, Aptroot, Arup, Bárcenas Peña, Bawingan, Benatti and Betancourt2011; Seavey & Seavey Reference Seavey and Seavey2011; Farkas et al. Reference Farkas, Elix and Flakus2012). The genus is characterized by biatorine apothecia with brownish (rarely black) discs, amyloid hymenia, transversely septate to muriform ascospores, campylidia with well-developed lobes, and filiform, multiseptate conidia (Vězda Reference Vězda1986; Lücking Reference Lücking2008).
Fourteen species are recorded for Brazil (Müller Reference Müller1891; Malme Reference Malme1937; Santesson Reference Santesson1952; Kalb & Vězda Reference Kalb and Vězda1987; Fleig Reference Fleig1990, Reference Fleig1995; Marcelli Reference Marcelli1992; Cáceres Reference Cáceres2007; Lücking Reference Lücking2008; Farkas et al. Reference Farkas, Elix and Flakus2012), most of which are foliicolous taxa occurring in a variety of vegetation types, such as the Atlantic rainforest, the ‘Cerrado’, open dry forest, and ‘brejos de altitude’ (high altitude rainforest), from sea level to an altitude of 900 m.
From a lichenological point of view, rocky seashores are among the least studied habitats in Brazil. According to estimates by Marcelli (Reference Marcelli1998), at least 200 species are expected in these habitats, but only 25 species have been recorded previously. However, recent studies have revealed several new records and undescribed species, suggesting that the diversity of species that inhabit the rocky seashores may be greater than previously estimated (e.g. Benatti & Marcelli Reference Benatti and Marcelli2008, Reference Benatti and Marcelli2009; Benatti et al. Reference Benatti, Marcelli and Elix2008; Marcelli et al. Reference Marcelli, Benatti and Elix2008; Eliasaro et al. Reference Eliasaro, Gerlach and Gumboski2012; Gerlach & Eliasaro Reference Gerlach and Eliasaro2012; Gumboski & Eliasaro Reference Gumboski and Eliasaro2011, Reference Gumboski and Eliasaro2012a , Reference Gumboski and Eliasaro b , Reference Gumboski and Eliasaro c ).
The new species of Calopadia described here was found during intensive fieldwork conducted by the author along rocky seashores in southern Brazil. To date, this is the only species of campylidia-forming lichenized fungi found in this habitat.
Material and Methods
Fragments of rocks containing the specimens were collected using a chisel and hammer. Specimens were examined using standard techniques with stereoscopic (×20–40; Zeiss Stemi DV4) and light microscopes (×400–1000; Olympus CX 31). Hand-cut sections of the thalli, apothecia and campylidia were mounted in water. Spot tests were conducted according to Huneck & Yoshimura (Reference Huneck and Yoshimura1996) and Orange et al. (Reference Orange, James and White2001) and included observation under UV light, microcrystalization, and thin-layer chromatography (TLC) using solvent C.
The Species
Calopadia saxicola Gumboski sp. nov.
MycoBank No.: MB 810698
Differing from Calopadia chacoensis by the clearly defined thallus, brownish to reddish brown disc, thicker hymenium, and smaller conidia.
Type: Brazil, Santa Catarina State, Municipality of Penha, north of Praia Vermelha, on rocky seashore, 26°48′09′′S, 48°35′47′′W, 25 October 2011, E. Gumboski & F. Beilke 2963 (ICN—holotype; JOI, UPCB—isotypes).
(Fig. 1)
A, Calopadia saxicola, holotype (black arrows pointing to the apothecia, white arrow pointing to the prothallus); B, details of apothecia; C, details of 3-spored asci and muriform ascospores; D, anatomical section of apothecium. Scales: A=1 cm; B=1 mm; C=20 μm; D=100 μm. In colour online.
Thallus saxicolous, continuous, clearly defined, whitish to pale brown, dirty brown on older parts, surface smooth to rugose, weakly shiny, without vegetative propagules, corticate, up to 0·3 mm thick, and 10 cm diam.; cortex paraplectenchymatous, 6–10 μm thick, algal layer 7–18 μm thick, medulla white, 150–280 μm thick; prothallus smooth, whitish, 1·2–2·0 mm wide.
Apothecia biatorine, sessile, rounded, up to 1·2 mm diam.; disc plane to slightly convex, brownish to reddish brown with whitish pruina (K−, C−, KC−, UV−), margin distinct, thin, whitish to pale grey. Excipulum colourless, paraplectenchymatous, 90–155 μm thick; epithecium brownish, 10–20 μm thick; hymenium colourless, 120–230 μm thick, I+ dark blue; hypothecium prosoplectenchymatous, brownish to dark brown, 35–70 μm thick, K–; paraphyses sparsely branched, c. 1 μm thick. Asci 95–165 × 25–40 μm, (1–)2–3(–4)-spored; ascospores muriform, hyaline, with halo in fresh specimens (up to 3 μm thick), (63–)72–112(–128) × 10–18 μm, I−.
Campylidia sessile, hood-shaped, pale to dark grey, up to 1·0 mm high, up to 0·8 mm wide, pruinose on back side when young, discrete base; conidia filiform, curved with a single smooth clavate apex, 4–7 septate, hyaline, (35–)45–55(–60) × 2·0–3·5 μm.
Chemistry
[Cortex and medulla] K−, C−, KC−, UV−. No substances detected by microcrystalization and TLC.
Distribution and habitat
The new species is known only from rocky seashores in southern Brazil (Fig. 2), growing directly on shaded rocks near vegetated zones and protected from direct wave splash. Most specimens occur in isolation, away from other crustose lichens.
A, southern Brazil, black arrows point to the area of rocky seashores where specimens of Calopadia saxicola were found; B, northern rocky seashore at Praia Vermelha, Municipality of Penha, Santa Catarina State, southern Brazil. In colour online.
Discussion
Calopadia saxicola is characterized by the saxicolous, clearly delimited and corticate thallus, pruinose apothecia with brownish to reddish brown disc, mainly 2–3-spored asci, muriform ascospores, and the absence of secondary metabolites.
It is similar to C. chacoensis (Malme) Kalb & Vězda in general apothecium and campylidium features. However, C. saxicola has a clearly defined thallus, up to 0·3 mm thick, the disc is brownish to reddish brown with a thicker hymenium (120–230 μm), and it has shorter and broader conidia [(35–)45–55(–60) × 2·0–3·5 μm] with 4–7 septa. In C. chacoensis, the thallus is not sharply defined and is very thin, the disc is dark brown to black, and it has longer and narrower conidia (60–80 ×1·8 μm) with 5–12 septa (Malme Reference Malme1937; Kalb & Vězda Reference Kalb and Vězda1987).
Other species with more than one ascospore per ascus, such as C. foliicola (Fée) Vězda and C. phyllogena (Müll. Arg.) Vězda, have ecorticate and thin thalli (20–30 μm thick) (Kalb & Vězda Reference Kalb and Vězda1987; Lücking Reference Lücking2008), while C. saxicola has a corticate thallus up to 0·3 mm thick. They also differ in apothecium morphology. For example, C. foliicola has a convex disc with pale yellow pruina, and C. phyllogena has a flat disc lacking pruina (Lücking Reference Lücking2008).
Calopadia schomerae F. Seavey & J. Seavey (Reference Seavey and Seavey2011) also has a corticate thallus, pruinose apothecia and muriform ascospores, but the asci are single spored, the conidia are smaller (25–31 μm) and the thallus contains two xanthones (Seavey & Seavey Reference Seavey and Seavey2011), while C. saxicola lacks such substances.
The species Calopadia cinereopruinosa Bungartz & Lücking and C. editae Vězda ex Chaves & Lücking, both described in Lumbsch et al. (Reference Lumbsch, Ahti, Altermann, Amo De Paz, Aptroot, Arup, Bárcenas Peña, Bawingan, Benatti and Betancourt2011), have pruinose apothecia and muriform ascospores, as does C. saxicola. However, C. cinereopruinosa has an ecorticate (or with indistinct cortical layer) thallus with a grey-black apothecial disc and an aeruginous hypothecium. Calopadia editae also has an ecorticate thallus, but its apothecia have pale yellowish to cream-coloured pruina. In addition, both species have single-spored asci and shorter ascospores.
Calopadia saxicola is also similar to C. puiggarii (Müll. Arg.) Vězda (Reference Vězda1986) and C. fusca (Müll. Arg.) Vězda (Reference Vězda1986) in hypothecium colour and the muriform ascospore size, but both have an ecorticate thallus, epruinose apothecium, and a single-spored ascus with shorter ascospores (Lücking Reference Lücking2008).
Interestingly, the halonate ascospores of C. saxicola could only be observed in fresh specimens. Upon re-examination of the material, approximately six months later, the halo had disappeared. Another notable observation was that, when returning to the field c. 30 months after the material was first collected, the specimens of C. saxicola that originally had fertile apothecia, only featured an old campylidium and no apothecia.
Additional specimens examined
Brazil: Santa Catarina State: Municipality of Penha, north of Praia Vermelha, on rocky seashore [metamorphic rock, mylonite, of dynamic-thermal origin from shear zone], 26°48′09′′S, 48°35′47′′W, 2011, E. Gumboski & F. Beilke 2947 (UPCB), 2961, 2964 (JOI); Municipality of São Francisco do Sul, Morro da Enseada, on rocky seashore [ortho-metamorphic rock, granite-gneiss, cataclastic structure], 26°13′44′′S, 48°29′54′′W, 2009, E. Gumboski 1685, 1691 (JOI).
I am grateful to Robert Lücking (Field Museum, USA) for discussions about Calopadia pruinosa, to M.Sc. student Tarcísio Possamai (Universidade da Região de Joinville, Brazil) for geological identification of the rock substratum, to two anonymous reviewers for valuable contributions, to Manuela Dal-Forno and Morgan R. Gostel (George Mason University, USA) for the English review and suggestions, and to M.Sc. Flávio Beilke for assistance in the field.
