Introduction
The major part of species diversity in tropical crustose discolichens consists of species currently placed in Graphidaceae. A morphological group within this largest family of crustose lichens, the thelotremoid lichens, is characterized by immersed-erumpent, rounded ascomata with non-branched to slightly branched paraphyses, mostly distoseptate ascospores, and mostly a trentepohlioid photobiont. More than 1000 species of thelotremoid lichens were described by Frisch et al. (Reference Frisch, Kalb and Grube2006) and Hale (Reference Hale1981). Previously, these lichens were classified as Thelotremataceae, but molecular studies have shown that the family is polyphyletic with several thelotremoid clades nested within Graphidaceae (Mangold et al. Reference Mangold, Martin, Lücking and Lumbsch2008b; Staiger et al. Reference Staiger, Kalb and Grube2006). Hence, the family is now included in Graphidaceae and its species are informally accepted as thelotremoid lichens.
Traditionally, the Thelotremataceae was divided into large genera according to their spore septation and pigmentation following Müller Argoviensis (Reference Müller Argoviensis1887). This artificial classification was subsequently revised by Hale (Reference Hale1980) who produced a generic classification that relied largely on excipular characters, such as exciple pigmentation and presence of lateral paraphyses In a recent paper Frisch et al. (Reference Frisch and Kalb2006) provided a major revision of the generic concepts in thelotremoid lichens by proposing a classification based on combinations of several morphological character complexes. This new classification is largely followed here, with modifications as suggested by Mangold et al. (Reference Mangold, Elix and Lumbsch2009). These modifications include a wider concept of the genus Ocellularia to include the genus Stegobolus,which has been shown to be polyphyletic and clustered within Ocellularia in phylogenetic analyses (Mangold et al. Reference Mangold, Martin, Lücking and Lumbsch2008b).
Based on a Ph. D. study on taxonomy and ecology of Thelotremataceae in south-east Asia by Natsurang Homchantara submitted in 1999, Homchantara & Coppins (Reference Homchantara and Coppins2002) described numerous new species mainly from Thailand, and recorded several new records for south-east Asia. At that time, however, knowledge of the taxonomy of several tropical thelotremoid taxa was poor and hence some of the new species awaited comparison with poorly known previously described species. Recently, there has been a renewed interest in the taxonomy and systematics of thelotremoid lichens, resulting in a number of publications (Frisch & Kalb Reference Frisch and Kalb2006; Frisch et al. Reference Frisch, Kalb and Grube2006; Mangold et al. Reference Mangold, Elix and Lumbsch2006; Reference Mangold, Elix and Lumbsch2007a, Reference Mangold, Elix and Lumbschb, Reference Mangold, Martin, Kalb, Lücking and Lumbsch2008a, Reference Mangold, Martin, Lücking and Lumbschb, Reference Mangold, Elix and Lumbsch2009; Lumbsch et al. Reference Lumbsch, Mangold, Martin and Elix2008). Given this increased knowledge of the morphological and chemical variation of species and a re-evaluation of a large number of type specimens, we have re-evaluated the species described from Thailand by Homchantara & Coppins (Reference Homchantara and Coppins2002). This contribution includes new synonyms and changes of generic placement of some species to follow the generic concepts of Mangold et al. (Reference Mangold, Elix and Lumbsch2009). Additional species described by Homchantara & Coppins (Reference Homchantara and Coppins2002) from other Asian countries are not included in this study.
Materials and Methods
Material from the following herbaria was examined for this study: BM, C, E, H, RAMK, US. Types of all species mentioned in this paper have been studied by the authors. Thalli and apothecia were sectioned using a razor blade and a freezing microtome, and examined in water and lactophenol cotton blue. Thin-layer chromatography was carried out using solvent system B' (Lumbsch Reference Lumbsch, Kranner, Beckett and Varma2002) and high-performance liquid chromatography according to Feige et al. (Reference Feige, Lumbsch, Huneck and Elix1993).
The Species
Myriotrema grandisporum Homchantara & Coppins
This species is a synonym of Thelotrema patwardhanii (Hale) Rivas Plata & Mangold described from India (Hale Reference Hale1978a; Rivas Plata et al. Reference Rivas Plata, Lücking, Sipman, Mangold, Kalb and Lumbsch2010b). The types of the two species agree well in containing norstictic acid and having large, transversely septate ascospores that turn brown at maturity and inconspicuous lateral paraphyses. The hymenia of both species include numerous brown ascospores. The ascospore size in the protologue of T. patwardhanii is given as 150–210 × 21–25 μm with 20–30 transverse septa. However, we have also found up to 46 transverse septa in the type material and also ascospores up to 230 μm. These measurements fall within the variability recorded by Homchantara & Coppins (Reference Homchantara and Coppins2002) for M. grandisporum (169·5–271·0 × 17·0–28·5 μm and 45–49 transverse septa). In addition, we found the transverse septation of ascospores in the type of M. grandisporum to be more variable (35–49). Accessory connorstictic acid was found in addition to norstictic acid.
Myriotrema khaoyaianum Homchantara & Coppins
Myriotrema khaoyaianum is a synonym of Ocellularia perforata (Leight.) Müll. Arg. The species was placed in Myriotrema by Homchantara & Coppins (Reference Homchantara and Coppins2002) based on the lack of carbonization, following the generic concept of Hale (Reference Hale1980). As discussed by Frisch et al. (Reference Frisch and Kalb2006), however, O. perforata typically has only a weak carbonization and may lack it completely. Myriotrema khaoyaianum falls within the variability of O. perforata as circumscribed by Frisch et al. (Reference Frisch and Kalb2006) and hence it is placed into synonymy with this species. Conprotocetraric and virensic acids were found as accessory substances.
Myriotrema khuntanense Homchantara & Coppins
The species was placed in Myriotrema (Homchantara & Coppins Reference Homchantara and Coppins2002) based on the colourless exciple and columella. The species belongs to Ocellularia sensu Frisch et al. (Reference Frisch, Kalb and Grube2006) and Mangold et al. (Reference Mangold, Elix and Lumbsch2009). The new combination is proposed here: Ocellularia khuntanensis (Homchantara & Coppins) Lumbsch & Papong comb. nov. [Basionym: Myriotrema khuntanense Homchantara & Coppins, Lichenologist 34: 115, 2002]. The size of the ascospores is similar to that of Ocellularia auberiana (Mont.) Hale, but this species differs by the presence of a reticulate columella. Another similar species is O. minutula Hale, which, however, is readily distinguished by its smaller ascospores (Hale Reference Hale1978b). Accessory substances, 2'-O-demethylpsoromic and subpsoromic acids were found.
Myriotrema rongklaense Homchantara & Coppins
Myriotrema rongklaense is a synonym of Ocellularia papillata (Leighton) Zahlbr. As discussed previously (Mangold et al. Reference Mangold, Elix and Lumbsch2009), the ascomata of O. papillata vary from weakly or non-carbonized to distinctly carbonized. The type of M. rongklaense agrees well with specimens of O. papillata with weakly to non-carbonized ascomata and hence it is synonymized with that species here.
Myriotrema subanamaliense Homchantara & Coppins
Myriotrema subanamaliense is a synonym of Wirthiotrema glaucopallens (Nyl.) Rivas Plata & Kalb (Rivas Plata et al. Reference Mangold, Elix and Lumbsch2010a).
Myriotrema subgranulosum Homchantara & Coppins
This species belongs to Ocellularia as currently circumscribed (Frisch et al. Reference Frisch, Kalb and Grube2006; Mangold et al. Reference Mangold, Elix and Lumbsch2009) and therefore we propose the new combination here: Ocellularia subgranulosa (Homchantara & Coppins) Lumbsch & Papong comb. nov. (Basionym: Myriotrema subgranulosum Homchantara & Coppins, Lichenologist 34: 117, 2002). The taxon is characterized by perithecioid ascomata, 1–2-spored asci with hyaline, amyloid, transversely septate ascospores and by the presence of the norisonotatic and norsubnotatic acids (formerly named Chonestoma unknowns). Similar species include O. chonestoma (Leighton) Zahlbr. and O. nylanderiana Hale; the former species being readily distinguished by its smaller ascospores, while the latter has longer and thinner ascospores with up to 18 loculi (Hale Reference Hale1981).
Myriotrema subminutum Homchantara & Coppins
Myriotrema subminutum is a further synonym of Ocellularia perforata; fumarprotocetraric acid occurs as minor constituent in several specimens of that species (Mangold et al. Reference Mangold, Elix and Lumbsch2009). Conprotocetraric and virensic acids were found as accessory substances.
Myriotrema thailandicum Homchantara & Coppins
Myriotrema thailandicum is a synonym of Ocellularia thelotremoides (Leight.) Zahlbr. The type fits well into the variability of that species as circumscribed by Mangold et al. (Reference Mangold, Elix and Lumbsch2009).
Myriotrema whalleyanum Homchantara & Coppins
The type material of Myriotrema whalleyanum does not contain a thelotremoid lichen; it is a pyrenocarpous lichen. It is synonymous to Porina exocha (Nyl.) P. M. McCarthy.
Ocellularia brunneospora Homchantara & Coppins
This species is characterized by small, transversely septate ascospores and the presence of the norisonotatic chemosyndrome. It agrees chemically with O. chonestoma (Leight.) Zahlbr. but this species differs in having larger ascospores. Other Ocellularia spp. containing norisonotatic and norsubnotatic acids (formerly named Chonestoma unknowns) include O. allosporoides (Nyl.) Patw. & C. Kulk. and O. baileyi Müll. Arg. (Mangold et al. Reference Mangold, Elix and Lumbsch2009). Both of these species have larger hyaline ascospores (50–130 and 18–40 μm, respectively).
Ocellularia diospyrosis Homchantara & Coppins
This species is characterized by large and hyaline, transversely septate ascospores, a simple columella and by the presence of the stictic acid chemosyndrome. It is superficially similar to O. pyrenuloides Zahlbr., which, however is readily distinguished by smaller ascospores with less loculi (18–24 × 6–7 μm with 5–6 loculi). The South African O. henatomma (Ach.) Müll. Arg. differs in having longer ascospores and the presence of the hypoprotocetraric acid chemosyndrome (Frisch et al. Reference Frisch, Kalb and Grube2006). α-acetylconstictic was found as accessory substance.
Ocellularia flavescens Homchantara & Coppins
This species is readily recognized by the presence of lichexanthone, which is rare in thelotremoid lichens. Similar species containing lichexanthone include Ocellularia metaphorica (Nyl.) Hale, Melanotrema astrolucens (Sipman) A. Frisch and M. lirelliforme (Tuck.) A. Frisch. The first differs in having a reticulate columella and brown, ornamented ascospores (Frisch et al. Reference Frisch, Kalb and Grube2006), while the two Melanotrema species are distinguished by having brown, transversely septate ascospores.
Ocellularia inthanonensis Homchantara & Coppins
This species is characterized by 1-spored asci, large, muriform, hyaline ascospores, ecolumellate ascomata, and the presence of the (newly identified) 2-hydroxy-hypoprotocetraric and hypoprotocetraric acids. Similar species include O. arecae (Vain.) Hale and O. eumorpha (Stirt.) Hale. The latter has 1–2-spored asci, the ascospores turn brown when mature, and it contains convirensic acid as a major constituent in addition to hypoprotocetraric acid. Ocellularia arecae differs in having a columella.
Ocellularia kansriae Homchantara & Coppins
Ocellularia kansriae is a synonym of Ocellularia microstoma (Müll. Arg.) Hale. This species is characterized by ecolumellate, emergent, perithecioid ascomata, 1-spored asci with large, hyaline, muriform ascospores and the presence of the protocetraric acid chemosyndrome (Mangold et al. Reference Mangold, Elix and Lumbsch2009). Conprotocetraric and virensic acids were found as accessory substances.
Ocellularia krathingensis Homchantara & Coppins
Homchantara & Coppins (Reference Homchantara and Coppins2002) mentioned the presence of an unidentified substance in this species. We have been unable to detect any secondary metabolites in the type material. Ocellularia krathingensis can be recognized by the combination of ascomata with an only apically carbonized exciple and a complex, carbonized columella, 8-spored asci with hyaline, amyloid, transversely septate ascospores and the lack of secondary metabolites.
The Neotropical taxon, Ocellularia guianensis (Sipman) Divakar & Mangold comb. nov. [Basionym: Myriotrema guianense Sipman, Trop. Bryol. 5: 83, 1992; syn. Stegobolus guianensis (Sipman) A. Frisch, Bibl. Lichenol. 92: 464, 2006], is similar, but differs by containing ‘guianensis unknown’ and psoromic acid, larger ascomata with a more distinctly complex columella, and by a reddish pruina (Frisch et al. Reference Frisch, Kalb and Grube2006). Another similar species is the Neotropical Ocellularia percolumellata (Sipman) Divakar & Mangold comb. nov. [Bas.: Myriotrema percolumellatum Sipman, Acta Bot. Fenn. 150: 170, 1994; syn. Stegobolus percolumellatus (Sipman) A. Frisch, Bibl. Lichenol. 92: 474, 2006]; it differs in having ascospores with fewer loculi and with acute to subacute ends. These two species, originally described in Myriotrema, and recently transferred to Stegobolus, have been transferred here to Ocellularia following the generic concept of Mangold et al. (Reference Mangold, Elix and Lumbsch2009), in which Stegobolus is included in Ocellularia and Myriotrema does not include species having a columella.
Ocellularia melanophthalma Homchantara & Coppins
This species is characterized by a broad, simple carbonized columella and carbonized, free exciple, hyaline, transversely septate ascospores, an ecorticate thallus, and by the presence of the protocetraric acid chemosyndrome. The species belongs to Melanotrema A. Frisch, which was described in Frisch et al. (Reference Frisch, Kalb and Grube2006) to accommodate species with a broad, carbonized columella, carbonized ascomata and a thallus covered by a protocortex. Hence, the following new combination is proposed: Melanotrema melanophthalmum (Homchantara & Coppins) Papong & Lumbsch comb. nov. (Basionym: Ocellularia melanophthalma Homchantara & Coppins, Lichenologist 34: 125, 2002). The pantropical Melanotrema platystomum (Mont.) A. Frisch is similar but differs in lacking secondary metabolites and having smaller ascospores. Conprotocetraric and virensic acids were found as accessory substances.
Ocellularia neoleucina Homchantara & Coppins
This taxon is characterized by hyaline, submuriform ascospores, a reticulate columella and the presence of the stictic acid chemosyndrome. Ocellularia leucina (Müll. Arg.) Hale and O. subleucina are similar species. The latter differs by having larger ascospores and lacking secondary metabolites, while the former taxon contains psoromic acid. Constictic acid was found as accessory substance.
Ocellularia peremergens Homchantara & Coppins
Ocellularia peremergens is another synonym of the palaeotropical Ocellularia microstoma. For characters to recognize this species, see under O. kansriae. Conprotocetraric and protocetraric acids were found as accessory substances.
Ocellularia pluriporoides Homchantara & Coppins
This taxon is characterized by a continuous thallus, ascomata with a reticulate columella, transversely septate, hyaline ascospores and by the presence of psoromic acid. It is similar to O. terebrata (Ach.) Müll. Arg. but differs in having larger ascospores (17–32 × 7–10 μm, with 6–10 locules in O. terebrata). 2'-O-demethylpsoromic and subpsoromic acids were found as accessory substances.
Ocellularia rhicnoporoides Homchantara & Coppins
This taxon is characterized by immersed, perithecioid, ecolumellate ascomata, an apically carbonized exciple, 8-spored asci with hyaline, transversely septate ascospores and by the lack of secondary metabolites. Ocellularia albocincta (Hale) Divakar & Mangold comb. nov. [Basionym: Myriotrema albocinctum Hale, Bull. Brit. Mus. (Nat. Hist.), Bot. ser. 8: 273 (1981); type: Sri Lanka, Sabaragamuwa Prov., Ratnapura Distr., Gilimale Forest Reserve, 150 m elev., 12 ii 1976, M. E. Hale 46331 (US—holotype)] is similar, but differs in having a non-carbonized exciple and a shorter hymenium (Hale Reference Hale1981).
Ocellularia subleucina Homchantara & Coppins
This taxon is characterized by perithecioid ascomata with a simple columella, 8-spored asci with hyaline, amyloid, submuriform ascospores and by the lack of secondary metabolites. A similar species is Ocellularia subcalvescens (Nyl.) Divakar & Mangold comb. nov. [Basionym: Thelotrema subcalvescens Nyl., Bull. Soc. Linn. Normand. III 7: 168, (1873); type: India, Andaman Islands, Kurz, 1867 (H-NYL 22726—holotype)]. It is distinguished by faintly amyloid ascospores that do not exceed 21μm in length.
Ocellularia wolseleyana Homchantara & Coppins
This species is characterized by perithecioid ascomata lacking a columella, hyaline, muriform ascospores and the presence of psoromic acid. Morphologically it resembles O. profunda (Stirt.) Mangold, Elix & Lumbsch, which, however, is readily distinguished by its brown ascospores at late maturity, a cone-shaped columella, and larger ascospores (Mangold et al. Reference Mangold, Elix and Lumbsch2007b). 2'-O-demethylpsoromic was found as accessory substance.
Thelotrema laemense Homchantara & Coppins
This species is characterized by chroodiscoid ascomata, hyaline, 8-spored asci with muriform ascospores and by the presence of the stictic acid chemosyndrome. The species belongs to Chapsa as circumscribed by Frisch et al. (Reference Frisch, Kalb and Grube2006). Hence, the following new combination is proposed here: Chapsa laemensis (Homchantara & Coppins) Lumbsch & Papong comb. nov. (Basionym: Thelotrema laemense Homchantara & Coppins, Lichenologist 34: 130, 2002). A similar species is C. alstrupii A. Frisch, which differs in having larger ascomata (up to 2 mm), a higher hymenium and lacking secondary metabolites (Frisch et al. Reference Frisch, Kalb and Grube2006).
Thelotrema mongkolsukii Homchantara & Coppins
Thelotrema mongkolsukii has lepadinoid ascomata, 8-spored asci with hyaline, transversely septate ascospores and contains the hypostictic acid chemosyndrome. Morphologically similar species include T. bicinctulum Nyl. and T. kamatii (Patw. & C.R. Kulk.) Hale. The latter differs in having larger ascospores (70–110 μm long) and lacking secondary metabolites (Patwardhan & Kulkarni Reference Patwardhan and Kulkarni1977; Nagarkar et al. Reference Nagarkar, Sethy and Patwardhan1988). Thelotrema bicinctulum has smaller ascomata and faintly amyloid ascospores (Frisch et al. Reference Frisch, Kalb and Grube2006; Mangold et al. Reference Mangold, Elix and Lumbsch2009).
Thelotrema phliuense Homchantara & Coppins
Thelotrema phliuense and also Leptotrema phaeosporum var. vainiona Räsänen, Arch. Soc. Zool. Bot. Fenn. Vanamo 3: 87 (1949); type: Philippines, Distr. Mindanao, Zamboanga, Malangas, Oct-Nov 1919, M. Ramos & G. Edano (TUR-V 35049-holotype) are synonyms of Thelotrema calathiforme Vain. The species belongs to Chapsa as circumscribed by Frisch et al. (Reference Frisch, Kalb and Grube2006); consequently, the following new combination is proposed: Chapsa calathiformis (Vain.) Lumbsch & Papong comb. nov. [Basionym: Thelotrema calathiforme Vain., Hedwigia 46: 174 (1907); type: Thailand, Koh Chang island, “ad truncos arb.”, 1899–1900, J. Schmidt XXIII (C—holotype)]. This species is readily identified by its shiny, greenish grey, continuous thallus, 8-spored asci and muriform ascospores that become brown when mature. The species is distinctive and difficult to confuse with any other taxon.
Thelotrema rhododiscum Homchantara & Coppins
Thelotrema rhododiscum is synonymous to Ocellularia cruentata (Mont.) Hafellner & Magnes, which is described elsewhere (Magnes Reference Magnes1997; Mangold et al. Reference Mangold, Elix and Lumbsch2009).
Summary of synonyms
Myriotrema grandisporum Homchantara & Coppins = Thelotrema patwardhanii (Hale) Rivas Plata & Mangold.
Myriotrema khaoyaianum Homchantara & Coppins = Ocellularia perforata (Leight.) Müll. Arg.
Myriotrema rongklaense Homchantara & Coppins = Ocellularia papillata (Leighton) Zahlbr.
Myriotrema subanamaliense Homchantara & Coppins = Wirthiotrema glaucopallens (Nyl.) Rivas Plata & Kalb.
Myriotrema subminutum Homchantara & Coppins = Ocellularia perforata
Myriotrema thailandicum Homchantara & Coppins = Ocellularia thelotremoides (Leight.) Zahlbr.
Myriotrema whalleyanum Homchantara & Coppins = Porina exocha (Nyl.) P. M. McCarthy.
Ocellularia kansriae Homchantara & Coppins = Ocellularia microstoma (Müll. Arg.) Hale.
Ocellularia peremergens Homchantara & Coppins = Ocellularia microstoma
Thelotrema rhododiscum Homchantara & Coppins = Ocellularia cruentata (Mont.) Hafellner & Magnes.
This study was supported by a NSF grant (DEB-0516116) to The Field Museum (PI: HTL) and the Spanish Ministry of Science and Innovation through a Ramon y Cajal grant (RYC02007-01576) to PKD. We wish to thank the curators of the herbaria cited that sent us material on loan for examination. HTL thanks Brian Coppins (Edinburgh) for providing a copy of the thesis by Natsurang Homchantara.
