Andreas Frisch; Klaus Kalb; Martin Grube:

Contributions towards a new systematics of the lichen family Thelotremataceae

I. The lichen family Thelotremataceae in Africa / A. Frisch. II. A monograph of Thelotremataceae with a complex structure of the columnella / A. Frisch; K. Kalb. III.Molecular phylogeny of the Thelotremataceae / Frisch/Kalb/Grube

2006. 556 pages, 159 figures, 9 tables, 26 plates, 14x23cm, 960 g
Language: English

(Bibliotheca Lichenologica, Band 92)

ISBN 978-3-443-58071-1, paperback, price: 88.00 €

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lichen familyThelotremataceaeAfricaCameroonTanzania


Synopsis top ↑

A new genus classification of the Thelotremataceae is presented. Myriotrema, Ocellularia and Thelotrema sensu HALE (1980, 1981) were found to be heterogeneously circumscribed and were segregated into more natural units. The following changes are made: Ampliotrema Kalb is validated, and Chapsa Massal., Leptotrema Mont., Leucodecton Massal. and Stegobolus Mont. are resurrected. The genera Acanthotrema A. Frisch, Gyrotrema A. Frisch, Melanotrema A. Frisch and Redingeria A. Frisch are described as new to science. 19 genera are accepted for the family: Acanthotrema, Ampliotrema, Chapsa, Chroodiscus, Diploschistes (not treated), Fibrillithecis, Gyrotrema (part II), Ingvariella (not treated), Leptotrema, Leucodecton, Melanotrema (part II), Myriotrema, Nadvornikia (not treated), Ocellularia, Redingeria (part II), Reimnitzia, Stegobolus (part II), Thelotrema and Topeliopsis. The Thelotrema glaucopallens- and the Ocellularia clandestina-group are of uncertain generic affiliation.

Review: International Lichenological Newsletter vol. 39, no. 1 (Sept. 2006) top ↑

The new volume in this prestigious series consist of three parts: The lichen family Thelotremataceae in Africa by A. FRISCH (pp. 3-370), A monograph of Thelotremataceae with a complex structure of the columella by A. FRISCH & K. KALB (pp. 371-516) and Molecular phylogeny of the Thelotremataceae by A. FRISCH, K. KALB & M. GRUBE (pp. 517-539).

The first and major part is based on the PhD thesis of the first author of all 3 papers.

A new genus classification of the Thelotremataceae is presented which became necessary because Myriotrema, Ocellularia and Thelotrema (sensu Hale) were found to be heterogeneous. 19 genera are now accepted for the family including the resurrection of Chapsa A. Massal., Leptotrema Mont., Leucodecton A. Massal. and Stegobolus Mont., the validation of Ampliotrema Kalb and the newly described genera Acanthotrema A. Frisch, Gyrotrema A. Frisch, Melanotrema A. Frisch and Redingeria A. Frisch. Unfortunately two groups of uncertain generic affiliation remain, the Thelotrema glaucopallens- and the Ocellularia clandestina-group.

The revision is based on some 1300 collections by the author from Cameroon and Tanzania and about 120 additional specimens obtained from public herbaria. 38 of the formerly recorded 73 taxa from Africa are accepted as valid species, but some had to be excluded from the family. 17 species are described as new to science (in parts one and two) and a further 47 species are recorded for the first time from Africa. In all, 94 species are presently known from the continent. All these species are described and illustrated in detail and keys to genera and species are given. Checklists for Thelotremataceae in the African countries based on verified names and some reliable, more recent literature sources are presented in an appendix. This is an enormous step forward in the knowledge of African crustose lichens independent from the acceptance of all the taxonomic changes which can only be proofed by time and deeper knowledge. In the final paper of this collection, the authors reinforce their classical taxonomy with molecular methods, obtaining new sequence data for 46 species of Thelotremataceae, representing 13 out of the 19 accepted genera and the uncertain Thelotrema glaucopallens- and Ocellularia clandestina-groups. The results of the Bayesian analysis of mitochondrial 16S rDNA gene data are in fairly good congruence with the proposed new classification scheme.

The volume is concluded by a taxonomic index for all three contributions together. A minor criticism might be that not all authors are cited according to the widely accepted index of authors of fungal names (e.g. "Dodge" instead of "C. W. Dodge" or "Massal." instead of "A. Massal.") or that the names in appendix 2 "Excluded or dubious names" are not completely in alphabetical order, but these are rather unimportant points compared to the huge work presented with these contributions. Clearly, this book belongs in every taxonomic lichen library. It is the most important contribution to African lichenology since SWINSCOW & KROGs Macrolichens of East Africa published in 1988.

The Editor

International Lichenological Newsletter vol. 39 no. 1 (Sept. 2006), p.3-4

Review: Nova Hedwigia 84 3-4, p. 549-552 top ↑

The CONTRIBUTIONS TOWARDS A NEW SYSTEMATICS OF THE LICHEN FAMILY THELOTREMATACEAE is a three-part monograph based on the Ph.D. thesis of Andreas Frisch. The main part of the book deals with THE LICHEN FAMILY THELOTREMATACEAE IN AFRICA (370 pages), authored by Frisch, completed by A MONOGRAPH OF THELOTREMATACEAE WITH A COMPLEX STRUCTURE OF THE COLUMELLA (with Kalb; 146 pages), a MOLECULAR PHYLOGENY OF THE THELOTREMATACEAE (with Kalb and Grube; 23 pages), and a taxonomic index. This monumental work is another milestone, which significantly improves our knowledge of tropical crustose lichens. The numerous photographic plates and line drawings are of excellent quality. In the main part, African Thelotremataceae are critically revised, completed by genera with complex columella treated in the second part. The total number of accepted species for Africa is 94, including 17 new to science and 47 new records for the continent, while 35 names are synonymized. This is an important achievement and an invaluable contribution to the African lichen biota, especially considering that most of the relevant collections were made by the author himself. Many types were studied and new characters explored, closing substantial gaps in our knowledge of the Thelotremataceae at the world level. Besides the taxonomic treatment, the profound generic revision makes this work outstanding. Sixteen genera are accepted, compared to the five ascospore genera distinguished by Müller Argoviensis in 1887 and the three excipular genera from Hale’s revision in 1980. Besides Chroodiscus, Leptotrema, Myriotrema, Ocellularia, and Thelotrema, the genera treated in this monograph include three reinstated names (Chapsa, Leucodecton, Stegobolus), three recently established taxa (Ampliotrema, Reimnitzia, Topeliopsis), and five new genera introduced by the author: Acanthotrema, Fibrillithecis, Gyrotrema, Melanotrema, and Redingeria. This work is thus a very important step towards a natural generic delimitation in the family and confirms other recent studies that ascoma morphology, wall structures, and ascospore types (but not necessarily septation and color) are important characters to distinguish genera. In some instances it is even shown that species with pale and others with carbonized excipulum, previously separated in Myriotrema and Ocellularia, are closely related. The separation of four genera with chroodiscoid apothecia, traditionally included in Thelotrema, comes as a surprise, but is backed by morphological and molecular data. Chroodiscus is now restricted to foliicolous taxa, while the non-foliicolous species are assigned to Chapsa. Reimnitzia is certainly an oddball deserving its own genus, but the new Acanthotrema for the single species A. brasilianum needs further study. The diagnostic character are the spiny paraphyses and periphysoids, but the author presumes that certain species with smooth paraphyses might also belong in Acanthotrema. In the phylogenetic analysis, the genus falls outside Chapsa and Chroodiscus, but its position is unresolved and hypothesis testing to reject a monophyletic Chapsa that includes Acanthotrema would have been appropriate.

In the second part, the authors show that taxa with complex columella structures evolved independently and make sense of this by establishing three new genera, Gyrotrema, Melanotrema, and Redingeria, and reinstating the old name Stegobolus, while retaining a couple of species in Myriotrema and Ocellularia. Except for Redingeria, for which no sequences were available, and the apparently polyphyletic Stegobolus, the concept is confirmed by molecular data. However, one might have problems to distinguish Redingeria and Stegobolus. In the discussion of Redingeria, it is stated that Stegobolus is "... well distinguished ... in morphology and might be only distantly related." (p. 406), but the picture of Redingeria glyphica (Pl. 20) closely resembles Stegobolus species (e.g., Pl. 21, 23). According to the key, the diagnostic differences are the Redingeria-type ascospores and the inclusion of ascospore remnants in the excipulum, but it takes a while to find out what exactly Redingeria-type ascospores are. The difference in ornamentation, depicted in Fig. 121 (Redingeria) versus 129b (Stegobolus), does not appear significant, especially as the ascospore in Fig. 121 is fully turgescent, while the one in Fig. 129b appears collapsed. The structure of the ornamentation itself is similar and could even be interpreted as a synapomorphy. As for the inclusion of old ascospores in the excipulum and columella, the authors themselves state that this character is "... of limited taxonomic relevance." (p. 406). The remaining differences are the thick-walled ascospores (especially when young) with irregular lumina in Redingeria, but it remains to be tested whether these hold as diagnostic characters at genus level.

One also wonders about the separation of Melanotrema versus the Ocellularia auberianoides group, including the common neotropical O. bahiana (formerly in Myriotrema). In the key (p. 378), the main difference is the carbonized versus pale to brown excipulum, but species with different excipular pigmentation are accepted in Ocellularia. The Ocellularia auberianoides group is said to have an excipulum with "... clearly radiating hyphae ..."; the corresponding character is not mentioned for Melanotrema, but in the discussion the latter genus is said to have an excipulum with "... clearly radiating hyphae ..." (p. 383). The phenocortex of Melanotrema is said to be "... loosely organised or cartilaginous ...", while the corresponding alternative for the Ocellularia auberianoides group is not given. In the descriptions, the phenocortex is given as formed from irregular hyphae for both groups. At the species level, some conclusions are difficult to follow. The African material of Acanthotrema brasilianum differs from neotropical populations by submuriform versus 3-septate ascospores and might warrant recognition at the species level. Specimens from Africa identified as Chapsa alborosella differ from neotropical material by the presence of stictic acid, but it is argued that the TLC results were contaminated by dead thalli of Graphis growing under the Chapsa specimens. It is highly unlikely that the two widely separated African collections from Tanzania and Réunion grew on dead thalli of Graphis species that both produced stictic acid, a substance which is comparatively rarer in Graphis than in Chapsa. Thelotrema platycarpoides is listed as synonym of Chapsa platycarpa and said to represent a juvenile form of the latter because of the small apothecia. However, the ascospores of the latter are mostly 5-septate, while typical C. platycarpa has 3-septate ascospores, which contradicts the hypothesis of the former being a juvenile form of the latter.

The genus keys work relatively well, but a good knowledge of the morphological concepts outlined throughout the book are required to use the keys, since terms such as Ocellularia-type excipulum or Redingeria-type ascospores are frequently used. A quick reference as to where these terms are defined, or perhaps a short, illustrated glossary, would have been helpful. The lengthy couples in the genus keys make it sometimes difficult to filter the characters that separate a genus from another; it might have been better to exclude most of the non-differential information. The species keys work well, although in some instances (e.g., Redingeria), they strongly rely on chemistry, and one is required to do TLC before even starting to work with the key, especially in cases where spot tests do not work.

The third part of the work is a first attempt to test the generic rearrangement with DNA data. The number of newly produced sequences is impressive and many of the genera are supported, such as Chapsa, Fibrillithecis, Leucodecton, and Melanotrema, while a few need further study. The inclusion of the molecular phylogeny in this work supports the systematic changes, but as a stand-alone paper, one would have wished for more rigorous analyses of the data, including maximum parsimony and alternative hypothesis testing. The placement of the figures as appendix is odd, and it also takes some time to realize that the four trees do not represent different analyses, but map different taxonomic groups and characters on the same tree. Otherwise, this analysis is an excellent base for further studies and identifies the problematic genera and species groups.

The taxonomic index at the end of the book is a bit difficult to use since the epithets are listed under the genera in which they were described. In order to find an epithet, one has to know the original genus or scroll through the entire index. Alphabetical arrangement of epithets, with corresponding genera in brackets, would have been a more practical solution. A few other inconsistencies might also be mentioned. The concept of "phenocortex" does not conform to its original definition, according to which a phenocortex is a cortex-like structure formed by dead algal cells, hyphal fragments, and other materials. From the descriptions and illustrations (p. 37ff), it is obvious that Thelotremataceae largely feature a true cortex formed 552 by fungal hyphae (e.g., Pl. 1d). Naming the perfectly conical columella shape in Fig. 5c "truncated conical", while the shape that resembles a skittle (Fig. 5a) is termed "conical", will cause confusion. It probably stems from the notion that in German, skittles are named "Kegel" ("cones"), even if those "Kegel" are not conical in the technical sense. The species descriptions are reversed, mentioning ascospore characters before asci and paraphyses, which makes them more difficult to read. In some places, data on distributions are inconsistent. Chapsa indica is given as ´Africa and tropical Asia¡, while the pantropical Thelotrema pycnophragmium is listed as a synonym. On page 328, is is stated that Thelotrema glaucopallens "... might be rare or even absent in some areas for no obvious reasons ..." (citing Hale’s Sri Lanka paper from 1981), but it is difficult to understand how the absence of that species in East Africa "... can be explained by this ...". A few Latin epithets are incorrect. Chapsa cinchonara should read cinchonarum, as it represents the genitive plural of the tree genus Cinchona. Ocellularia polydisca should read polydiscus, the epithet being a noun. In the citations of Leucodecton subcompunctum (p. 163) and Reimnitzia santensis (p. 272), the term "lectoparatype" is used, suggested some time ago to denote those syntypes or paratypes remaining after lectotypification. However, it was argued (Vorster, Taxon 35: 316-317, 1986) that such a designation has no meaning, since syntypes and paratypes are not types and, with the selection of a lectotype, cease to have value for typification, except for the original protologue in which they continue to be syntypes or paratypes. Thus, there is no provision in the Code for the term "lectoparatype" and such material cannot be cited as type. The (≡) sign is applied against current usage to denote heterotypic taxonomic synonyms, for which the (=) sign should have been used instead.

Overall, the CONTRIBUTIONS TOWARDS A NEW SYSTEMATICS OF THE LICHEN FAMILY THELOTREMATACEAE is an important work, indispensable for colleagues and students dealing with tropical lichens. It represents an outstanding treatment of African Thelo-tremataceae and an important step towards a generic rearrangement of the family, including a wealth of data and new ideas which will stimulate many further studies in this diverse group of lichens. The book invites for comparison with Staiger’s DIE FLECHTENFAMILIE GRAPHIDACEAE, and while both have a similar underlying philosophy, the CONTRIBUTIONS TOWARDS A NEW SYSTEMATICS OF THE LICHEN FAMILY THELOTREMATACEAE has the advantage of being entirely in English and thus accessible for a wide audience. The taxonomic treatment, even if geographically restricted to Africa or taxonomically to the species with complex columella, is very useful for identifying species at the world level, especially as many non-African taxa are discussed in the first part. Students will be happy to see that, while Staiger’s Graphidaceae from 2002 is priced at 128,- (approx. $ 165,-), the 88,- ((approx. $ 113,-) for the present book are much more reasonable, especially considering that it has 40 pages more and twice as many photographic plates, all integrated in the text.


Nova Hedwigia 84 3-4, p. 549-552

Review: Mycotaxon vol. 107, 2009 top ↑

This volume is based on the PhD thesis of Andreas Frisch, which was carried out at the University of Regensburg under the supervision of Klaus Kalb. The work is divided into three distinct parts. The first is entitled “The lichen family Thelotremataceae in Africa” by Andreas alone. The revision is based on collections he made in 19 localities in Cameroon in January-April 1999, and in Tanzania in August-October 1999. Habitats sampled included mangroves, coastal forests, and the eastern mountains including Kilimanjaro. About 1300 collections were made, and in addition some 320 type and other specimens from different herbaria were studied. Ninety-four species are accepted, of which 17 are described as new, and 47 are first records for Africa. In parallel with the segregation of additional genera in Graphidaceae by Staiger (2002), 19 genera are now recognized, of which 12 are known in Africa, including two described in this part for the first time: Acanthotrema and Fibrillithecis. The characters used include apothecial types, structure of the phenocortex, columella types, and especially ascospore structure (e.g. amyloidity in the endospore). Some characters emphasized previously, such as the carbonization of the exciple, proved too variable as generic criteria. For the accepted species,detailed descriptions are provided with full synonymies and details of types, information on ecology and distribution, and collections other than those from Africa studied are also listed. The whole is well illustrated by macrophotographs of the habit, and also photomicrographs and line drawings of apothecia sections, asci, and ascospores in many of the species. Appendices summarize the species known from different African countries and also the various collection sites.

The first part excludes taxa with complex columella structures, which are dealt with in the second part, co-authored by Klaus Kalb. This revises taxa worldwide with a reticulate or fissured hymenium. Some 650 specimens, including pertinent types, have been examined and 42 species are accepted dispersed through five genera, three of which are newly described (viz. Gyrotrema, Melanotrema, and Redingeria). The largest is Stegobolus (26 spp.), a resurrected generic name introduced by Montagne in 1845 and hardly used since. The other genera are much smaller: Gyrotrema has one species, Melanotrema six, Ocellularia four, and Redingeria five.

In the final part, the authors combine with Martin Grube to test the robustness of the new systematic proposed by molecular methods using material of 46 species representing 13 of the now recognized genera. There was a “fairly good congruence” (p. 518); Fibrillithecis, Myriotrema, and Ocellularia formed a monophyletic clade, and the rest of the genera a polyphyletic looser Thelotrema cluster. However, Ampliotrema was not supported, and the family concept is brought into question by two Graphis species clustering with the Ocellularia clade. It would be interesting to see the results of an analysis including larger numbers of species, and especially representatives of genera currently placed in Graphidaceae.

The contrast of the generic classification proposed here with the three-genera system (viz. Myriotrema, Ocellularia, and Thelotrema) adopted by Mason E. Hale in the early 1980s, can only be described as staggering. The systematics of the thelotrematoid fungi is raised to a new level by this major work, and the generic placement of many Asian and Neotropical species lacking complex columella structures will now have to be revisited. It is an outstanding achievement.

Mycotaxon vol. 107, 2009 p. 520

Contents top ↑

1. Abstract 6
2. Introduction 8
3. Acknowledgements 10
4. Material and methods 12
4.1 Material 12
4.2 Methods 12
4.2.1 Light microscopy 12
4.2.2 Scanning electron microscopy 12
4.2.3 Thin-layer chromatography 13
4.3 Citations 13
4.4 Abbreviations 13
4.4.1 General abbreviations 13
4.4.2 Genus abbreviations 14
5. History, geography, ecology and biogeography 14
5.1 History and delimitation of the Thelotremataceae 14
5.2 Previous collections and research in Africa 22
5.3 Geography of Cameroon and Tanzania 24
5.3.1 Cameroon 24
5.3.2 Tanzania 27
5.4 Ecology and biogeography 30
5.4.1 General ecology of the Thelotremataceae 30
5.4.2 Ecology of the Thelotremataceae in Africa 31
5.4.3 Distribution of the Thelotremataceae in Africa 34
5.4.4 Phytogeographical affinities 35
6. Morphological characters and definition of terms 36
6.1 Thallus 36
6.1.1 General morphology 36
6.1.2 Phenocortex 37
6.1.3 Photobiont layer 38
6.1.4 Medulla 40
6.1.5 Vegetative reproduction 42
6.2 Conidiomata 46
6.2.1 General morphology 46
6.2.2 Conidiophores 46
6.2.3 Conidia 47
6.3 Apothecia 48
6.3.1 General morphology 48
6.3.2 Thalline margin 49
6.3.3 Proper exciple 51
6.3.4 Columella structures 54
6.3.5 Hymenium 56
6.3.6 Paraphyses 56
6.3.7 Epiphymenium 57
6.3.8 Asci 58
6.3.9 Ascospores 59
6.4 Chemistry 65
6.4.1 ß-Orcinol depsidones 66
6.4.2 Xanthones 67
6.4.3 Anthrachinones and other pigments 67
6.4.4 Unknown compounds 68
7. Synoptic key to the genera of the Thelotremataceae 71
8. The genera (Melanotrema, Redingeria and Stegobolus: see
part II)
8.1 Acanthotrema A. Frisch 77
8.2 Ampliotrema Kalb 81
8.3 Chapsa Massal. 84
8.4 Chroodiscus (Müll. Arg.) Müll. Arg. 126
8.5 Fibrillithecis A. Frisch 135
8.6 Leptotrema Mont. 142
8.7 Leucodecton Massal. 148
8.8 Myriotrema Fée 166
8.9 Ocellularia G. Mey. 186
8.10 Reimnitzia Kalb 271
8.11 Thelotrema Ach. 275
8.12 Topeliopsis Kantv. & Vezda 322
8.13 Species of unknown taxonomic position 325
8.13.1 Thelotrema glaucopallens-group 325
8.13.2 Ocellularia clandestina-group 334
9. References 345
10. Appendices 361
10.1 Appendix 1 - Checklists of African Thelotremataceae 361
10.2 Appendix 2 - Excluded or dubious names 367