Recent studies of the global diversity of the lichenized fungal family Graphidaceae suggest that there are a large number of species remaining to be discovered. No less than 640 species have been described since 2002, including 175 new species introduced in a collaborative global effort in a single issue in this journal. These findings suggest that the largest family of tropical crustose lichens may have an even higher number of species than Parmeliaceae. To estimate whether the discovery of 175 new species is a significant step forward in cataloguing extant diversity in this family, we employed a parametric method to predict global species richness of Graphidaceae using a GIS-based grid map approach. The model employs linear regression between observed species richness and sample score and vegetation composition per grid to predict individual grid species richness, and interpolation of species grid distributions to predict global species richness. We also applied a non-parametric species-area curve approach and non-parametric species richness estimators (Chao, Jackknife, Bootstrap) to compare the results from the different methods. Our approach resulted in a prediction of 4,330 species of Graphidaceae, including approximately 3,500 (sub-)tropical species in the core subfamilies Fissurinoideae, Graphidoideae, Redonographoideae, plus 125 species restricted to extratropical regions (outside the zone between 30° northern and 30° southern latitude) and 700 species in subfamily Gomphilloideae. Currently, nearly 2,500 species are known in the family, including species not yet formally described. Thus, our model suggests that even after describing 175 species in this issue and with another approximately 140 awaiting publication, the number of species still to be discovered and described is more than 1,800, and much work remains to be done to close this substantial gap. Based on our approach, we predict that most of this undiscovered diversity is to be found in Mexico, the northern Andean region, the eastern Amazon and central and southern Brazil, tropical West Africa, continental Southeast Asia, Indonesia, and Papua New Guinea.

CHECKLISTKawinnat Buaruang et al. / MycoKeys 23: 1-91 (2017) 2 Abstract A new revised checklist of lichenized fungi in Thailand is presented, including 1,292 species. Recent work on the taxonomy of these organisms in Thailand resulted in an enormous increase in our knowledge of the lichen biota of the country -the current checklist includes more than twice as many species as the previous catalogue published 15 years ago -and phylogenetic studies resulted in numerous changes in the generic classification of lichenized fungi. Hence, a new checklist is here presented summarizing the current knowledge of lichens in Thailand. Six new records are reported, viz. Acanthothecis salazinica, Bactrospora metabola, Buellia parastata, Diploschistes cinereocaesius, Rolfidium coccocarpioides, and Trapelia placodioides. Five previously recorded species, namely Lecanora carpinea, Platismatia glauca, P. lacunosa, P. tuckermanii and Roccella phycopsis are shown to be based on misidentifications and are excluded from the checklist. Three new combinations of species previously placed in Pertusaria to Lepra are proposed: L. bulolensis

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A revision of 245 Heterodermia s.lat. collections from Thailand preserved in RAMK, herb. F. Schumm and herb. K. Kalb is presented. The 39 species found in this material are assigned to the genera Heterodermia Trevis. s.str. with a lower cortex and Pachysporaria-type ascospores (without sporoblastidia), Leucodermia Kalb, gen. nov., with foliose to subfruticose, linear-elongate, ribbon-like, dichotomously branched lobes, loosely attached to the substrate, without a lower cortex, apothecia often with pruinose discs and Polyblastidium-type ascospores (with sporoblastidia) and Polyblastidium Kalb, gen. nov. distinguished by a foliose thallus attached to the substrate, no lower cortex and mostly Polyblastidium-type ascospores. The remaining species are assigned to groups without a formal generic name, awaiting further results from molecular phylogenies. The Heterodermia comosa group contains species which are similar to Leucodermia, but differ in having a subfruticose or rosulate thallus with ascending, spathulate or paddle-shaped lobes and the Heterodermia obscurata group which contains species with a fluffy cottony woolly lower surface which is totally or at least partly impregnated by anthraquinones. Standardized descriptions are provided for all the better known Heterodermia species s.str. worldwide and all other species found in the material studied or reported for Thailand in the literature, as well as species which might be expected to occur in the country. The new species, Leucodermia borphyllidiata Kalb & Meesim, similar to L. boryi, but differing in having a phyllidiate thallus is described, and the new combinations, Leucodermia appalachensis (Kurok.) Kalb, L. arsenii (Kurok.) Kalb, L. boryi (Fée) Kalb, L. ciliatomarginata (Linder) Kalb, L. circinalis (Zahlbr.) Kalb, L. fertilis (Moberg) Kalb, L. leucomelos (L.) Kalb, L. lutescens (Kurok.) Kalb, L. vulgaris (Vain.) Kalb, Polyblastidium appendiculatum (Kurok.) Kalb, P. casarettianum (A. Massal.) Kalb, P. corallophorum (Taylor) Kalb, P. dendriticum (Pers.) Kalb, P. fragilissimum (Kurok.) Kalb, P. hypocaesium (Yasuda) Kalb, P. hypoleucum (Ach.) Kalb, P. japonicum (M. Satô) Kalb, P. magellanicum (Zahlbr.) Kalb, P. microphyllum (Kurok.) Kalb, P. neglectum (Lendemer, R.C. Harris & Tripp) Kalb, comb. nov. [Mycobank MB 813853; Basionym: Heterodermia neglecta Lendemer, R.C. Harris & Tripp, The Bryologist 110(3): 490 (2007)], P. propaguliferum (Vain.) Kalb, P. queenslandicum (Elix) Kalb, P. subneglectum (Elix) Kalb and P. violostriatum (Elix) Kalb, are made. Chaudhuria Zahlbr. is a synonym of Heterodermia s.str. and Chaudhuria indica Zahlbr. is an older synonym for Heterodermia verdonii Elix, but as the name Heterodermia indica (H. Magn.) D.D. Awasthi already exists for another species, the correct name for this taxon reverts to H. verdonii. Chemical analyses revealed that Heterodermia reagens (Kurok.) Elix must be placed into synonymy with Polyblastidium propaguliferum (Vain.) Kalb. Dichotomous keys for the identification of all species are provided. Characteristic TLC profiles for selected species are presented and Rf values for the most important terpenes and pigments are given for the first time in the standard solvents A, B' and C. Photographs showing the species as well as characteristic structures in the genera and groups are also provided. A new epitype for H. comosa from Réunion is designated.

A revision of the Pyxine collections from Thailand is presented. Sixteen previously described species were found in this material and descriptions are provided for P