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Premise: Southern Africa is a biodiversity hotspot rich in endemic plants and lichen‐forming fungi. However, species‐level data about lichen photobionts in this region are minimal. We focused on Trebouxia (Chlorophyta), the most common lichen photobiont, to understand how southern African species fit into the global biodiversity of this genus and are distributed across biomes and mycobiont partners. Methods: We sequenced Trebouxia nuclear ribosomal ITS and rbcL of 139 lichen thalli from diverse biomes in South Africa and Namibia. Global Trebouxia phylogenies incorporating these new data were inferred with a maximum likelihood approach. Trebouxia biodiversity, biogeography, and mycobiont–photobiont associations were assessed in phylogenetic and ecological network frameworks. Results: An estimated 43 putative Trebouxia species were found across the region, including seven potentially endemic species. Only five clades represent formally described species: T. arboricola s.l. (A13), T. cf. cretacea (A01), T. incrustata (A06), T. lynniae (A39), and T. maresiae (A46). Potential endemic species were not significantly associated with the Greater Cape Floristic Region or desert. Trebouxia species occurred frequently across multiple biomes. Annual precipitation, but not precipitation seasonality, was significant in explaining variation in Trebouxia communities. Consistent with other studies of lichen photobionts, the Trebouxia–mycobiont network had an anti‐nested structure. Conclusions: Depending on the metric used, ca. 20–30% of global Trebouxia biodiversity occurs in southern Africa, including many species yet to be described. With a classification scheme for Trebouxia now well established, tree‐based approaches are preferable over "barcode gap" methods for delimiting new species. [ABSTRACT FROM AUTHOR]

Additions and corrections are provided for the South African species of Graphidaceae tribe Graphideae with hyaline ascospores. Allographa oldayana I. Medeiros sp. nov. is described as new to science based on morphological, chemical and molecular data. The new species is characterized by lirellae with striate labia and a complete thalline margin, a completely carbonized excipulum, large, muriform ascospores, and the presence of hirtifructic acid. Allographa consanguinea (Müll. Arg.) Lücking, A. leptospora (Vain.) Lücking & Kalb, Diorygma aff. minisporum Kalb et al., Graphis crebra Vain., Gr. dupaxana Vain., Gr. furcata Fée, Gr. handelii Zahlbr., Gr. longula Kremp., Gr. pinicola Zahlbr., Gr. proserpens Vain, Gr. subhiascens (Müll. Arg.) Lücking and Platythecium sp. are reported as new records for South Africa. Allographa striatula (Ach.) Lücking & Kalb, Graphis analoga Nyl. and Gr. scripta (L.) Ach. are shown to be misapplied names that should be removed from the South African checklist. The new combination Mangoldia bylii (Vain.) I. Medeiros comb. nov. (bas. Graphis bylii Vain) is made; this represents an earlier name for M. atronitens (A. W. Archer) Lücking et al. Taxonomic notes are provided for Graphis bylii var. lividula Vain. and Gr. denudans Vain., species that are known only from their South African holotypes. Phylogenetic analyses that include new DNA sequence data from the nrLSU, mtSSU and RPB 2 loci confirm the generic placements of several species for which molecular data were lacking: Allographa consanguinea , Glyphis atrofusca (Müll. Arg.) Lücking, Graphis crebra and Gr. subhiascens. [ABSTRACT FROM AUTHOR]

Biotic specialization holds information about the assembly, evolution, and stability of biological communities. Partner availabilities can play an important role in enabling species interactions, where uneven partner availabilities can bias estimates of biotic specialization when using phylogenetic diversity indices. It is therefore important to account for partner availability when characterizing biotic specialization using phylogenies. We developed an index, phylogenetic structure of specialization (PSS), that avoids bias from uneven partner availabilities by uncoupling the null models for interaction frequency and phylogenetic distance. We incorporate the deviation between observed and random interaction frequencies as weights into the calculation of partner phylogenetic α‐diversity. To calculate the PSS index, we then compare observed partner phylogenetic α‐diversity to a null distribution generated by randomizing phylogenetic distances among the same number of partners. PSS quantifies the phylogenetic structure (i.e., clustered, overdispersed, or random) of the partners of a focal species. We show with simulations that the PSS index is not correlated with network properties, which allows comparisons across multiple systems. We also implemented PSS on empirical networks of host–parasite, avian seed‐dispersal, lichenized fungi–cyanobacteria, and hummingbird pollination interactions. Across these systems, a large proportion of taxa interact with phylogenetically random partners according to PSS, sometimes to a larger extent than detected with an existing method that does not account for partner availability. We also found that many taxa interact with phylogenetically clustered partners, while taxa with overdispersed partners were rare. We argue that species with phylogenetically overdispersed partners have often been misinterpreted as generalists when they should be considered specialists. Our results highlight the important role of randomness in shaping interaction networks, even in highly intimate symbioses, and provide a much‐needed quantitative framework to assess the role that evolutionary history and symbiotic specialization play in shaping patterns of biodiversity. PSS is available as an R package at https://github.com/cjpardodelahoz/pss. [ABSTRACT FROM AUTHOR]

The new genus Burrowsia (Caliciaceae) is proposed to accommodate the new species B. cataractae , which is known from only a single locality in Mpumalanga, South Africa. Burrowsia is characterized by its pigmented, submuriform ascospores and ascus with an apical tube structure, and also by its DNA sequence data that place it outside related buellioid genera. We also describe the new species Scoliciosporum fabisporum, also known from a single locality in Mpumalanga, which differs from all other species of that genus in having distinctive kidney-shaped, 0–1-septate ascospores. It is most closely related to the Northern Hemisphere species S. intrusum, which is here confirmed by molecular data as belonging to this genus in a well-supported Scoliciosporaceae. The potential of the region to yield additional novel lichen taxa is explored. [ABSTRACT FROM AUTHOR]

Background In 1868, Nylander described 15 new lichen taxa from collections made near Durban, South Africa. The locality was not specified and the collector was identified only as 'Miss Armstrong'. Objectives To identify the collector and type locality of Nylander's species. Method Scientific literature, maps, letters, notebooks and genealogical sources were consulted to reconstruct the provenance of the specimens. Results 'Miss Armstrong' was likely Olivia Armstrong; she collected in the Karkloof area of the KwaZulu-Natal Midlands. Conclusion This investigation facilitates future work to determine whether the species described and reported by Nylander are still extant in the same locality. [ABSTRACT FROM AUTHOR]

Peltigera globulata Miadl. & Magain, a new species in the P. ponojensis/monticola species complex of section Peltigera , is formally described. This clade was previously given the interim designation Peltigera sp. 17. It is found in sun-exposed and xeric habitats at high altitudes in Peru and Ecuador. Peltigera globulata can be easily recognized by its irregularly globulated margins covered mostly by thick, white pruina, somewhat resembling the sorediate thallus margins of P. soredians , another South American species from section Peltigera. The hypervariable region of ITS1 (ITS1-HR), which is in general highly variable among species of section Peltigera , does not have diagnostic value for species identification within the P. ponojensis/monticola complex. Nevertheless, no significant level of gene flow was detected among eight lineages representing a clade of putative species (including P. globulata) within this complex. ITS sequences from the holotype specimens of P. monticola Vitik. (collected in 1979) and P. soredians Vitik. (collected in 1981) and lectotype specimens of P. antarctica C. W. Dodge (collected in 1941) and P. aubertii C. W. Dodge (collected in 1952) were successfully obtained through Sanger and Illumina metagenomic sequencing. BLAST results of these sequences revealed that the type specimen of P. monticola falls within the P. monticola/ponojensis 7 clade, which represents P. monticola s. str., and confirmed that the type specimen of P. aubertii falls within a clade identified previously as P. aubertii based on morphology. The ITS sequence from the type specimen of P. soredians , which superficially resembles P. globulata , confirms its placement in the P. rufescens clade. Finally, we discovered that the name P. antarctica was erroneously applied to a lineage in the P. ponojensis/monticola clade. The ITS sequence from the type specimen of P. antarctica represents a lineage within the P. rufescens clade, which is sister to the P. ponojensis/monticola clade. [ABSTRACT FROM AUTHOR]

Seventy-four lichen species, identified from both modern and historical vouchers, are reported for Lizard Lick, Wake County, North Carolina. Like many granite flat rock areas in the southeastern United States, the Lizard Lick flora is a unique combination of Piedmont and Coastal Plain species. The Lizard Lick lichen flora shares 24 species in common with two similar, nearby granite flat rock sites, Temple Flat Rock Preserve and Turnipseed Nature Preserve. Species characteristic of granite flat rock habitats were found, including Peltula cylindrica and Pyrenopsis portoricensis; the latter collection represents the second record of this species for North America. [ABSTRACT FROM AUTHOR]