Examinando por Autor "Millanes, Ana María"

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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
(International Mycological Association, 2018-05-24) Zamora, Juan Carlos; Svensson, Måns; Kirschner, Roland; Olariaga, Ibai; Ryman, Svengunnar; Parra, Luis Alberto; Geml, József; Rosling, Anna; Millanes, Ana María; Prieto, Marìa; Ekman, Stefan
Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
Five new species in the Tremella caloplacae complex
(Cambridge University Press, 2023) Freire-Rallo, Sandra; Diederich, Paul; Millanes, Ana María; Wedin, Mats
Tremella caloplacae (Zahlbr.) Diederich is a species complex including at least nine different species. Here, we formally describe the new species Tremella elegantis, T. nimisiana, T. parietinae, T. pusillae and T. sorediatae. Tremella elegantis induces galls in the hymenium of Rusavskia elegans and forms 2-celled basidia, where cells rarely elongate and sometimes give the appearance of two immature, independent basidia. Tremella nimisiana has small basidiomata (less than 1 mm diam.), narrowly ellipsoid to pyriform 2-celled, occasionally clavate to subcylindrical 3-celled basidia, and grows in the hymenium of Xanthocarpia species. Tremella parietinae is characterized by the exclusive growth in the hymenium of Xanthoria parietina, the broadly fusiform to ellipsoid probasidia, and the subspherical, pyriform or ellipsoid 2(–3)-celled basidia. Tremella pusillae has ellipsoidal probasidia, 2(–3)-celled pyriform or ellipsoidal basidia that sometimes are constricted at the septum, and grows only on Calogaya pusilla. Tremella sorediatae is characterized by inducing galls on the thallus of Rusavskia sorediata and by pyriform to ellipsoid basidia that sometimes are constricted at the septum. Three species are not formally described and are left unnamed as Tremella sp. 13 on Calogaya biatorina, Tremella sp. 14 on Calogaya decipiens and Tremella sp. 15 on Polycauliona sp. Tremella caloplacae in the strict sense is re-circumscribed as a species confined to Variospora species.
Flora of Lichenicolous Fungi, Vol. 1, Basidiomycota
(National Museum of Natural History, Luxembourg, 2022-08-20) Diederich, Paul; Millanes, Ana María; Wedin, Mats; Lawrey, James D
This first volume of a worldwide Flora of Lichenicolous Fungi deals with the Basidiomycota. A total of 197 species are accepted, described, illustrated and keyed out, and 13 additional species are shortly introduced but not formally described. They belong to the Agaricomycetes (4 species in 2 genera of Agaricales, 2 – 1 Atheliales, 1 – 1 Boletales, 11 – 8 Cantharellales, 12 – 5 Corticiales) and the Tremellomycetes (8 – 1 Filobasidiales, 129 – 3 Tremellales) in the Agaricomycotina, and to the Agaricostilbomycetes (18 – 1 Agaricostilbales), Cystobasidiomycetes (9 – 1 Cyphobasidiales) and Microbotryomycetes (1 – 1 Kriegeriaceae) in the Pucciniomycotina, while 2 species incertae sedis are provisionally treated in ‘Syzygospora’. The species of Agaricomycetes belong to the informal group of homobasidiomycetes and are mainly generalists, while the species of Tremellomycetes, Agaricostilbomycetes, Cystobasidiomycetes, Microbotryomycetes and ‘Syzygospora’ belong to the heterobasidiomycetes and are all host-specific. Three new genera, 74 new species, 1 new subspecies, and 3 new combinations are introduced. Phylogenetic trees are given for each taxonomic group, some being obtained from previous papers, while most are based on new phylogenetic results, based on hundreds of new DNA sequences obtained during the preparation of this volume. The former Biatoropsis usnearum, Syzygospora physciacearum, Tremella parmeliarum and T. pertusariae are regarded as species complexes, including many newly described species, while some other species complexes, especially Cyphobasidium hypotrachynicola, C. usneicola, Tremella caloplacae, T. lobariacearum and T. ramalinae need further studies. Six new species of Biatoropsis or Tremella have basidia producing conidia instead of basidiospores, one new Tremella species has deciduous epibasidia acting as diaspores, and four new asexual taxa of Tremella have a layer of conidiogenous cells producing clamped conidia. Six types of host-specific galls resembling Tremella basidiomata, but probably induced by bacteria, are briefly described and included in the host-based key.
To explore strange new worlds – The diversification in Tremella caloplacae was linked to the adaptive radiation of the Teloschistaceae
(ELSEVIER, 2023-12-23) Freire-Rallo, Sandra; Wedin, Mats; Diederich, Paul; Millanes, Ana María
Lichenicolous fungi are a heterogeneous group of organisms that grow exclusively on lichens, forming obligate associations with them. It has often been assumed that cospeciation has occurred between lichens and lichenicolous fungi, but this has been seldom analysed from a macroevolutionary perspective. Many lichenicolous species are rare or are rarely observed, which results in frequent and large gaps in the knowledge of the diversity of many groups. This, in turn, hampers evolutionary studies that necessarily are based on a reasonable knowledge of this diversity. Tremella caloplacae is a heterobasidiomycete growing on various hosts from the lichen-forming family Teloschistaceae, and evidence suggests that it may represent a species complex. We combine an exhaustive sampling with molecular and ecological data to study species delimitation, cophylogenetic events and temporal concordance of this association. Tremella caloplacae is here shown to include at least six distinct host-specific lineages (=putative species). Host switch is the dominant and most plausible event influencing diversification and explaining the coupled evolutionary history in this system, although cospeciation cannot be discarded. Speciation in T. caloplacae would therefore have occurred coinciding with the rapid diversification – by an adaptive radiation starting in the late Cretaceous – of their hosts. New species in T. caloplacae would have developed as a result of specialization on diversifying lichen hosts that suddenly offered abundant new ecological niches to explore or adapt to.
Tremella macrobasidiata and Tremella variae have abundant and widespread yeast stages in Lecanora lichens
(Applied Microbiology International, 2021-03) Tuovinen, Veera; Millanes, Ana María; Freire-Rallo, Sandra; Rosling, Anna; Wedin, Mats
Dimorphism is a widespread feature of tremellalean fungi in general, but a little-studied aspect of the biology of lichen-associated Tremella. We show that Tremella macrobasidiata and Tremella variae have an abundant and widespread yeast stage in their life cycles that occurs in Lecanora lichens. Their sexual filamentous stage is restricted to a specific lichen: T. macrobasidiata only forms basidiomata on Lecanora chlarotera hymenia and T. variae only on Lecanora varia thalli. However, the yeast stage of T. macrobasidiata is less specific and can occur in L. varia lichens, whilst all life stages of T. variae may be specific to L. varia. Contrary to the hyphal stages, the yeasts are distributed across the thalli and hymenia of Lecanora lichens, and not limited to specimens with basidiomata. Tremella macrobasidiata was present in all studied L. chlarotera, and in 59% of L. varia specimens. Only in 8% of the L. varia thalli could none of the two Tremella species be detected. Our results indicate that lichen-associated Tremella may be much more abundant and widespread than previously assumed leading to skewed estimations about their distribution ranges and lichen specificity, and raise new questions about their biology, ecology and function in the symbiosis.