1,295 research outputs found
Foliicolous lichens and their lichenicolous fungi collected during the Smithsonian International Cryptogamic Expedition to Guyana 1996
A total of 233 foliicolous lichen species and 18 lichenicolous fungi are reported from Guyana as a result of the Smithsonian „International Cryptogamic Expedition to Guyana“ 1996. Three lichens and two lichenicolous fungi are new to science: Arthonia grubei sp.n., Badimia subelegans sp.n., Calopadia pauciseptata sp.n., Opegrapha matzeri sp.n. (lichenicolous on Amazonomyces sprucei), and Pyrenidium santessonii sp.n. (lichenicolous on Bacidia psychotriae). The new combination Strigula janeirensis (Bas.: Phylloporina janeirensis; syn.: Raciborskiella janeirensis) is proposed. Apart from Amazonomyces sprucei and Bacidia psychotriae, Arthonia lecythidicola (with the lichenicolous A. pseudopegraphina) and Byssolecania deplanata (with the lichenicolous Opegrapha cf. kalbii) are reported as new hosts for lichenicolous fungi. Arthonia pseudopegraphina growing on A. lecythidicola is the first known case of adelphoparasitism at generic level in foliicolous Arthonia. Arthonia flavoverrucosa, Badimia polillensis, and Byssoloma vezdanum are new records for the Neotropics, and 115 species are new for Guyana, resulting in a total of c. 280 genuine foliicolous species reported for that country, while Porina applanata and P. verruculosa are excluded from its flora. The foliicolous lichen flora of Guyana is representative for the Guianas (Guyana, Suriname, French Guiana) and has great affinities with the Amazon region, while the degree of endemism is low. A characteristic species for this area is Amazonomyces sprucei. Species composition is typical of Neotropical lowland to submontane humid forests, with a dominance of the genera Porina, Strigula, and Mazosia. The table mountain vegetation supports elements of the upper montane forest, such as Echinoplaca fusconitida and Logilvia gilva. Foliicolous lichen diversity is highest in undisturbed lowland to submontane humid forest, much lower in the table mountain vegetation and drastically decreased in semi-open secondary vegetation and the coastal savanna. Species composition in semi-open, disturbed vegetation is similar to that found in the undisturbed forest canopy. Site preferences of foliicolous lichens follow those established by studies in other Neotropical regions like Costa Rica
Additions and corrections to the knowledge of the foliicolous lichen flora of Costa Rica : the genus Fellhanera, with notes on Bacidia pauciseptata
This further contribution to the knowledge of the foliicolous lichen flora of Costa Rica provides a detailed account on the genus Fellhanera. In total, 25 species and five undescribed taxa are treated. Ten species are described as new: Fellhanera angustispora sp.n., F. dictyospora sp.n., F. dispersa sp.n., F. emarginata sp.n., F. pilomarginata sp.n., F. longispora sp.n., F. muhlei sp.n., F. montana sp.n., F. verrucifera sp.n., and F. viridis sp.n. New combinations are F. pauciseptata (R. Sant.) R. Lücking comb.n. [Bas.: Bacidia pauciseptata R. Sant.] and F. rubida (Müll. Arg.) R. Lücking comb.n. [Bas.: Patellaria rubida Müll. Arg.]. F. dominicana (Vain.) Vezda is placed into synonymy with F. fuscatula (Müll. Arg.) Vezda, whose type has 7-septate ascospores, and the name F. subfuscatula R. Lücking sp.n. is introduced for the taxon with 5-septate ascospores formerly known as F. fuscatula. F. misionensis Ferraro & R. Lücking ined. and F. sublecanorina (Nyl.) Vezda are reported for the first time from Costa Rica. The formerly invalidly published names F. farinosa nom. nud. and F. pilosa nom. nud. are considered to be synonyms of F. fuscatula (Müll. Arg.) Vezda and F. rhapidophylli (Rehm) Vezda, respectively. Specimens identified as F. tuckeri nom. nud. belong to F. rhapidophylli as well. F. buxi is excluded from the foliicolous lichen flora of Costa Rica. A keys is provided to the complex group of species of Fellhanera with brownish apothecia and 3-septate ascospores. Infrageneric relationships within Fellhanera are briefly discussed, and notes on the ecology of the species are provided.La presente contribución al conocimiento de la líquenoflora foliícola de Costa Rica trata en detalle el género Fellhanera, incluyendo 25 especies y otros cinco taxa aún no descritos hasta la fecha. Se describen diez especies nuevas: Fellhanera angustispora sp.n., F. dictyospora sp.n., F. dispersa sp.n., F. emarginata sp.n., F. pilomarginata sp.n., F. longispora sp.n., F. muhlei sp.n., F. montana sp.n., F. verrucifera sp.n., y F. viridis sp.n., además de las nuevas combinaciones F. pauciseptata (R. Sant.) R. Lücking comb.n. [Bas.: Bacidia pauciseptata R. Sant.] y Fellhanera rubida (Müll. Arg.) R. Lücking comb.n. [Bas.: Patellaria rubida Müll. Arg.]. F. dominicana (Vain.) Vezda es puesta en sinonimía con F. fuscatula (Müll. Arg.) Vezda, cuyo material tipo tiene esporas 7-septadas, y el nombre F. subfuscatula R. Lücking sp.n. es introducido para el taxon con esporas 5-septadas, hasta ahora conocido como F. fuscatula. F. misionensis Ferraro & R. Lücking ined. y F. sublecanorina (Nyl.) Vezda son comunicados por primera vez de Costa Rica. Los nombres F. farinosa nom. nud. and F. pilosa nom. nud., invalidamente publicadas por el autor en una publicación anterior, son considerados como sinónimos de F. fuscatula (Müll. Arg.) Vezda y F. rhapidophylli (Rehm) Vezda, respectivamente. Especimenes entonces identificados como F. tuckeri nom. nud. actualmente pertenecen a F. rhapidophylli; igualmente, F. buxi Vezda & Vivant es excluida de la líquenoflora foliícola de Costa Rica. Se presenta una clave para el dificil grupo de especies de Fellhanera con apotecios marrones y esporas 3-septadas. Finalmente, se discutan las relaciones infragenericas dentro del género Fellhanera, y se dan notas sobre la ecología de las especies
Key to Latin American species of Bazzania S. F. Gray
A new key to neotropical species of the genus Bazzania, based on the descriptions by Fulford (1946, 1963), is provided. A list of the treated species is added
A passive de-orbiting strategy for high altitude CubeSat missions using a deployable reflective balloon
A de-orbiting strategy for small satellites, in particular CubeSats, is proposed which exploits the effect of solar radiation pressure to increase the spacecraft orbit eccentricity so that the perigee falls below an altitude where atmospheric drag will cause the spacecraft orbit to naturally decay. This is achieved by fitting the spacecraft with an inflatable reflective balloon. Once this is fully deployed, the overall area-to-mass ratio of the spacecraft is increased; hence solar radiation pressure and aerodynamic drag have a greatly increased effect on the spacecraft orbit. An analytical model of the orbit evolution due to solar radiation pressure and the J2 effect as a Hamiltonian system shows the evolution of an initially circular orbit. The maximum reachable orbit eccentricity as a function of semi-major axis and area-to-mass ratio can be found and used to determine the size of balloon required for de-orbiting from circular orbits of different altitudes. A system design of the device is performed and the feasibility of the proposed de-orbiting strategy is assessed and compared to the use of conventional thrusters. The use of solar radiation pressure to increase the orbit eccentricity enables passive de-orbiting from significantly higher altitudes than conventional drag augmentation devices
Ein nichtpulsatiles Herz-Kreislauf-Barorezeptor-Modell: Herleitung, Vergleich und Simulationen
New species or interesting records of foliicolous lichens : 7., Calenia flava (Ostropales: Gomphillaceae)
Calenia flava spec. nova from Papua New Guinea is described and illustrated. The new species is closely related to C. phyllogena but differs in the larger apothecia with yellow disc and the abundance of sterile thallus hairs
Peter D. Crittenden: meta-analysis of an exceptional two-decade tenure as senior editor of The Lichenologist, the flagship journal of lichenology
Peter D. Crittenden served as senior editor of The Lichenologist, the flagship journal in the field of lichenological research, for a period of two decades, between 2000 and 2019. A review of the development of the journal and the publication output during this period is provided. The number of papers published during this period (1197) matches that of all papers published under the three previous senior editors, Peter W. James, David L. Hawksworth and Dennis H. Brown, during a much longer period of 42 years from 1958 to 1999. Peter oversaw important editorial changes to the layout and content of the journal: an increased size with a modern cover design, leaving behind the classic mint-coloured cover of more than 40 years; the addition of ‘thematic issues’ and encouragement of large monographs; implementation of substantial changes to the Code, such as effective electronic publication and obligate registration of new fungal names; and more recently a new policy to reject so-called ‘single naked species descriptions’. Shortly before Peter took over as senior editor, The Lichenologist had received its first impact factor, and Peter managed to continuously increase this measure from around 0.9 to lately up to over 1.5, higher than most other competing journals. The 1197 papers between 2000 and 2019 were published by a total of 1138 different authors, more than half of whom appeared just once as author, whereas a small number participated in numerous (up to 93) papers. There was a continuous increase in the mean number of authors per paper per year, from below 2.5 to around 3.5, the highest numbers ranging between 11 and 30; still, c. 75% of all papers between 2000 and 2019 were single-authored or had up to three authors. Based on affiliations at the time of publication, two thirds of author contributions came from Europe (66%), 13% from North America, 9% from Asia and 7% from Latin America. Likewise, almost half of the study areas were located in Europe and around 10% each in North America, South America and Asia. The countries with the highest number of studies included, in descending order, the United States, Spain, the United Kingdom, Norway and Sweden. North America and Europe were over-represented in terms of author contributions, whereas Africa, Latin America, Australia and Oceania were over-represented in terms of study areas. The 1197 papers analyzed encompassed a broad diversity of topics, classified into 32 categories. Taxonomy of lichenized fungi was the most frequent component, representing the focal point in almost half of all studies, followed by phylogeny and evolution, ecology, and the taxonomy of lichenicolous fungi. Around two thirds of the currently accepted genera of lichenized fungi were treated, with a significant correlation between known species richness and the number of papers in which a genus was treated, underlining the taxonomic representativity of papers published in the journal during the past two decades. Examples of genera that were treated more frequently than expected included commonly studied model organisms, such as Lobaria, and those frequently featured in ecological or other non-taxonomic studies, such as Xanthoria. Species-rich tropical genera, particularly in the Graphidaceae, were generally under-represented. Mean number of authors per paper per volume and total number of country origins of authors per volume were the best predictors of impact factor, followed by diversity of study countries per volume, mean number of study countries per paper per volume, mean number of topics per paper per volume, and proportion of studies with phylogenetic components per volume. Individual papers that contributed to high impact factors included broad-scale revisionary treatments and worldwide keys to species-rich taxa, substantial phylogenetic reclassifications of known taxonomic groups, papers dealing with novel methodological approaches of broad interest, and broad-scale studies related to environmental change and lichen biomonitoring
Estado actual de las investigaciones sobre líquenes foliícolas en la región neotrópica : con un análisis biogeográfico preliminar
An overview over the present state of investigations on foliicolous lichens in the Neotropics is provided. Historically, a division can be made into (1) the initial period, dominated by the work of J. Müller Argoviensis, (2) the monography of R. Santesson, (3) the Brazilian phase, characterized by the Brazilian mycologist A. C. Batista and his working group, and (4) the modern period, with detailed monographical and floristical studies and an increasing interest in the ecology of foliicolous lichens and their use as bioindicators. We now have rather good knowledge of the taxonomy and systematics of most groups, although new species are continuously described and some families and genera are in need of revision. Detailed floristical information is available from a few regions only, and biogeographical data are therefore incomplete and controversial. Modern ecological studies have been made to some extent, yet the results and their implications have to be verified by extended studies inside and outside the Neotropics. Preliminary data indicate that foliicolous lichens are useful as bioindicators in various respects. Biogeographically, the Neotropics are characterized by a high number of exclusive species and by their affinity with tropical Africa. Within the Neotropics, biogeographical subdivisions, as established by higher plant distribution patterns, are only in a few instances supported by the distribution of foliicolous lichens. In general, subtile biogeographical conclusions with respect to foliicolous lichens are difficult, because of the wide distribution of many species and the insufficient floristic knowledge of particular regions.Se presenta un resumen del estado actual de investigaciones sobre líquenes foliícolas en la región Neotrópica. Historicamente, se puede hacer una división en (1) el período inicial, dominado por las obras de J. Müller Argoviensis, (2) la monografía de R. Santesson, (3) la fase brasileña, caracterizada por el micólogo Brasileño A. C. Batista y sus colaboradores, y (4) el período moderno, con estudios detallados monográficos y florísticos y un creciente interés en la ecología de líquenes foliícolas. Actualmente tenemos un conocimiento -taxonómico y sistemático relativamente bueno en la mayoría de los grupos, aunque nuevas espécies son descritas continuamente y algunas familias y géneros necesitan revisiones. Información florística detallada existe solamente de pocas regiones, y por esa razon los datos biogeográficos quedan incompletos y controversos. Estudios ecológicos modernos fueron realizados en varias ocasiones, pero falta verificar los resultados por estudios extensivas en otras regiones dentro y fuera del Neotrópico. Investigaciones preliminares demuestran que los líquenes foliícolas pueden ser usados como bioindicadores en diferentes formas. Biogeograficamente, la región Neotrópica esta caracterizada por un alto número de espécies exclusivos y por su afinidad con África tropical. Debido a la amplia distribución de muchos taxa y al déficit del conocimiento florístico, las subdivisiones biogeográficas dentro del Neotrópico, establecidas con patrones de distribución de plantas superiores, solo en pocos casos son apoyadas por la distribución de líquenes foliícolas
- …