Distribution of asteroid genera (Echinodermata) off South Shetland Islands and the Antarctic Peninsula

Se analizan la frecuencia y distribución de los géneros de Asteroidea en la zona de las islas Shetland del Sur a partir en los datos obtenidos en 24 arrastres con Agassiz efectuados durante la campaña Bentart 95. Las estrellas fueron recogidas en más del 90 % de las estaciones, sobre todo tipo de fondos, con riqueza que osciló entre 0-10 géneros. Los asteroideos encontrados pertenecieron a 27 géneros y 12 familias, siendo Astropectinidae, Goniasteridae y, sobre todo, Asteriidae, las familas con el número más elevado de representantes (3 y 7 géneros, respectivamente). Odontaster Verrill, 1880 y Labidiaster Lütken, 1872, seguidos por Psilaster Sladen, 1885 y Diplasterias Perrier, 1888 presentaron la más amplia distribución y la frecuencia más elevada. Odontaster fue más frecuente hasta 100 m de profundidad y Labidiaster entre 200-300 m. Los géneros más raros fueron Notioceramus Fisher, 1940 y Chitonaster Sladen, 1889, endémicos de aguas antárticas. Las estaciones que mostraron una riqueza más alta (10 géneros) fueron las localizadas cerca de la península antártica y el norte de la isla Livingston. La pobreza de asteroideos fue notable en el interior de la isla Decepción, donde se encontraron sólo tres géneros.Frequency and distribution of asteroid genera in the South Shetlands zone are analysed, based on data from 24 Agassiz trawls carried out during the Bentart 95 Survey. Asteroids were collected at more than 90 % of the stations, on all types of bottoms, with richness per station ranging from 0-10 genera. The specimens belonged to 27 genera and 12 families, with Astropectinidae, Goniasteridae and, above all, Asteriidae having the highest number of representatives (3 and 7 genera, respectively). Odontaster Verrill, 1880 and Labidiaster Lütken, 1872, followed by Psilaster Sladen, 1885 and Diplasterias Perrier, 1888, were found to have the widest distribution and highest occurrence. Odontaster was more frequent to a depth of 100 m, and Labidiaster between 200 and 300 m. The rarest genera were Notioceramus Fisher, 1940 and Chitonaster Sladen, 1889, endemic to Antarctic waters.Stations showing the highest richness (10 genera) were those located near the Antarctic Peninsula and north of Livingston Island. Asteroid poverty was noticeable inside Deception Island, where a mere 3 genera were recorded. As shown by similarity and grouping analysis based on presence-absence data, stations are mainly grouped in relation to genera richness when double absence is considered. These results show the distintiveness of the stations around Deception Island, probably due to its special geological characteristics.Instituto Español de Oceanografí

Effect of Environmental and Spatial Factors on the Phylogenetic and Functional Diversity of the Mediterranean Tree Communities of Europe

The tree flora of the Mediterranean Basin contains an outstanding taxonomic richness and a high proportion of endemic taxa. Contrary to other regions of the Mediterranean biome, a comprehensive phylogenetic analysis of the relationship between phylogenetic diversity, trait diversity and environmental factors in a spatial ecological context is lacking. We inferred the first calibrated phylogeny of 203 native tree species occurring in the European Mediterranean Basin based on 12 DNA regions. Using a set of four functional traits, we computed phylogenetic diversity for all 10,042 grid cells of 10 × 10 km spatial resolution to completely cover Mediterranean Europe. Then, we tested the spatial influence of environmental factors on tree diversity. Our results suggest that the nature of the relationship between traits and phylogeny varies among the different studied traits and according to the evolutionary distance considered. Phylogenetic diversity and functional diversity of European Mediterranean trees correlated strongly with species richness. High values of these diversity indices were located in the north of the study area, at high altitude, and minimum temperature of the coldest month. In contrast, the two phylogenetic indices that were not correlated with species richness (Mean Phylogenetic Distance, Phylogenetic Species Variability) were located in the south of the study area and were positively correlated with high altitude, soil organic carbon stock and sand soil texture. Our study provides support for the use of phylogenies in conservation biology to assess ecosystem functioning, and provides insights for the implementation of sustainable forest ecosystem management

State of the world’s plants and fungi 2020

Kew’s State of the World’s Plants and Fungi project provides assessments of our current knowledge of the diversity of plants and fungi on Earth, the global threats that they face, and the policies to safeguard them. Produced in conjunction with an international scientific symposium, Kew’s State of the World’s Plants and Fungi sets an important international standard from which we can annually track trends in the global status of plant and fungal diversity

Chemical constituents of Coix lacryma-jobi

Chemical investigation of the dichloromethane extracts of Coix lacryma-jobi afforded triglyceride (1) and β-sitosterol (2) from the grains; 1 and a mixture of 2 and stigmasterol (3) in a 4:3 ratio from the stems; and 1 and phytyl fatty acid ester (4) from the leaves. Their structures were identified by comparison of their 1H and/or 13C NMR data with those reported in the literature

El mundo en 1908 : breve reseña histórica, política, administrativa ...

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