Abstract The Snow Hill Island Formation (SHIF; late Campanian – early Maastrichtian) crops out in the northeast of the Antarctic Peninsula and constitutes the basal part of the late Campanian-early Maastrichtian sedimentary succession of the James Ross Basin (NG Sequence). Its major exposures occur at the James Ross and Vega islands. Several fossil-bearing localities have been identified in the SHIF providing a valuable fauna of invertebrates and vertebrates, and flora. Our study focuses on the vertebrate fauna recovered at Gamma and Cape Lamb members of the SHIF. The marine vertebrate assemblages include chondrichthyans, actinopterygians, and marine reptiles (elasmosaurid plesiosaurs and mosasaurs). A diverse terrestrial vertebrate assemblage has been reported being characterized by dinosaurs (sauropod, elasmarian ornithopods, nodosaurid ankylosaur, and a paravian theropod), pterosaurs and birds. Most SHIF dinosaurs share close affinities with penecontemporaneous taxa from southern South America, indicating that at least some continental vertebrates could disperse between southern South America and Antarctica during the Late Cretaceous. The Snow Hill Island Formation provides the most diverse Late Cretaceous marine and continental faunas from Antarctica. The present study summarizes previous and new vertebrate findings with the best actualized stratigraphical framework, providing a more complete fauna association and analyzing further perspectives.

Resumo O Aedes aegypti é um culicida que vem ganhando relevância ao longo dos anos devido à sua capacidade de transmitir diversos vírus causadores de doenças em humanos que ao longo dos anos ocasionam altas taxas de mortalidade na população mundial. O principal problema é que Ae. aegypti tem conseguido estabelecer e manter uma relação próxima com o homem e seu habitat, por isso a busca por alternativas para o controle das populações de vetores torna-se imperativa. O objetivo do presente trabalho foi estudar os efeitos de duas cepas de Beauveria bassiana sobre Ae. aegypti. Larvas de terceiro instar de Ae. aegypti em recipientes plásticos de 250 mL foram inoculados com as cepas GHA e NB3 em diferentes concentrações (1.5 × 104, 1.5 × 105, 1.5 × 106 e 1.5 × 107 conídios/mL). A cepa NB3 apresentou os maiores valores de mortalidade com 63% na concentração mais alta, ou seja, 1.5 × 107, enquanto para a cepa GHA o maior valor de mortalidade foi 30.7% na mesma concentração. Os resultados mostraram diferença significativa na mortalidade com relação à cepa e dias pós-tratamento (P = 0.0001), mas não com relação à concentração de conídios (P = 0.634). A mortalidade média de larvas por dia para o NB3 para diferentes concentrações variou de 20 a 25 larvas por dia, enquanto para o GHA a mortalidade diária variou de 5 a 12 larvas. Na mortalidade pós-tratamento, a maior mortalidade foi registrada nas larvas de terceiro estágio para o NB3, enquanto para o GHA o maior percentual de mortalidade foi observado em indivíduos que conseguiram atingir o estado adulto. Os resultados da pesquisa atual retratam o papel notável de B. bassiana no manejo de um importante vetor de doenças humanas.

Abstract Aedes aegypti is a culicide that has gained relevance over the years due to its ability to transmit various viruses that cause diseases in humans that all the years cause high mortality rates in the world population. The main problem is that Ae. aegypti has managed to establish and maintain a close relationship with humans and their habitat, which is why the search for alternatives to control vector populations becomes imperative. The objective of the present work was to study the effects of two Beauveria bassiana strains on Aedes aegypti. Third instar larvae of Ae. aegypti in 250 mL plastic containers were inoculated with the GHA and NB3 strains at different concentrations (1.5 × 104, 1.5× 105, 1.5 × 106 and 1.5 × 107 conidia/mL). The NB3 strain presented highest mortality values with 63% in the highest concentration i.e., 1.5 × 107, while for the GHA strain the highest mortality value was 30.7% at the same concentration. The results showed significant difference in mortality with respect to the strain and days post treatment (P = 0.0001), but not with respect to the conidial concentration (P = 0.634). The average mortality of larvae per day for the NB3 for different concentrations ranged from 20 to 25 larvae per day, while for the GHA daily mortality ranged from 5 to 12 larvae. In post-treatment mortality, the highest mortality was recorded in the third stage larvae for the NB3, while for GHA the highest percentage mortality was observed in individuals who managed to reach the adult state. The findings of the current research depicted the noteworthy role of B. bassiana for the management of an important vector of human disease.

The aim of this study was to determine the mycorrhizal status of four species of natural pastures of the community of Ccarhuaccpampa. The number of spores per 100 g of soil, the characterization of spores and the percentage of colonization of the roots were determined. The number of spores / 100 g of rhizospheric soil varied according to the plant species (66-732). Sixteen morphotypes of mycorrhizal fungi were located in three genera: Glomus, Acaulospora and Entrophospora, the first one was considered the most important because it had the highest number of morphotypes and was present in the different soils evaluated. A low mycorrhization of the analyzed roots was found (20 and 27%) and the presence of the arbuscular mycorrhizal association in all the species studied. A high correlation was determined between the number of spores per 100 g of soil and the percentage of mycorrhization of the roots, which indicated a similar tendency between both determinations.

La investigación se realizó con el objetivo de determinar el estado de micorrización de cuatro especies de pastos naturales de la comunidad de Ccarhuaccpampa. Se determinó el número de esporas por 100 g de suelo, la caracterización de esporas y el porcentaje de colonización de las raíces. El número de esporas/100 g de suelo rizosférico varió de acuerdo a la especie de planta (66 - 732). Destacaron 16 morfotipos de hongos micorrízicos ubicados en tres géneros: Glomus, Acaulospora y Entrophospora, el primero se consideró el más importante por poseer el mayor número de morfotipos y estar presente en los diferentes suelos evaluados. Se comprobó una baja micorrización de las raíces analizadas (20 y 27%) y la presencia de la asociación micorrízica de tipo arbuscular en todas las especies estudiadas. Se determinó alta correlación entre el número de esporas por 100 g de suelo y el porcentaje de micorrización de las raíces, lo cual indicó similar tendencia entre ambas determinaciones.

We describe and comment on an isolated upper molar belonging to Woodburnodon casei gen. et sp. nov. (Mammalia, Marsupialia, Microbiotheria, Woodburnodontidae fam. nov.), from the Eocene of the La Meseta Fm (TELM 5 or Cucullaea I Member), Marambio (Seymour) Island, Antarctic Peninsula. With a body mass estimated between 900 to 1,300 g (depending on the type of equation and the possible molar locus of the type specimen), it represents the largest known Microbiotheria, living or extinct. Besides its size, other diagnostic features include a proportionally large metacone, reduced or absent para- and metaconules, and an unusual labial notch between stylar cusps C and D. Woodburnodon casei is an undoubted Microbiotheria; however, its reference to the Microbiotheriidae is discarded: almost all its morphological characters are plesiomorphic when compared with South American microbiotheriids, even with respect to the oldest representatives of this family. This suggests (a) a quite ancient and southern origin for Woodburnodon and its ancestors, and (b) that the origins and initial radiation of the Microbiotheria may have occurred from a generalized peradectoid. The new taxon, here referred to the new family Woodburnodontidae, constitutes the second microbiotherian known from these Antarctic levels and age; this confirms the association of representatives of this order within a common, Andean-Patagonian-Antarctic biogeographic region, already present since the Late Cretaceous. Microbiotherians stand as the plesiomorphic sister-group of Bonapartheriiform marsupials, the latter including Glasbius and allied taxa.

Se describe y comenta un molar superior aislado perteneciente a Woodburnodon casei gen. et sp. nov. (Mammalia, Marsupialia, Microbiotheria, Woodburnodontidae fam. nov.), procedente de niveles eocénicos de la Fm. La Meseta (Miembro TELM 5 o Cucullaea I), Isla Marambio (Seymour), Península Antártica. Con una masa corporal estimada entre 900 y 1.300 g (dependiendo de la ecuación analizada y del locus molar posible), se trata del más grande microbioterio, fósil o viviente, conocido hasta el momento. Además del tamaño, sus rasgos diagnósticos incluyen un metacono proporcionalmente grande, para- y metacónulo reducidos o ausentes, y una inusual muesca labial entre las cúspides estilares C y D. Woodburnodon casei es un indudable Microbiotheria, si bien su pertenencia a los Microbiotheriidae debe descartarse. Casi todos sus caracteres son plesiomorfos en comparación con los microbiotéridos sudamericanos, incluso cuando se lo compara con los más tempranos representantes de la familia. Esto sugiere (a) un origen antiguo y austral para Woodburnodon y sus ancestros, y (b) que la evolución inicial de los Microbiotheria pudo haber tenido su origen a partir de un generalizado peradectoideo. El nuevo taxón, aquí asignado a la nueva familia Woodburnodontidae, constituye el segundo Microbiotheria conocido para los mismos niveles y edad de la Antártida, lo que confirma la asociación de los representantes de este orden con una región biogeográfica común, Andino-Patagónico- Antártica, ya existente desde por lo menos el Cretácico Tardío. Los Microbiotheria constituyen el grupo hermano plesiomorfo de los marsupiales Bonapartheriiformes, estos últimos incluyendo a Glasbius y taxones afines.

No Setor de Microbiologia do Solo, Departamento de Solos, da Universidade Federal do Rio Grande do Sul, Porto Alegre, Brasil, de janeiro de 1994 a março de 1995, quatro estirpes de Rhizobium leguminosarum bv. trifolii foram avaliadas para recomendação para a produção de inoculantes de trevo vermelho (Trifolium pratense). Em experimentos de casa de vegetação, as quatro estirpes apresentaram igual eficiência na fixação do nitrogênio. Contudo, em experimento de mistura de pares de estirpes, a estirpe SEMIA 222 foi mais competitiva na formação de nódulos. Em meio levedura manitol sacarose, a taxa de crescimento foi maior para as estirpes SEMIA 222, T107 e T154 do que a estirpe SEMIA 235. O tempo de geração da estirpe 222 foi mais baixo, seguido da T107 e T154, e maior para a estirpe 235. Em inoculante com veículo de turfa esterilizada, avaliado até seis meses de armazenamento, as estirpes 222 e T154 apresentaram boa sobrevivência, enquanto em inoculante com a mistura das estirpes, a T154 dominou a população. As duas estirpes apresentaram similar sobrevivência nas sementes tratadas por inoculação simples e por peletização.

Four strains of Rhizobium leguminosarum bv. trifolii were screened for their use in inoculants for red clover (Trifolium pratense) in the Soil Microbiology Sector, Department of Soils, University of Rio Grande do Sul, Porto Alegre, Brazil, from January 1994 to March 1995. In greenhouse experiments, all four strains presented similar efficiency in nitrogen fixation. However, when mixed strains were used, the strain SEMIA 222 was more effective in nodule formation. In a yeast manitol sucrose medium, growth rate was higher for strains SEMIA 222, T107 and T154, than for strain SEMIA 235. Generation time was lower for strain 222, followed by T107 and T154, and highest for 235. Strains 222 and T154 survived well in an inoculant with sterilized peat carrier evaluated at six months of storage, though the latter dominated the population in an inoculant with mixed strains. These two strains survived in a similar manner in inoculated seed.