Revision of Pseudastenus Bernhauer, synonym with Xenasterides Newton and six new species (Coleoptera, Staphylinidae, Paederinae).

The genus Xenasterides Newton, 2017 is considered here as a junior synonym of Pseudastenus Bernhauer, 1933, both monotypic and Neotropical genera of Paederinae (Staphylinidae). A thorough description of the genus is provided. The species Pseudastenus barretoi Bernhauer, 1933 and P. plaumanni (Bierig, 1939) are redescribed and illustrated, six new species are described, and a dichotomous key is available for species. These new species are: P. amazonicus, P. ferrugineus, P. latus, P. oculatus, P, ribeirocostae, and P. schubarti.

Matter turnover in the oligotrophic restinga ecosystem and the importance of the key species Clusia hilariana / Ciclagem de matéria nos ecossistemas oligotróficos de restinga e a importância da espécie chave Clusia hilariana

Abstract: Restingas are sandy areas spread along the Brazilian coast made up of a mosaic of forest and open woodland vegetation adapted to varying conditions of aridity, oligotrophy and salinity. Two vegetation types are very common in southeast Brazilian restingas, open Clusia formations and seasonally dry forest formation. Litter production and nutrient (C and N) turnover were studied comparatively in forest formations and Clusia formations, in vegetation patches with and without Clusia hilariana. The results showed that the breakdown process is extremely retarded in Clusia formations, with or without C. hilariana, leading to C accumulation in the soil. Microbial and soil fauna activity is lower in Clusia formations in comparison to forest formations; patches without Clusia hilariana showed intermediate conditions regarding total matter and carbon loss. Nitrogen loss was lowest in patches without C. hilariana, where soil micro-organisms accumulate N during the decomposition process, such as in the forest. The ratio of lignin in litter and the slow release of N reinforce the importance of the dominant tree Clusia hilariana as a potential key species for organic matter turnover. The accumulation of organic matter under the Clusia formation vegetation may be determinant for the humus richness of some bodies of water in the restinga, demonstrating the importance of this species to the ecosystem.

Resumo: Restingas são terraços arenosos dispostos ao longo da costa brasileira. Dois tipos de vegetação são muito comuns nas restingas do sudeste brasileiro, formações Clusia e formação florestal sazonalmente seca. A produção de serapilheira e o turnover de nutrientes (C e N) foram estudados comparativamente na formação florestal e na formação aberta de Clusia, em moitas de vegetação com e sem Clusia hilariana. Os resultados mostraram que a decomposição é muito lenta na formação de Clusia levando a acumulação de C no solo. A ação microbiana e da fauna do solo também é mais lenta nessa formação em comparação com a formação florestal; moitas sem Clusia hilariana apresentaram condições intermediárias com relação a perda de carbono total. A liberação de nitrogênio também é menor em moitas sem C. hilariana, onde os microrganismos do solo acumulam o N durante o processo de decomposição, como na floresta. A proporção de lignina na serapilheira e a liberação lenta de N reforçaram a importância da espécie dominante Clusia hilariana como uma espécie chave para o turnover da matéria orgânica do ecossistema. Por fim o acúmulo de altos teores orgânicos sob a vegetação da formação de Clusia pode ser o fator responsável pela riqueza de húmus de alguns corpos de água na restinga, demostrando a importância desta espécie para o ecossistema.

Four new species of the genus Thoracophorus Motschulsky, 1857 for the Neotropical region (Coleoptera: Staphylinidae: Osoriinae).

Four new species of the genus Thoracophorus Motschulsky, 1857 of the Neotropical region are described: T. verhaaghi n. sp., T. zicsii n. sp., T. struyvei n. sp., and T. perplexus n. sp. The new species originate from French Guiana, Peru, and Ecuador. Similar species T. filum Sharp, 1887, T. proximus Irmler, 1985, T. exilis (Erichson, 1840) and T. aequalis Sharp, 1887 are compared to discuss differences between them and the newly described species and their known distribution.

Considerations on structure and function of the "Central-Amazonian inundation forest ecosystem" with particular emphasis on selected soil animals.

Studies were carried out in Central-Amazonian inundation forests having seasonal inundations during the emersion phase (e.p.) and the submersion phase (s.p.). Two várzea forests (white water areas), one in the Amazon valley on Ilha de Curarí and one at Lago Janauarí, and an igapó (black water area) situated in the Rio Negro valley at Rio Tarumã Mirím were investigated. A community analysis consisting of the species diversity and species similarity of the aquatic and terrestrial soil fauna was executed in these forests. Each forest is differentiated into an inner, middle, and outer part. The annual development of the soil invertebrates is dictated by the periodic changes in water level. Data on species diversity indicate an alternate occurrence of the soil- and trunk-dwelling carabids and staphylinids (Coleoptera). Low species diversity is obtained for the aquatic soil fauna during the high water period. This is correlated with both oxygen concentration and relative abundance of a few specialized species.A function model approach was tried. Investigations showed that both the phytophages and the saprophages consumed about 9.4% and 13% respectively of the yearly litter fall. Litter decomposition is retarded during the inundation period (170 g·m-2·s.p.-1 is decomposed) but is accelerated during the emersion phase (420 g·m-2·e.p.-1 is decomposed). Nearly 14% of the yearly litter fall is presumed to be exported by the current from the inundation forest during the inundation phase, probably into the surrounding rivers and lakes. A rough estimation of a nutrient budget containing some selected elements was given. The estimation allowed us to suppose, that in the igapó the loss of some elements cannot be compensated for by the input from the river water and the precipitation. Unlike the igapó, the várzea forest may compensate for this loss of litter through input of nutrients from the inflowing white water. The igapó may thus be considered as a source of nutrients while the várzea forest is a nutrient sink.