On the Brazilian Prosierola (Hymenoptera, Bethylidae), with description of a new species from Amazonas, Brazil

Prosierola rotunda sp. nov. from northern Brazil is described and illustrated. Additional specimens of P. lata (Cameron, 1888) were examined with species variation analyzed and new distribution data are added.

Diatoms from the Colombian Amazon: some species of the genus Eunotia (Bacillariophyceae)

This research was carried out in three of the most important basins of the Colombian Amazon (Upper Solimões, Iça and Japurá Rivers). The creeks and lakes that were studied contain abundant diatom species, particularly those of the genus Eunotia. Ten species are described; five of them are registered for the first time in the Amazon basin, and six in all of Colombia. All taxa were photographed with scanning electron microscopy. Fine valve morphology of E. anamargariate, E. pseudoindica, E. triodon, and E. zydodon var. compacta is described for the first time.

New records of Fredius denticulatus (H. Milne-Edwards, 1853) and F. reflexifrons (Ortmann, 1897), and the eastern limits of the distribution of pseudothelphusid crabs (Crustacea: Decapoda) in Brazil

The occurence of Fredius reflexifrons (Ortmann, 1897), a pseudothelphusid crab widely distributed in the Amazon region and the Atlantic Guianas, is recorded from the state of Ceará, northeastern Brazil. Other records of this species and Fredius denticulatus (H. Milne-Edwards, 1853) from the Amazon region are also presented. A discussion is made on the eastern limits of the distribution of the family Pseudothelphusidae in Brazil.

Actinella species (Bacillariophyta) from an Amazon black water floodplain lake (Amazonas - Brazil)

The genus Actinella Lewis was studied using planktonic samples from a black water floodplain lake in Central Amazon region. For species identification the taxa were morphological and morphometricaly analyzed on base in light microscope (LM) and scanning electronic microscope (SEM). Five species were registered: Actinella brasiliensis Grunow, A. guianensis Grunow, A. gracile Kociolek, A. mirabilis (Eulenstein ex Grunow) Grunow and A. robusta Hustedt. A. gracile is reported for the first time for Amazon State and black water systems and it is firstly documented with SEM. In addition, a review of geographic distribution of Actinella species in Brazilian Amazon region is given.

The aggregation of Chauliognathus species (Coleoptera, Cantharidae) and its possible role for coexistence and mimicry

The relative population sizes of a species complex of Chauliognathus are reported, as well as their spatial distribution associated with different patches of food plants. Field work was done at Fazenda Santa Isabel, municipality of Guaíba, State of Rio Grande do Sul, Brazil. The results suggest that two mechanisms account for the reduction in food competition among the species involved: one is asynchrony in the appearance of the species in the area, and the other is aggregation in different patches of food plants. Since the species here reported show a similar colour pattern (yellow-black) the possibility of the occurrence of serial mimicry in this complex of species is dicussed.

Distribution and morphometrics of Natalus stramineus from South America (Chiroptera, Natalidae)

Morphometric and distributional data and some observations on the biology of Natalus stramineus Gray, 1838 collected in eastern Bolivia and in northern, northeastern, central, and southeastern Brazil are presented. All new records, combined with the records of the species from Paraguay and Mato Grosso, significantly change the known distribution of N. stramineus in South America. The specimens from northeastern Brazil (Rio Grande do Norte, Ceará, Bahia) are smaller than those found in the northern (Pará), eastern (Espírito Santo, São Paulo) and central regions of the country (Distrito Federal, Goiás, Mato Grosso do Sul). Natalus stramineus specimens from the three latter regions are about the same size, but are larger than those from Santa Cruz, Bolivia. Their size is intermediate between those of central samples and northeastern Brazil samples. The type locality of this species is discussed.

Sewage impact on the composition and distribution of Polychaeta associated to intertidal mussel beds of the Mar del Plata rocky shore, Argentina

The polychaete composition and distribution within mussel beds were studied in order to assess organic pollution due to domestic sewage in a rocky shore of Mar del Plata (Argentina) during 1997. Four stations and a control site were randomly sampled around the local effluent. Quantitative data on polychaetes, as well as sediment accumulated among mussels and its organic carbon content were measured. Polychaete distribution patterns are related to the organic matter gradient, being Capitella cf. capitata, Neanthes succinea (Frey & Leuckart, 1847) and Boccardia polybranchia (Haswell, 1885) the dominant indicator species close to the effluent. At medial distances, the cirratulids Caulleriella alata (Southern, 1914) and Cirratulus cirratus (Müller, 1776) are very important in abundance. The syllids Syllis prolixa Ehlers, 1901 and S. gracilis Grube, 1840 are distributed along the study area, but dominate at the medial stations and at the control site. The orbiniid Protoariciella uncinata Hartmann-Schröder, 1962 is subdominant at the control station.

Five new Brazilian species of the genus Trybliophorus (Orthoptera, Romaleidae)

The new species Trybliophorus amazonicus, T. nigrus, T. rubricerus, T. olivaceus and T. paraensis from Amazonian region are described. Illustrations of male and female genitalia, as well as a map showing the geographical distribution of the species are included.

Chaetognatha of the Brazil-Malvinas (Falkland) confluence: distribution and associations

The planktonic chaetognaths from the Brazil-Malvinas (Falkland) confluence, extending between 36º 30' - 50º 5' S and 60º 33' - 41º 7' W, were studied. Ten species were found: Eukrohnia hamata (Möbius, 1875) (Eukrohniidae), Pterosagitta draco (Krohn, 1853) (Pterosagittidae), Sagitta enflata Grassi, 1881, Sagitta gazellae Ritter-Zahony, 1909, Sagitta hexaptera d´Orbigny, 1834, Sagitta lyra Krohn, 1853, Sagitta minima Grassi, 1881, Sagitta planctonis Steinhaus, 1896, Sagitta serratodentata Krohn, 1853, and Sagitta tasmanica Thomson, 1947 (Sagittidae). Sagitta gazellae was the most abundant species followed by E. hamata, S. tasmanica and S. serratodentata. The association analysis among the different species, salinity and temperature revealed two groups of species, one related to higher salinities and warmer waters (P. draco, S. hexaptera and S. serratodentata) and the other to lower salinities and colder waters (E. hamata, S. gazellae and S. tasmanica). The fact that P. draco and S. hexaptera, formerly defined as warm-water species, appeared further south than previously reported might be related to the existence of warm core eddies up to 46º S in September and October 1988.

Spatial and temporal distribution of decapod larvae in the subtropical waters of the Arvoredo archipelago, SC, Brazil

The present paper aims to describe the temporal and spatial distribution of the composition and abundance of Decapoda larvae in the shallow waters around Arvoredo Marine Biological Reserve. Stomatopod occurrence is also discussed. Plankton samples were collected at five sites around the Arvoredo Island every two months for one year from May, 2002 to April, 2003. Thirty-nine morphotypes, 11 genus and 4 species (Artemesia longinaris Bate, 1888, Hexapanopeus schmitii Rathbun, 1930, Menippe nodifrons Stimpson, 1859 and Pleoticus muelleri Bate, 1888) were identified, among them only two morphotypes of Stomatopoda larvae, and the remainder Decapoda larvae. Brachyuran zoeae were the most abundant group and they were well represented by Portunidae and Xanthidae zoeae. Lucifer sp. and Caridea zoeae were the most abundant non-brachyuran taxa. Decapod larvae were observed to occur at all sampling sites, however the spatial distribution demonstrated a general tendency to greater abundance and diversity at the southern sites of the Island. Decapoda and Stomatopoda larvae occurred throughout the year, showing that reproduction is continuous, but that larval input in planktonic community was significantly higher during autumn and spring.

Ostracodes (Crustacea) from Cananéia-Iguape estuarine/lagoon system and geographical distribution of the mixohaline assemblages in southern and southeastern Brazil

The ostracode assemblages from Cananéia-Iguape estuarine/lagoon system (southernmost State of São Paulo) are here discussed in detail for the first time. Thirty-four sites, approximately 1 km equidistant, were sampled along the system, including the Cananéia Sea, Pequeno Sea, Cubatão Sea, Ribeira de Iguape River and Itapitangui River. The ostracodes throughout this area have poor assemblages, with a total of 662 specimens of dead and living organisms. The majority of the ostracode fauna is composed of euryhaline species, as follows: Cyprideis multidentata Hartmann, 1955 (174 specimens), Minicythere heinii Ornellas, 1974 (54 specimens), Tanella gracilis Kingma, 1948 (96 specimens) and Whatleyella sanguinettiae Coimbra, Carreño & Ferron, 1994 (226 specimens). Although there are few studies on the Brazilian mixohaline ostracode faunas, including the euryhaline marginal marine taxa, the published data show that the group is best known in the south and southeast regions. Based on this review and with the new data presented in this paper, the geographical distribution of eight mixohaline key species in southern and southeastern Brazil is also discussed.

Assemblages of drosophilids (Diptera, Drosophilidae) in mangrove forests: community ecology and species diversity

Brazilian fauna of drosophilids has been researched in various ecosystems, but those in mangrove forests remain overlooked in Brazil and elsewhere. The present study attempts to characterise the assemblages of drosophilids of this environment, based on 28 collections taken in three mangrove areas in Santa Catarina Island, southern Brazil. The three mangroves surveyed were different in their surroundings, which varied from highly urbanised areas to conservation areas with natural vegetation. Overall, 69 species were collected, and no remarkable difference was detected in species composition and abundances or in the richness, evenness and heterogeneity between sites. The species abundance distribution observed fitted to a theoretical lognormal distribution in the three mangroves. The species richness scored and the performance of the species richness estimators showed an unexpectedly high diversity, considering the very low floristic diversity and the harsh conditions of the environment. Regarding species composition and abundances, the drosophilid mangrove assemblages were shown to be more similar to those found in open environments, with a marked dominance of exotic species. Finally, considering the apparent lack of feeding and breeding sites, we suggest that mangrove forests are acting as sink habitats for the drosophilids populations.

Spatial and temporal distribution of Pseudis minuta (Anura, Hylidae, Hylinae) and environmental variables related to its reproductive activity in Reserva Biológica do Lami, southern Brazil

We studied the reproductive biology of a population of Pseudis minuta Günther, 1858 from Reserva Biológica do Lami (30º 15' S; 51º 05' W), Porto Alegre, southern Brazil. We assessed the spatial and temporal distribution of individuals (males, females, juveniles) and explored potential relationships with environmental variables. Field activities encompassed bimonthly surveys in three semi-permanent ponds, each one during approximately two days and two nights, from August 2004 to July 2005. We recorded differences in the sites used by males, females and juveniles, with males occupying deeper and more distant places from the border. The temporal distributions of individuals, calling sites and amplectant pairs indicated that the reproductive activity of P. minuta is related to some of the studied abiotic factors. Calling males presented statistical differences in relation to non-calling males for all daily abiotic variables analyzed (air temperature, water temperature, relative humidity and rainfall), as well as to monthly temperature and rainfall. The number of active males, females and juveniles was influenced by at least one of the daily or monthly environmental variables analyzed. We conclude that the reproduction in this species is seasonal and may be partially determined by abiotic factors.

Recognition characters and new records of two species of Phylloscyrtini (Orthoptera, Gryllidae, Trigonidiinae) from southern Brazil

The Phylloscyrtini occurs from eastern United States to Argentina and includes 21 valid species. It is a highly neglected group of crickets and little is known about its biology and distribution. Cranistus colliurides Stål, 1861 and Phylloscyrtus amoenus (Burmeister, 1880) were recorded for the state of Rio Grande do Sul, southern Brazil, and information on calling song, stridulatory file and recognition characters were provided.

Description of the male of Mangora brokopondo (Araneae, Araneidae), with notes on Mangora species from Brazilian Oriental Amazon

The male of Mangora brokopondo Levi, 2007 is described and illustrated for the first time. Variation in the color pattern of the females is documented. Mangora woytkowskii Levi, 2007 is considered a junior synonym of M. hirtipes (Taczanowski, 1878). New records of M. alinahui Levi, 2007 and M. pia Chamberlin & Ivie, 1936 are presented.