Argulus chicomendesi sp. n. (Crustacea: Argulidae) parasita de peixes da Amazônia brasileira

Uma nova espécie de Branchiura é descrita para o Brasil. Os espécimens foram coletados parasitando peixes da Amazônia brasileira. A nova espécie é caracterizada pela: coloração e desenhos da superfície dorsal da carapaça, tórax e abdômen; presença de espinhos em toda a margem externa da superfície ventral do abdômen (pléon); ornamentações das antenas, antênulas, maxilas, pernas, superfície ventral do corpo; forma e pigmentação das estruturas copulatórias acessórias do macho.

Biologia reprodutiva do Camarão Macrobrachium brasiliense (Heller, 1862) (Crustacea: Decapoda: Palaemonidae) em Igarapés de terra firme da Amazônia Peruana

Foi estudada a biologia reprodutiva de Macrobrachium brasiliense (Decapoda: Palaemonidae) com base em 2604 indivíduos coletados entre outubro de 1994 e agosto de 1995, em dois igarapés de terra firme da estrada Iquitos-Nauta, Loreto (Amazônia peruana). A proporção sexual fêmea: macho foi de 1,7:1 sendo que as fêmeas foram um pouco mais abundantes que os machos durante todo o período de coleta. M. brasiliense apresentou dimorfismo sexual no comprimento cefalotorácico, sendo as fêmeas ligeiramente menores que os machos. A reprodução foi contínua, com o pico reprodutivo entre abril e julho. A fecundidade variou de 15 a 168 ovos por fêmea, observando-se uma relação significativa entre a fecundidade e o comprimento cefalotorácico e o peso. O volume do ovo não apresentou relação significativa com o comprimento cefalotorácico e a fecundidade.

The systematic and biogeographical status of Fredius reflexifrons (Ortmann, 1897) and Fredius fittkaui (Bott, 1967) (Crustacea: Brachyura: Pseudothelphusidae) from the Amazon and Atlantic Guianas River basins

There is considerable confusion in the literature regarding the systematic position and distribution of two pseudothelphusid crabs originally described as Potamocarcinus reflexifrons Ortmann, 1897 and Potamocarcinus reflexifrons fittkaui Bott, 1967, and now included in the genus Fredius Pretzman, 1965, as F. reflexifrons and F. fittkaui. Study of numerous specimens from recent collections, together with a critical analysis of the data published in the literature, shows that both taxa could be easily separated by gonopodal characters. The two species occupy discrete areas of distribution along the main axis of the Amazon River and in the upper Rio Negro Basin, respectively, with an overlap in the Atlantic Guianas. It is postulated that they originated from a common ancestor, through a process of vicariance, in the two areas observed at present. Permeability of barriers allowed their further occupancy of the Atlantic Guianas after the marine regressions in this area.

Revisão taxonômica dos camarões de água doce (Crustacea: Decapoda: Palaemonidae, Sergestidae) da Amazônia Peruana

Foi realizada uma revisão taxonômica das espécies de camarões de água doce da Amazônia peruana que abrangeu oito espécies da família Palaemonidae e uma espécie da família Sergestidae. São descritas duas novas espécies do gênero Pseudopalaemon e feitos os primeiros registros de Euryrhynchus amazoniensis Tiefenbacher, 1978, Macrobrachium jelskii Miers, 1877 e Palaemonetes ivonicus Holthuis, 1950 para o Peru. São fornecidos chave de identificação, dados distribucionais e ilustrações para as espécies estudadas.

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.

Mangrove sedimentary characteristics and implications for crab Ucides cordatus (Crustacea, Decapoda, Ucididae) distribution in an estuarine area of the Amazonian region

At the coastal zone sediments, water and organisms interact intensely. At equatorial tidal-dominated coast mangroves are abundant. These areas are well-known for their ecological importance. Considering the mangroves of Atlantic South America, the mangrove crab, Ucides cordatus has ecological and economic prominence. High densities of this crab are found on the Amazon coast. This study investigates the sediment distribution of the Bragança mangrove area (Amazon coast, Brazil) and its correlations with vegetation and mangrove crab distribution. Sediments of 47 sites, as well as crabs from sites with different sediment and vegetation, were sampled. Results show that surface sediment of the area is mainly composed by silt (59%), with 21% sand and 20% clay. Variations in sorting and skewness are the product of local variations in clay and sand content. The vegetation type was significantly correlated to mangrove crab characteristics, abundance and weight/size. Sediment characteristics are also substantially different according to the vegetation type. Areas where Avicennia germinans prevails have more sand and clay than areas of Rizophora mangle, in which silt is dominant and crabs were significantly heavier. The present results have showed that the distribution of sediments, crabs and vegetation at mangrove areas are strongly correlated. Thus, they should be studied in conjunction.

Bioecology of the crab Ucides cordatus (Crustacea, Decapoda) in mangroves influenced by the Amazon River, Brazil

The mangrove crab (Ucides cordatus) is a valuable fishery resource, overfished along the Brazilian coast. This study aimed to obtain bioecological data on this crab along the coast of the State of Amapá. Six bimonthly samplings were conducted between December 2008 and January 2010. Transects were used to estimate the density (burrows m-2) and population abundance (individuals m-2). All the animals were subjected to biometrics, with females being classified according to their stage of gonadal maturation. The mean density (1.09 burrows m-2) and abundance (0.31 individuals m-2) were influenced by the climate with the highest values in summer (1.17 burrows m-2 and 0.34 individuals m-2). The male to female ratio was 1.38:1 showing significant difference in the proportion of sexes. The individuals showed sexual dimorphism, with linear measurements significantly higher in males. The sampled animals also had larger carapace length and width (CL and CW) compared to crabs studied in other Brazilian states. There was a positive relationship between CW and CL and individual weight (IW) and CW for males (R² = 0.83 and 0.90) and females (R² = 0.79 and 0.84). The growth was negative allometric (CL increases to a lesser extent than CW) for both sexes. The highest frequency of ovigerous females (78%) and in maturation stage IV (38%) occurred in the CW size class between 59.8 and 67.5 mm. The peak of mature females occurred in May and August, showing a reproductive period different from those in other Brazilian states.

Natural diet and feeding habits of a freshwater prawn (Macrobrachium carcinus: Crustacea, Decapoda) in the estuary of the Amazon River

Macrobrachium carcinus is a Brazilian native prawn with recognized potential for use in aquaculture activities. However, there is little information about the natural diet and feeding habits of this species. The aim of this study was the identification of the diet items of M. carcinus based on the analysis of the stomach contents. Specimens were collected in the Amazon River estuary between January 2009 and January 2010. The stomach analysis was carried out by using the frequency of occurrence (FO), methods of points (MP) and feeding index (FI). It was observed that prawns fed on detritus, animals and plant fragments as the most important food items. Sediment accounted for the main stomach content, accounting for 43.2% by the MP, 44.9% by FI and 100% by the FO. Sexual differences in feeding preferences were not found in this study, and seasonal differences in the frequency of items ingested by M. carcinus were not observed. The results indicated that M. carcinus can be considered omnivorous species, but with an important carnivorous component, similar to that found in other Macrobrachium species.

Foregut morphology of Macrobrachium carcinus (Crustacea, Decapoda, Palaemonidae)

ABSTRACT Macrobrachium carcinus is a Brazilian native prawn with recognized potential for use in aquaculture activities. The aim of this study was to describe and illustrate in detail the morphology of the M. carcinus foregut. The foregut comprises the mouth, esophagus and stomach. It is lined by a simple cylindrical epithelium overlain by chitinous cuticle. The cardiac chamber is well supplied with muscles and lined with chitin thickened in places to form a complex, articulating set of ossicles. The ossicles and setae inside the cardiac chamber seem to direct the food movement through the cardiac chamber and sort the food according to particle size as digestion takes place. Twenty-one basic ossicles were observed in the stomach ofM. carcinus and are divided into seven categories, reflecting their presumed functional roles. The significance of these morphological features is discussed in terms of its implication in feeding management that can support future commercial farms of this important fishery resource.

An account of the Crustacea of Norway, with short descriptions and figures of all the species. By G.O. Sars ...

v.5 Copepoda-Harpacticoida

An account of the Crustacea of Norway, with short descriptions and figures of all the species. By G.O. Sars ...

v.1 Amphipoda (text)