Abstract in English:The genus Chlamydotheca Saussure, 1858 is a typical representative of the Neotropical ostracod fauna that occupies lotic and lentic environments including temporary and permanent ponds. Up to the present, four species have been recorded in Argentina: C. iheringi (Sars), C. incisa (Claus) and C. leuckarti (Claus), and C. symmetrica (Vávra). Temporary and permanent ponds of this region were sampled for ostracods, using a fine mesh net. Three species belonging to the genus Chlamydotheca were collected of which C. arcuata (Sars) is recorded for first time for the Chacoan region. Limb morphology was studied under light microscope and line drawings were made using camera lucida. Valves were photographed under scanning electron microscope and redescriptions of C. arcuata and C. iheringi are provided and distributional aspects of the species sampled are discussed.
Abstract in English:The aim of this study was to identify patterns of vertical distribution of planktonic cladocerean populations throughout the diel cycle, during the low and high water periods, and its ecological implications for a black water Amazonian lake. Tupé Lake is a black water lake located near the Brazilian city of Manaus. A channel links the lake with the Negro River and its flood pulse. This study was performed in a low-water period (November 2005) and in a high-water period (June 2006). Samples were taken on a 24-hour cycle, every 4 hours and at each meter of the water column, using a Schindler-Patalas trap equipped with a 55µm size mesh. A total of 16 species were registered during the low water period, wherein Bosminopsis deitersi, Moina minuta, and Ceriodaphnia cornuta were the most abundant species. B. deitersi migrated to the bottom during the afternoon, while M. minuta, Moina reticulata, and Holopedium amazonicum remained at the bottom for the entire diel cycle. During the high-water period, a total of 18 species were observed, and B. deitersi, C. cornuta, and Diaphanosoma polyspina were the most abundant species. During both sampling periods, no pattern was detected for C. cornuta. Generally, vertical patterns of distribution were less evident in the high water period, due to the mixing of the lake.
Abstract in English:In Oniscidea, the marsupium is a ventral pouch where the offspring develop independently of an external water source. The marsupium is formed by five pairs of overlapping oostegites that develop in the females during their reproductive period. In this study, ovigerous females of 35 species were dissected, their oostegites were extracted, and the intra-marsupial offspring were counted. Two marsupium forms were recognized: distended, in which the oostegites protrude distally in relation to the sternites; and non-distended, in which the oostegites are parallel to the sixth and seventh sternites. Armadillidium nasatum, A. vulgare, Pudeoniscus birabeni, Circoniscus gaigei and Cubaris murina, conglobating species with a non-distended marsupium, and Neotroponiscus daguerri and N. carolii, non-conglobating species with a distended marsupium, have a concavity on the ventral floor of the 6th and 7th pereionites, here called the marsupial extension. This is the first record of a marsupial extension which extends beyond the area formed by the oostegites in Oniscidea.
Abstract in English:A large population of Neocrangon resima (Rathbun, 1902) is reported for the northern Gulf of California, Mexico, in depths of 205-580 m, with environmental conditions varying from 6.21 to 11.29ºC and 0.50 to 1.54 ml O2/l. With a total of 33 specimens collected, this is the largest sample reported to date for the northern Gulf of California. The species had previously been reported from two localities. The distribution range in this area is increased by ca 1º30' of latitude to the south. Maximum and minimum estimated densities were of 2.7 and 54.0 orgs/ha, thus indicating that a relatively large population of N. resima occurs in the area.
Abstract in English:The relationship between species abundance and environmental factors such as the bottom water temperature and salinity, the texture and organic matter content of the sediment and the distribution of Pleoticus muelleri and Artemesia longinaris were investigated. Specimens and samples of abiotic factors were collected monthly from May 2008 to April 2010 at 4 locations in Santos Bay on the southern coast of the State of São Paulo. A shrimp boat equipped with an otter-trawl net with an 8 m mouth aperture and a mesh size of 20 mm tapering to 18 mm at the cod end was used for sampling. Shrimp abundances were compared with an analysis of variance (ANOVA). However, when the data did not follow a normal distribution, we used the Kruskal-Wallis test. The relationship between environmental factors and the abundance of individuals was assessed with a Pearson's correlation. The largest catches of individuals of both species occurred in the late spring of 2008. The greatest abundance occurred at the outer part of the bay (collection point 4). The greatest abundance of P. muelleri was associated with lower temperatures and sediments with higher clay and organic matter content, whereas for A. longinaris, there was no significant correlation with any of the abiotic factors recorded. However, the occurrence of both species was related to lower bottom temperatures associated with the intrusion of the South Atlantic Central Water in the region.
Abstract in English:This study provides a detailed description of the macro- and microscopic anatomy of the female reproductive system of the mangrove land crab, Ucides cordatus. A total of 277 females were collected between October 1998 and September 1999 in mangroves of the Victoria Bay, State of Espírito Santo, Southeast Brazil. The reproductive system of this species is composed of two ovaries united together by a bridge, present in the form of an H when viewed dorsally, and two seminal receptacles. Histological analysis revealed the following six stages of oocyte development: I. young germ cells (oogonias); II. oocytes of the germinative centers; III. oocytes with lipid vitellogenesis; IV. vitellogenic oocytes with lipid and protein; V. oocytes with completed vitellogenesis; and VI. oocytes in hyalinization. The anatomy of the ovary is characterized by the following six stages of development: I. immature; II. at maturity; III. mature; IV. partly spawned; V. fully spawned; and VI. in recovery. Reproduction was observed in summer, and the results suggesting that this species showed multiple spawnings.
Abstract in English:The aim of this study was to analyze reproductive aspects of Callinectes danae in one of the most productive estuarine systems in the Northeast Brazil, Santa Cruz Channel. A total of 1.573 individuals, being 756 females (23 ovigerous) and 817 males were examined from January to December 2009. Mature males and females, as well as couples of C. danae, occurred in all months of the year. Ovigerous females occurred in nearly all months. The reproductive activity, based on the macroscopic observation of the gonads, occurs continuously, with distinguishable peaks in February, March and September. Ovigerous females were only recorded nearest to the sea, while couples were only in the inner estuary. Thus, a migration pattern is proposed, with couples mating inside the estuary, followed by a migration of females to the area of greater marine influence for egg laying and, probably, larval release. After this, probably the females of do not return to the estuary, characterizing habitat partitioning. The present study is the first contribution on the reproductive period of C. danae in an estuarine ecosystem of the Brazilian northeast coast, and elucidates some aspects of its reproductive behavior.
Abstract in English:There are over 120 species of freshwater decapod crustaceans in Brazil. This paper contributes to the knowledge of the species richness and distribution of decapod crustaceans from Jacupiranga State Park, South of São Paulo State. The main objectives were to investigate the geographical distribution of A. strinatii and to generate a checklist of the decapod species collected from the sampling sites. Sixteen sampling sites were investigated during the year of 2007 and four species were collected. The present report represents a new record of A. strinatii from São Paulo State and adds three more localities at Jacupiranga State Park where the occurrence of T. fluviatilis is confirmed.