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Acesso aberto (Open Access)
Acute toxicity and histopathology in ornamental fish amazon bluespotted corydora (Corydoras melanistius) exposed to formalin
(2012-12) SANTOS, Rudã Fernandes Brandão; DIAS, Henrique Malta; FUJIMOTO, Rodrigo Yudi
The objective of this work was to evaluate the acute toxicity of formalin and histopathological effects on the Amazon ornamental fish, bluespotted coridora (Corydoras melanistius). A randomized design was used, with ten concentrations of formalin (40%) (0, 3, 6, 12, 25, 50, 100, 150, 200 and 250mg.L-1) with four replicates and five fish per container (3L) in static system for 96 hours. The moribund fish were killed and fixed in 10% formalin to proceed the histopathological analysis of gill, liver and kidney. At the end of this experiment the following mortality rates (%) were obtained in increasing order of exposure: 0, 0, 0, 0, 0, 65, 85, 100, 100 and 100%. The lethal concentration 50% (LC50-96h (I)) estimated was 50.76 mg.L-1 with regression of y = 0.51x, and r² = 0.80. Further, in higher concentrations morphological changes as gill hyperplasia, with filling of interlamellar spaces, disorganization of liver arrangement, and necrosis in kidney were observed. In this study, the formalin can be considered slightly toxic to bluespotted corydora, and cause morphological changes when exposed to high concentrations. The use of formalin to treat of ornamental fish in the inner river of capture with wrong concentration can provoke negative environmental and biological effects.
Acesso aberto (Open Access)
Acute toxicity of sodium metabisulphite on mangrove crab Ucides cordatus (Decapoda, Ucididae)
(2012-12) PEDALE, Adriana Batista; FUJIMOTO, Rodrigo Yudi; SANTOS, Rudã Fernandes Brandão; ABRUNHOSA, Fernando Araujo
The sodium metabisulphite salt is usually used in shrimp culture to prevent black spot. Unfortunately the toxicological effect of this xenobiotic in decapod crabs is unknown. Thus, the present study aims to investigate the sodium metabisulphite LC50 - 96 h in the mangrove species Ucides cordatus. Crabs were collected in the tidal creek margins in Bragança estuarine and were submitted to preliminary test (screening) and posterior definitive test. Crabs were exposed in five different concentrations and a control group in five replicates, two crabs per recipient (5 L) during 96 hours. A negative correlation was observed to sodium metabisulphite concentration in relation to dissolved oxygen and pH. At the end of the experiment were obtained the following mortality index in relation to sodium metabisulphite concentrations: 100% in 86.0 mg.L-1, 74% in 62.0 mg.L-1, 52% in 52.0 mg.L-1, 44% in 38.0 mg.L-1. The value of LC50 - 96 h for U. cordatus was determinate at 42.58 mg.L-1/Na2S2O5. The results strongly indicate that sodium metabisulphite is toxic for U. cordatus, and this crab could be used for biomonitoring the environmental impact.
Acesso aberto (Open Access)
Analysis of fish assemblages in sectors along a salinity gradient based on species, families and functional groups
(2013-12) PASSOS, Ana Carolina dos; CONTENTE, Riguel Feltrin; ABBATEPAULO, Felippe Veneziani; SPACH, Henry Louis; VILA, Ciro Colodetti; JOYEUX, Jean Christophe; CARTAGENA, Beatriz Fernanda Chinchilla; FÁVARO, Luis Fernando
Here we test the effects of the east-west salinity gradient in the subtropical Paranaguá Bay Estuarine Complex (PEC) on the structure of shallow water fish fauna, determined according to taxonomic (families and species) and functional composition metrics. A total of 152 species were observed. The families with the largest number of species were the Sciaenidae, Carangidae, Haemulidae and Gobiidae. The most abundant species were Atherinella brasiliensis, Harengula clupeola, Anchoa januaria and Anchoa tricolor. Marine stragglers dominated in number of species, followed by marine migrants and estuarine species. Most species were zoobenthivores, followed by piscivores and zooplanktivores. Families and species more frequently associated with estuarine conditions dominated in the mesohaline sector, and those more frequently associated with marine conditions dominated in the euhaline sector. The fish assemblages along the estuarine salinity gradient were found to be better characterized by taxonomic metrics than by functional ones. This is most likely because individuals of all functional groups inhabit all salinity sectors, and thus these metrics are not useful for differentiating assemblages along salinity gradients. Our results differ from those of other studies in tropical and subtropical estuaries, which have emphasized the importance of functional groups in determining fish assemblages along salinity gradients.
Acesso aberto (Open Access)
Analysis of propagule pressure and genetic diversity in the invasibility of a freshwater apex predator: the peacock bass (genus Cichla)
(2014-03) CARVALHO, Daniel Cardoso de; OLIVEIRA, Denise Aparecida Andrade de; SAMPAIO, Maria Iracilda da Cunha; BEHEREGARAY, Luciano Bellagamba
An important step in invasive biology is to assess biological variables that could be used to predict invasion success. The study of genetics, evolution, and interactions of invasive and native species in invaded ranges provides a unique opportunity to study processes in population genetics and the capability of a species' range expansion. Here, we used information from microsatellite DNA markers to test if genetic variation relates to propagule pressure in the successful invasion of an apex predator (the Amazonian cichlid Cichla) into Southeastern Brazilian River systems. Invasive populations of Cichla have negatively impacted many freshwater communities in Southeastern Brazil since the 1960s. Reduction of genetic variation was observed in all invasive populations for both Cichla kelberi (CK) and Cichla piquiti (CP). For instance, heterozygosity was lower in the invasive range when compared to native populations from the Amazon basin (CP HE = 0.179/0.44; CK HE = 0.258/0.536 respectively). Therefore, despite the successful invasion of Cichla in southeast Brazil, low genetic diversity was observed in the introduced populations. We suggest that a combination of factors, such as Cichla's reproductive and feeding strategies, the "evolutionary trap" effect and the biotic resistance hypothesis, overcome their depauperete genetic diversity, being key aspects in this apex predator invasion.
Acesso aberto (Open Access)
Aspleniaceae (Polypodiopsida) do corredor de biodiversidade do norte do Pará, Brasil: um fragmento do Centro de Endemismo Guiana
(2012-06) GÓES NETO, Luiz Armando de Araújo; PIETROBOM, Marcio Roberto
This paper is part of a series that will treat the lycophyte and fern species of the Northern Pará Biodiversity Corridor, and is part of the project "Diagnóstico da Biodiversidade das Unidades de Conservação Estaduais do Mosaico Calha Norte, Estado do Pará". Aspleniaceae are treated in this article, and an identification key, illustrations, geographic distributions, brief descriptions, and taxonomic comments are provided. There are eight species of Aspleniaceae in this region (Asplenium angustum Sw., A. auritum Sw., A. cruegeri Hieron., A. delitescens (Maxon) L.D. Gómez, A. juglandifolium Lam., A. salicifolium L., A. serratum L. and A. stuebelianum Hieron.). The majority of the species are epiphytes that grow on decaying trunks inside the forest. For this family, the registered species correspond to 35% of the species in the Brazilian Amazon, and 40% of species in Pará State.
Acesso aberto (Open Access)
Can Lutjanus purpureus (South red snapper) be "legally" considered a red snapper (Lutjanus campechanus)?
(2008) GOMES, Grazielle Fernanda Evangelista; SCHNEIDER, Horacio; SOUZA, Marcelo Nazareno Vallinoto de; SILVA, Simoni Santos da; ORTI, Guillermo; SAMPAIO, Maria Iracilda da Cunha
Red snappers (Lutjanus purpureus in Brazil and Lutjanus campechanus in USA and Gulf of Mexico) are both under clear effect of overfishing. Because of their high morphological similarity it has already been suggested that they could possibly be considered as a single species. To investigate the degree of similarity and the genetic structure of red snapper populations we constructed a common dataset of partial D-loop mtDNA sequences of L. purpureus from Brazil (Amapá, Pará and Maranhão) and L. campechanus from the Atlantic coast of the USA (Florida, Louisiana and Mississippi). Phylogenetic and population genetic analyses surprisingly depicted high similarity between L. campechanus and L. purpureus, compatible with the hypothesis of a single species of red snapper for the Western Atlantic Ocean. These preliminary but very curious findings open an important discussion regarding the legislation involved on the capture of this overexploited fish resources as well as regarding their taxonomy.
Acesso aberto (Open Access)
Características sedimentares fluviais associadas ao grau de preservação da mata Ciliar - Rio Urumajó, Nordeste Paraense
(Instituto Nacional de Pesquisas da Amazônia, 2009-03) BRITO, Roney Nonato Reis de; ASP NETO, Nils Edvin; BEASLEY, Colin Robert; SANTOS, Helane Súzia Silva dos
Rivers are the main ways of sediment transport from inland to the coastal zone and oceans. Despite direct influence of climate, the vegetation coverage plays a central role in liquid and solid fluvial discharge. In this context, the present work aimed to study the fluvial sedimentology of the Urumajó River (Pará, Brazil) in relation to the preservation state of riparian vegetation. Sediment samples were collected at five sites (A to E), including a five-sample transversal profile at each site. The sites were distributed from the source to the estuarine area. The characteristics and preservation state of the riparian vegetation were analyzed at each site as well. The collected sediments were submitted to grain size analysis, where mean grain size, median, asymmetry, selection and kurtosis were obtained. The results made it possible to recognize the regular characteristics (sites A and C), which included median sand as the main sediment class and well-sorted and approximate symmetric grain size distribution, directly related to the well-preserved riparian vegetation at sites A and C. On the other hand, sites B, D and E showed substantial differences in relation to the regular pattern. This fact could be associated to the vegetation degradation at those sites, resulting in margin erosion. Furthermore, at site E, reflexes of tide influence on the sediment characteristics could be observed, subsidizing the estuary delimitation.
Acesso aberto (Open Access)
Caracterização quali-quantitativa do fitoplâncton da zona de arrebentação de uma praia amazônica
(Sociedade Botânica do Brasil, 2012-12) QUEIROZ, Jislene Brito Matos; SILVA, Nayra Iris Sozinho da; PEREIRA, Luci Cajueiro Carneiro; COSTA, Rauquírio André Albuquerque Marinho da
The structure of the phytoplankton community of Princesa beach (Maiandeua island) was investigated during a nyctemeral cycle in the months of November/08, March/09, June/09 and September/09 to verify the effects of certain environmental variables on this community. The microphytoplankton of Princesa beach was represented by 98 taxa with the dominance of the diatoms, which were followed by the dinoflagellates and cyanophytes. The qualitative study revealed that Coscinodiscus perforatus Ehrenberg was abundant in March (45.6%) and June (45.1%), whereas in the quantitative analysis Dimeregramma minor (Gregory) Ralfs was dominant, mainly in November/08 (82.0%) and September/09 (83.0%). Biomass (chlorophyll-a content) was significantly higher in March/08 (U= 0.0; p <0.05). The average total phytoplankton density was significantly higher during the rainy period (F= 6.2; p< 0.05), mainly in June (1,223 ±110 x 103 cell L-1). K-dominance curves showed a gradual decrease in diversity along the dry period. Non-Metric Mul
Acesso aberto (Open Access)
Characterization of the acute inflammatory response in the hybrid tambacu (Piaractus mesopotamicus male × Colossoma macropomum female) (Osteichthyes)
(2009-08) MARTINS, Maurício Laterça; Myiazaki, DMY; DIAS, Marcos Tavares; FENERICK JÚNIOR, Jaime; ONAKA, Eduardo Makoto; BOZZO, Fabiana Rizzi; FUJIMOTO, Rodrigo Yudi; MORAES, Flávio Ruas de
This work evaluated the acute inflammatory response induced by injections of 0.5 mL saline solution (control), 500 µg carrageenin and 0.5 mL thioglycollate 3% in the swim bladder of juvenile tambacu hybrid. Fish were distributed in three treatments, three replications and acclimated for a period of 10 days before assay. The cell characterization from the inflammatory exudate was performed in Giemsa and PAS stained smears. Carrageenin, injected in fish, showed an increase on the total number of cells in the inflammatory exudate when compared to saline and thioglycollate injected. Whereas, for carrageenin-injected fish, the percentage of thrombocyte was higher than thioglycollate. On the other hand, granulocyte percentage in thioglycollate-injected fish was higher than the ones injected using carrageenin. Carrageenin provoked the highest migration of macrophage to the inflammatory site. The PAS method confirmed the presence of three types of granulocytes: eosinophilic granular cell (EGC) type 1 with the characteristics of a special granulocytic cell commonly found in the circulating blood; EGC type 2 shorter than the last one and neutrophil. This study contributes to a better understanding of the inflammatory response and infectious processes in native fish.
Acesso aberto (Open Access)
Chemometric identification and nutritional evaluation of three species of Lutjanidae (Perciformes) from the Amazonian Atlantic Coast based on fatty acid profiles
(Instituto Nacional de Pesquisas da Amazônia, 2016-12) ALMEIDA, Edilene Santos de; SILVA, Evaldo Martins da
The fatty acid (FA) profiles of fish species with a similar genetic or geographic origin are important quality parameters that attract bioecological interest because they are inﬂuenced by the nutritional habits of the species. The aim of this study was to determine the proximate compositions and FA profiles of heart, brain and muscle tissues from three fish species (Lutjanus purpureus, Lutjanus synagris and Ocyurus chrysurus) captured from the Amazonian Atlantic Coast. In addition to performing nutritional analysis of the FA profiles, principal components analysis (PCA) was performed as a chemometric tool to discriminate among the species. Lutjanus synagris had the highest protein content (18.23%), while O. chrysurus possessed the highest lipid content (4.25%). All of the nutritional quality parameters (the n-6/n-3 and Σ polyunsaturated FA/Σ saturated FA ratios and dietary indices of atherogenicity and thrombogenicity) of the FA profiles of the three species are of interest to consumers. In general, the predominant FA in the tissues of all species analyzed was palmitic acid, followed by stearic acid. Oleic acid was predominant among the monounsaturated FAs, while docosahexaenoic acid was the most prevalent polyunsaturated FA. Chemometric analysis was an effective tool for fish identification. PCA showed that the FA profiles of the brain tissues were optimal for discriminating among the species, with O. chrysurus showing the most different FA profile from the others. The muscle FA profile was the most useful for identifying L. purpureus.
Acesso aberto (Open Access)
Comparative morphology of the first zoea of twelve brachyuran species (Crustacea: Decapoda) from the Amazon region
(2013-06) SOUZA, Adelson Silva de; COSTA, Rauquírio André Albuquerque Marinho da; ABRUNHOSA, Fernando Araujo
The laboratory-hatched first zoeal stage of twelve brachyuran species collected in the estuarine area of the Caeté River in the Amazonian region are described and illustrated in the present study: P. americanus Saussure, 1857, Eurytium limosum (Say, 1818), Sesarma curacaoense De Man, 1892, S. rectum Randall, 1840, Armases rubripes (Rathbun, 1897), Aratus pisonii (H. Milne Edwards, 1837), Ocypode quadrata (Fabricius, 1787), Uca rapax (Smith, 1870), U. maracoani (Latreille, 1802), U. thayeri Rathbun, 1900, Ucides cordatus (Linnaeus, 1763) and Pachygrapsus gracilis (Saussure, 1858). Through intraspecific comparisons of the respective larval stage, an identification key was generated and provided. Most of the studied species presented morphological differences (e.g. type and presence or absence of setae) when compared to the same species previously described in the literature.
Acesso aberto (Open Access)
Composição corporal e eficiência de utilização de nutrientes por pacus alimentados com ração suplementada com cromo trivalente
(2007-12) FUJIMOTO, Rodrigo Yudi; CASTRO, Marcello Pardi de; HONORATO, Claucia Aparecida; MORAES, Flávio Ruas de
The objective of this work was to evaluate body composition as well as nutrient efficiency use by pacus fed on diet supplemented with chromium at two stocking densities. The experimental design was completely randomized with 24 treatments, in factorial scheme: four levels of chromium in the diet (0, 6, 12, and 18 mg kg-1), two stocking densities (4 and 20 kg m-3) and three periods (30, 60 and 90 days). Increases in efficiency of crude protein retention and in percentage of crude protein and decrease in efficiency of fat retention and smaller values of fat percentage in the carcass were observed. In the smallest density, the level of 6 mg kg-1 of chromium was enough to make possible the higher accumulation of protein and smaller fat concentration in the carcass. In the density of 20 kg m-3, the need of chromium was higher, 12 mg kg-1, to obtain similar results. Pacus fed on diet supplement with chromium present lean meat, with smaller fat concentration, until 60 days of experiment.
Acesso aberto (Open Access)
Controle alternativo de helmintos de Astyanax cf. zonatus utilizando fitoterapia com sementes de abóbora (Cucurbita maxima) e mamão (Carica papaya)
(2012-01) FUJIMOTO, Rodrigo Yudi; CORDEIRO, Helrik da Costa; RAMOS, Fabrício Menezes
The objective of this study was to evaluate the effectiveness of an alternative method with pumpkin and papaya seeds, dried and ground, for control of helminth parasites of Astyanax cf. zonatus. Sixty fish were distributed into twelve containers, with one fish/liter. The experiment consisted of four treatments and three replications: TJ = fish in fasting; TRC = fish fed with commercial diet; TSA = fish fed ad libitum with pumpkin seed, and TSM = fish fed ad libitum with papaya seeds. After seven days of feeding, all fish were weighed and blood was taken for blood smears. Efficacy was determined by checking the presence of parasites in the gills, stomach and intestine, in 40% of fishes per treatment (n=6). TJ and TSM showed 39% and 25% of weight loss respectively. The TSA showed better efficacy against the nematode in intestine and stomach (95.26% and 92.48%). The TSM promoted 72% of efficiency on monogeneans control. Hematology revealed an increase of monocyte values to treatment TSM. A decrease of eosinophil values was observed in treatments TSA, TSM and TRC. Thus, feeding fishes with pumpkin is a effective alternative method of low cost for control of nematodes in Astianax cf. zonatus.
Acesso aberto (Open Access)
Crescimento de mudas de mangue sob diferentes níveis de sombreamento na península de Ajuruteua, Bragança, Pará
(Instituto Nacional de Pesquisas da Amazônia, 2013-09) LOPES, Elaine Cristina; ARAÚJO, Erneida Coelho de; COSTA, Rejane Silva da; DAHER, Rogerio Figueiredo; FERNANDES, Marcus Emanuel Barroncas
The purpose of this study was to evaluate the influence of different levels of shading on the development of seedlings of three mangrove species (Avicennia germinans (L.) Stearn., Rhizophora mangle L. and Laguncularia racemosa (L.) Gaertn. f.). The experiment was conducted at the community of Tamatateua, Ajuruteua peninsula, Bragança, PA, Brazil. For seedling production, the propagules and seeds of the mangrove species were planted in polyethylene bags (17 x 27 cm), filled with a typical mangrove substrate. The seedlings of the three species were grown under full sun (0), 30% and 60% shading, in a completely randomized design, a 3 x 3 factorial (three species and three shading levels), with eight seedlings per replication. After nine months under shading, plant samples were taken. The variables evaluated were: the shoot/height ratio, stem diameter, shoot dry matter, stem mass, root dry matter, total dry mass matter and morphological indices. Growth of seedlings of R. mangle occurred at all light levels. Seedlings of A. germinans grew faster at full sun and at 30% shading. Whereas, seedlings of L. racemosa were able to grow at 30 and 60% shading, but they also grew faster at full sunlight.
Acesso aberto (Open Access)
Cyatheales (Polypodiopsida) do Corredor de Biodiversidade do Norte do Pará, Brasil
(2014-09) GÓES NETO, Luiz Armando de Araújo; PIETROBOM, Marcio Roberto
This paper is part of a series where the lycophyte and fern species of the Biodiversity Corridor ofnorthern Pará State are presented, produced under the project "Diagnóstico da Biodiversidade das Unidades de ConservaçãoEstaduais do Mosaico Calha Norte, Estado do Pará". In this manuscript the taxonomic treatment of Cyatheales is presented with identification keys, illustrations, distribution, descriptions, and comments to the studied taxa. Two families (Cyatheaceae and Metaxyaceae), three genera (Cnemidaria, Cyathea, and Metaxya), eight species, and one variety are registered. Cyathea is the most representative genus with seven species.
Acesso aberto (Open Access)
Cytogenetic and DNA barcoding reveals high divergence within the trahira, Hoplias malabaricus (Characiformes: Erythrinidae) from the lower Amazon River
(2013-06) MARQUES, Diego Ferreira; SANTOS, Fabíola Araújo dos; SILVA, Simoni Santos da; SAMPAIO, Maria Iracilda da Cunha; RODRIGUES, Luis Reginaldo Ribeiro
Molecular and cytogenetic data have provided evidence of cryptic speciation in the widespread South American trahira, Hoplias malabaricus. In the present study, karyotypes and DNA barcode sequences of specimens from seven populations inhabiting the lower Amazon River were analyzed in order to characterize the levels of genetic divergence within a single karyomorph. All the specimens presented karyotypes with 2n = 40 chromosomes (20m+20sm) that were consistent with the species' C karyomorph. The DNA barcodes revealed six haplogroups, with clear divergence between populations from Brazil and Argentina. The results support the species complex hypothesis and indicate that a single karyomorph of H. malabaricus may harbor more than one species.
Acesso aberto (Open Access)
Cytogenetic studies in six species of Scinax (Anura, Hylidae) clade Scinax ruber from northern and northeastern Brazil
(2015-06) SILVA, Lídia Nogueira; ZANONI, Juliani Bruna; SOLÉ, Mirco; AFFONSO, Paulo Roberto Antunes de Mello; SIQUEIRA, Sérgio; SAMPAIO, Maria Iracilda da Cunha
Scinax species are still underrepresented in cytogenetic studies, mainly with respect to populations from northeastern and northern Brazil. In this study, we provide new chromosomal information on Scinax boesemani, S. camposseabrai, S. garbei, S. pachycrus, S. trilineatus and S. x-signatus, all belonging to clade S. ruber. They were collected at two locations in the Caatinga biome (northeastern Brazil) and at one in the Amazon (northern Brazil) biomes. Chromosomes were analyzed by conventional staining, C-banding, Ag-NOR staining, and fluorochrome staining. All species shared a modal diploid value of 2n = 24 and fundamental arm number (FN) of 48. Moreover, both chromosomal size and morphology were similar to other species in this Scinax clade. C-banding revealed centromeric heterochromatin in all species, along with terminal species-specific C-bands in some species. Active nucleolar organizer regions (Ag-NORs) were identified at 11q in most species, except for S. boesemani and S. garbei (Ag-NORs at interstitial region of 8q). Differing from most anurans, GC-rich regions were not restricted to NORs, but also coincident with some centromeric and terminal C-bands. These data contribute to the cytotaxonomy of Scinax by providing chromosomal markers and demonstrating the occurrence of microstructural rearrangements and inversions on chromosomal evolution of Scinax.
Acesso aberto (Open Access)
Dactylogyrids (Platyhelminthes: Monogenoidea) from the gills of Hassar gabiru and Hassar orestis (Siluriformes: Doradidae) from the Xingu Basin, Brazil
(Universidade Federal do Pará, 2018-07) SOARES, Geusivam Barbosa; SANTOS NETO, João Flor dos; DOMINGUES, Marcus Vinicius
Four species of Cosmetocleithrum (three new) and one new species of Vancleaveus are described or reported parasitizing the gills of doradid catfishes (Siluriformes) from Xingu River and related tributaries: Cosmetocleithrum phryctophallus sp. nov. and Cosmetocleithrum bifurcum Mendoza-Franco, Mendoza-Palmero & Scholz, 2016 from Hassar orestis; Cosmetocleithrum leandroi sp. nov. from Hassar gabiru; Cosmetocleithrum akuanduba sp. nov. and Vancleaveus klasseni sp. nov. from Hassar orestis and H. gabiru. Cosmetocleithrum phryctophallus sp. nov. differs from its congeners by possessing a male copulatory organ (MCO) with 2 ½ counterclockwise rings, and an accessory piece with an elongate torch-shaped blade. Cosmetocleithrum leandroi sp. nov. has a MCO comprising a coil of about 3 ½ rings, a sigmoid accessory piece with a cup-shaped distal portion, a single type of hooks, and anchors with poorly differentiated roots. Cosmetocleithrum akuanduba sp. nov. is characterized mainly by having a J-shaped MCO, an elongate accessory piece with sharp distal region, distal portion with a small gutter, and a heavily sclerotized vagina with short “S”-shaped vaginal canal. Vancleaveus klasseni sp. nov. differs from the other species of the genus occurring in doradids by possessing anchors with triangular to subtriangular superficial root, developed deep root, and a coiled MCO with 2 ½ counterclockwise rings. Cosmetocleithrum bifurcum was reported for the first time parasitizing doradids from Brazilian Amazon.
Acesso aberto (Open Access)
Development and functional morphology of the foreguts of larvae and postlarvae of three crustacean decapods
(2008-02) ABRUNHOSA, Fernando Araujo; MELO, Marlon Aguiar
The development of the foregut structure and the digestive function of the decapods Litopenaeus vannamei, Sesarma rectum and Callichirus major larvae and post larvae were examined. The protozoeal foregut of L. vannamei is simple, lacking a cardiopyloric valve and bearing a rudimentary filter press. In mysis, the filter press is more developed. In the juvenile stage, grooves and a small lateral tooth arise. In S. rectum, the foregut has a functional cardiopyloric valve and a filter press. The megalopal and juvenile stages of this species have a gastric mill similar to those in adult crabs. In C. major, the foregut of the zoeae is specialized, with the appearance of some rigid structures, but no gastric mill was found. Calcified structures are observed in the megalopae and they become more developed in the juvenile stage. The results support suppositions, previously reported in other studies, that feeding behavior of each larval and postlarval stage is directly related to the morphological characteristics of the foreguts.
Acesso aberto (Open Access)
Development and functional morphology of the larval foregut of two brachyuran species from Northern Brazil
(2011-12) ABRUNHOSA, Fernando Araujo; SIMITH, Darlan de Jesus de Brito; MONTEIRO, Joely Raquel Costa; SOUZA JUNIOR, Antonio Nivaldo de; OLIVA, Pedro Andrés Chira
Feeding is an important factor for the successful rearing of larvae of the crab species. Further information on the morphological features of the foregut may to reveal larval feeding behaviour and or/whether there is a lecithotrophy in some or even in all stages of the larval cycle. In the present study, the structural development of the foregut and their digestive functions were examined in larvae of two brachyurans, Uca vocator and Panopeus occidentalis, reared in the laboratory. During larval development, the foreguts of the larvae in the first and last zoeal stages and in the megalopa stage were microscopically examined, described and illustrated. The zoeal foreguts of both species were well developed, showing specialization with a functional cardiopyloric valve and a filter press. The megalopa stage had a complex and specialized gastric mill similar to that found in adult crabs with the appearance of rigidly calcified structures. These results support the hypothesis that the feeding behaviour of each larval stage is directly related to the morphological structure of the foregut. Such facts strongly indicate that all larval stages of both . vocator and P occidentalis need an external food source before completing the larval development in a planktonic environment.