Gnathostomatidae nematode parasite of Colomesus psittacus (Osteichthyes, Tetraodontiformes) in the Ilha de Marajó, Brazilian Amazon / Nematoide Gnathostomatidae parasito de Colomesus psittacus (Osteichthyes, Tetraodontiformes) na Ilha de Marajó, Amazônia Brasileira

The genus Gnathostoma comprises 17 species, whose adult specimens are found in the stomach serosa of animals that consume raw fish; some species of the genus are zoonotic agents. The present study describes the presence of a nematode (Gnathostomatidae) parasitizing the digestive tract of Colomesus psittacus in the Ilha de Marajó in the eastern Brazilian Amazon. Thirty specimens of C. psittacus were collected in the municipality of Soure, Ilha de Marajó, state of Pará, Brazil, transported to the laboratory, necropsied and the helminths were collected and fixed. Of the 30 fish that were studied, 16.67% were parasitized with nematodes. The nematode larvae found encysted in the intestinal serosa have anterior region with two lips, each with a pair of papillae; a cephalic bulb armed with six rows of discontinuous spines; four cervical sacs; a claviform esophagus; cuticular striations along the body; a simple excretory pore; and a short tail ending in a mucron. These morphological structures are diagnostic characters of the genus Gnathostoma, whose adults parasitize the stomach of carnivorous mammals and, rarely, the stomach of fish. However, fish, amphibians, reptiles, and birds are intermediate hosts of the third-stage larvae (L3), and humans may act as accidental hosts.(AU)

O gênero Gnasthostoma é composto por 17 espécies, sendo reportado o caráter zoonótico para algumas. Este trabalho descreve a presença de nematoide da família Gnathostomatidae, parasito do trato digestório de Colomesus psittacus, na Ilha de Marajó, Amazônia oriental brasileira, transportados para o laboratório, necropsiados os helmintos colhidos e fixados. Dos 30 animais analisadas 16,67% estavam parasitados por nematoides. As larvas de nematoides foram encontradas encistadas na serosa intestinal, apresentam na região anterior dois lábios com duas papilas cada, bulbo cefálico armado de 6 fileiras de espinhos descontínuos, quatro sacos cervicais, esôfago claviforme, estrias cuticulares ao longo do corpo, abertura anal simples, cauda curta, terminando em um mucron. A junção de todos esses caracteres morfológicos, são características diagnósticas para gênero Gnathostoma. Os indivíduos adultos são parasitos de estômago de mamíferos carnívoros e raramente de peixes, porém peixes, anfíbios, répteis e aves atuam como hospedeiros intermediários das larvas (L3) e o homem pode atuar como hospedeiro acidental.(AU)

Pathology and morphometry of Hystrichis acanthocephalicus (Nematoda) from Phimosus infuscatus (Pelecaniformes) in southern Brazil / Patologia e morfometria de Hystrichis acanthocephalicus (Nematoda) em Phimosus infuscatus (Pelecaniformes) no Sul do Brasil

Species of Hystrichis are parasite nematodes of the digestive tract of aquatic birds in South America, Europe and Asia. In Brazil, Hystrichis acanthocephalicus has been reported in Phimosus infuscatus. There are few data on the morphometry of this species and there are no reports on pathological conditions that it causes. Therefore, the purpose of this study was to report morphometric data from H. acanthocephalicus and describe the pathological effects of this parasite on the Phimosus infuscatus proventriculus. Thirty gastrointestinal tracts of P. infuscatus were examined to search for nematodes and H. acanthocephalicus occurred in 83% of hosts. Were measured the total length and body width of males and females, and of their respective cuticular spines, esophagus, spicules and eggs, and the internal and external diameter of copulatory bursa. Histopathological examination revealed parasitic structures in the proventriculus from the lumen (anterior end) to the outer layers of the organ (intermediate and posterior parts), in which we observed inflammatory reaction with infiltration of heterophils, hemorrhage and hemosiderin. The results of this study of histopathology, morphometry and parasitological indices are the first ones reported to H. acanthocephalicus and should contribute to the identification and recognition in cases of outbreaks in the Neotropical region.(AU)

Espécie de Hystrichis são nematoides parasitos do trato digestório de aves aquáticas, na América do Sul, Europa e Ásia. No Brasil, foi registrado Hystrichis acanthocephalicus, em Phimosus infuscatus. Existem poucos dados sobre a morfometria e não há registros relativos à patologia desta espécie. Portanto, o objetivo deste estudo foi relatar dados morfométricos de H. acanthocephalicus e descrever os efeitos patológicos deste parasito no proventrículo de Phimosus infuscatus. Foram examinados trinta tratos gastrintestinais de P. infuscatus para a pesquisa de nematoides e H. acanthocephalicus ocorreu em 83% dos hospedeiros. Mediu-se o comprimento total e largura do corpo de machos e fêmeas, dos espinhos cuticulares, do esôfago, dos espículos, dos ovos, respectivamente, e a largura interna e externa da bolsa copuladora. Nos exames histopatológicos foram encontradas estruturas parasitárias no proventrículo, desde o lúmen (porção anterior) até as camadas mais externas do órgão (porções intermediária e posterior), nas quais se observou reação inflamatória com infiltrado de heterófilos, presença de hemorragia e deposição de hemossiderina. Os resultados desse estudo sobre histopatologia, morfometria e índices parasitológicos são os primeiros relatados para H. acanthocephalicus e deverão contribuir para a identificação e reconhecimento em casos de surtos na região Neotropical.(AU)

Wettability and morphology of the leaf surface in cashew tree from the Amazon, Northern Brazil / Molhabilidade e morfologia da superfície da folha em cajueiro da Amazônia na Região Norte do Brasil

Leaves surfaces, which represent an interface with plants and the environment, have several structures with specific functions. Some foliar properties, including wettability and mechanical containment, are inferred in terms of cellular adaptation and the presence or absence of cuticular wax. Various morphological parameters, ranging from macro- to nano scales, are analyzed and contribute to the study of taxonomy, pharmacognosy, and ecology of plants. The aim of this paper was to analyze the effect and influence of epicuticular wax granules on the hydrophobicity of Anacardium occidentale L. leaf surfaces. Leaf specimens were directly examined with an environmental scanning electron microscope without metal coating. Images revealed epidermis ornament, stomata type, was, and trichomes. Static contact angle between water and the surface was also measured on both sides. On the adaxial side, an angle of 104.09° ± 0.95° was found, suggesting that adaxial surface is hydrophobic. On the abaxial side, the angle was 62.20° ± 1.60°, which indicates a hydrophilic nature, probably because of the greater amount of epicuticular wax on the adaxial leaf surface. The present investigation provided an important contribution to morphological and ultrastructural characterization of leaves of cashew tree, which is a plant of great medicinal and economic importance.(AU)

Superfícies de folhas têm diversas estruturas com funções específicas e contribuem para a relação delas com o meio ambiente. Algumas propriedades foliares, incluindo molhabilidade e contenção mecânica, são inferidas em termos de adaptação celular e da presença ou ausência de cera cuticular. Diversos parâmetros morfológicos, variando da macroescala até a nanoescala, são analisados e contribuem para o estudo de taxonomia, farmacognosia e ecologia de plantas. O objetivo deste trabalho foi analisar o efeito e a influência de grãos de cera epicuticular na hidrofobicidade da superfície de folhas de Anacardium occidentale L. Amostras de folha foram examinadas com um microscópio eletrônico de varredura ambiental sem recobrimento metálico. As imagens evidenciaram algumas características (epiderme, tipo de estômato, cera e tricomas). O ângulo de contato estático entre a água e a superfície também foi medido em ambos os lados. No lado adaxial, foi encontrado um ângulo de 104,09° ± 0,95°, sugerindo que esta é hidrofóbica. No lado abaxial, o ângulo foi de 62,20° ± 1,60°, que indica uma natureza hidrofílica, provavelmente devido à grande quantidade de cera epicuticular na superfície abaxial da folha. A presente investigação forneceu uma contribuição importante para a caracterização morfológica e ultra-estrutural de folhas de cajueiro, que é uma planta de grande importância econômica.(AU)

ATIVIDADE ANTI-HELMÍNTICA IN VITRO DE NANOEMULSÕES DE CARVONA SOBRE Haemonchus contortus

A resistência anti-helmíntica tem dificultado o controle de nematoides gastrintestinais em pequenos ruminantes. Dessa forma, novas alternativas de controle estão sendo estudadas, como o nanoencapsulamento de compostos bioativos, na tentativa de maximizar a eficácia parasitária desses compostos. Este trabalho teve como objetivo avaliar a atividade ovicida, larvicida e adulticida de nanoemulsões de carvona produzida por diferentes métodos de homogeneização sobre Haemonchus contortus. Três nanoemulsões de R-carvona foram preparadas usando dois equipamentos de homogeneização (ultra homogeneizador e sonicador) e com e sem revestimento de alginato de sódio: nanoemulsões de R-carvona sem revestimento homogeneizada em sonicador (NSR-son) e homogeneizadas em ultra homogeneizador (NSR- ultra) e R-carvona com revestimento de alginato de sódio (NCR-ultra). Foi realizada a análise de estabilidade, eficiência de encapsulamento e caracterizações físico-químicas das nanoemulsões. Os efeitos das nanoemulsões foi avaliado sobre H. contortus multirresistente no teste de eclosão de ovos (TEO), teste de desenvolvimento larvar (TDL) e teste de motilidade em adultos (TMA). As alterações na cutícula induzidas em H. contortus adultos foram avaliadas por meio da microscopia eletrônica de varredura (MEV) e microscopia confocal de varredura a laser. Os resultados foram submetidos à análise de variância (ANOVA) e comparados pelo teste Tukey (P<0,05). A concentração efetiva para inibir 50% da eclosão dos ovos e do desenvolvimento larvar (CE50) foi calculada no programa SPSS 17.0. NSR-ultra e NCR-ultra, foram mais estáveis frente à sedimentação e cremeação, respectivamente. Os tamanhos de partículas foram de 281,1 nm (NSR-son), 152,7 nm (NSR-ultra) e 557,8 nm (NCR-ultra) e os potenciais zeta de -15 mV (NSR-son), -10,8 mV (NSR-ultra) e -24,2 mV (NCR-ultra). A eficiência de encapsulamento foi de 99,84±0,01%. A microscopia eletrônica de varredura nas nanoemulsões detectou aumento no tamanho, distribuição não uniforme das partículas e presença de estruturas esféricas agregadas a rede polimérica. No TEO, as CE50 de NSR-son, NSR-ultra e NCR-ultra foram de 0,19 mg/mL, 0,02 mg/mL e 0,17 mg/mL, respectivamente. No TDL foram de 0,29 mg/mL, 0,31 mg/mL e 0,95 mg/mL para NSR-son, NSR-ultra e NCR- ultra, respectivamente. A inibição da motilidade de adultos foi de 100%, após 12h de exposição a NSR-ultra e NCR-ultra, enquanto que para NSR-son foi de 79,16%. A microscopia confocal e de varredura detectaram alterações na cápsula bucal e danos cuticulares. Conclui-se que as nanoemulsões de R-carvona com e sem revestimento de alginato de sódio produzidas por diferentes métodos de homogeneização causaram alterações morfológicas e inibiram a eclosão dos ovos, o desenvolvimento larvar e a motilidade de H. contortus adulto, sendo promissoras para controle de infecções por nematoides gastrintestinais em pequenos ruminantes após avaliações futuras no que se refere à segurança toxicológica desses produtos assim como a comprovação da eficácia anti-helmíntica in vivo.

Anthelmintic resistance has made it difficult to control gastrointestinal nematodes in small ruminants. Thus, new control alternatives are being studied, such as the nanoencapsulation of bioactive compounds, in an attempt to maximize the parasitic efficacy of these compounds. This work aimed to evaluate the ovicidal, larvicidal and adulticidal activity of carvone nanoemulsions produced by different homogenization methods on Haemonchus contortus. Three R-carvone nanoemulsions were prepared using two homogenization equipment (ultra homogenizer and sonicator) and with and without sodium alginate coating: uncoated R-carvone nanoemulsions homogenized in sonicator (UNAlg-son) and homogenized in ultra homogenizer (UNAlg-ultra) and sodium alginate coated R-carvone (CNAlg-ultra). Stability analysis, encapsulation efficiency and physicochemical characterizations of the nanoemulsions were performed. The of the nanoemulsions were evaluated on multidrug resistant H. contortus in the egg hatch test (EHT), larval development test (LDT) and adult worm motility test (AWMT). Changes in cuticle induced in adult H. contortus were evaluated by means of scanning electron microscopy (SEM) and confocal laser scanning microscopy. The results were submitted to analysis of variance (ANOVA) and compared using the Tukey test (P<0.05). The effective concentration to inhibit 50% of egg hatching and larval development (EC50) was calculated using the SPSS 17.0 program. UNAlg-ultra and CNAlg-ultra were more stable against sedimentation and creamation, respectively. The particle sizes were 281.1 nm (UNAlg-son), 152.7 nm (UNAlg-ultra) and 557.8 nm (CNAlg-ultra) and the zeta potentials were -15 mV (UNAlg-son), - 10.8 mV (NSR-ultra) and -24.2 mV (CNAlg-ultra). The encapsulation efficiency was 99.84±0.01%. Scanning electron microscopy of the nanoemulsions detected an increase in size, non-uniform distribution of particles and presence of spherical structures aggregated to the polymeric network. In EHT, the EC50 of UNAlg-son, UNAlg-ultra and CNAlg-ultra were 0.19 mg/mL, 0.02 mg/mL and 0.17 mg/mL, respectively. In LDT they were 0.29 mg/mL, 0.31 mg/mL and 0.95 mg/mL for UNAlg- son, UNAlg-ultra and CNAlg-ultra, respectively. The adult motility inhibition was 100% after 12h of exposure to UNAlg-ultra and CNAlg-ultra, while for UNAlg-son it was 79.16%. Confocal and scanning microscopy detected changes in the buccal capsule and cuticular damage. It is concluded that R-carvone nanoemulsions with and without sodium alginate coating produced by different homogenization methods caused morphological changes and inhibited egg hatching, larval development and adult motility of H. contortus, being promising for control of infections by gastrointestinal nematodes in small ruminants after further evaluations regarding the toxicological safety of these products as well as proof of anthelmintic efficacy in vivo.

Oxitetraciclina para marcação química de juvenis de piava Leporinus obtusidens: determinação de doses e duração do tratamento / Oxytetracycline for chemical marking of piava juveniles Leporinus obtusidens: determining concentration and time of treatment

The aim of this study was to define the concentrations and immersion periods for the chemical marking of piava juveniles Leporinus obtusidens, using oxytetracycline (OTC). Twenty piava juveniles were used per treatment and submitted to six concentrations of OTC (50, 100, 150, 300, 500, 800 mg OTC L-1) and three immersion periods (6, 12, 24 h), and one treatment as control. Scales of three fishes per treatment were evaluated under a confocal microscope with UV light. The mean values of temperature, pH and dissolved oxygen were kept at 27.4ºC, 7.2, and 7.4 mg L-1, respectively. No mortality was observed in the treatments. The presence of a chemical mark was only observed from the treatment 100 mg L-1 24 h-1, however it was of low intensity and discontinuous. Treatments with immersion periods of 12 and 24 h produced visible marks in 300 mg L-1, and clear bright and continuous marks in 500 mg L-1. Treatments of 800 mg L-1, for all immersion periods, produced clear bright and continuous marks.(AU)

O objetivo deste estudo foi definir concentrações e tempos de imersão para a marcação química de juvenis de Leporinus obtusidens, utilizando oxitetraciclina (OTC). Foram utilizados 20 juvenis por tratamento submetidos a banhos com seis concentrações de OTC (50, 100, 150, 300, 500, 800 mg L-1) e três tempos de imersão (6, 12, 24 h), mais um tratamento controle. Foram avaliadas escamas de três indivíduos por tratamento em microscópio confocal com luz UV. Os valores médios de temperatura, pH e OD se mantiveram em 27,4C; 7,2 e 7,4 mg L-1, respectivamente. Em nenhum dos tratamentos foi observada mortalidade. A presença da marca só foi observada a partir do tratamento 100 mg L-1 24 h-1, sendo de fraca intensidade. Os tratamentos com 12 e 24 h produziram marcas visíveis para 300 mg L-1 e fortemente visíveis e contínuas para 500 mg L-1. Nos tratamentos com 800 mg L-1, todos os tempos de exposição produziram marcas fortemente visíveis e contínuas.(AU)

Oxitetraciclina para marcação química de juvenis de piava Leporinus obtusidens: determinação de doses e duração do tratamento / Oxytetracycline for chemical marking of piava juveniles Leporinus obtusidens: determining concentration and time of treatment

The aim of this study was to define the concentrations and immersion periods for the chemical marking of piava juveniles Leporinus obtusidens, using oxytetracycline (OTC). Twenty piava juveniles were used per treatment and submitted to six concentrations of OTC (50, 100, 150, 300, 500, 800 mg OTC L-1) and three immersion periods (6, 12, 24 h), and one treatment as control. Scales of three fishes per treatment were evaluated under a confocal microscope with UV light. The mean values of temperature, pH and dissolved oxygen were kept at 27.4ºC, 7.2, and 7.4 mg L-1, respectively. No mortality was observed in the treatments. The presence of a chemical mark was only observed from the treatment 100 mg L-1 24 h-1, however it was of low intensity and discontinuous. Treatments with immersion periods of 12 and 24 h produced visible marks in 300 mg L-1, and clear bright and continuous marks in 500 mg L-1. Treatments of 800 mg L-1, for all immersion periods, produced clear bright and continuous marks.

O objetivo deste estudo foi definir concentrações e tempos de imersão para a marcação química de juvenis de Leporinus obtusidens, utilizando oxitetraciclina (OTC). Foram utilizados 20 juvenis por tratamento submetidos a banhos com seis concentrações de OTC (50, 100, 150, 300, 500, 800 mg L-1) e três tempos de imersão (6, 12, 24 h), mais um tratamento controle. Foram avaliadas escamas de três indivíduos por tratamento em microscópio confocal com luz UV. Os valores médios de temperatura, pH e OD se mantiveram em 27,4C; 7,2 e 7,4 mg L-1, respectivamente. Em nenhum dos tratamentos foi observada mortalidade. A presença da marca só foi observada a partir do tratamento 100 mg L-1 24 h-1, sendo de fraca intensidade. Os tratamentos com 12 e 24 h produziram marcas visíveis para 300 mg L-1 e fortemente visíveis e contínuas para 500 mg L-1. Nos tratamentos com 800 mg L-1, todos os tempos de exposição produziram marcas fortemente visíveis e contínuas.

Distribution and structural aspects of extrafloral nectaries in leaves of Pyrostegia venusta (Bignoniaceae) / Distribuição e aspectos estruturais de nectários extraflorais em folhas de Pyrostegia venusta (Bignoniaceae)

Pyrostegia venusta (the orange trumpet or commoly called cipَ-de-Sمo-Joمo in Brazil), a medicinal plant that grows with other plants, has an ecological importance due to the presence of nectaries on the leaves. The aim of this work was to study structural and histochemical aspects and the distribution of extrafloral nectaries (ENFs) in P. venusta leaves. Young leaves were collected, fixed and processed by usual techniques, and studied under light microscopy and scanning electron microscopy. Analyses showed that the extrafloral nectaries are dispersed throughout the leaf, with concentrations mainly in the basal third section. Nectaries lie in epidermal depressions and can be found in abaxial and adaxial leaf blades. Their morphology may be characterized macroscopically by achlorophyllous halos and microscopically as structures consisting of a short pedicel, oval multicellular head, covered by a thin cuticular layer with a secretory pole. Reducing sugars, neutral polysaccharides, proteins, starch and phenolic compounds were detected in extrafloral nectaries.(AU)

. Pyrostegia venusta (cipَ-de-Sمo-Joمo) é uma planta medicinal que cresce junto a outras plantas e que apresenta também importância ecolَgica, pela presença de nectلrios na regiمo dos folيolos. O objetivo deste trabalho foi estudar aspectos estruturais, histoquيmicos e da distribuiçمo de nectلrios extraflorais (NEFs) em folhas de P. venusta. Folhas jovens foram coletadas, fixadas e processadas por técnicas usuais e estudadas sob microscopia de luz e eletrônica de varredura. As anلlises mostraram que os NEFs estمo dispersos por toda a folha, concentrando-se preferencialmente no terço basal. Os nectلrios estمo localizados em depressُes epidérmicas e podem ser encontrados nas faces abaxial e adaxial da lâmina foliar. Macroscopicamente, os NEFs podem ser caracterizados como halos aclorofilados e microscopicamente, como estruturas com pedicelo curto, cabeça ovoide pluricelular, recobertos por uma fina camada cuticular e um polo secretor. Nos nectلrios extraflorais foram detectados açْcares redutores, polissacarيdeos neutros, proteيnas, amido e compostos fenَlicos.(AU)

Diversity and arrangement of the cuticular structures of Hyalella (Crustacea: Amphipoda: Dogielinotidae) and their use in taxonomy

This study describes the morphology and arrangement of the cuticular structures of Hyalella castroi González, Bond-Buckup & Araujo, 2006 and Hyalella pleoacuta González, Bond-Buckup & Araujo, 2006, to identify specific characters that can be used in taxonomstudies of this genus. The entire cuticular surface of both species was examined by optical and scanning electron microscopy. The data obtained were compared with available information for other members of Peracarida, mainly Amphipoda and Isopoda. Five different types of cuticular structures, including 30 types of setae, four types of microtrichs, three types of pores, and some structures formed by setules and denticles were identified. The results were compared with other groups of gammarids, and peracarideans, such as Thermosbaenacea and Isopoda. The use of cuticular structures as a tool for taxonomic studies showed important results, not only at species level, but also at genus, and family levels.

Diversity and arrangement of the cuticular structures of Hyalella (Crustacea: Amphipoda: Dogielinotidae) and their use in taxonomy

This study describes the morphology and arrangement of the cuticular structures of Hyalella castroi González, Bond-Buckup & Araujo, 2006 and Hyalella pleoacuta González, Bond-Buckup & Araujo, 2006, to identify specific characters that can be used in taxonomstudies of this genus. The entire cuticular surface of both species was examined by optical and scanning electron microscopy. The data obtained were compared with available information for other members of Peracarida, mainly Amphipoda and Isopoda. Five different types of cuticular structures, including 30 types of setae, four types of microtrichs, three types of pores, and some structures formed by setules and denticles were identified. The results were compared with other groups of gammarids, and peracarideans, such as Thermosbaenacea and Isopoda. The use of cuticular structures as a tool for taxonomic studies showed important results, not only at species level, but also at genus, and family levels.

Diversity and arrangement of the cuticular structures of Hyalella (Crustacea: Amphipoda: Dogielinotidae) and their use in taxonomy

This study describes the morphology and arrangement of the cuticular structures of Hyalella castroi González, Bond-Buckup & Araujo, 2006 and Hyalella pleoacuta González, Bond-Buckup & Araujo, 2006, to identify specific characters that can be used in taxonomstudies of this genus. The entire cuticular surface of both species was examined by optical and scanning electron microscopy. The data obtained were compared with available information for other members of Peracarida, mainly Amphipoda and Isopoda. Five different types of cuticular structures, including 30 types of setae, four types of microtrichs, three types of pores, and some structures formed by setules and denticles were identified. The results were compared with other groups of gammarids, and peracarideans, such as Thermosbaenacea and Isopoda. The use of cuticular structures as a tool for taxonomic studies showed important results, not only at species level, but also at genus, and family levels.

Post-marsupial development of Hyalella pleoacuta (Crustacea: Amphipoda): stages 1-4

The goal of this study is to describe and compare the initial stages of the post-marsupial development of Hyalella pleoacuta González, Bond-Buckup & Araujo, 2006, prior to the development of sexual dimorphism. Ovigerous females were collected in São José dos Ausentes, RS, Brazil and kept in laboratory. Juveniles were kept separately after emerging from the marsupium and were monitored daily for the presence of exuvia. Individuals from post-marsupial stages (S) 1 to 4 were dissected and illustrated. Cuticular structures were observed through SEM. Twenty three types of setae, one type of setule, two types of pores, two types of denticles and one type of penicilium were found. Cuticular structures undergo modification through development in the matters of haste size, number and size of setules, and formation of the polygonal pattern, although there is no change from one type to another. Gnathopods and antennae are the appendages that go through more modifications. The articles number of the flagellum is constant until S2. The size of the coxal plate of gnathopods in relation to the propodus has a tendency to increase throughout the stages. The uropod proportion becomes smaller in S3 when compared to S1. The number of serrate setae in the external plate of maxilla 1 varies up to S4, being different from the adult whose number is 9. The telson modifies its shape but its setae number is constant.

Post-marsupial development of Hyalella pleoacuta (Crustacea: Amphipoda): stages 1-4

The goal of this study is to describe and compare the initial stages of the post-marsupial development of Hyalella pleoacuta González, Bond-Buckup & Araujo, 2006, prior to the development of sexual dimorphism. Ovigerous females were collected in São José dos Ausentes, RS, Brazil and kept in laboratory. Juveniles were kept separately after emerging from the marsupium and were monitored daily for the presence of exuvia. Individuals from post-marsupial stages (S) 1 to 4 were dissected and illustrated. Cuticular structures were observed through SEM. Twenty three types of setae, one type of setule, two types of pores, two types of denticles and one type of penicilium were found. Cuticular structures undergo modification through development in the matters of haste size, number and size of setules, and formation of the polygonal pattern, although there is no change from one type to another. Gnathopods and antennae are the appendages that go through more modifications. The articles number of the flagellum is constant until S2. The size of the coxal plate of gnathopods in relation to the propodus has a tendency to increase throughout the stages. The uropod proportion becomes smaller in S3 when compared to S1. The number of serrate setae in the external plate of maxilla 1 varies up to S4, being different from the adult whose number is 9. The telson modifies its shape but its setae number is constant.

Post-marsupial development of Hyalella pleoacuta (Crustacea: Amphipoda): stages 1-4

The goal of this study is to describe and compare the initial stages of the post-marsupial development of Hyalella pleoacuta González, Bond-Buckup & Araujo, 2006, prior to the development of sexual dimorphism. Ovigerous females were collected in São José dos Ausentes, RS, Brazil and kept in laboratory. Juveniles were kept separately after emerging from the marsupium and were monitored daily for the presence of exuvia. Individuals from post-marsupial stages (S) 1 to 4 were dissected and illustrated. Cuticular structures were observed through SEM. Twenty three types of setae, one type of setule, two types of pores, two types of denticles and one type of penicilium were found. Cuticular structures undergo modification through development in the matters of haste size, number and size of setules, and formation of the polygonal pattern, although there is no change from one type to another. Gnathopods and antennae are the appendages that go through more modifications. The articles number of the flagellum is constant until S2. The size of the coxal plate of gnathopods in relation to the propodus has a tendency to increase throughout the stages. The uropod proportion becomes smaller in S3 when compared to S1. The number of serrate setae in the external plate of maxilla 1 varies up to S4, being different from the adult whose number is 9. The telson modifies its shape but its setae number is constant.

Post-marsupial development of Hyalella pleoacuta (Crustacea: Amphipoda): stages 1-4

The goal of this study is to describe and compare the initial stages of the post-marsupial development of Hyalella pleoacuta González, Bond-Buckup & Araujo, 2006, prior to the development of sexual dimorphism. Ovigerous females were collected in São José dos Ausentes, RS, Brazil and kept in laboratory. Juveniles were kept separately after emerging from the marsupium and were monitored daily for the presence of exuvia. Individuals from post-marsupial stages (S) 1 to 4 were dissected and illustrated. Cuticular structures were observed through SEM. Twenty three types of setae, one type of setule, two types of pores, two types of denticles and one type of penicilium were found. Cuticular structures undergo modification through development in the matters of haste size, number and size of setules, and formation of the polygonal pattern, although there is no change from one type to another. Gnathopods and antennae are the appendages that go through more modifications. The articles number of the flagellum is constant until S2. The size of the coxal plate of gnathopods in relation to the propodus has a tendency to increase throughout the stages. The uropod proportion becomes smaller in S3 when compared to S1. The number of serrate setae in the external plate of maxilla 1 varies up to S4, being different from the adult whose number is 9. The telson modifies its shape but its setae number is constant.

Post-marsupial development of Hyalella pleoacuta (Crustacea: Amphipoda): stages 1-4

The goal of this study is to describe and compare the initial stages of the post-marsupial development of Hyalella pleoacuta González, Bond-Buckup & Araujo, 2006, prior to the development of sexual dimorphism. Ovigerous females were collected in São José dos Ausentes, RS, Brazil and kept in laboratory. Juveniles were kept separately after emerging from the marsupium and were monitored daily for the presence of exuvia. Individuals from post-marsupial stages (S) 1 to 4 were dissected and illustrated. Cuticular structures were observed through SEM. Twenty three types of setae, one type of setule, two types of pores, two types of denticles and one type of penicilium were found. Cuticular structures undergo modification through development in the matters of haste size, number and size of setules, and formation of the polygonal pattern, although there is no change from one type to another. Gnathopods and antennae are the appendages that go through more modifications. The articles number of the flagellum is constant until S2. The size of the coxal plate of gnathopods in relation to the propodus has a tendency to increase throughout the stages. The uropod proportion becomes smaller in S3 when compared to S1. The number of serrate setae in the external plate of maxilla 1 varies up to S4, being different from the adult whose number is 9. The telson modifies its shape but its setae number is constant.