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The hepatopancreas is the digestive organ of crustaceans, and plays important roles also in the synthesis and secretion of sexual hormones, immunological defenses and xenobiotic detoxification. Although the importance of this organ in crustaceans cannot be underestimated, the effects of ultraviolet B (UVB) radiation on hepatopancreas are poorly understood. Moreover, Macrobrachium prawns, have a transparent carapace, which make them more susceptible to UVB radiation, since their internal organs, such as hepatopancreas, are easily reached by solar radiation. Therefore, we aimed to evaluate UVB radiation toxicity on the morphology and morphometry of hepatopancreatic epithelial cells, and to investigate these UVB effects in subcellular compartments of the ecologically-important freshwater decapod, Macrobrachium olfersii. Hepatopancreas from the UVB-irradiated group showed a granular cytoplasm, with non-defined cell limits. Morphometric analyses revealed that the UVB-irradiated group exhibited a higher frequency of fibrillar (F-cell), resorptive (R-cell) and midget (M-cell), and decreased the blister-like (B-cell). It was also observed increased vacuole frequencies and increased F-, B- and R-cell volumes in the UVB-irradiated group. In addition, it was observed increased B-cell vacuolar volumes and decreased R-cell vacuolar volumes. Ultrastructural alterations occurred in subcellular compartments in F- and R-cells, e.g. loss of mitochondrial crests, morphologically compatible with mitochondrial fission, rough endoplasmic reticulum cisternae dilation, dilation of Golgi lamellar sacs, and increased vacuole and concentric membrane formation in the UVB-irradiated group. Our data showed that the hepatopancreas is an important target of UVB radiation, as demonstrated by a series of organ-specific morphological and morphometric impairments. Therefore, cell damage caused by UVB radiation can compromise metabolic functions in epithelial cells from the hepatopancreas, potentially affecting absorption, secretion and digestion processes, vitellogenin synthesis, immune responses and xenobiotic detoxification.

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Callichirus seilacheri (Bott, 1955) is considered one of the most common ghost shrimps in the intertidal zone of sandy beaches along the eastern tropical Pacific. The present study provides new observations on the morphology of C. seilacheri, based on the revision of abundant material collected along the Pacific coast of Central America, including specimens from the type locality (Playa Los Blancos, El Salvador) of this species. The new features of C. seilacheri include: carapace with low triangular rostrum, without setae on tip; pereiopod 1 highly dissimilar in adult males, but not in females and juveniles of both sexes; first pleopod sexually dimorphic; females with oval gonopores, each one of them on the ventral coxal segment of the third pereiopod, and extra genital pores on the ventral coxal segment of the fifth pereiopod, these latter non-functional (non connected with the ovaries). Apparently, the presence of extra gonopores in females of C. seilacheri is a vestigial character shared with other representatives of the same genus.(AU)

Callichirus seilacheri (Bott, 1955) é considerado um dos camarões-fantasmas mais comuns em zonas intertidais de praias arenosas, ao longo do Pacífico oriental tropical. O presente estudo fornece novas observações sobre a morfologia de C. seilacheri, com base numa revisão de material abundante coletado ao longo da costa do Pacífico, na América Central, incluindo espécimes da localidade tipo desta espécie (Playa Los Blancos, El Salvador). As características inéditas de C. seilacheri, incluem: carapaça com pequeno rostro triangular, e sem cerdas na extremidade; Pereiópodos 1 muito desiguais em machos adultos, mas não nas fêmeas e juvenis, de ambos os sexos; Primeiro pleópodo sexualmente dimórfico; Fêmeas com gonóporos ovais, cada um na porção ventral da coxa do terceiro par de pereiópodos, e poros genitais extras na porção ventral da coxa do quinto pereiópodo, estes últimos não funcionais (não conectados aos ovários). Aparentemente, a presença de gonóporos extras em fêmeas de C. seilacheri é um caráter vestigial, compartilhado com outros representantes do mesmo gênero.(AU)

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Callichirus seilacheri (Bott, 1955) is considered one of the most common ghost shrimps in the intertidal zone of sandy beaches along the eastern tropical Pacific. The present study provides new observations on the morphology of C. seilacheri, based on the revision of abundant material collected along the Pacific coast of Central America, including specimens from the type locality (Playa Los Blancos, El Salvador) of this species. The new features of C. seilacheri include: carapace with low triangular rostrum, without setae on tip; pereiopod 1 highly dissimilar in adult males, but not in females and juveniles of both sexes; first pleopod sexually dimorphic; females with oval gonopores, each one of them on the ventral coxal segment of the third pereiopod, and extra genital pores on the ventral coxal segment of the fifth pereiopod, these latter non-functional (non connected with the ovaries). Apparently, the presence of extra gonopores in females of C. seilacheri is a vestigial character shared with other representatives of the same genus.

Callichirus seilacheri (Bott, 1955) é considerado um dos camarões-fantasmas mais comuns em zonas intertidais de praias arenosas, ao longo do Pacífico oriental tropical. O presente estudo fornece novas observações sobre a morfologia de C. seilacheri, com base numa revisão de material abundante coletado ao longo da costa do Pacífico, na América Central, incluindo espécimes da localidade tipo desta espécie (Playa Los Blancos, El Salvador). As características inéditas de C. seilacheri, incluem: carapaça com pequeno rostro triangular, e sem cerdas na extremidade; Pereiópodos 1 muito desiguais em machos adultos, mas não nas fêmeas e juvenis, de ambos os sexos; Primeiro pleópodo sexualmente dimórfico; Fêmeas com gonóporos ovais, cada um na porção ventral da coxa do terceiro par de pereiópodos, e poros genitais extras na porção ventral da coxa do quinto pereiópodo, estes últimos não funcionais (não conectados aos ovários). Aparentemente, a presença de gonóporos extras em fêmeas de C. seilacheri é um caráter vestigial, compartilhado com outros representantes do mesmo gênero.

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The morphology of the mouthparts and foregut of the larvae and post-larvae of Macrobrachium jelskii was investigated to determine their functional roles in feeding, in order to understand the larval feeding behaviour and the changes that occur during its development. The mouthparts and foregut of the zoea I and II are morphologically similar, rudimentary and non-functional in feeding. Only in the final larval stage, zoea III, do the external mouthparts and foregut become structurally more complex and thus likely to play a potential role in feeding. Two behavioral trials (point of no return, point of reserve saturation) evaluated the resistance to starvation in zoea I, II, and III. The results indicate that they have sufficient nutritional reserves to permit them to complete metamorphosis without feeding. Overall, our results suggest that the zoea I and II of Macrobrachium jelskii engage in obligate lecithotrophy and zoea III in facultative lecithotrophy.

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This review compiles all the research done on gametes and fertilization in the rock shrimp, R. typus, and describes the sequence of events from the first gamete interaction to zygote formation and the first cleavage of the embryo, with light, fluorescence confocal and electron microscopes. Early studies showed that sperm from the vas deferens have a tack-shape with a "needle-like process" or rigid spike (RS) that extends from a semi-spherical body that contains the arms with chromatin and spines. Upon contact with seawater and by action of Na +, the arms and spines extend, producing an inverted umbrella form of the spermatozoa. The first sperm-oocyte interaction occurs between protein receptors type lectins of the sperm RS and oocyte chorion sperm ligands. These ligands contain residues of α-Glu, Man (α 1-3) Man, α and ß-GlcNAc and α-GalNA terminal residues. It was found that α-Man and GlcNAc residues are the ligands that are directly related to the adhesion process and further penetration of sperm. After this first interaction, the RS enters the oocyte envelope by the action of a trypsin-like enzyme, rhynchocinecine, present in the acicular process. Later, arms and spines penetrate the oocyte cytoplasm, where the chromatin of the arms begin to migrate to the central area of the sperm, condensing in a cup-shaped structure near the connecting piece, which forms the male pronucleus.

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This review compiles all the research done on gametes and fertilization in the rock shrimp, R. typus, and describes the sequence of events from the first gamete interaction to zygote formation and the first cleavage of the embryo, with light, fluorescence confocal and electron microscopes. Early studies showed that sperm from the vas deferens have a tack-shape with a "needle-like process" or rigid spike (RS) that extends from a semi-spherical body that contains the arms with chromatin and spines. Upon contact with seawater and by action of Na +, the arms and spines extend, producing an inverted umbrella form of the spermatozoa. The first sperm-oocyte interaction occurs between protein receptors type lectins of the sperm RS and oocyte chorion sperm ligands. These ligands contain residues of a-Glu, Man (a 1-3) Man, a and p-GlcNAc and a-GalNA terminal residues. It was found that a-Man and GlcNAc residues are the ligands that are directly related to the adhesion process and further penetration of sperm. After this first interaction, the RS enters the oocyte envelope by the action of a trypsin-like enzyme, rhynchocinecine, present in the acicular process. Later, arms and spines penetrate the oocyte cytoplasm, where the chromatin of the arms begin to migrate to the central area of the sperm, condensing in a cup-shaped structure near the connecting piece, which forms the male pronucleus.

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Se describe la citología axonal y la ultraestructura de las aperturas mielínicas (nudos de Ranvier) de las fibras mielinizadas no gigantes del camarón Penaeus, comparándolas con las características morfológicas de otros nudos de Ranvier en invertebrados y vertebrados

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