Evaluation of an alternative technique for preserving crustaceans in dry conditions with joint mobility: a proposal for didactic purposes

Although crustaceans are traditionally preserved in liquids (formaldehyde and/or ethyl alcohol), those substances tend to alter their morphological aspects. Glycerin, used in human anatomy, is considered a good substitute for formaldehyde, as it preserves animals in states similar to in vivo conditions. There are no records in the literature, however, concerning the use of glycerin for conserving invertebrates. The objective of this work was to elaborate and evaluate alternative techniques for conserving the crustacean Ucides cordatus (Linnaeus, 1763). Six fixatives (1, 3, 4 and 5% formaldehyde, 70% alcohol, and dietrich solution) and two controls (positive and negative) were tested, as well as the effects of freezing before fixation on the integrity of U. cordatus specimens. Our results were evaluated with respect to nine variables. The treatments that demonstrated the best aesthetic results were 4% formaldehyde and 70% ethyl alcohol. The freezing of the animals resulted in brittle organs in all treatments tested. The technique discussed here is extremely promising for the conservation of animals for educational purposes, as it produces preserved specimens that are aesthetically similar to their in vivo conditions.

Trends in freshwater microcrustaceans studies in Brazil between 1990 and 2014 / Tendências nos estudos de microcrustáceos de água doce no Brasil entre 1990 e 2014

Abstract This study presents a review of scientiometric data about freshwater microcrustaceans (Copepoda, Ostracoda, Branchiopoda: Cladocera, Anostraca, Notostraca and Conchostraca) in Brazil from 1990-2014. This review is based on 179 papers published across four databases, using the following keywords in the search: microcrustaceans, Copepoda, Cyclopoida, Calanoida, Harpacticoida, Ergasilidae, Daphniidae, Moinidae, Cladocera, Ostracoda, Conchostraca, zooplankton, reservoir, river, ponds, reservoirs, wetlands, caves, lakes, limnology, ecology, aquatic, taxonomy, systematics, morphology and biogeography. No studies were identified that addressed freshwater microcrustaceans in four (Amapá, Roraima, Alagoas and Espírito Santo) of the 27 Brazilian Federative States. Forty-five percent of the included studies were concentrated within three of the most populous states (São Paulo, Minas Gerais and Paraná), which also have a long tradition of limnological study. The included studies mostly addressed reservoirs for hydropower generation (22%), multiple environments (22%), rivers (14%) and small artificial reservoirs (11%). Pools, ponds, small lakes, wetlands and phytothelma were not widely studied. Cladocera (48%) and Copepoda (48%) were the most studied groups. No studies were identified that addressed Notostraca, Anostraca or Conchostraca. The sharp increase in the number of published freshwater studies after 2000 is likely a result of increased internet facilities and the implementation of the Scielo platform. Ecology was most frequently the study focus (~50%), followed by taxonomy. Three journals (two Brazilian and one international) accounted for the publication of 44% of the Brazilian studies on microcrustaceans. We expect the frequency of studies employing newer technologies to increase in the coming years. Based on our findings, we propose that future studies should focus on the least well-studied states and should integrate biogeography and systematic approaches. Further data on the fauna within environmental sub-types in Brazil is required.

Resumo Esse estudo apresenta uma revisão cienciométrica para trabalhos com microcrustáceos de água doce (Copepoda, Ostracoda, Branchiopoda: Cladocera, Anostraca Notostraca e Conchostraca) no Brasil entre 1990-2014. Essa revisão foi baseada em 179 artigos científicos encontrados em quatro bases de dados, usando as seguintes palavras-chave: Microcrustáceos, Copepoda, Cyclopoida, Calanoida, Harpacticoida, Ergasilidae, Chydoridae, Daphniidae, Moinidae, Cladocera, Ostracoda, Conchostraca, Zooplankton, reservatório, rio, lagoas, áreas inundáveis, cavernas, lagos, limnologia, ecologia, aquático, taxonomia, sistemática, morfologia e biogeografia. Não foram encontrados estudos para microcrustáceos de água doce em quatro (Amapá, Roraima, Alagoas e Espírito Santo) dos 27 Estados da Federação Brasileira. Quarenta e cinco por cento dos estudos foram concentrados em três dos estados mais populosos (São Paulo, Minas Gerais e Paraná), os quais têm longa tradição em estudos limnológicos. A maioria dos estudos analisou reservatórios de hidrelétricas (22%), ambientes múltiplos (22%), rios (14%) e pequenos reservatórios artificiais (11%). Ambientes tais como, pequenos lagos, poças, lagoas, brejos e fitotelmatas não foram muito estudados. Cladocera (48%) e Copepoda (48%) foram os grupos mais estudados. Não foram encontrados trabalhos que analisaram Notostraca, Anostraca ou Conchostraca. O salto no número de estudos publicados depois do ano 2000 parece ser resultado do aumento das facilidades da internet e criação da plataforma Scielo. Ecologia foi a área mais focada nos estudos (~50%), seguida pela taxonomia. Três revistas (duas brasileiras e uma internacional) contêm 44% dos artigos publicados sobre microcrustáceos no Brasil. Espera-se que a frequência de estudos utilizando novas tecnologias aumente nos próximos anos. Baseado nos nossos resultados, propõe-se que trabalhos futuros devam focar os estados menos estudados e integrem abordagens biogeográficas e sistemáticas. Mais dados sobre a fauna de microcrustáceos dentro dos tipos de ambiente menos estudados no Brasil também são necessários.

On Limnocytherina axalapasco, a new freshwater ostracod (Podocopida: Limnocytheridae) from Mexican crater lakes / Limnocytherina axalapasco, un nuevo ostrácodo dulceacuícola (Podocopida: Limnocytheridae) de lagos de cráter mexicanos

Limnocytherina is a genus conformed by 12 species; its distribution in the American continent is known to be exclusively on the North (neartics), but little is reported about its distribution from Mexico (transition zone) and Central America (Neotropics). Different sampling campaigns were undertaken in three crater lakes from the Axalapascos region in east-central Mexico, during 2008, 2009 and 2011. As a product of these campaings, the new species of Limnocytherina axalapasco was found, which displays some intraspecific variability among populations. In this study, we described the taxonomy, the habitat, the ecological preferences and the larval development of this new species. A total of 10 sediment samples (8 littoral, 2 deepest point) were collected from lakes Alchichica, La Preciosa and Quechulac. We found that L. axalapasco is closely related to two North American species: L. posterolimba and L. itasca as well as one Central American species L. royi comb. nov. With the inclusion of L. axalapasco and L. royi to the genus, the distribution of Limnocytherina is extended to Central America. The four most important distinguishing characters of this new species are: 1) valve surface and margins covered with small, spine-like projections; 2) most of the A1 setae with a highly developed setule at distal part, producing a bifurcate appearance; 3) the upper ramus on the hemipenis is elongated, and by far overpasses dorsal/distal margins, distal lobe is triangular and short, while the hook-like process is prominent, outward orientated, and overpassing the tip of the distal lobe; 4) the UR is moderately developed with seta f3 elongated and setae f1 and f2 short. Considering its ecological characteristics and larval development, L. axalapasco was preferably found in alkaline waters dominated by Cl- or HCO3- and Na+ or Mg2+, temperatures ranging between 19.1 to 20.3°C, and dissolved oxygen concentrations from 5 to 6.5mg/L. This species was abundant in deeper (~64m) areas of the saline Alchichica lake, where surface water displayed conductivity values of up to 2 250μS/cm, and the sand with low percentage of silt resulted the preferred substrate. Along with the description of L. axalapasco, we provide additional information on the hemipenis of L. itasca, L. royi and L. sanctipatricii, and we discuss on the Limnocytherina-type of hemipenis.

Limnocytherina es un género conformado por 12 especies; su distribución en el continente Americano se conoce exclusivamente en el norte (zona neártica), pero se sabe poco de su distribución en México (zona de transición) y Centro América (zona neotropical). Luego de diferentes campañas de muestreo en tres lagos cráter de la región de los Axalapascos en la zona centroeste de México, durante 2008, 2009 y 2011, se encontró a Limnocytherina axalapasco, una nueva especie, que mostró variabilidad intraespecífica entre poblaciones. Un total de 10 muestras de sedimentos (8 del litoral, 2 del punto más profundo) fueron recolectadas de los lagos Alchichica, La Preciosa y Quechulac. L. axalapasco esta estrechamente relacionada con dos especies norteamericanas: L. posterolimba y L. itasca, así como con una especie centroamericana Limnocytherina royi comb. nov. Con la inclusión de L. axalapasco y L. royi al género, la distribución de Limnocytherina se extiende hasta Centro América. Los cuatro caracteres distintivos más importantes de esta nueva especie son: 1) superficie y márgenes de valvas cubiertos por pequeñas proyecciones parecidas a espinas; 2) La mayoría de las setas de A1 tienen una setula muy desarrollada en la zona distal, con apariencia de estar bifurcadas; 3) El ramo superior del hemipene es alargado y por mucho sobrepasa los márgenes dorsal/distal; el lóbulo distal es corto y triangular, mientras que el proceso prensil es prominente, orientado externamente y sobrepasa la longitud del lóbulo distal; 4) el UR esta moderadamente desarrollado con la seta f3 alargada y las setas f1 y f2 cortas. Para esta especie se describe también su hábitat, preferencias ecológicas y desarrollo larvario. L. axalapasco prefiere aguas alcalinas dominadas por Cl- o HCO3 - y Na+ o Mg2+, temperaturas entre 19.1 a 20.3°C y concentraciones de oxígeno disuelto de 5 a 6.5 mg/L. Esta especie es más abundante en las zonas profundas (~64m) del lago salino Alchichica, donde la conductividad del agua es de hasta 2 250μS/cm. Arenas con bajos porcentajes de limo parecen ser el sustrato preferido. Aunado a la descripción de L. axalapasco, proveemos información adicional para los hemipenes de L. itasca, L. royi y L. sanctipatricii, y discutimos el tipo de hemipene en Limnocytherina.

Distribution of macroinvertebrates on intertidal rocky shores in Gorgona Island, Colombia (Tropical Eastern Pacific) / Distribución de macroinvertebrados en costas rocosas intermareales en Isla Gorgona, Colombia (Pacífico Oriental Tropical)

Organisms found on rocky shores must endure harsh environmental conditions during tidal changes but scientific studies on tropical rocky shores are scarce, particularly in Colombian shores. Here we describe the spatial distribution of macroinvertebrates associated to the intertidal rocky ecosystems of Gorgona Island, Colombia (Tropical Eastern Pacific). Sampling was carried out in four localities around the Island: La Ventana and La Camaronera (sampled during October 2010) and La Mancora and El Muelle (sampled during March 2011). Two methodologies were used: rapid ecological assessments for qualitative data and quadrats for quantitative data. The richness, abundance, diversity (Shannon-Wiener H’), and evenness (Pielou J’) of macroinvertebrates were determined for and compared between, using one way ANOVA, each locality and the three intertidal zones of La Ventana (see methods). One hundred twenty-one species of macroinvertebrates were found during the sampling period. In all localities, Mollusca was the richest and most abundant taxon (46% of the species and 59% of the individuals), followed by Crustacea (32% of the species and 33% of the individuals). The other groups accounted for the remaining 22% of the richness and 8% of the abundance. Several studies have demonstrated that mollusks and crustaceans are the richest and most abundant taxa in marine benthic communities. Most of the abundant species found were herbivores. The species composition varied among zones. The results of dominant species for each zone are consistent with the ones observed in other tropical rocky intertidal shores. All response variables showed a decreasing pattern from the low to the high intertidal (in La Ventana). Post-hoc results indicated that the high intertidal, the zone with the harshest environmental conditions, had significantly lower values than the other two zones for all response variables. Comparisons between the low intertidal zones of the different localities in Gorgona Island showed higher values in all response variables for localities with intertidal pools. The most topographically homogeneous localities showed the lowest richness, abundance, and diversity. Both, tide pools and substrate heterogeneity and/or micro-topography are known to offer refuge against extreme physical conditions to the intertidal dwelling organisms. Results suggest that environmental stress, heterogeneity, and stability are important factors affecting the spatial distribution of macroinvertebrate species on intertidal rocky shores of Gorgona Island. Rev. Biol. Trop. 62 (Suppl. 1): 189-198. Epub 2014 February 01.

Se estudió la distribución especial de los macroinvertebrados asociados al intermareal rocoso de la Isla Gorgona, Colombia (Pacífico Oriental Tropical). Los muestreos se hicieron en cuatro localidades alrededor de la Isla: La Ventana y La Camaronera (muestreadas durante Octubre de 2010) y La Mancora y El Muelle (muestreadas durante Marzo de 2011). Se usaron dos métodos: evaluaciones ecológicas rápidas para datos cualitativos y cuadrantes para datos cuantitativos. Se calcularon la riqueza, la abundancia, la diversidad de Shannon-Wiener (H’), y la equidad de Pielou (J’) de las muestras y se compararon, usando ANOVA de una vía, entre las diferentes localidades y las tres zonas intermareales de La Ventana (ver métodos). Se encontraron 121 especies de macroinvertebrados durante el estudio. En todas las localidades, Mollusca fue el taxón más rico y abundante (46% de las especies y 59% de los individuos), seguido por Crustacea (32% de las especies y 33% de los individuos). Los otros grupos equivalieron al 22% de la riqueza y menos 8% de la abundancia. Muchos estudios han mostrado que los moluscos y los crustáceos son los taxa más ricos y abundantes en las comunidades bentónicas marinas. La mayoría de las especies más abundantes fueron herbívoros. La composición específica varió entre zonas. Los resultados de las especies dominantes para cada zona son consistentes con los observados en otras costas rocosas intermareales tropicales. Todas las variables de respuesta mostraron un patrón decreciente desde la zona intermareal baja a la alta (en La Ventana). Los resultados post-hoc indicaron que la zona superior, la zona con las condiciones ambientales más rigurosas, tuvo valores significativamente más bajos que las otras dos zonas para todas las variables de respuesta. Las comparaciones entre las zonas intermareales bajas de las diferentes localidades en la Isla Gorgona mostraron valores más altos en todas las variables de respuesta para las localidades con charcos intermareales. Las localidades más homogéneas topográficamente mostraron la riqueza, abundancia y diversidad más bajas. Se conoce que tanto los charcos intermareales como la heterogeneidad y/o microtopografía del sustrato ofrecen refugio a los organismos habitantes del intermareal contra condiciones físicas extremas. Los resultados sugieren que el estrés ambiental, la heterogeneidad y la estabilidad son factores importantes que afectan la distribución espacial de las especies de macroinvertebrados de las costas rocosas intermareales de la Isla Gorgona.

Gorgona, Baudó y Darién (Chocó Biogeográfico, Colombia): ecorregiones modelo para los estudios ecológicos de comunidades de quebradas costeras / Gorgona, Baudó and Darién (Biogeographic Chocó, Colombia): model ecoregions for coastal stream ecology studies

This paper summarizes the available information on the geology, hydrology, and biota of coastal streams located in the Gorgona National Natural Park (GNNP), and the Baudó and Darién ecoregions within the Biogeographic Chocó (Colombia). Despite of the scant number of studies, we hypothesized that these streams are consistent with the typology observed in volcanic oceanic islands in the Caribbean and the Pacific that do not conform to the tenets of the River Continuum Concept. Coastal streams in the Biogeographic Chocó are short (10(0)-10¹km) and steep and waterfalls and cascades are frequent due to tectonic origin. Step-and-pool sequences are common in montane reaches, while cobble-bed glides and riffles dominate in coastal plain reaches. Flow regimes are flashy in Pacific drainages (annual rainfall: <7000mm), but seasonally dry in the Caribbean drainages (<3500mm). Therefore, floods and droughts are important drivers of communities and ecosystem processes. Canopies are closed in low-order streams discharging directly to the ocean, thus contributing large amounts of litter. Diadromous fish and shrimp dominate consumer assemblages and various species are shared with streams in the Central America and the Antilles. These species play ecological roles probably equivalent to those found in other regions. These coastal streams are unique in terms of the number of primary freshwater fishes found (some endemics), and the functionally absence of diadromous gastropods. Rev. Biol. Trop. 62 (Suppl. 1): 43-64. Epub 2014 February 01.

A pesar de la escasez de estudios sobre la geología, hidrología y biota de las quebradas costeras ubicadas en el Chocó Biogeográfico, se hipotetiza que éstas se ajustan a la tipología observada en las islas oceánicas volcánicas del Caribe y el Pacífico, las cuales no cumplen con las predicciones del Concepto del Río Continuo. Estas quebradas son cortas (<10¹km) y muy pendientes debido a su origen tectónico, y presentan lechos dominados por bloques y cantos rodados. El régimen de caudal es torrencial en la vertiente Pacífico, pero estacionalmente seco en la vertiente Caribe. Los doseles cerrados aportan grandes cantidades de hojarasca a las quebradas que desembocan al mar con bajo orden. Las especies diádromas, con afinidades centroamericanas y antillanas, dominan los ensamblajes y posiblemente cumplen papeles ecológicos equivalentes a los establecidos en otras regiones. Particularmente, las quebradas costeras de esta provincia presentan varias especies de peces dulceacuícolas primarios, algunas endémicas, y carecen de gasterópodos. Los procesos geomorfológicos e hidrológicos de las cabeceras influyen sobre la dinámica ecosistémica de estas quebradas. Se proponen cinco hipótesis sobre la estructura y composición comunitaria. Se advierte que el PNNG es un modelo útil para la ecología lótica costera, pero que tiene particularidades.

Condition factor of Astyanax intermedius Eigenmann, 1908 (OSTEICHTHYES, CHARACIDAE) parasitised by Paracymothoa astyanaxi Lemos de Castro, 1955 (CRUSTACEA, CYMOTHOIDAE) in the Grande River, Serra do Mar State Park - Santa Virgínia Unit, São Paulo, Brazil / Fator de condição de Astyanax intermedius Eigenmann, 1908 (OSTEICHTHYES, CHARACIDAE) parasitados por Paracymothoa astyanaxi Lemos de Castro, 1955 (CRUSTACEA, CYMOTHOIDAE) no Rio Grande, Núcleo Santa Virgínia, Parque Estadual da Serra do Mar, São Paulo, Brasil

In this work the length-weight relationship and the condition factor of Astyanax intermedius parasitised and not by Paracymothoa astyanaxi were analysed in the Grande River. The length-weight relationship was estimated for females, males and immatures, and seasonally for the fishes and the parasites through the expression W = aLb. The condition factor of non-parasitised specimens differed seasonally and between sexes, contrasting with the results for parasitised fishes which showed no differences between sexes and season. The condition factor of non-parasitised specimens was higher than that of the parasitised fishes. Specimens of Astyanax intermedius parasitised do not have the same biotic conditions compared to non-parasitised individuals, in which the condition factor was similar over the years. In conclusion, parasitism by P. astyanaxi has deleterious effects on this host population which may cause changes in the reproductive and food dynamics of parasitised specimens due to low body conditions.

Foram analisados a relação peso-comprimento e o fator de condição de Astyanax intermedius parasitados ou não pelo isópode Paracymothoa astyanaxi. A relação peso-comprimento foi estimada para fêmeas, machos e imaturos, e sazonalmente tanto para os peixes quanto para o parasito, por meio da expressão P = aCb. O fator de condição dos exemplares não parasitados diferiu sazonalmente e entre os sexos, contrastando com os valores do fator de condição dos peixes parasitados, que não apresentaram diferenças sazonais e entre os sexos. O fator de condição dos exemplares não parasitados foi sempre maior do que o dos exemplares parasitados. Os exemplares de Astyanax intermedius parasitados não passaram pelas mesmas condições bióticas dos indivíduos não parasitados, apresentando um fator de condição semelhante ao longo do ano. Conclui-se que o parasitismo por P. astyanaxi atua de forma deletéria na população desse hospedeiro, podendo causar alterações nas dinâmicas reprodutiva e alimentar dos exemplares parasitados em razão da baixa condição corpórea.

Extant freshwater ostracodes (Crustacea: Ostracoda) from Lago Petén Itzá, Guatemala

Ostracode taxonomy has been of great interest because of their possible use as indicator species in climate and ecosystem changes. In Central and South America, few studies have been carried out and this study includes a contribution to the group. Eleven ostracode species were collected in Lago Petén Itzá (~100km2), the second largest lowland lake in Guatemala, and from its inflow tributary, Río Ixlú in November 2005 and February 2008. Twenty-seven surface sediment samples were retrieved at water depths from the littoral zone to the lake’s maximum depth (>160m). Hard and soft parts of ostracodes were analyzed, and each ostracode species was described for taxonomy, size, ecology, biology and geographic distribution. Species recorded include: Candonocypris serratomarginata?, Cypretta brevisaepta?, Cypridopsis okeechobei, Cytheridella ilosvayi, Darwinula stevensoni, Heterocypris punctata, Limnocythere opesta, Physocypria globula, Pseudocandona sp., Stenocypris major and Strandesia intrepida. Most of the species have a neotropical distribution, two are distributed world-wide (D. stevensoni and S. major), and C. okeechobei and P. globula display nearctic and neotropical distributions. We present new records of C. brevisaepta?, C. serratomarginata?, S. major, and S. intrepida in Guatemala. Physocypria globula was misidentified previously in Lago Petén Itzá as Cypria petenensis, Pseudocandona sp. was misidentified as Candona sp., and C. okeechobei was identified in the past as C. vidua. Limnocythere opesta is the only endemic species of the Petén Lake District, Guatemala. The most abundant and widely distributed species in the lake are P. globula, C. okeechobei, and Pseudocandona sp. Species restricted to the littoral zones and water depths <15m are C. brevisaepta?, D. stevensoni, H. punctata, and S. intrepida. Limnocythere opesta, C. ilosvayi, C. okeechobei, and Pseudocandona sp. are distributed from the littoral zone to a depth of 40m. Species collected only in the Ixlú tributary and in a littoral zone on the west side of the lake were C. serratomarginata? and S. major. During November, live adult L. opesta and C. okeechobei were abundant, but no C. brevisaepta? or C. serratomarginata? adults were found. Adult specimens of C. ilosvayi were more abundant in February. In general, ostracodes collected were smaller than those reported in the literature. An accurate taxonomy will improve the use of ostracode fossil assemblages in long sediment cores when reconstructing past climatic and environmental changes in the northern lowland Neotropics. Rev. Biol. Trop. 58 (3): 871-895. Epub 2010 September 01.

La taxonomía de los ostrácodos ha sido de gran interés debido a su posible uso como especies indicadoras de cambios del clima y de los ecosistemas. En América Central y del Sur se han llevado a cabo pocos estudios. Once especies de ostrácodos fueron colectadas en el 2005 y 2008 en el Lago Petén Itzá (~100km²), el segundo lago más grande de Guatemala y en su afluente, el Río Ixlú. Veintisiete muestras de sedimentos superficiales fueron extraídas a diferentes profundidades desde la zona litoral hasta la profundidad máxima (160m) del lago. Partes duras y blandas de los ostracódos colectados fueron analizadas. Este estudio describe cada especie de ostrácodo con respecto a su taxonomía, tamaño, ecología, biología y distribución geográfica. Especies reportadas incluyen: Candonocypris serratomarginata?, Cypretta brevisaepta?, Cypridopsis okeechobei, Cytheridella ilosvayi, Darwinula stevensoni, Heterocypris punctata, Limnocythere opesta, Physocypria globula, Pseudocandona sp., Stenocypris major y Strandesia intrepida. La mayoría de las especies poseen una distribución neotropical, dos tienen una distribución mundial (D. stevensoni and S. major) y C. okeechobei y P. globula tienen una distribución neártica y neotropical. Presentamos un nuevo récord de C. brevisaepta?, C. serratomarginata?, S. major y S. intrepida para Guatemala. Physocypria globula fue identificada erróneamente en el Lago Petén Itzá como Cypria petenensis, Pseudocandona sp. había sido identificada como Candona sp. y C. okeechobei como C. vidua. Limnocythere opesta es una especie endémica de la región. Las especies más abundantes y de mayor distribución en el lago son P. globula, C. okeechobei y Pseudocandona sp. Especies restringidas a zonas litorales y aguas con una pronfundidad <15m son: D. stevensoni, H. punctata y S. intrepida. Limnocythere opesta y C. ilosvayi están distribuidas de la zona litoral a una profundidad de 40m. Especies recolectadas solamente en el afluente Ixlú y en la zona litoral oeste, fueron C. serratomarginata? y S. major. En general, los ostrácodos adultos identificados fueron más pequeños que los tamaños reportados en la literatura. Una correcta taxonomía mejorará el uso de las comunidades de ostrácodos fósiles de núcleos de sedimentos para la reconstrucción climática y ambiental de la región neotropical.

A new species of pentastomida infecting Tropidurus hispidus (Squamata: Tropiduridae) from Caatinga in Northeastern Brazil

This article describes a new species of Brazilian Raillietiella Sambon, 1910 from lungs of Tropidurus hispidus (Spix, 1825). Between July and October 2005 eighteen specimens of T. hispidus were actively captured with elastic rubber slings in granite outcrops (lajeiros) (06° 59’ S and 39° 31’ W) from caatinga formations in the municipality of Farias Brito, State of Ceará, Northeastern Brazil. One female and one male of T. hispidus had lungs infected by Raillietiella mottae sp. nov. (prevalence 11.1 percent and mean intensity of infection 6.0 ± 1.4, range 5-7). The parasite’s main diagnostic characteristics include the dimensions of sharp hooks and strongly curved or "C-shaped" male copulatory spicules with knob-like posterior projection from the base towards the inner curvature of the spicule.

Este artigo descreve uma nova espécie de Raillietiella Sambon, 1910 a partir dos pulmões de Tropidurus hispidus (Spix, 1825). Entre julho a outubro de 2005, dezoito espécimes de T. hispidus foram coletados ativamente usando-se estilingues em formações rochosas (lajeiros) (06° 59’S e 39° 31’W) no domínio da caatinga no município de Farias Brito, estado do Ceará, nordeste do Brasil. Uma fêmea e um macho de T. hispidus tinham seus pulmões infectados por Raillietiella mottae sp. nov. (prevalência 11,1 por cento e intensidade média de infecção 6,0 ± 1,4, amplitude 5-7). As principais características diagnósticas dos parasitas incluem as dimensões dos ganchos com ponta aguda e as espículas copulatórias curvadas ou "em forma de C", com base posterior em forma de maçaneta, cuja parte distal é direcionada para o interior da curvatura da espícula.

Assessment of the decapod crustacean diversity in the Guayana Shield region aiming at conservation decisions / Avaliação da diversidade de crustáceos decápodos na região do escudo das Guianas como subsídio a decisões de conservação

The current state of knowledge of freshwater decapod crustacean diversity of the Guayana Shield Region is briefly assessed, based upon information gathered from the scientific literature as well as unpublished data from academic theses, technical reports, and carcinological collections. The decapod fauna of the region is presently known to include 64 species and subspecies within six families and 17 genera. Diversity by countries, basins, and rivers is listed, comments on endemic, rare or threatened species are made, and information about relevant taxonomic literature is presented. Seven priority areas for conservation actions concerning crustacean decapods are suggested and related to the 25 priority areas defined by the Fishes and Freshwater Working Group at the Guayana Shield Conservation Priority Setting Workshop, held at Paramaribo (Suriname) in April 2002.

Avalia-se resumidamente a situação atual do conhecimento sobre a diversidade dos crustáceos decápodos de água doce da região do Escudo das Guianas com base em informações obtidas da literatura científica e dados inéditos de trabalhos acadêmicos, relatórios técnicos e coleções carcinológicas. A fauna de decápodos da região está atualmente constituída por 64 espécies e subespécies em seis famílias e 17 gêneros. Relaciona-se a diversidade por país, bacias e rios, faz-se comentários sobre espécies endêmicas, raras ou ameaçadas, e apresenta-se informações sobre a literatura taxonômica relevante de cada grupo. Em relação aos crustáceos decápodos, sugere-se sete áreas prioritárias para ações conservacionistas e relaciona-se essas áreas com as 25 áreas prioritárias definidas pelo Grupo de Trabalho em Peixes e Organismos Dulcícolas no "Guayana Shield Conservation Priority Setting Workshop", realizado em Paramaribo (Suriname), em abril de 2002.

Microanatomical characteristics of marginal ommatidia in three different size-classes of the semi-terrestrial isopod Ligia exotica (Crustacea / Isopoda)

The aims of this paper have been (a) to characterize marginal ommatidia from different eye regions through a detailed description of their distinct ultrastructural features in three different size-classes of L. exotica, and (b) to compare microanatomical characteristics of the marginal ommatidia with those of ommatidia of the same eye, but located further centrally. On the basis of transverse as well as longitudinal sections we conclude that new ommatidia are added from a crescentic dorso-anterio-ventral edge of the eye and that maturing ommatidia go through a sequence in which originally the nuclei of cone-, pigment-, and retinula cells are arranged in three separate layers. At the beginning of the microvillar development, the organization of the corresponding rhabdomeres is still quite different (much less regular) from that of those rhabdomeres that make up the mature rhabdom. Marginal ommatidia always possess smaller diameters than more centrally located ones and retinal screening pigment granules are most apparent in the retinula cells only after the first microvilli have appeared. The diameters of rhabdom microvilli (approx. 55 nm) do not differ in ommatidia from the five investigated eye regions in small specimens (< 1.5 cm body length), but show a tendency to be slightly wider in the anterior (= frontal or rostral) regions of the eye (approx. 65 nm) in larger specimens (> 2.0 cm body length).

Decapod crustacean chelipeds: an overview.

The structure, growth, differentiation and function of crustacean chelipeds are reviewed. In many decapod crustaceans growth of chelae is isometric with allometry level reaching unity till the puberty moult. Afterwards the same trend continues in females, while in males there is a marked spurt in the level of allometry accompanied by a sudden increase in the relative size of chelae. Subsequently they are differentiated morphologically into crusher and cutter making them heterochelous and sexually dimorphic. Of the two, the major chela is used during agonistic encounters while the minor is used for prey capture and grooming. Various biotic and abiotic factors exert a negative effect on cheliped growth. The dimorphic growth pattern of chelae can be adversely affected by factors such as parasitic infection and substrate conditions. Display patterns of chelipeds have an important role in agonistic and aggressive interactions. Of the five pairs of pereiopods, the chelae are versatile organs of offence and defence which also make them the most vulnerable for autotomy. Regeneration of the autotomized chelipeds imposes an additional energy demand called "regeneration load" on the incumbent, altering energy allocation for somatic and/or reproductive processes. Partial withdrawal of chelae leading to incomplete exuviation is reported for the first time in the laboratory and field in Macrobrachium species.

Ergasilus hypophthalmi n. sp. (Copepoda, Poecilostomatoida, Ergasilidae) from the gill rakers of the Amazonian catfishes, Hypophthalmus edentatus Spix and H. fimbriatus Kner

A fêmea de Ergasilus hypophthalmi sp.n. (Copepoda, Poecilostopmatoida, Erhasilidae) é descrita dos rastros branquiais dos bagres amazônicos, Hypophthalmus edentatus Spix e H. fimbriatus Kner. A nova espécie é morfologicamente semelhante a E. hydrolycus Thatcher e Boeger, 1984, da qual se difere principalmente por ter o segmento torácico II fusionado ao cefalotórax e uma antena relativamente mais curta. Ergasilus hypophthalmi é a terceira espécie de Ergasilidae descrita dos rastros branquiais de peixe

An automated system for detection and analysis of locomotor behavior in crustaceans

An efficient and simple system in presented for the analysis of crustacean locomotor behavior. The system is composed by six dual-compartment actographic chambers with photocoupling circuit for movement detection, and a device for acquisition and analysis of cata. Such device is made by a digital interface which feeds in to a microcomputer with disc unit and printer. Information is processed in real time during the experiment, with a simultaneous printout and storage in a floppy disc