RCAAP Repository

ABSTRACT Life history traits of Characidium pterostictum Gomes, 1947 (Characiformes, Crenuchidae) from three different reaches of the upper Sinos river, southern Brazil, were described and comparatively analyzed according to the longitudinal gradient. For all reaches, results indicated a seasonal reproductive strategy with a higher intensity during warmer months of higher photoperiod (November to February). Only females were found in the upstream reach and they were more numerous than males in all the sampled reaches. Mean absolute fecundity ranged from 5189 (±2131 SD) to 7394 (±3807 SD), whereas mean relative fecundity (oocytes per mg of female total weight) ranged from 1.08 (±0.40 SD) to 1.12 (±0.29 SD). Oocyte development was characterized as synchronic in two groups, typical of total spawning. Longitudinal gradient comparison suggests that body size (standard length) of C. pterostictum individuals and sex ratio were the only characteristics that differed between sampled reaches. Larger individuals and thus females tended to be more frequently found in upstream reaches of the Sinos river, with a decrease in body size and in the proportional number of females towards downstream.

ABSTRACT Estuaries are highly dynamic ecosystems subjected to variability of their fish communities over different time scales. The nearshore fish community of the lower Pando estuary, a temperate sub-system of the Río de la Plata estuary, was sampled from May 2002 to June 2003. A total of 2,165 fishes, represented by 16 species were caught by seine netting. Captures were dominated by juveniles (>90%), as well as by the sciaenid Micropogonias furnieri (Desmarest, 1823) (82.8%). The fish community showed high seasonal variability, with the greatest diversity and biomass in summer and spring and the highest species richness during summer. Lowest values of all community parameters occurred in winter and autumn, seasons that presented the highest similarity in fish composition. Number of species was correlated with water temperature and salinity. The ichthyofaunal composition showed significant diel differences in summer and spring. Diel changes were observed in the density of M. furnieri and Odontesthes argentinensis (Valenciennes, 1835), occurring mainly during the day, and of Mugil liza Valenciennes, 1836, Parapimelodus valenciennis (Lütken, 1874) and Brevoortia aurea (Spix & Agassiz, 1829), caught mostly during the night. Temporal variability was attributed to environmental fluctuations, life cycle of species as well as to feeding patterns and small-scale displacements. Presented findings in the Pando sub-estuary denote similar juvenile use and seasonal patterns to those found in estuaries. Further studies in the nursery function and juvenile dynamics over the year are recommended in order to better understand the ecological role of sub-estuaries.

ABSTRACT We studied the reproductive biology of Megalobulimus paranaguensis (Pilsbry & Ihering, 1900), a large and long-lived land gastropod from the Atlantic Rainforest of Brazil. The study was conducted at an urban park in the city of Santos, state of São Paulo. For 4 years, we counted the egg postures and annual eclosion rate of 32 captive snails and looked for associations between egg posture and the climatical variables of the period. The annual mean posture of 8.7 eggs per snail obtained in our results is a small number, but typical of Brazilian macromollusks. The annual eclosion rate was 31%. The beginning of the annual activity period of snails occurred in the middle of March, and lasted 33.97±3.02 weeks. The dormancy period started in the beginning of November, and lasted 18.39±3.11 weeks. There were two egg posture peaks, a minor peak between March and May, and a major peak between August and November, with greater values in September. Megalobulimus paranaguensis has a well-defined seasonal reproductive pattern influenced by environmental temperature and temperature range. Furthermore, in this snail, reproduction is negatively influenced by temperature increasing and temperature range.

ABSTRACT Diversity analysis by partition is an approach employed in order to understand how communities spatially structure themselves and the factors that operate in the generation and maintenance of distribution patterns. We examined the spatial structure of species diversity of four taxonomic groups, with different dispersal abilities, in 16 forest fragments in the southern region of the state of Minas Gerais, Brazil. Specifically, we tested: i) if the similarity in species composition would be negatively related to geographical distance between the 16 fragments; and ii) if the beta diversity of the different groups could be negatively related to their dispersal abilities. Alpha diversity and the compositional similarity between localities were both low. Beta diversity was not correlated with distance for any of the groups. Primates, followed by birds, showed a higher tendency of forming similarity groupings, although in a manner that was independent from distance between fragments, as well as showed the lowest beta diversity relative values. Spermatophytes and amphibians did not define groupings and presented the highest values of beta diversity. We interpreted such results as indications that the groups with higher dispersal ability (primates and birds) tend to reach, on average, farther localities and, therefore, to define more similar groupings (low beta diversity). The groups with lower dispersal ability (spermatophytes and amphibians) showed the opposite tendency. Although most of the species were restricted to few localities, contributing to the low similarity, beta and gamma diversity values showed the extent which the localities are, respectively, different and complementary to each other in terms of species composition. Such features reinforce and justify future conservation initiatives, both in local and regional levels.

RESUMO A estruturação das assembleias de peixes em riachos de cabeceira sofre forte influência dos modelos de uso e ocupação do solo. O avanço da fronteira agrícola tem se mostrado uma das principais ameaças às comunidades desses ambientes. Este estudo teve como objetivo avaliar a influência das formas de uso e ocupação do solo sobre a estrutura da comunidade de peixes em riachos de cabeceira, localizados na bacia do Alto Paraguai, Mato Grosso, Brasil. As amostragens foram realizadas nos riachos Ararão, Queima Pé e Russo, no município de Tangará da Serra, MT, usando rede de arrasto e peneira, entre os meses de julho e dezembro de 2013. Foram coletados 4.192 indivíduos pertencentes a 35 espécies, sendo que Moenkhausia lopesi (Britski & de Silimon, 2001) e Knodus moenkhausii (Eigenmann & Kennedy, 1903) mostraram-se dominantes, representando 68,5% dos indivíduos amostrados. A riqueza e abundância não apresentaram diferenças significativas entre os três riachos, porém o índice de diversidade de Shannon foi maior no riacho Russo (H´ = 2,33). Os altos percentuais de conversão da vegetação nativa em campos de agricultura (49,20%) e pecuária (30,69%), revelaram forte relação negativa da agricultura com a riqueza, indicando que quanto menor a área de agricultura maior é a riqueza.

ABSTRACT Conservation of biodiversity in agroecosystems is an urgent need, and a suitable approach to maximize animal biodiversity and their services is the restoration of habitat heterogeneity. Here we investigated the value of increasing litter complexity in tree plantations of exotic pine for ground spiders. We hypothesized that increasing the litter complexity of these systems, as it would be the case in ecologically designed plantations, would increase spider aggregations. We performed a small-scale litter manipulation experiment within an exotic pine stand in the municipality of Minas do Leão, Rio Grande do Sul, Brazil, and compared spider diversity in simple (only pine needles) and complex substrates (with the addition of diverse native broadleaves). We found 1,110 spiders, 19 families and 32 morphospecies. The most abundant families were Linyphiidae, Theridiidae and Salticidade, and the dominant morphospecies were Thymoites sp. 2 and Lygarina sp. Web-building spiders represented 61% of total spider abundance, and 17 species, while hunting spiders, 49% and 15 species. As expected, densities of spider individuals and species from both web-building and hunting spiders were higher in complex litter substrate. Potential preys (Collembola) also responded positively to the treatment, and had influence of spider community patterns. Our results suggest that ensuring some degree of plant and litter diversity within pine stands (e.g. understory establishment) might foster spider aggregations and possibly help to conserve their diversity at local-scales.

ABSTRACT Fish exhibit morphological, physiological and behavioral specializations which enable them to display different ways to explore the environments and resources. Thus, the aim of this study was to verify how four Auchenipteridae species differ in the distribution, feeding habits and morphological traits: Auchenipterichthys longimanus (Günther, 1864), Auchenipterus nuchalis (Spix & Agassiz, 1829), Tatia intermedia (Steindachner, 1877) and Trachelyopterus galeatus (Linnaeus, 1766). This study was conducted in rivers and bays of the Anapú Basin, Pará State (Brazil), where these species are abundant. Specimens were collected using gillnets, and after caught the stomachs were removed for the contents analyzes. Eighteen morphometric measurements from ten adult specimens of each species were taken, combined into fifteen ecomorphological attributes. The species distribution showed that A. longimanus was restricted to rivers, while the others were exclusively caught in the bays. All four species had their diet composed of allochthonous insects, but A. longimanus also exhibited a great frugivorous habit. The most important ecomorphological attributes were relative to the consumption of larger food items (for A. longimanus and T. galeatus) and to the longer swimming capacity (for A. longimanus and T. intermedia). These morphological differences and the trophic diversity presented in this study highlighted some important information about how ecomorphological similar species behave and share resources, which may play a significant role on the coexistence of these species in the Anapú Basin.

ABSTRACT Caraguata Bechyné, 1954 (Galerucini, Galerucina) includes 38 species exclusively Neotropical, among them two sympatric species, C. atricornis (Clark, 1865) and C. guaporensis Bechyné, 1958. Given the lack of morphological studies in this group, we aimed to characterize the adult morphology of two species, providing descriptions, illustrations and comparisons of structures of the head, thorax, abdomen and genitalia. The external morphology includes the description of head, thorax, abdomen and its appendices; the internal morphology comprises endosternites, and male and female genitalia. Some similarities were observed, such as pubescence, mouth parts, apparent sexual dimorphism on ventrite V, spermatheca and vaginal palpi. The main differences are in (1) the body and antenna shape, (2) the antenna color pattern, (3) the depression of the pronotum, (4) the presence/absence of the tibial spur, (5) the form of the median lobe, (6) the tegmen and (7) the sternite VIII of the females. The morphological study of these species contributes to the knowledge of Galerucina, presenting important specific characteristics not employed until now. Thus, it can be a contribution for studies of comparative morphology, systematics and evolution of the group.

ABSTRACT Sexual differences in some of the components of the pectoral girdle and forelimb of Chaetophractus villosus (Desmarest, 1804) were investigated by means of geometric morphometrics. A total of 15 scapulae (7 males, 8 females) and 50 humeri-ulnae complexes (24 males, 26 females) were examined. No size differences were detected between sexes for any of the bones, but shape differences were found for the humerus and the ulna that enhance the in-forces or the related in-levers. Females had a more robust humerus, with an enlarged deltoid tuberosity, a more spherical head, higher tubercular and epicondylar widths, and more developed supracondylar crests. The ulna of the females was characterised by a more pronounced curvature along its main axis, a caudal displacement of the lateral fossa, a longer olecranon, and a deeper trochlear notch. For both bones, the discriminant analysis classified correctly all the specimens according to their sex. A small percentage of the variance (5.2% for the humerus; 6.8% for the ulna) was explained by allometry. The morphological traits found for the humerus and ulna of the females suggest an increased structural strength that could result in powerful digging strokes while keeping shoulder and elbow stabilisation, suggesting a fossorial advantage over males.

RESUMEN Ante la acelerada pérdida de biodiversidad causada por actividades humanas, las áreas protegidas (APs) constituyen la principal respuesta para mitigar esta crisis. La Reserva Natural Iberá (RNI) incluye 13000 km2 de territorios privados y fiscales, que contienen humedales y tierras altas con elevada biodiversidad, endemismos e importantes poblaciones de especies amenazadas. Para implementar su conservación, a finales del siglo pasado se definieron cinco Unidades de Conservación (UC) priorizadas en infraestructura y guardaparques, seleccionadas mediante criterios pobremente explicitados. En este trabajo definimos áreas prioritarias para la conservación (APC) usando los patrones de distribución de los reptiles en la RNI, para evaluar la eficiencia de las UC instauradas y detectar otras posibles áreas a ser consideradas en gestiones de conservación. La RNI se dividió en 28 celdas de 0,25° de latitud-longitud y mediante muestreos de campo y revisión de colecciones se obtuvieron 1 482 registros de 71 especies de reptiles computándose su presencia/ausencia en las celdas. Se calculó por celda riqueza específica e Índice Combinado de Biodiversidad (ICB) (que incluye rareza y grado de amenaza). Las APC fueron definidas mediante una búsqueda exacta (Complementariedad), obteniendo el mínimo conjunto de áreas que contuvieran a todas las especies y valores del ICB, lo que se denomina “eficiencia máxima”. La superficie mínima necesaria que representa a todas las especies es de diez celdas (36%) y sólo dos incluyen UC actuales. Se necesitan adicionar ocho celdas para cubrir los vacíos de conservación de reptiles, particularmente en el norte de la RNI. Sobre 20 especies amenazadas o insuficientemente conocidas, 12 (60%) no fueron registradas en celdas con UC. Proponemos UC adicionales para efectivizar la protección de todos los reptiles e incluir especies amenazadas.

ABSTRACT Physiological reorganization is described for the first time for the hypotrich ciliate genus Apoamphisiella Foissner, 1997, based on a population of A. vernalis (Stokes, 1887) Berger, 2006 collected from an eutrophic pond in the state of Minas Gerais, Brazil. Stomatogenesis is epiapokinetal, and the cirral pattern reorganizes from six typical fronto-ventral-transverse primordia, plus at least one short primordium located between IV and V. Primordia I and II originate from disaggregating undulating membranes and buccal cirrus, respectively; primordium III originates from left frontoventral cirrus plus a streak of basal bodies extending from the anterior end of oral primordium; primordium IV and the short extra primordia are formed from basal bodies perhaps associated to the posterior end of III plus the disaggregation of anteriormost cirri of the left ventral row. Primordia V and VI arise within the right ventral row as a single streak, splitting to form the two primordia. Marginal primordia develop initially within the pre-existent marginal rows, continuing to reorganize outside, pushing the old marginal cirri leftwards. Two dorsomarginal kineties develop associated to the right marginal row primordium. Dorsal ciliature also reorganizes from within the pre-existent dorsal kineties. The two macronuclear nodules approach each in middle reorganizers, briefly touching each other. At least one micronucleus undergo division. The process of physiological reorganization in A. vernalis resembles that of the North American Paraurostyla weissei complex representative, and along with features of the interphase morphology, indicate that Apoamphisiella belongs or is related to the Cyrtohymena-Paraurostyla group, within the Dorsomarginalia.

RESUMEN En Chile los armadillos Zaedyus pichiy (Desmarest, 1804) y Chaetophractus villosus (Desmarest, 1804) tienen poblaciones periféricas restringidas a planicies de altura y estepa patagónica en la vertiente occidental de la Cordillera de los Andes, donde además han sido escasamente estudiadas. En este trabajo entregamos información sobre los hábitos alimenticios de ambas especies de armadillos, obtenida mediante el análisis de heces colectadas en dos áreas de la región de Aysén, Patagonia chilena. En 38 heces de Z. pichiy identificamos dos taxones de plantas, seis de invertebrados y cuatro de vertebrados, mientras que en 72 heces C. villosus identificamos tres, nueve y cuatro taxones de las mismas categorías. En ambas especies de armadillos los invertebrados fueron la categoría más diversa y con mayor frecuencia de ocurrencia, siendo Coleoptera, Orthoptera y Hemiptera los grupos mejor representados en términos de abundancia. Entre los vertebrados se observó mayor frecuencia de restos del camélido Lama guanicoe (Müller, 1776) y el lagomorfo Lepus europaeus (Pallas, 1778). El análisis de rarefacción muestra que la riqueza de taxones fue mayor en C. villosus que en Z. pichiy, y el índice de Pianka indica que no existió un solapamiento trófico significativo entre especies de armadillos. Nuestras observaciones indican que poblaciones periféricas de ambas especies de armadillos muestran dietas omnívoras oportunistas, con un mayor consumo de invertebrados y plantas; además, sugieren que C. villosus se desarrolla en un rango ambiental más amplio, con una dieta más diversa y mayor presencia de esta especie en ambas áreas de estudio.

ABSTRACT Currently, it is widely recognized that invertebrates play key roles in neotropical floodplains and in many other environments worldwide. However, little information has been published concerning their biometry, in spite that it represents an essential tool for many different studies. Here, we provided length-mass and length-length relationships by fitting the linearized model (log10 Y = log10a + b log10 X) and several mean biomass ratios ± SE for bivalves, gastropods, quironomids, ephemeropterans, oligochaetes and hirudineans. We measured, weighed, oven dried and incinerated to ashes specimens collected from 2005 to 2014 in the Paraná River, Argentina. The lineal equations had fit levels higher than 75% in most of the significant regressions. Hence, when slopes were compared, differences raised from ontogeny and phylogeny of taxa. Additionally, slopes resulted different from constants of other regions, types of environments and climates. In addition, organic matter ratios resulted significantly different among invertebrates according to their feeding types. The equations and ratios that we provided will facilitate future research on life history, productivity and energy transference in the food webs of invertebrates inhabiting floodplain wetlands and can be used as tools for planning management strategies and in restoration projects of aquatic environments.

RESUMO Trichogramma pretiosum Riley, 1879 mantido em ovos de Ephestia kuehniella Zeller, 1879, tem sido utilizado no controle biológico de Spodoptera frugiperda (J. E. Smith, 1797). No entanto, fatores como idade do hospedeiro e experiência prévia, podem influenciar o parasitismo e o comportamento do parasitoide. Esse estudo avaliou a influência da idade dos ovos e da experiência em ovos e extrato de ovos de S. frugiperda no comportamento quimiotáxico e no parasitismo de T. pretiosum. Ovos de S. frugiperda com 24, 48 e 72 horas, foram expostos a fêmeas de T. pretiosum. Também foi avaliado o tempo de experiência do parasitoide, no mesmo hospedeiro, por 1, 3, 4, 5, 6 e 24 horas, assim como, seu tempo de exposição (1, 2, 3 e 24 horas). As respostas quimiotáxicas de T. pretiosum (experiente e não experiente) em extrato de ovos de S. frugiperda foram observadas em olfatômetro tipo Y. As taxas de parasitismo foram registradas em teste de escolha, com insetos experientes e inexperientes com ovos e extrato de ovos de S. frugiperda. O parasitismo em S. frugiperda foi significativamente maior em ovos com 24 horas de idade. Fêmeas inexperientes e experientes por 1, 3 e 4 horas, apresentaram uma menor taxa de parasitismo, quando comparadas a fêmeas expostas por 5, 6 e 24 horas. Não houve diferença de parasitismo em fêmeas expostas por 2, 3 e 24 horas, comparadas às expostas por uma hora. Fêmeas experientes foram mais atraídas ao extrato de ovos de S. frugiperda, do que ao controle (hexano). A porcentagem de parasitismo, em fêmeas inexperientes, foi maior em ovos de E. kuehniella (hospedeiro de origem), no entanto, o mesmo resultado não foi observado em fêmeas experientes.

ABSTRACT The hybridization is a widely-discussed issue in several studies with fish species. For some authors, hybridization may be related with diversification and speciation of several groups, or also with the extinction of populations or species. Difficulties to differentiate species and hybrids may be a problem to correctly apply a management of wild species, because hybrid lineages, especially the advanced ones, may resemble the parental species. The genus Cichla Bloch & Schneider, 1801 constitutes an interesting experimental model, considering that hybridization and taxonomic uncertainties hinder a correct identification. Considering these problems, in this study, we developed genetic methodologies and applied meristic and morphometric approaches in wild samples in order to identify species and for test a possible hybridization between Cichla kelberi Kullander & Ferreira, 2006 and Cichla piquiti Kullander & Ferreira, 2006. For this, C. kelberi, C. piquiti and potential hybrid ( carijó) individuals were collected in Paraná and Tietê rivers (SP, Brazil). For meristic and morphometric methods, the individuals were analyzed using the statistical software Pcord 5:31, while for molecular methods, primers for PCR-multiplex were designed and enzyme for PCR-RFLP were selected, under the species-specific nucleotide. All results indicated that the carijó is not an interspecific hybrid, because it presented identical genetic pattern and morphology closed to C. piquiti. Thus, we propose that carijó is a C. piquiti morphotype. In addition, this study promotes a new molecular tool that could be used in future research, monitoring and management programs of the genus Cichla.

ABSTRACT The attractiveness of a given leaf detritus to invertebrates depends on the chemical composition, physical structure, stage of microbial colonization and decomposition level. In addition to the leaf detritus quality, water temperature also affects organic matter cycling in aquatic environments. In this context, the objectives of this study were: i) to increase knowledge about the role of invertebrate shredders on fragmenting senescent, conditioned senescent and green leaves of Richeria grandis Vahl. (Phyllanthaceae) under gradual temperature rise and check leaf mass loss; ii) to verify the preference of Phylloicus sp. (Trichoptera) for leaves for larval case production. The experiment I consisted of three treatments with different water temperatures: 20°C, 24°C and 28°C. In the experiment II, we added 10 discs of green leaves of R. grandis and two shredder invertebrates (Phylloicus sp.) to each aquarium. Leaf mass loss in the presence or absence of fragmentation was not significantly influenced by differences in the intraspecific quality of the detritus or temperature. Intraspecific quality of resources mixed with green leaves can lead to increased contact of phenolic content on senescent leaves, leading to a similarity in food exploitation by invertebrates. However, the production of larval cases by Phylloicus sp. seems to be dependent on the resistance presented by the resource rather than the phenolic content, thus leading the shredders to use significantly more senescent detritus, regardless temperature.

ABSTRACT Low thermal quality environments, such extreme latitudes or high elevation regions, are highly expensive for reptiles in terms of thermoregulation. Thus, physiological adaptations or behavioral adjustments to live in these habitats have evolved in some species. Anolis heterodermus (Duméril, 1851) is an anole lizard that lives at high elevations in the Andes region. In this paper, we attempted to elucidate the thermoregulation strategy of a population of this species from the eastern cordillera of Colombia during wet and dry seasons. We measured body temperatures (Tb), operative temperatures (Te) and preferred temperatures (Tpref). Based on these data, we obtained accuracy ( b ), environmental thermal quality ( e ) and efficiency of thermoregulation (E) indexes. There were no significant differences of Tb or b between seasons, sexes, ages, and for Tpref between sexes or ages, but we found differences in Te and e between seasons. The indexes suggested high thermoregulatory accuracy, low thermal environment quality and indicated that A. heterodermus was an active thermoregulator in both seasons. Broad ranges of Tb and the species association with microhabitats with high solar radiation suggest eurythermy and heliothermy. Anolis heterodermus lives in a low thermal quality habitat, using exposed perches, which seems the most efficient thermal microhabitats. We concluded that A. heterodermus performed behavioral adjustment for compensating seasonal variation in the environmental thermal costs.

ABSTRACT Spiders are generalist predators and present a high diversity of capturing and foraging, as well as considerable species richness in tropical habitats. Although, generally, not presenting specific relations to the host plant, they can be influenced by its phenology, structure and resource availability. So, this study analyzed temporal variation on the structure and composition of Araneae assemblage in Callisthene fasciculata (Spr.) Mart. (Vochysiaceae) canopies, in an area of monodominant vegetation, in the periods of high water, receding water, dry season and rising water in Pantanal of Mato Grosso, Brazil. The collection was performed on 24 individuals of C. fasciculata, six in each seasonal period, in 2010 and 2011, making use of canopy fogging with insecticide. For that, ten nylon funnels were distributed under each canopy of C. fasciculata individuals, in a total of 240 m² of sampled canopies. In all, 3,610 spiders were collected and distributed in 24 families and 55 species. Anyphaenidae (43.3%; 6.5 ind./m2), Pisauridae (16.2%; 2.4 ind./m2), Araneidae (12.7%; 1.9 ind./m2) and Salticidae (12.4%; 1.9 ind./m2) were the most representative. Osoriella tahela Brescovit, 1998 was the most abundant species (12.2%). The nocturnal aerial runners of foliage (45.6%; 6.9 ind./m2), nocturnal aerial ambushers of foliage (17.3%; 2.6 ind./m2), aerial orb weavers (13.3%; 2.0 ind./m2) and the diurnal aerial runners of foliage (12.5%; 1.9 ind./m2) spiders represented the most abundant guilds. Significant differences were observed in the composition of families and behavioral guilds, as well as abundance and richness among seasonal periods. The assemblage showed the highest abundance in receding water and highest species richness in high water period, probably related to the hydrologic cycle of the area and its influence on C. fasciculata phenology, indicating the importance of this plant species for spider’s diversity maintenance in the Pantanal.

ABSTRACT Knowing the feeding biology of a population and its ontogenetic aspects can help in understanding the functioning of fish assemblages, essential to the conservation of the habitat biodiversity in which these species are found. Annual fishes complete their life cycle in temporary aquatic environments, existing in adult stage only for brief annual periods. Changes in the feeding habits between different size classes could indicate that a species belongs to different feeding groups in different growth phases. The aim of this work was to characterize the diet of Cynopoecilus fulgens Costa, 2002 in a temporary flooded area in the coastal plain of southern Brazil, taking into consideration possible alterations in feeding habits in different body size classes caused by ontogenetic changes, to explain the coexistence of these individuals in a short space of time. The diet analysis indicated that C. fulgens is a generalist, consuming small crustaceans and autochthonous insects. Intraspecific differences in diet were determined when compared between nine classes of standard length. Adults fed mainly on autochthonous insects, and juveniles ingested mostly crustaceans, with the population being separated into two trophic groups: invertivores and invertivores with a tendency towards zooplanktivory. It is possible to conclude that the ontogenetic changes in the diet of C. fulgens are related to morphological restrictions due to the size of the individuals, since feeding competitive relations are probably not so evident.

ABSTRACT A new species of Simlops Bonaldo, Ott & Ruiz, 2014, S. kartabo sp. nov., from Guyana is described. The new species belongs to the putatively basal bodanus species group, sharing with other species of the group a relatively simple embolar distal third. The presence of a filiform accessory process on the conductor, previously evidenced only for S. guatopo Brescovit, 2014 is also identified here for S. bodanus (Chickering, 1968), S. guyanensis Santos, 2014 and S. kartabo sp. nov. and may support the monophyly of the bodanus group.