Paléoécologie des foraminifères benthiques de nouvelles coupes de basse latitude du passage Crétacé-Paléogène : Coupes de l’Oued Es Smara et de l’Oued Abiod (région de Téjerouine,NW Tunisie)

Due to an impact of a bolide at the K/Pg boundary, the planktonic foraminifera have suffered sever mass extinction. However, no small Benthic Foraminifera species have documented mass extinction at the K/Pg boundary. Nevertheless, many species showed disturbance. The Maastrichtian assemblages may be different from those of the lower Paleogene by their species content, diversity and frequencies. At Oued Es Smara and Oued Abiod sections, the small benthic foraminifera indicate lower bathyal environment, and manifest significant faunal turnover. Until the uppermost Maastrichtian, their assemblages are highly diversified, with 77 species and 76 species respectively at Oued Es Smara and Oued Abiod sections. These are dominated by endobenthic morphotypes. At the K/Pg boundary, although 33 species (42,85%) (Oued Es Smara section) and 27 species (35,52%) (Oued Abiod section) of them seem to disappear, but only few species have really extinct such as Arenobulimina obesa. Nevertheless, the majority of species persist elsewhere at the Danian (e.g., Pseudoglandulina manifesta, Cibicioides proprius, Clavulinoides amorpha, Coryphostoma plaitum, Pullenia coryelli). At the lower Danian, the survivor Maastrichtian species are of 58% (Oued Es Smara) and 65% (Oued Abiod). Throughout the Parasubbotina pseudobulloides subzone, 4 others species were progressively disappeared. They are oligotrophic and low oxygen tolerant. About the Masstrichtian species, at the two studied sections (e.g. Gaudryina inflata and Tritaxia midwayensis) they seem to be more trophic exigent. Consequently, the benthic Foraminifera did not suffer massive extinction at the K/Pg boundary, but their assemblages underwent a significant faunal turnover which reflects important environmental changes. These changes are compatible with the catastrophic scenario induced by the large asteroid impact.     

Nouvelles données micropaléontologiques(Foraminifères planctoniques et petits Foraminifères benthiques) sur le stratotype de l'Aquitanien

The authors study the microfauna of small benthonic and planktonic Foraminifera from the Aquitanian stratotype and of a few exposures in the stratotype vicinity.Benthonic microfauna is rich: more than 150species have been collected; among them Miliolidae mainly belonging to the genera Quinqueloculina and Miliola.Planktonic Foraminifera are much less abundant:only 20 species. They authorize to place the stratotype at the boundary of N4–N5 Blow's zones.The figurations of many species are made withthe scanning electronic microscope.     

The Foraminifera of the Pitcairn Islands

Foraminifera were recovered from 18 samples collected in the Pitcairn Islands, 12 from Henderson Island (including the best and most comprehensive collections) and three each from Oeno Atoll and Pitcairn Island itself. Although both algae and sediment samples were collected, the living Foraminifera came, almost exclusively, from phytal (attached or clinging) habitats. Foraminifera in the sediment samples are mainly thanatocoenoses. The fauna is an exclusively calcareous, relatively low diversity assemblage, dominated by large soritids [Marginopora, Amphisorus, Sorites) and Amphistegina , all of which are ubiquitous throughout the tropical Pacific. These larger Foraminifera are usually accompanied by small miliolids in particular, as well as by small attached Foraminifera (discorbids and the like). Typical reefal Foraminifera are generally under-represented. So far, no endemic species have been found. Of more significance, perhaps, is the apparent absence of Calcarina , small rotaliids, elphidiids and agglutinating species, so common in the western Pacific islands. One sample of fossil Foraminifera was analysed, from a shelly sand (c. 30 m above present sea-level) on Henderson Island. Though, for the most part, like the Recent assemblages, this was characterized by Archaias , a soritid which was not found in any of the modern collections made by the 1991– 92 Expedition. This could either be a sampling artifact or refer to a real environmental change since the Pleistocene.     

Palaeozoic Foraminifera: Systematics, palaeoecology and responses to global changes

Because the Foraminifera are very sensitive to various environmental parameters (e.g., water temperature, salinity, light, etc.), there are important proxies used for palaeoenvironmental and palaeogeographic reconstructions. The evolution of the structure, shape and size of the mineralized tests of Foraminifera can directly reflect the variation of these parameters through geological time. Furthermore, their biostratigraphic value has been widely demonstrated. In this context, the systematics, evolution and ecological behaviour of the first mineralized Palaeozoic Foraminifera are important to discuss in order to have a clearer picture of former shallow marine environments, and finally understand their distribution through space and time. The systematics of the fossil group of Foraminifera that first developed a mineralized test remains under discussion. These early foraminifers are considered as Textulariata (as generally admitted), recrystallized Fusulinata or an independent group, sometimes called Astrorhizata. In this paper, we argue to assign the early foraminifers to the Fusulinata, and to subdivide this class into six orders: Parathuramminida, Archaediscida and Earlandiida (forming together the subclass Afusulinana n. subcl.), and Tournayellida, Endothyrida and Fusulinida (subclass Fusulinana nom. translat.). These subdivisions are discussed and linked to the first occurrences of the later classes: Miliolata, Nodosariata and Textulariata. The environmental living conditions of the first fossilized foraminifers remain enigmatic during the Early Palaeozoic (Cambrian-Silurian). During the Late Silurian, the unilocular Parathuramminida started to colonize the inner parts of ramps and platforms. The first plurilocular microgranular foraminifers (Semitextulariidae, Nanicellidae, and Eonodosariidae) developed in back-reefal systems and in deeper-water environments (“griottes”-type nodular limestone) from the late Early Devonian to the early Late Devonian. The Moravamminida, another group of possible Protista, are typical markers of Devonian inner ramp systems. The Semitextulariidae, Nanicellidae, and Eonodosariidae did not survive the Frasnian/Famennian crisis. From the Tournaisian to the Serpukhovian (Mississippian subsystem or Early Carboniferous), numerous new genera and species of Archaediscida, Tournayellida and Endothyrida flourished but remained confined to inner ramp environments. In deeper water depositional systems (i.e. coral thrombolite microbialites and/or nodular limestones), a few opportunistic Foraminifera were living up to the disphotic zone. During the Pennsylvanian (Bashkirian to Gzhelian), the habitats extended to more confined, shallower areas of the inner ramp (with Staffelloidea). During the Late Carboniferous and Permian, the larger Fusulinida (Schwagerinoidea) reached the outer platform as they have been commonly reworked in calciturbidites. During the Late Permian, some taxa were even able to live in hypersaline environments such as sabkhas and hypersaline lagoons. Two major biotic crises occurred during the Permian (post-Middle and post-Late Permian crisis), but the number of survivors after the PTE (Permian/Triassic Extinction) is probably higher than previously admitted. From the Cambrian to the Serpukhovian, the Foraminifera were probably all infaunal or living at the sediment/seawater interface. The TROX and TROX-2 models are consequently applicable. Anoxia, often suggested as triggering environmental crises, was likely not systematically lethal for many infaunal foraminifers. The late Tournaisian-Changhsingian Tetrataxis genus was probably the first epiphyte foraminifer, because of its conical, limpet-like test. The Tetrataxidae (e.g., Tetrataxis, Pseudotaxis and Abadehella) constituted the unique trochospirally coiled plurilocular foraminiferal family of the Palaeozoic. The Bradyinoidea, Ozawainelloidea, Staffelloidea, and the Pseudoschwagerinidae (Schwagerinoidea) are other examples of Pennsylvanian-Permian epiphytes but cannot be considered as planktonic taxa. All the other Schwagerinoidea are related to high-energy environments and coarse-grained substrates. Their history, as well as that of the Neoschwagerinoidea, was likely subject to the vicissitudes of their endosymbiotic algae.     

Late Jurassic (Kimmeridgian) larger benthic Foraminifera from Santiago Coatepec, SE Puebla, Mexico

A micropaleontologic study was carried out from samples collected along a section that crops out in the Santiago Coatepec Stream, located in the southeast of the state of Puebla, Mexico. The sedimentary sequence begins with a reddish conglomerate. Above, thick and thin layers of grey-greenish sandstones that continue in fine-grained, calcareous sandstones, and, finally, in limestones. The reddish conglomerate may represent a continental environment, and the marine transgression began with the sandstone deposit that contains a marine association of Invertebrates such as Trigonids (Myophorella sp.), and other Mollusks such as Trichites sp., Ostreids and Gastropods, Echinoderms, and Sponges as Cladocoropsis mirabilis. This sequence also provides a rich assemblage of larger Foraminifera as well as Algae, which is reported for the first time in this site. The larger agglutinated Foraminiferal assemblage is composed of Alveosepta jaccardi, Pseudocyclammina lituus, Everticyclammina virguliana, Rectocyclammina chouberti, Choffatella cf. Ch. tingitana, Mesoendothyra croatica, Nautiloculina oolithica, Freixialina planispiralis, Audienusina fourcadei, Placopsilina sp., Pseudocyclammina sp., Meandrospira sp. and Lenticulina sp. All those taxa were adapted to special paleoecological conditions, such as a continuous terrigenous input. The Algae are Marinella lugeoni, Pseudoepimastopora jurassica, Permocalculus sp., and Halimeda sp. The stratigraphic distribution of the larger benthic Foraminifera allow us to propose a Kimmeridgian age for the studied sequence. The opening of the Atlantic Ocean permitted the colonization of its margins by the larger Foraminifera during this time. The data provided by the larger Foraminifera, the Algae, and the lithology may suggest an internal platform environment of warm shallow water. This foraminiferal association is constituted by cosmopolitan species which are frequent in the Tethyan Realm.     

Ecology of the Ogun River estuary,Nigeria

The distribution of benthonic communities (particularly Foraminifera) were studied from fourteen samples obtained from the Ogun River estuary and environs. Ten species of benthonic Foraminifera were identified; two of these constitute over 90% of the total foraminiferal population.Two broad biofacies are recognisable, namely the upper estuarine facies of Ammobaculites and the lower estuarine facies comprising arenaceous and calcereous forms with a preponderance of Ammonia beccarii (Linnaeus).Large populations of few species occur in the lower estuary, an area of weakly saline water with marked salinity fluctuations. The upper estuary on the other hand is sparsely populated and contains tests mainly of arenaeous Foraminifera. A few species are distinctive of particular facies but some are distributed throughout the estuary. Substrate is not a causal ecological factor, because sediments are similar in physical attributes throughout the estuary. Salinity and rate of sedimentation are among the more important factors affecting the distribution of all species. The low-energy nature of the environment is established by the abundance of faecal pellets and the fragility of the tests of the arenaceous Foraminifera.     

Latest Miocene-Pliocene Larger Foraminifera and depositional environments of the carbonate bank of La Désirade Island, Guadeloupe (French Antilles)

In this paper we present first results of the study of planktonic Foraminifera, large benthic Foraminifera and carbonate facies of La Désirade, aiming at a definition of the age and depositional environments of the Neogene carbonates of this island. The study of planktonic Foraminifera from the Detrital Offshore Limestones (DOL) of the Ancienne Carrière allows to constrain the biochronology of this formation to the lower Zone N19 and indicates a latest Miocene to early Pliocene (5.48-4.52 Ma) age. Large benthic Foraminifera were studied both as isolated and often naturally split specimens from the DOL, and in thin sections of limestones from the DOL and the Limestone Table (LT). The assemblages of Foraminifera include Nummulitidae, Amphisteginidae, Asterigerinidae, Peneroplidae, Soritidae, Rotalidae (Globigerinidae: Globigerinoides, Sphaeroidenellopsis, Orbulina) and incrusting Foraminifera (Homotrema and Sporadotrema). The genera Amphistegina, Archaias and Operculina are discussed. Concerning the Nummulitidae we include both “Paraspiroclypeus” chawneri and “Nummulites” cojimarensis, as well as a newly described species, Operculina desiradensis new species, in the genus Operculina, because the differences between these 3 species are rather on the specific than the generic level, while their morphology, studied by SEM, is compatible with the definition of the genus Operculina (D’Orbigny emend. Hottinger). The three species can be easily distinguished on the basis of their differences in spiral growth: while O. desiradensis has an overall logarithmic spiral growth, O. cojimarensis and especially O. chawneri show a tighter and more geometric spiral growth. O. cojimarensis and O. chawneri were originally described from Cuba in outcrops originally dated as Oligocene and later redated as early Pliocene. Therefore, O. chawneri was considered until now as restricted to the early Pliocene. However, in the absence of a detailed morphometric and biostratigraphic study of the Caribbean Neogene nummulitids, it is difficult to evaluate the biochronologic range of these species. The history of the carbonates begins with the initial tectonic uplift and erosion of the Jurassic igneous basement of La Désirade, that must have occurred at latest in late Miocene times, when sea-level oscillated around a long-term stable mean. The rhythmic deposition of the Désirade Limestone Table (LT) can be explained by synsedimentary subsidence in a context of rapidly oscillating sea-level due to precession-driven (19-21 kyr) glacio-eustatic sea-level changes during the latest Miocene-Pliocene. Except for a thin reef cap present at the eastern edge of the LT, no other in-place reefal constructions have been observed in the LT. The DOL of western Désirade are interpreted as below wave base gravity deposits that accumulated beneath a steep fore-reef slope. They document the mobilisation of carbonate material (including Larger Foraminifera) from an adjacent carbonate platform by storms and their gravitational emplacement as debris and grain flows. The provenance of both the reefal carbonate debris and the tuffaceous components redeposited in the carbonates of La Désirade must be to the west, i.e. the carbonate platforms of Marie Galante and Grande Terre.     

Nouvelles données micropaléontologiques(Foraminifères planctoniques et petits Foraminifères benthiques) sur le stratotype bordelais du Burdigalien

The present work deals with the microfauna of small benthonic and planktonic Foraminifera from the Burdigalian stratotype of Aquitaine basin (France) and from a few outcrops in the stratotype vicinity showing the upper or lower boundary of the stratotype.Benthonic fauna is rich: more than 250 species divided in 92 genera have been collected. The most frequent are hyaline Foraminifera (Pararotalia, Elphidium, Asterigerina, Florilus, Virgulopsis, Bolivina). The miocene feature is more pronounced than in the Aquitanian stratotype.Planktonic Foraminifera are much less abundant:only 20 species. However, some of them authorize to place the stratotype (or its equivalent l. s.) in N5 Blow's zone and perhaps in the basel N6 zone.The figurations of many species are made withthe scanning electronic microscope.     

Diet,intestinal morphology,and nitrogen assimilation efficiency in the damselfish,Stegastes lividus,in Guam

Synopsis Analysis of stomach contents of Stegastes lividus revealed a shift from omnivory in juveniles to herbivory in adults. Red algae, primarily Polysiphonia spp., Gelidiopsis intricata and Ceramium spp., formed the bulk of the diet in all size classes. Foraminifera and small crustaceans were of particular importance in the diet of juveniles. Net nitrogen assimilation efficiency of field-fed S. lividus was approximately 61%, and did not vary with fish size. The net assimilation efficiencies of fish fed on Enteromorpha in the laboratory ranged from size-class means of 36–79% for nitrogen and from 29–72% for total organic material, and increased from juveniles to adults. Apparently, juveniles compensate for a lower efficiency in assimilating plant food by including a higher percentage of animal material in their natural diets. The ratios of intestine length to standard length (IL/SL) and to intestine diameter (IL/ID) increased rapidly in juveniles and leveled off in adults. The retention time for ingested food items may only be about one-half as long in juveniles as in adults. The combination of observed IL/ID ratios and estimated retention times proved most valuable in the interpretation of ontogenetic changes in feeding habits and assimilation efficiency.     

Digestibility of chitin in cod,Gadus morhua,in vivo

Sixteen cod,Gadus morhua (L.), were individually fed a single ration of shrimps,Crangon allmanni. Four fish were killed and examined 6, 12, 24 and 48 h after the fish had been fed. Chitinase activities were measured in the extracts of stomach contents, stomach tissue, pyloric caecae, intestinal contents and intestinal tissue. The level of enzyme activity in different parts of the digestive tract was shown to be dependent on the phase of the digestive process. High concentrations of the chitin degradation product N-acetyl-D-glucosamine were determined in the stomach and in the intestinal contents. Based on the chitin concentration in the food organisms and the individual food uptake, the amount of chitin consumed by each fish could be calculated. Only up to 9% of the ingested chitin was recovered from the intestinal contents of the fish at any given time after feeding (6, 12, 24 and 48 h). In addition, only 2.4% of the chitin consumed with the food could be recovered in the collected faeces of the fish. The 4 cod killed 48 h after feeding had completely emptied their stomach. Chitin digestion in these fish was calculated to have been 90%.     

Growth,reproduction, and feeding oF Fundulus heteroclitus (L.) on a North Carolina salt marsh

Fundulus heteroclitus (L.) from a North Carolina Spartina marsh teed largely on small crustaceans (amphipods, tanaids and copepods) and polychaetes. Fish longer than 30 mm standard length also ingested considerable amounts of living plant material. Smaller individuals were distinctly carnivorous. Recognizable particles of Spartina detritus occurred in less than 15% of the guts examined. The relationship of weight to length changed significantly during the year. Although females were larger than males of the same age. males were heavier than females of the same length, except for a brief period at the peak of the spawning season in the early spring. An average second season fish may lay up to 512 eggs from March through August, but first season fish did not reach reproductive size by the end of the spawning season. Growth of first season fish in mid-summer averaged 5% of their total weight per day. These significant seasonal changes in ecological properties of killifish populations are important in any estimates of growth, reproduction, and production.     

Small subunit ribosomal DNA suggests that the xenophyophorean Syringammina corbicula is a foraminiferan

Xenophyophorea are giant deep-sea rhizopodial protists of enigmatic origins. Although species were described as Foraminifera or sponges in the early literature, the xenophyophoreans are currently classified either as a class of Rhizopoda or an independent phylum. To establish the phylogenetic position of Xenophyophorea, we analysed the small subunit (SSU) rRNA gene sequence of Syringammina corbicula Richardson, a newly described xenophyophorean species from the Cape Verde Plateau. The SSUrDNA analyses showed that S. corbicula is closely related to Rhizammina algaeformis, a tubular deep-sea foraminiferan. Both species branch within a group of monothalamous (single-chambered) Foraminifera, which include also such agglutinated genera as Toxisarcon, Rhabdammina, and Saccammina, and the organic-walled genera Gloiogullmia and Cylindrogullmia. Our results are congruent with observations of similar cytoplasmic organisation in Rhizammina and Syringammina. Thus, the Xenophyophorea appear to be a highly specialised group of deep-sea Foraminifera.     

Aspects of food intake,food selection,and alimentary canal morphology of mugil cephalus (Linnaeus, 1958), Liza Tricuspidens (Smith, 1935), L. Richardsoni (Smith, 1846), and L. Dumerili (Steindachner, 1869)

Feeding periodicity, selection efficiency and food consumption of Liza dumerili (Steindachner, 1869) and L. richardsoni (Smith, 1846) were determined. The effects of particle size and nature of ingested food on aspects of the morphology of the alimentary canal of L. dumerili, L. richardsoni, Mugil cephalu (Linnaeus, 1958) and Liza tricuspidens (Smith, 1935) are discused. It was found that the dominant mullet species in the Swartkops estuary (South Africa) not only exhibit different feeding periodicities (L. dumerili and L. richardsoni but that selected material in all the species differs in chemical as well as physical properties. Alimentary canals of each species are morphologically well adapted for selection, ingestion and digestion of its preferredi food items. These factors reduce interspecific competition among the different mullet species.     

Stable carbon isotope ratios in Fundulus heteroclitus (L.) muscle tissue and gut contents from a North Carolina spartina marsh

Recent food habit and productivity research on the killifish, Fundulus heteroclitus (L.), suggests that this species is important in the movement of organic material within and out of the salt marsh ecosystem. The stable carbon isotope ratios of Fundulus muscle tissue and gut contents were measured seasonally to determine the carbon source of the killifish. For muscle δ¹³C values ranged from -13.9% to -15.8% and -15.8% to -18.4% for gut contents, suggesting differential assimilation of ingested material. Muscle tissue indicate that assimilated carbon probably originated from a mixture of benthic algae and Spartina ingested by major prey species: the filddle: crab, Uca pugnax (Smith): the polychaete, Nereis (Neanthes) succinea Frey and Leuckart; the tanaid, Leptochelia rapax Harger; and other small crustaceans. Small fish (age0–1 yr) showed slightly lower δ¹³C values than larger fish (age 1–3 yr), consistent with differences in their feeding habits. The only seasonal pattern was an enrichment in tissue ¹³C that occurred for both small and large fish in the spring, corresponding to the peak spawning period. The δ¹³C determination is a useful tool in identifying and tracing carbon sources through the salt marsh food web, detecting differences in feeding habits between age classes of organisms, and assessing the relative nutritive value of ingested dietary items if differential assimilation is suspected.     

Planktic foraminiferal biostratigraphy of theMaastrichtian sedimentary beds at Ain Mdeker,northeastern Tunisia

Maastrichtian Foraminifera from the sedimentary beds at Ain Mdeker are recorded and identified. The fauna examined is found to be clearly Tethyan in composition. On the basis of this fauna, four planktic foraminiferal zones, the Globotruncana falsostuarti Zone, the Rugotruncana gansseri Zone, the Abathomphalus mayaroensis Zone and the Globotruncana falsocalcarata Zone are distinguished in the Maastrichtian of the sequence studied. These zones are futher compared with the zones established in equivalent strata in the sequence at El Kef, the most complete sequence in Tunisia. In addition to the index species only the biostratigraphically most important species from the fauna studied are illustrated.     

Ecological zonation of the hyperhaline estuary of the Casamance River (Senegal): Foraminifera,zooplankton and abiotic variables

Due to a long-lasting drought afflicting the Sahel, the Casamance River has been transformed into a hyperhaline estuary, with salinities up to 170% at a distance of 210 km from the sea. Foraminifera and zooplankton populations both show a marked decrease in the number of species in increasingly confined water, the distribution of species being closely related to the evolution of abiotic variables. Our three-prong study allowed us to identify six zones, upwards from the sea. The uppermost ones are characterized by drastic conditions which considerably reduce the number of species. Therefore, the populations of Foraminifera, zooplankton and even fish become oligo or mono specific. The Casamance River appears to fit quite well into the general rules concerning hyperhaline environments. However, it shows some peculiar features which are: the large dimensions of the hyperhaline estuary (over 230 km long and over 5 km wide in the lower course); peak salinities among the highest known for a permanently open estuary (up to 170%); and water remaining trapped inside the river for several years.     

Inundation timing,more than duration,affects the community structure of California vernal pool mesocosms

The food source utilization and trophic relationship of the fish assemblage in the Red River mangrove ecosystem, Vietnam were examined using dual isotope analysis. The carbon and nitrogen stable isotope signatures of 23 fish species ranged from ?24.0 to ?15.7‰ and from 8.8 to 15.5‰, respectively. Cluster analysis based on the δ¹³C and δ¹⁵N signatures clearly separated the mangrove fish into five feeding groups, representing detritivores, omnivores, piscivores, zoobenthivores, and zooplanktivores, which concurred with the dietary information. The results suggested that mangrove carbon contributed a small proportion in the diets of the mangrove fish, with dominant food sources coming from benthic invertebrates, including ocypodid and grapsid crabs, penaeid shrimps, bivalves, gastropods, and polychaetes. The δ¹⁵N values showed that the food web structure may be divided into different trophic levels (TLs). The lowest TLs associated with Liza macrolepis, Mugil cephalus, and Periophthalmus modestus; 18 fish species had TLs between 3.0 and 3.8; and Pennahia argentata had the highest TL (c. 4.0).     

Contamination of food by crude oil affects food selection and growth performance,but not appetite,in an Arctic fish,the polar cod (Boreogadus saida)

The polar cod (Boreogadus saida) is recognized as a key species in Arctic marine food webs and it may, therefore, be important for the transfer of xenobiotics from lower trophic levels to its main predators, birds and sea mammals. The present work examines the effects of foods contaminated with 200 or 400 ppm crude oil on food selection patterns and appetite-growth relationships in polar cod using X-radiography. It is shown that sexually mature polar cod consumed mixtures of uncontaminated and oil-contaminated foods, and did not show a reduced overall appetite as compared with fish provided with uncontaminated food only. Food selection was, however, influenced by both sex and individual appetite. Male fish selected uncontaminated food when appetite was low, whereas females ingested contaminated and uncontaminated foods equally, irrespective of appetite level. The ingestion of oil-contaminated food led to a significant depression in growth performance in both male and female fish. Food contaminated with oil at a concentration of 500 ppm was completely rejected by both sexes.     

Astronotus ocellatus (Cichlidae:Pisces) and Macropodus opercularis (Anabatidae:Pisces) as predators of immature Aedes fluviatilis (Diptera:Culicidae) and Biomphalaria glabrata (Mollusca:Planorbidae).

Two fish species, Astronotus ocellatus (Cichlidae) and Macropodus opercularis (Anabatidae) were tested for predacious behavior toward immature mosquitoes (Aedes fluviatilis, Diptera:Culicidae) and schistosomiasis snail hosts (Biomphalaria glabrata, Mollusca:Planorbidae), in the presence or absence of non-living food and in laboratory conditions. A. ocellatus, a species indigenous to Brazil, was a very efficient predator of both organisms (alpha = 0.05); M. opercularis, an exotic species, preyed well on immature mosquitoes, but small snails and snail egg-masses were ingested only irregularly. Both fish species seemed to prefer live to non-living food.     

Fishborne Trematode Metacercariae in Freshwater Fish from Guangxi Zhuang Autonomous Region, China

A survey was performed to investigate the infection status of fishborne trematode (FBT) metacercariae in freshwater fish from Guangxi Zhuang Autonomous Region, China. A total of 307 freshwater fish of 31 species were collected from 5 administrative regions of Guangxi Zhuang Autonomous Region. They were examined by artificial digestion method from July 2003 to August 2004. No metacercariae were detected in fish from Fusui-xian. In fish from Mashan-xian and a market in Nanning, 3 species of metacercariae, Haplorchis taichui, Haplorchis pumilio, and Centrocestus formosanus, were mainly detected. Metacercariae (8 in number) of Clonorchis sinensis were found in 1 Chanodichthys dabryi purchased from a market in Nanning. In fish from Yangshuo, Metagonimus yokogawai metacercariae were detected from all 18 fish species examined. Total 13 C. sinensis metacercariae were found in 3 out of 10 Hemibarbus maculatus from Yangshuo. All 7 Zacco platypus from Yangshuo were infected with 8-112 Echinochasmus perfoliatus metacercariae. In fish from Binyang-xian, H. pumilo metacercariae were mainly detected in all 5 fish species examined, and only 1 metacercaria of C. sinensis was found in a Hemiculter leucisculus. From the above results, it was confirmed that some species of freshwater fish play a role of second intermediate hosts for FBT in Guangxi Zhuang Autonomous Region, China. In particular, 4 species of intestinal flukes, M. yokogawai, H. taichui, H. pumilio, and C. formosanus, were prevalent in fish hosts, whereas C. sinensis metacercariae were detected only in 3 fish species.