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At least 487 records · Page 27Linked to original sources
PubMed2003

Revision of the Natada fusca complex and description of six new neotropical species (Lepidoptera: Limacodidae).

Six new species in the genus Natada, which have been hidden under Natada fusca Druce, are described and defined primarily by genitalia. New species include N. burnsi, N. truncata, N. singulara, N. chaconi, N. covelli, and N. confusa. Five of eight species in the Natada fusca complex, which also includes N. fuscodivisa Dognin, occur in Costa Rica. Distribution of the complex ranges from Mexico to the upper Amazon Basin and Guianas. Detailed geographic information and multiple genitalic drawings of males of one species, N. confusa, are provided to help define and separate species. The lectotype and paralectotype of N. fusca are designated.

Animals↗
PubMed2004

Lethal effects of elevated pH and ammonia on juveniles of neotropical fish Colosoma macropomum (Pisces, Caracidae).

Ammonia is the main nitrogenous waste material excreted by gills, then is oxided first to nitrite and then to nitrate. The proportion of ionized-un-ionized ammonia depends on pH and temperature, when this variables increase in a solution containing ammonia the equation goes to left, so the proportion of NH3 increases and the solution becomes more toxic. The purpose of this study was to investigate the acute lethal effects of elevated pH and ammonia on tambaqui juveniles. With a constant ammonia concentration of 5.0 mg/l NH3, there was no mortality a pH of 6.0 (control) and 7.0; but was of 10-20% a pH of 8.0 and 100% at 9.0. The lethal effects of elevated pH and un-ionized ammonia should be recognized as a potential factor contributing to the variable success of tambaqui production ponds, but this species is highly resistant in comparison with other freshwater fish.

Age Factors↗
PubMed1992

Cestode parasites in Potamotrygon motoro (Natterer) (Chondrichthyes: Potamotrygonidae) from southwestern Brazil, including Rhinebothroides mclennanae n. sp. (Tetraphyllidea: Phyllobothriidae), and a revised host-parasite checklist for helminths inhabiting neotropical freshwater stingrays.

Specimens of 5 species of cestodes were collected in 6 specimens of the freshwater stingray species Potamotrygon motoro (Natterer), collected in the vicinity of Corumba, Mato Grosso do Sul, Brazil. Acanthobothrium regoi, Potamotrygonocestus orinocoensis, Rhinebothroides venezuelensis, and Rhinebothrium paratrygoni are reported from P. motoro and from southwestern Brazil for the first time. Rhinebothroides mclennanae n. sp. appears to be the sister species of Rhinebothroides glandularis, the only other member of the genus exhibiting darkly staining glandular cells lying free in the parenchyma surrounding the terminal genitalia. The new species resembles Rhinebothroides glandularis, Rhinebothroides freitasi, and Rhinebothroides scorzai by having poral ovarian arms that extend anteriorly beyond the posterior margin of the cirrus sac, coiled vaginae, and vitelline follicles not interrupted on the poral side in the vicinity of the genital pore. It differs from all 6 previously described members of the genus by possessing an average of 31 testes per proglottid, compared with an average of 45 for R. glandularis, 55 for R. freitasi and R. venezuelensis, 77 for Rhinebothroides circularisi and Rhinebothroides moralarai, and 80 for R. scorzai. An updated phylogenetic tree for Rhinebothroides is presented.

Animals↗
PubMed1992

Origins, diversification, and historical structure of the helminth fauna inhabiting neotropical freshwater stingrays (Potamotrygonidae).

Members of the freshwater stingray family Potamotrygonidae occur throughout the major river systems of eastern South America that empty into the Atlantic Ocean. Ichthyologists have tended to assume that the ancestor of the potamotrygonids was an Atlantic marine or euryhaline stingray that dispersed into freshwater, presumably during the last marine ingression 3-5 million years ago. The helminth parasites that inhabit potamotrygonids suggest an alternative perspective on their origin. Phylogenetic and biogeographic analysis of the helminths inhabiting potamotrygonids suggest that the hosts are derived from an ancestral Pacific urolophid stingray that was trapped in freshwater by the uplifting of the Andes beginning perhaps as early as the early Cretaceous period and ending by the mid-Miocene epoch, changing the course of the Amazon River, which previously had flowed into the Pacific Ocean.

Animals↗
PubMed1991

Canestriniid mites (Acari, Astigmata, Canestriniidae) occurring on Chrysomelidae (Insecta, Coleoptera) in neotropical region. I. Genera Grandiellina Fain, Arrunsithiana n. gen.

Genus Arrunsithiana and nine species are described as new: Grandiellina tacjannae from Brazil, Argentina, G. rogeri from Peru, G. longini from Bolivia, G. marinae from Mexico, G. soniae from Colombia, Peru, Ecuador, Mexico, Arrunsithiana artemoni from Ecuador, A. erinnae from Ecuador, A. ilosi from Colombia, A. battosi from Bolivia, Peru, Brazil, Ecuador. Redescription of the genus Grandiellina Fain is given.

Animals↗
PubMedDate not supplied

A one year survey of airborne pollen and spores in the neotropical city of Bogota (Colombia).

A one-year study of potentially allergenic airborne biological particles was carried out in Bogotá, the capital city of Colombia. Bogotá is a populous city of approximately 6 million inhabitants. Located at 4 degrees Lat N and 2,600 m on the sea level, it has a mild tropical climate. The mean annual temperature of the city is 14 degrees C, the annual rainfall 1,013 mm and the relative humidity 72%. During the year June '86-May '87 the pollen count was 7,626 contributed by 72 grain types. Among these, 24 taxa have been identified. The majority of the grains came from imported trees; Cupressus spp was the main contributor. Weed pollen counts, which include the Compositae (ragweed), were notoriously low (4% of the total). The spore count was 13,264, almost twice as large as that of pollen. Fourty-four spore taxa were identified out of 72 types recorded. More than two-thirds (72%) of the spore count was contributed by the deuteromycetes. Cladosporium was the more frequently recorded genus, Penicillium/Aspergillus second next. Miscellaneous particles recorded were 609 Algae and 142 fern spores. Because of its location in the tropics, Bogotá has neither true seasons nor the large variations in atmospheric particle counting which are typical of temperate zones. However, distinct periodical increments in the counts of various species (peaks) may be the cause of seasonal allergic symptoms.

Air Pollutants↗
PubMed1988

Behavioural and ecomorphological responses of the neotropical pacu Piaractus mesopotamicus (Teleostei, Serrasalmidae) to oxygen-deficient waters.

The serrasalmid Piaractus mesopotamicus is an obligate gill-breather encountered in the floodplains of the Paraná-Paraguay River system, even when the O2 concentrations there are below 0.5 mg 1(-1). Similar conditions occur in fish ponds where this species is cultured. Locomotory activity is affected by both O2 concentration and surface access. Activity increases with hypoxia if fish have surface access, but decreases if surface access is denied by floating macrophytes. Below 0.4 mg 1(-1), larvae as well as larger fish are capable of utilizing the oxygen-rich surface layer of the water for respiration, in order to survive periods of habitat-induced hypoxia. This so-called aquatic surface respiration (ASR) entails an increase in locomotory activity and an ecomorphosis, involving the formation of a dermal extension on the lower jaw in larger fish, that apparently has a hydrodynamic funciton of using the surface layer for gill respiration. Although larvae display ASR, no ecomorphological adaptations were found. When the water is aerated, the extended lip of the larger fish regresses to its original size. Below a macrophyte cover fish are not able to survive O2 depletion. Histological examinations show that the extension is formed by edematous processes in the stratum spongiosum. Ventilation frequency increases with falling O2 and decreases during ASR, thus demonstrating a better O2 supply at the surface layer of the water.

Animals↗
PubMed1988

Neotropical monogenea. 13. Rhinonastes pseuodocapsaloideum n. gen., n. sp. (Dactylogyridae, Ancyrocephalinae), a nasal parasite of curimatã, Prochilodus nigricans Agassiz (Cypriniformes, Prochilodontidae), in Brazil.

Rhinonastes pseudocapsaloideum n. sp. (Dactylogyridae, Ancyrocephalinae) is described from the nasal cavity of Prochilodus nigricans Agassiz (Cypriniformes, Prochilodontidae) in Brazil. Rhinonastes n. gen. is proposed for species possessing a dextroventral genital pore, a bilobed testis, a ventral C-shaped ovary lying between the 2 testicular lobes, and a disc-shaped haptor armed with a ventral anchor-bar complex and 14 hooks.

Animals↗
PubMed1986

A coprological survey of parasites of wild neotropical felidae.

In conjunction with an ecological study of jaguars in the Cockscomb Basin of Belize, Central America, fecal samples from jaguars (Panthera onca), jaguarundis (Felis yagouaroundi), ocelots (Felix pardalis), and pumas (Felix concolor) were examined for parasite products (eggs, larvae, and oocysts). Of the 45 samples examined, 39 (86.7%) were positive for parasite products, 23 of 25 (92%) jaguar samples were positive, as were all of the puma (4/4) and ocelot (8/8) samples. Four of 6 samples from unknown species were positive (66.7%). Two jaguarundis samples were negative. The following were identified in the samples: Paragonimus sp. eggs, Taeniidae eggs, Strongylate eggs, Toxocara cati eggs, Toxascaris sp. eggs, Capillaria sp. eggs, Spiruridae eggs, Aelurostrongylus sp. larvae, Oncicola sp. eggs, Hammondia pardalis oocysts, Isospora sp. oocysts, Toxoplasma gondii-like oocysts and Sarcocystis sp. sporocyst.

Animals↗
PubMedDate not supplied

Population genetics of Biomphalaria straminea in Hong Kong. A neotropical schistosome-transmitting snail recently introduced into China.

Since its introduction in the early 1970s Biomphalaria straminea (Gastropoda: Planorbidae) has spread rapidly and is locally the most abundant fresh water snail in Hong Kong. Studies of 19 electrophoretically detected loci in four populations show that the colonists retain high levels of variability (P = 0.26, H = 0.056 - 0.097), comparable with those found in autochthonous samples of related species. Genotype frequencies at the five polymorphic loci, and a comparison of maternal and progeny genotypes of individual field-collected snails, revealed no evidence for self-fertilization in these functional hermaphrodites. F statistics indicated minimal genetic structuring, presumably because of outcrossing and recency of origin of the populations. Geographic distribution of various alleles and their frequencies suggest that two southern populations were derived from the original colonists by dispersal but that a northern population represents a second introduction in about 1982. This interpretation (based on genetics) is consistent with the known history of the various populations. The Asian populations of this South American snail are interpreted as being in the "flush" phase of the colonization process. Finally, the probability of the secondary spread of this snail from Hong Kong, and the probability of its parasite, the human blood fluke Schistosoma mansoni, being introduced to Asia are discussed.

Alleles↗