| paraorientatractis semiannulata n. g., n. sp. (cosmocercoidea: atractidae) from the large intestine of the side-necked turtle, podocnemis unifilis troschel, 1848 (testudines: pelomedusidae) in brazil. | specimens collected from the large intestine of the side-necked turtle podocnemis unifilis troschel, 1848 in the region of cuminá and trombetas rivers near pará, brazil are assigned to a new genus and new species of the nematode superfamily cosmocercoidea and family atractidae and named paraorientatractis semiannulata. the new genus is separated from the nearest genus orientatractis by the funnel-shaped mouth opening, the presence of 4 distinct lips, 4 papillae in the internal cycle, one on each ... | 1997 | 9332602 |
| the distal forelimb musculature in aquatic and terrestrial turtles: phylogeny or environmental constraints? | we compared the muscular anatomy of the distal front limb in terrestrial and aquatic chelonians to test whether observed differences between the two groups are associated with their divergent lifestyles and locomotor modes. given the different use of the forelimb in the two environments (body support and propulsion on land vs. mainly propulsion in water) we expected that: (1) aquatic and terrestrial turtles would show differences in their muscular anatomy, with aquatic species having more indivi ... | 2008 | 19172731 |
| mercury levels in muscle of six species of turtles eaten by people along the rio negro of the amazon basin. | mercury levels in the amazon river are generally high, but there are no published studies on hg levels in turtles from the region. in this study, levels of hg were examined in the muscle of six species of turtles in the rio negro in the amazon basin of brazil, including podocnemis unifilis, podocnemis expansa, podocnemis erythrocephala, podocnemis sextuberculata, peltocephalus dumerilianus, and chelus fimbriatus. it is important to analyze hg levels in chelonians in this region because of the po ... | 2010 | 19621205 |
| nesting ecology of podocnemis expansa (schweigger, 1812) and podocnemis unifilis (troschel, 1848) (testudines, podocnemididae) in the javaés river, brazil. | nest site has influence on incubation duration and hatching success of two neotropical turtles, the giant amazon river turtle (podocnemis expansa) and yellow-spotted side-neck turtle (podocnemis unifilis--'tracajá'). the 2000 and 2001 nesting seasons have been monitored at the javaés river in bananal island, brazil. although they nest on the same beaches, there is a separation of the nesting areas of p unifilis and p. expansa nests on the upper parts of the beach. the incubation duration for p. ... | 2010 | 20231963 |
| enterobacteriaceae associated with eggs of podocnemis expansa and podocnemis unifilis (testudines:chelonia) in nonpolluted sites of national park of araguaia plains, brazil. | fertile eggs of podocnemis expansa and podocnemis unifilis were investigated for the presence of enterobacteria, as these two endangered species have the potential for conservation measures that include egg transfer. knowledge of normal microflora associated with turtles and turtle eggs would help effectively manage the transfer of these eggs among institutions. thirty eggs of each species were collected, aseptically transferred, cracked inside plastic bags containing tetrathionate broth, and sp ... | 2010 | 21370647 |
| side-necked turtle (pleurodira, chelonia, reptilia) hemoglobin: cdna-derived primary structures and x-ray crystal structures of hb a. | red blood cells of yellow-spotted river turtles (podocnemis unifilis, pleurodira, chelonia, reptilia) have two hemoglobin (hb) components, hb a and hb d. we purified the hemoglobin component homologous to amniote (reptiles, birds, and mammals) adult hb a which comprises two identical a(a) -globin polypeptides and two identical ß-globin polypeptides. to establish the crystal structure of podocnemis hb a, we first determined the globin primary structures using cdna nucleotide sequencing with the a ... | 2011 | 21445850 |
| new insights of karyoevolution in the amazonian turtles podocnemis expansa and podocnemis unifilis (testudines, podocnemidae). | cytogenetic studies were conducted in the brazilian amazon turtles, podocnemis expansa schweigger, 1912 (pex) and podocnemis unifilis troschel, 1848 (pun) to understand their karyoevolution. their chromosomal complements were compared using banding techniques (c, g-, ag-nor and chromomycin a3) and fluorescence in situ hybridization (fish), and efforts were made to establish evolutionary chromosomal relationships within the podocnemidae family. | 2016 | 27708713 |
| a new myxidium species (myxozoa: myxosporea) infecting the gallbladder of the turtle podocnemis unifilis (testudines: podocnemididae) from peruvian amazon. | a new myxosporean species, myxidium peruviensis n. sp., is described parasitizing the gall bladder of the yellow-spotted river turtle podocnemis unifilis kept in captivity in an amazonian peruvian turtle rescue unit in the city of iquitos, state of loreto, peru. the parasite was found in four of ten (40%) p. unifilis examined. the new species was characterized based on morphological and molecular phylogeny analyses. ssu rdna sequence of the spores of m. peruviensis n. sp. resulted in 1876 nucleo ... | 2017 | 28450209 |
| mercury concentrations in different tissues of turtle and caiman species from the rio purus, amazonas, brazil. | total mercury (hg) concentrations of muscle, liver, blood, and epidermal keratin were measured in typically consumed, economically and culturally important species of turtle (podocnemis unifilis and podocnemis expansa) and caiman (melanosuchus niger and caiman crocodilus) from the rio purus in the amazon basin, brazil. methylmercury (mehg) concentrations were also measured in muscle tissue, representing the first analysis of mehg concentrations in amazonian reptile species. in muscle tissues hg ... | 2015 | 26387493 |
| an evaluation of the use of reptile dermal scutes as a non-invasive method to monitor mercury concentrations in the environment. | reptiles are ideal organisms for the non-invasive monitoring of mercury (hg) contamination. we have investigated hg bioaccumulation in tissue layers of reptile dermis as a basis for establishing a standardized collection method for hg analysis. tissue samples from freshwater turtle species podocnemis unifilis and podocnemis expansa and caiman species melanosuchus niger and caiman crocodilus, all from the amazonian region, were analysed in this study. we first tested the relationships between hg ... | 2015 | 24974226 |
| ventilation and gas exchange in two turtles: podocnemis unifilis and phrynops geoffroanus (testudines: pleurodira). | turtles (testudines) have two major taxa, pleurodira and cryptodira. to date, only limited data are available regarding the respiratory physiology of pleurodirans. to begin to address this, we studied ventilation and gas exchange in podocnemis unifilis and phrynops geoffroanus. breathing pattern in both species could be described as episodic with breathing episodes separated by large non-ventilatory periods. we measured duration of inspiration and expiration, breathing frequency, duration of the ... | 2016 | 25534144 |
| relationship between multiple paternity and reproductive parameters for podocnemis sextuberculata (testudines: podocnemididae) in the trombetas river, brazil. | genetic studies of multiple paternity are a valuable tool to gain information on the reproductive biology of turtles. we analyzed paternity type in podocnemis sextuberculata and related number of fathers per nest to nesting period (beginning, middle, or end of nesting season); clutch size (number of eggs); female size; and hatchling success. females were captured and maximum linear carapace lengths measured during the 60 days that encompass the nesting season at rio trombetas biological reserve ... | 2016 | 26909934 |
| cytogenetic comparison of podocnemis expansa and podocnemis unifilis: a case of inversion and duplication involving constitutive heterochromatin. | podocnemis expansa and p. unifilis present 2n = 28 chromosomes, a diploid number similar to those observed in other species of the genus. the aim of this study was to characterize these two species using conventional staining and differential cbg-, gtg and ag-nor banding. we analyzed specimens of p. expansa and p. unifilis from the state of tocantins (brazil), in which we found a 2n = 28 and karyotypes differing in the morphology of the 13(th) pair, which was submetacentric in p. expansa and tel ... | 2013 | 24130442 |
| conservation genetics of harvested river turtles, podocnemis expansa and podocnemis unifilis, in the peruvian amazon: all roads lead to iquitos. | we present a mtdna analysis of podocnemis expansa (n = 81) and podocnemis unifilis (n = 228) turtles traded in peru to evaluate the potential origin of these animals. in particular, we were interested in the relationship between samples reported in the iquitos markets (ims) and a pacaya samiria natural reserve (psnr) where illegal hunting is presumed. our mtdna data showed that, for both species, all haplotypes found within the psnr were observed in the im, and that these markets also displayed ... | 2012 | 22651234 |
| beyond harm's reach? submersion of river turtle nesting areas and implications for restoration actions after amazon hydropower development. | the global expansion of energy demands combined with abundant rainfall, large water volumes and high flow in tropical rivers have led to an unprecedented expansion of dam constructions in the amazon. this expansion generates an urgent need for refined approaches to river management; specifically a move away from decision-making governed by overly generalized guidelines. for the first time we quantify direct impacts of hydropower reservoir establishment on an amazon fresh water turtle. we conduct ... | 2018 | 29333347 |
| experiences from harvest-driven conservation: management of amazonian river turtles as a common-pool resource. | understanding what causes variability in the outcomes of common-pool resources management and governance has important policy implications for biodiversity conservation, in particular for the conservation of wild plants and animals subject to harvest. we report an exploratory study focusing on amazonian river turtles as a common-pool resource under harvest-driven conservation and management efforts in peru. based on document analysis, literature review and a series of interviews, we describe the ... | 2017 | 28940178 |
| mercury concentration in different tissues of podocnemis unifilis (troschel, 1848) (podocnemididae: testudines) from the lower xingu river - amazonian, brazil. | studies using chelonians as biosentinels of environment quality or health risks associated with turtle consumption are very rare, especially in the amazon basin. this study aims to measure mercury levels (hg) in muscle, liver, fat and blood of podocnemis unifilis from the lower xingu river, assessing the possible difference in concentration between sexes and also evaluating the potential bioaccumulation along different body sizes. samples were collected during the dry season (october 2012) and m ... | 2015 | 26691083 |
| population structure and allometry of podocnemis unifilis (testudines, podocnemididae) in a protected area upstream belo monte dam in xingu river, brazil. | amazon river turtles are increasingly threatened by habitat loss and alteration due to the brazilian energy policy based on construction of hydroelectric dams, meanwhile, populational studies remain scarce. we described the population structure, and established body allometric relationships of podocnemis unifilis in the terra do meio ecological station in the iriri river, tributary of the xingu river upstream the belo monte dam under construction turtles were captured by hand net and diving in 2 ... | 2015 | 26628030 |
| haemogregarina spp. in a wild population from podocnemis unifilis troschel, 1848 in the brazilian amazonia. | the study objectives were to characterize the morphology of the parasitic forms and describe the prevalence and intensity of haemogregarina spp. in a population of the turtle podocnemis unifilis as well as to examine the relationships between parasitism and turtle variables such as gender, size, and weight. samples were taken in the tapajós and jamanxim rivers, itaituba, pará state, brazil. blood was collected from the tail vein of 72 p. unifilis specimens, including 35 males, 36 females, and on ... | 2014 | 25284256 |
| complete sequence and gene organization of the mitochondrial genome of podocnemis unifilis (pleurodira: podocnemididae). | the mitochondrial genome of podocnemis unifilis (pleurodira: podocnemididae) is 16,493 bp in length, which contains 13 protein-coding genes, 2 ribosomal rnas, 22 transfer rnas, and a control region. the a+t content of the overall base composition of h-strand is 61.7% (t: 27.7%, c: 25.5%, a: 34.0%, g: 12.8%). atp6, atp8, co3, nd4-6 and cyt b genes begin with atg as start codon, nd1, nd2 and nd4l begin with att, co1 starts with gtg, co2 starts with ata, nd3 starts with atc. atp6, co2, nd4l and nd5 ... | 2016 | 24865914 |
| effect of dietary cadmium on fitness, growth, genotoxicity and accumulation in the yellow-spotted river turtle, podocnemis unifilis. | the aim of this study was to expose the yellow-spotted river turtle, podocnemis unifilis, to dietary cadmium (cd) contamination. the p. unifilis were fed with a cd contaminated diet (590 µgg(-1)) or a control diet for 30 and 60 days. after the cd feeding period, the locomotor performance and specific growth rate were assessed. blood samples were drawn for micronuclei analysis and tissues were collected to analyze the cd concentration. dietary cd influenced the fitness of turtles at 30 days (righ ... | 2013 | 23827776 |
| coelioscopic orchiectomy can be effectively and safely accomplished in chelonians. | coelioscopic orchiectomy was performed in 27 male turtles (25 juvenile to adult red-eared sliders (trachemys scripta elegans), one adult eastern painted turtle (chrysems picta picta), and one juvenile male yellow-spotted amazon river turtle (podocnemis unifilis)). orchiectomy was conducted under coelioscopic visualisation using ligation and transection of the mesorchium, or transection of the mesorchium with monopolar radiosurgical scissors. in 22 cases, bilateral orchiectomy was performed throu ... | 2013 | 23559425 |
| ontogeny of the shell bones of embryos of podocnemis unifilis (troschel, 1848) (testudines, podocnemididae). | the aim of the present study was to investigate the sequence of shell bone formation in the embryos of the pleurodira, podocnemis unifilis. their bones and cartilage were collected and cleared before staining. the shell was also examined by obtaining a series of histological slices. all the bony elements of the plastron have independent ossification centers, which subsequently join together and retain two fontanelles until the period of hatching. this turtle has a mesoplastra, which is character ... | 2011 | 21370497 |
| effects of lesions of the optic tectum on the ability of turtles to locate food stimuli. | in a previous experiment, it was demonstrated that the removal of portions of the optic tectum in a turtle, podocnemis unifilis, impaired its ability to perform a horizontal vs. vertical line discrimination task. to further elucidate the nature of this deficit, turtles (p. unifilis) were operantly conditioned to locate a food object at varying positions in an aquarium. preoperatively, all of the animals approach a food object in a direct manner. animals with a bilateral lesion of the optic tectu ... | 1977 | 871900 |
| effects of telencephalic and tectal ablations on visual behavior in the side-necked turtle, podocnemis unifilis. | | 1973 | 4714014 |
| chromosome studies of the cultured cells of two species of side-necked turtles (podocnemis unifilis and p. expansa). | | 1969 | 5800666 |
| evolutionary insights in amazonian turtles (testudines, podocnemididae): co-location of 5s rdna and u2 snrna and wide distribution of tc1/mariner. | eukaryotic genomes exhibit substantial accumulation of repetitive dna sequences. these sequences can participate in chromosomal reorganization events and undergo molecular cooption to interfere with the function and evolution of genomes. in turtles, repetitive dna sequences appear to be accumulated at probable break points and may participate in events such as non-homologous recombination and chromosomal rearrangements. in this study, repeated sequences of 5s rdna, u2 snrna and tc1/mariner trans ... | 2020 | 32229487 |
| community based actions save yellow-spotted river turtle (podocnemis unifilis) eggs and hatchlings flooded by rapid river level rises. | the conservation and recovery of increasingly threatened tropical freshwater turtle populations depends on effective management plans and actions. here we show that community-based actions saved yellow-spotted river turtle (podocnemis unifilis) eggs submerged by unseasonal flooding and ensured the release of hatchlings. we recovered 926 eggs and 65 premature hatchlings from 74 submerged nests at 16 flooded nesting areas along 75 km of waterways. the rescued eggs were transferred to a rearing cen ... | 2020 | 32995087 |
| effects of egg exposure to atrazine and/or glyphosate on bone development in podocnemis unifilis (testudines, podocnemididae). | this study was designed to investigate skeletal changes in podocnemis unifilis embryos derived from artificially incubated eggs exposed to different concentrations of atrazine, glyphosate or atrazine and glyphosate mixture. forty-two eggs were randomly allocated to one of seven trays containing vermiculite treated distilled water (control group) or the following solutions: 2 or 200 μg l-1 of atrazine (groups a1 and a2 respectively); 65 or 6500 μg l-1 of glyphosate (groups g1 and g2 respectively) ... | 2019 | 31276883 |
| levels of organochlorine pesticides in amazon turtle (podocnemis unifilis) in the xingu river, brazil. | due to the toxicity and high environmental persistence of organochlorine pesticides in aquatic organisms, turtles have been studied as environment biomonitors. these animals are important sources of protein for the riverside and indigenous peoples of the brazilian amazon. in the present study, organochlorine pesticide contamination was investigated in podocnemis unifilis. liver, muscle and fatty tissue samples were removed from 50 specimens collected from five sampling points located in the xing ... | 2018 | 30199320 |
| assessment of mercury concentration in turtles (podocnemis unifilis) in the xingu river basin, brazil. | many studies on mercury contamination in aquatic biota deal with the effect of consuming metal-contaminated organisms on human health. in this study, we examined the factors that cause mercury contamination in podocnemis unifilis in the xingu river basin of mato grosso and pará states, brazil. we quantified by atomic absorption spectroscopy with cold vapor the total mercury (thg) content in the liver and muscle samples of 50 podocnemis unifilis specimens collected from the basin. the live ... | 2018 | 29882772 |
| community involvement works where enforcement fails: conservation success through community-based management of amazon river turtle nests. | law enforcement is widely regarded as a cornerstone to effective natural resource management. practical guidelines for the optimal use of enforcement measures are lacking particularly in areas protected under sustainable and/or mixed use management regimes and where legal institution are weak. focusing on the yellow-spotted river turtles (podocnemis unifilis) along 33 km of river that runs between two sustainable-use reserves in the brazilian amazon as an illustrative example, we show that two y ... | 2018 | 29868271 |
| haemogregarina podocnemis sp. nov.: description of a new species of haemogregarina danilewsky 1885 (adeleina: haemogregarinaidae) in free-living and captive yellow-spotted river turtles podocnemis unifilis (testudines: podocnemididae) from brazil. | based on morphological, morphometric, and molecular data, we describe a new hemoparasite of the genus haemogregarina danilewsky 1885, isolated from the brazilian aquatic turtle podocnemis unifilis (testudines: podocnemididae). the new species, haemogregarina podocnemis sp. nov. (apicomplexa: haemogregarinidae), is characterized by small trophozoites with a single cytoplasmic vacuole on one side; pre-meronts with nuclear chromatin dispersed in the cytoplasm, with or without cytoplasmic vacuoles; ... | 2018 | 29564627 |