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Reproduction is a fundamental biological aspect of the recruitment of individuals and to maintenance of stable populations. Thus, an important question is understating the impact of human disturbances, such as fire, on reproduction success. In this study, we evaluated the effect of fire and environmental temperature on the reproductive recruitment of two Neotropical species of freshwater turtles (Podocnemis expansa, and Podocnemis unifilis). Our hypotheses are as follows: (i) nesting areas exposed to fire exhibit lower reproductive recruitment of turtles, and (ii) years with higher environmental temperatures are associated with increasing reproductive recruitment of turtles. To test these hypotheses, we used data collected from long-term monitoring of nesting sites (2006–2021) of freshwater turtles in Rio das Mortes, Central Brazil. The number of fire outbreaks and environmental temperature were our independent variables; while the number of live hatchlings per reproductive season, the number of unviable eggs, and the total number of eggs were our response variables. The findings indicated that fire harmed the reproductive recruitment of turtle species, and the total number of eggs was negatively influenced by fire and environmental temperature. Long-term monitoring and experimental studies are essential for the understanding of the relationship between human and natural effects on the Neotropical freshwater turtle population. In turn, it contributes to the implementation of effective conservation measures for freshwater turtles. [ABSTRACT FROM AUTHOR]

Nematodes collected from the stomach of the yellow-spotted turtle Podocnemis unifilis Troschel, 1848 (Testudinidae) in the Brazilian state of Pará are assigned to a new genus, allocated to the family Atractidae (Cosmocerdoidea). Acanthoatractis n. gen. differs from all other genera of Atractidae based on the combination of the following morphological characters: cephalic extremity surrounded by eight bifurcated, wrench-shaped sclerotized structures arranged in a circle; oral opening encircled by two sclerotized pieces with pointed ends and a median portion with a pair of hooks; in males the larger (left) spicule is narrower in the middle third and the gubernaculum is absent. The type species, Acanthoatractis xinguensis n. gen., n. sp., has nine pairs of caudal papillae and a single papilla anterior to the cloacal lip. The new species is the seventh record of an atractid genus parasitizing P. unifilis.

Methods: Sampling was performed at three sites in the Tapajós River mouth, Pará State, Brazil, and an aliquot of blood was collected from each turtle by post-occipital dorsal vein puncture. The aliquots were used for the determination of hematological parameters and for the study of hemoparasites in the blood samples. Results: A total of 37 turtles were sampled: 21 Podocnemis expansa, three P. sextuberculata, nine P. unifilis, and four P. erythrocephala. Parasitological analyses showed inclusions in erythrocytes compatible with Haemogregarina sp., representing an overall prevalence of parasitized animals of 64.8% with an average of 94,789 parasites/ml of blood. In this study, the evolutionary forms of Haemogregarina spp. from trophozoites, pre-meronts, meronts, and mature and immature gamonts were observed in three species of freshwater turtle species, and one morphotype of the parasite with high similarity to Haemogregarina podocnemis has been observed. Conclusion: Despite recent research on freshwater turtles, this study provides new information on the intensity of blood parasite infection and hematological parameters of free-living animals, highlighting the need for studies on infected and uninfected animals from the same population. [ABSTRACT FROM AUTHOR]

The current study describes a new species of nematode, Orientatractis matosi n. sp. (Atractidae), from the stomach and large intestine of Podocnemis unifilis Troschel, 1848 (Testudinidae), collected in the Tocantins and Xingu rivers in the Brazilian state of Pará. The new species was described using light and scanning electron microscopy and differs from its congeners mainly in the number and distribution of the male caudal papillae and by having a shorter right spicule. Orientatracits matosi n. sp. is the eleventh species of the genus Orientatractis Petter, 1966, the third reported from the Amazon, and the second described from P. unifilis.

The current study describes a new species of nematode, Orientatractis matosi n. sp. (Atractidae), from the stomach and large intestine of Podocnemis unifilis Troschel, 1848 (Testudinidae), collected in the Tocantins and Xingu rivers in the Brazilian state of Pará. The new species was described using light and scanning electron microscopy and differs from its congeners mainly in the number and distribution of the male caudal papillae and by having a shorter right spicule. Orientatracits matosi n. sp. is the eleventh species of the genus Orientatractis Petter, 1966, the third reported from the Amazon, and the second described from P. unifilis. [Display omitted] • Orientatractis matosi n. sp. (Atractidae) is a new parasite of Podocnemis unifilis (Testudines: Podocnemididae) from the Amazon region. • This is the second known species of the genus Orientatractis in P. unifilis. • Orientatractis matosi n. sp. has nine pairs of caudal papillae and the shortest right spicule amongst its congeners. • Orientatractis matosi n. sp. is the third species reported from the Amazon region. [ABSTRACT FROM AUTHOR]

ABSTRACT: The parasitic fauna of Podocnemididae species is of great relevance to understanding the ecological relationships of the organisms in this genus. The parasites can have a symbiotic relationship with their hosts; however, environmental imbalances may change this relationship. Therefore, these parasites may become agents that generate zoonoses, especially in animals used by parasites as a food source. The aim of this study was to investigate the gastrointestinal parasitic fauna of specimens of Podocnemis unifilis. The animals were collected from the Tocantins and Javaés Rivers, both of which flow in the State of Tocantins, predominantly in the Cerrado territory. Samples of stomach and intestinal contents were fixed in 10% formalin buffered with sodium phosphate, transferred to 70% alcohol for analysis, and separated after 72 hours. Parasites were isolated and identified according to morphology and identification key. Four species of parasites were observed in 100% of specimens of P. unifilis, namely Nematophila grandis (Trematoda) and Paratractis hystrix, Paraorientatractis semiannulata, and Orientatractis leiperi (Nematoda). N. grandis was the only parasite that was not observed in the intestine; it appeared to adhere to the inner wall of the stomach. All nematodes were observed both in the stomach and intestine. These data expand the knowledge related to the P. unifilis parasitic fauna and the geographic distribution of these parasites in P. unifilis from the Tocantins and Javaés Rivers.

Knowledge of suitable methods and reagents for assessing the health condition of specimens of a given species is essential. The present study evaluated the efficacy of the heparin anticoagulants 5,000 I.U. mL-1, Na2EDTA, and K3EDTA on the blood parameters of yellowspotted amazon river turtle Podocnemis unifilis, employing different solutions for red blood cells count. The use of the various anticoagulants evaluated after 10 hours of storage efficiently inhibited coagulation in blood samples from P. unifilis. An increased number of erythrocytes was observed with the use of K3EDTA 5% when compared with heparin. Statistically significant changes in the erythrocyte number were observed with the use of the different solutions. Solutions which featured sodium citrate and formaldehyde in their composition, allowed erythrocytes counting up to 120 hours after blood collection, without a change in values. The use of the heparin anticoagulants 5,000 I.U. mL-1, Na2EDTA 3%, Na2EDTA 5%, K3EDTA 3% was recommended in the hematological analysis of P. unifilis. Also recommended was the use of the formaldehyde-citrate solution containing 1.9 g of sodium citrate and 1.0 mL of formaldehyde (in 50 mL of distilled water) to perform red blood cells counts in yellow-spotted amazon river turtle. [ABSTRACT FROM AUTHOR]

During the last few decades, fungal pathogens have caused devastating population declines across a broad range of taxa. A newly emerging fungal disease, sea turtle egg fusariosis, caused by members of the Fusarium solani species complex (FSSC), has been reported to be responsible for hatching failure in sea turtles worldwide. However, this has not been detected in fresh water turtle species. Here, using relocated clutches and artificial incubation, we report high hatching failure in eggs symptomatic of fusariosis in the yellow‐spotted Amazon River turtle (Podocnemis unifilis) inhabiting a pristine environment in the Ecuadorian Amazon. In 2020, we screened 680 eggs of the yellow‐spotted Amazon River turtle, relocated from wild nesting areas to artificial nests, for visual symptoms of fusariosis and to estimate hatchability despite infection. We selected 68 eggs sampled in 2019 to confirm Fusarium infection by PCR amplification of the TEF‐1α gene and sequenced seven of those amplicons on an Illumina Miseq to assess FSSC membership. We observed fusariosis symptoms in 42% of the 680 eggs. The proportion of symptomatic eggs within nests was negatively linked to the proportion of eggs that hatched. Hatchability was 8% for symptomatic eggs compared with 72% of asymptomatic eggs. Through PCR testing, 58% of symptomatic and 8% of asymptomatic eggs sampled in 2019 tested positive for Fusarium spp., and sequencing revealed that nine sequence variants from three asymptomatic and four symptomatic eggs corresponded to F. keratoplasticum, F. solani and F. falciforme, the three major FSSC pathogens reported in sea turtle egg fusariosis. Our study suggests that hatching failure in eggs linked to symptoms of fusariosis appears to be partially caused by Fusarium pathogens within FSSC in a freshwater turtle. Thus, fusariosis is more widespread among the Testudines than previously reported and is not limited to sea environments, findings of particular conservation concern. [ABSTRACT FROM AUTHOR]

Nematodes collected from the stomach of the yellow-spotted turtle Podocnemis unifilis Troschel, 1848 (Testudinidae) in the Brazilian state of Pará are assigned to a new genus, allocated to the family Atractidae (Cosmocerdoidea). Acanthoatractis n. gen. differs from all other genera of Atractidae based on the combination of the following morphological characters: cephalic extremity surrounded by eight bifurcated, wrench-shaped sclerotized structures arranged in a circle; oral opening encircled by two sclerotized pieces with pointed ends and a median portion with a pair of hooks; in males the larger (left) spicule is narrower in the middle third and the gubernaculum is absent. The type species, Acanthoatractis xinguensis n. gen., n. sp., has nine pairs of caudal papillae and a single papilla anterior to the cloacal lip. The new species is the seventh record of an atractid genus parasitizing P. unifilis. [Display omitted] • A new genus and species of atractids parasitizing freshwater turtles from the Amazon region. • Acanthoatractis n. gen. differs from all other genera by the shape of sclerotized structures on the cephalic end. • This is the 27th genus of the family Atractidae. • This is the seventh record of an atractid genus parasitizing Podocnemis unifilis. [ABSTRACT FROM AUTHOR]

Objective. Evaluate different venipuncture points and the use of two anticoagulants to obtain blood samples in turtles. Materials and methods. Eighty-two turtles of the species Trachemys callirostris, Podocnemis unifilis and Chelonoidis carbonaria were sampled. Three venipuncture points were evaluated: subcarapacial venous sinus, dorsal coccygeal vein, and jugular vein. Two anticoagulants were tested: sodium heparin and EDTA. Results. The jugular vein was the best place to practice venipuncture as the blood samples obtained were free of hemodilution and enough volume to carry out a blood profile. In contrast, samples from the other venipuncture points were usually hemodiluted. Blood samples from C. carbonaria stored with EDTA (40 µl/ml of blood) showed haemolisis, which was not observed using sodium heparin (100 UI/ml of blood) as anticoagulant. Conclusions. The jugular vein is the most recommended venipuncture site for the extraction of blood samples for clinical purposes. Sodium heparin was the best anticoagulant to store blood samples due to the fact that it does not induce haemolisis in any sample. [ABSTRACT FROM AUTHOR]

ABSTRACT: Knowledge of suitable methods and reagents for assessing the health condition of specimens of a given species is essential. The present study evaluated the efficacy of the heparin anticoagulants 5,000 I.U. mL-1, Na2EDTA, and K3EDTA on the blood parameters of yellow-spotted amazon river turtle Podocnemis unifilis, employing different solutions for red blood cells count. The use of the various anticoagulants evaluated after 10 hours of storage efficiently inhibited coagulation in blood samples from P. unifilis. An increased number of erythrocytes was observed with the use of K3EDTA 5% when compared with heparin. Statistically significant changes in the erythrocyte number were observed with the use of the different solutions. Solutions which featured sodium citrate and formaldehyde in their composition, allowed erythrocytes counting up to 120 hours after blood collection, without a change in values. The use of the heparin anticoagulants 5,000 I.U. mL-1, Na2EDTA 3%, Na2EDTA 5%, K3EDTA 3% was recommended in the hematological analysis of P. unifilis. Also recommended was the use of the formaldehyde-citrate solution containing 1.9 g of sodium citrate and 1.0 mL of formaldehyde (in 50 mL of distilled water) to perform red blood cells counts in yellow-spotted amazon river turtle.

Hydropower dams are associated with adverse impacts on biodiversity, yet there remains a lack of robust scientific evidence documenting the magnitude of these impacts, particularly across highly biodiverse tropical waterways. Aquatic and semi‐aquatic vertebrates are disproportionately affected by human changes to aquatic environments and hydropower expansion is an increasing threat to the Endangered yellow‐spotted river turtle (Podocnemis unifilis) across its tropical South American range.Yellow‐spotted river turtle nesting areas were monitored as an indicator of dry season river level changes following run‐of‐river dam reservoir filling. A before–after control–impact (BACI) study design was used with multi‐year field campaigns monitoring turtle nesting areas upstream of the dam.The cause and extent of changes in nesting areas were established using generalized additive models. Nesting area density was evaluated in relation to time (before vs. after), treatment (control vs. impact), time–treatment interaction (BACI), distance to the dam and precipitation. The extent of changes was examined by comparing the remaining proportion of nesting areas after reservoir filling.Dam construction generated an immediate and apparently permanent dry season river‐level rise that extended more than 20 km beyond impact assessment limits. On average the density of nesting areas declined by 69% (from 0.48 to 0.15 per km) across 33 km of river directly affected by the dam. This loss was reflected in a significant BACI interaction. Nesting area density was not explained by seasonal precipitation.Monitoring of freshwater turtle nesting areas provided an effective means to quantify hydropower dam impacts across biodiverse yet rapidly changing waterways. The adverse impacts documented in this study should be preventable by mitigation actions including habitat creation and dry season flow regulation. Such measures are also likely to benefit multiple sandbar‐nesting species (including turtles, crocodiles and birds) in tropical rivers increasingly influenced by run‐of‐river dams. [ABSTRACT FROM AUTHOR]

Objetivo. Evaluar diferentes puntos de venopunción y el uso de dos anticoagulantes para la obtención de muestras sanguíneas en tortugas. Materiales y métodos. Se muestrearon 82 individuos de las especies Trachemys callirostris, Podocnemis unifilis y Chelonoidis carbonaria. Los puntos de venopunción evaluados fueron: seno venoso subcaparacial, vena coccígea dorsal y vena yugular; y se compararon dos anticoagulantes: heparina de sodio y EDTA. Resultados. A partir de la vena yugular se obtuvieron muestras sanguíneas sin hemodilución y en un volumen suficiente para realizar análisis hematológicos. Por el contrario, a partir de los otros sitios de venopunción se obtuvieron mayoritariamente muestras hemodiluidas. Las muestras de sangre obtenidas a partir de C. carbonaria se hemolizaron tras su almacenamiento en EDTA (40 µl/ml de sangre), lo que no se evidenció al utilizar heparina de sodio (100 UI/ml de sangre) como anticoagulante. Conclusiones. La vena yugular es el sitio de venopunción más recomendable para la extracción de muestras sanguíneas con fines clínicos. La heparina de sodio fue el anticoagulante de elección para almacenar dichas muestras al no inducir hemólisis en estas.

The endangered yellow-spotted river turtle (Podocnemis unifilis) has experienced a dramatic population decline in the Ecuadorian Amazonia, mainly due to overexploitation of its eggs. To reverse this trend, the Wildlife Conservation Society has developed a head-start program in Yasuní National Park since 2008, but the potential risk that microbes associated with its eggs might represent for hatching success has not been evaluated yet. Members of the Fusarium solani species complex (FSSC) are involved in egg failure in sea turtles under natural and hatchery conditions, but their role in infecting the eggs of P. unifilis is unknown. In this study, we collected eggshells of P. unifilis and obtained 50 fungal and bacterial isolates. Some potentially pathogenic fungi of the genera Fusarium, Penicillium and Rhizopus were identified based on molecular data. Most importantly, the sea turtle pathogenic species F. keratoplasticum not only was present, but it was the most frequently found. Conversely, we have also isolated other microorganisms, such as Pseudomonas or Phoma-like species, producing a wide spectrum of antifungal compounds that may have a protective role against fungal diseases. Our survey provides useful information on potential pathogens found in P. unifilis eggshells, upon which the success of conservation programs may depend. [ABSTRACT FROM AUTHOR]

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 center and incubated. Hatchlings emerged from eggs that had remained underwater for up to two days. Hatchlings were maintained in 250-500 L nursery tanks until yolk sac scars had closed. Healthy hatchlings were then immediately released around the original nesting areas. We released 599 hatchlings (60.4%) from 991 submerged eggs and hatchlings. Egg survival (61.7% (571/926)) was substantially less than hatchling survival (94.2% (599/636)) but within the expected range of values reported for this species. These findings suggest that Yellow-spotted river turtle eggs and embryos are resistant to short-term submersion, which could help explain the widespread distribution of this species across highly seasonal Amazonian rivers. Management plans should take the possible survival of submerged eggs into consideration as part of species conservation and recovery actions. [ABSTRACT FROM AUTHOR]

Nest‐site selection exerts a fundamental maternal effect on offspring fitness in oviparous species. In many freshwater turtles, females do not care for their eggs after oviposition but rather rely on a nest's micro‐environment to incubate developing embryos although linkages between oviposition choices and overall fitness remain poorly evaluated. We tested predictions derived from multiple hypotheses to examine nesting patterns of the yellow‐spotted river turtle Podocnemis unifilis, a species imperiled by egg harvesting by humans throughout its range, based on data collected from 73 nesting sites along 118 km of river in the eastern Brazilian Amazon. Nesting area size largely explained nest‐site selection by turtles, but only weakly explained turtle egg harvesting by humans. Despite the wide availability of alternative nesting habitats, turtles do not appear to be capable of avoiding hazardous nesting sites associated with increased egg harvesting by humans. Because signals used by female turtles to select nesting areas are apparently not sufficient for avoiding nesting along rivers accessible to humans, direct conservation action will be vital for persistence of these and likely other Amazonian freshwater turtles. [ABSTRACT FROM AUTHOR]

Sustainable use as a mechanism for the conservation and recovery of exploited wildlife populations remains intensely debated, including for freshwater turtles, a diverse and imperiled group of aquatic reptiles that are an important food source for many residents of tropical regions. Here we evaluated the geographical extent of recovery options for a heavily exploited tropical freshwater turtle fauna across 8.86 M km2 of South American river catchments under scenarios of Business-as-Usual (BAU), Protection (Pr) and Community-Based-Management (CBM). For the widespread indicator species, Podocnemis unifilis , demographic analysis showed that populations subject to moderate levels of female harvest (≤10%) can recover over broad areas if concurrent headstarting of hatchlings is practiced more widely. With regional strengthening of the protected area network unlikely, CBM developed with harvest frameworks derived from demographic rates appropriate to tropical species could catalyze a rapid continental scale recovery of Amazonian freshwater turtles within a few decades. • Although 32.7% of pan-Amazon rivers are protected, 57.2% (124 K km) are both accessible to turtle harvesters and unprotected. • Severe (≥50%) and rapid (<50 year) population losses were projected across 60% of the pan-Amazonian range (5.3 M km2). • Protected areas alone are insufficient to ensure the future range-scale viability of populations. • If community-based management (CBM) is implemented we predict fourfold continental scale population increase within 50 years. • This and related turtles have potential for continental scale conservation gains if CBM can be supported over broad areas. [ABSTRACT FROM AUTHOR]

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 Xingu River basin. Fourteen organochlorine pesticides were analysed via gas chromatography with an electron capture detector (CG-ECD). Eight organochlorine pesticides were detected with average concentrations of ∑DDT, ∑Endossulfan and ∑HCH which were 26.17 ± 26.35, 14.38 ± 23.77 and 1.39 ± 8.46 ng g−1 in moisture content, respectively. DDT compounds were the most predominant, with a greater concentration of pp′-DDT in the liver and pp′-DDD in the muscle. Significant differences were noted between the types of tissues studied, and the concentration of OCPs varied between sampling sites. [ABSTRACT FROM AUTHOR]

The yellow-spotted river turtle ( Podocnemis unifilis) plays ecological roles in the Amazonian aquatic ecosystem and has cultural and economic significance for indigenous peoples. Because spatial ecology and movement data are nonexistent for this species, we radio tracked 63 individuals in the Napo River between August 2015 and February 2017. Mean linear range size was 16.2 km ( n = 31) and mean home range size was 5.2 km2 ( n = 27). Our results are the first range size estimates for P. unifilis and suggest that the species could be treated as a short-distance facultative migrant with local seasonal movements. [ABSTRACT FROM AUTHOR]

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; meronts that are usually broad and slightly curved (kidney-shaped), with an average of eight small rectangular nuclei; immature gamonts (bean-shaped) with two morphological types: one with nuclear chromatin dispersed in the cytoplasm and the other with nuclei in the middle of the cell; mature gamonts of two morphological types: one with a length equal to or greater than that of the erythrocyte and the width of the nuclei similar to that of the hemoparasite and the other smaller than the erythrocyte with the width of the nuclei less than that of the hemoparasite. This is the first hemogregarine species described that infects the Brazilian turtle Po. unifilis. These findings highlight the need for further studies of Haemogregarina spp. to better determine the biodiversity of this understudied parasite group. [ABSTRACT FROM AUTHOR]

In oviparous vertebrates lacking parental care, resource allocation during reproduction is a major maternal effect that may enhance female fitness. In general, resource allocation strategies are expected to follow optimality models to solve the energy trade-offs between egg size and number. Such models predict that natural selection should optimize egg size while egg number is expected to vary with female size, thus maximizing offspring fitness and consequently, maternal fitness. Deviations from optimality predictions are commonly attributed to morphological constraints imposed by female size, such as reported for small-bodied turtle species. However, whether such anatomical constraints exist in smaller-bodied females within large-bodied clades remains unstudied. Here we tested whether resource allocation of the river turtle Podocnemis unifilis (a relatively smaller member of the large-bodied Podocnemididae) follows optimality theory, and found a pattern of egg elongation in smaller females that provides evidence of morphological constraints and of a reproductive trade-off with clutch size, whereas egg width supports the existence of an optimal egg size and no trade-off. Moreover, larger females laid larger clutches composed of rounder eggs, while smaller females laid fewer and relatively more elongated eggs. Elongated eggs from smaller females have larger volume relative to female size and to round eggs of equal width. We propose that elongated eggs represent a solution to a potential morphological constraint suffered by small females. Our results suggest that larger females may optimize fitness by increasing the number of eggs, while smaller females do so by producing larger eggs. Our data supports the notion that morphological constraints are likely more widespread than previously anticipated, such that they may not be exclusive of small-bodied lineages but may also exist in large-bodied lineages. [ABSTRACT FROM AUTHOR]

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 conducted surveys along 150 km of rivers upstream of a new dam construction during the low water months that correspond to the nesting season of Podocnemis unifilis in the study area. Comparison of nest-areas before (2011, 2015) and after (2016) reservoir filling show that reservoir impacts extend 13% beyond legally defined limits. The submerged nesting areas accounted for a total of 3.8 ha of nesting habitat that was inundated as a direct result of the reservoir filling in 2016. Our findings highlight limitations in the development and implementation of existing Brazilian environmental impact assessment process. We also propose potential ways to mitigate the negative impacts of dams on freshwater turtles and the Amazonian freshwater ecosystems they inhabit. [ABSTRACT FROM AUTHOR]

Habitat, population structure and consume of these resources by indigenous communities are determining factors for management and conservation of amazonian chelonians. The objectives of this research were: to identify the habitat types, to describe hunting patterns and to analyze population situation Podocnemis expansa and P. unifilis adult females. Therefore we researched and catalogued every habitat type used by turtles and the use of the community in the Curare – Los Ingleses reserve during hydrologic cycle period of Caquetá River, from March 2008 to January 2009. Caimán Port was the area with most incidents of two species during low-water period. On this place there were preserved 56 nests of P. unifilis. The indigenous community consumed mostly the nests on beaches close to the river. The capture effort on this sector it was 0,78 animals/day. Indigenous used cords and camuri in low waters close to nesting beaches, capturing overwhelmingly young of P. unifilis with sizes between 15 - 35 cm (N=23; X : 25,45; DS: 0,19) and adults females 36 - 55 cm (N=16; X =43,24; DS: 5,91). From nine studied beaches, eight were used by indigenous communities for catching eggs. We recommend making managements arrangements between Traditional Indigenous Authorities Criacia (Consolidation of Curare – Los Ingleses reserve) and pani (Indigenous from Cahuinari and three isles) in Bernardo – Zumaeta sector, with the government support and ngo. The start of co-managements and monitoring activities in the habitats is important in order to recommend management options of beaches and to control capture of chelonians methods.

Timing of nesting affects fitness of oviparous animals living in seasonal environments, and females may cue on environmental factors for their nesting behavior, but these relationships are understudied in tropical turtles. Here, the timing and synchrony of egg-laying relative to environmental factors were examined in the South American freshwater turtle Podocnemis unifilis on 11 nesting beaches during three nesting seasons. Daily measurements included number of nests laid, rainfall, river level, air temperature, and the phase of the lunar cycle (full moon, last quarter, new moon and first quarter). Results confirmed that P. unifilis nested at night and revealed that females in our population nest in groups from 2 to 17 females at a time. Nesting was not correlated with rainfall, but a significant relationship was found with river level, such that nesting started at the onset of the dry season when river levels dropped and nesting grounds emerged. Importantly, we found that (1) nesting events concentrated on days with intermediate daily maximum air temperature (although maxima changed annually), and that (2) larger groups of females nested around full moon, suggesting the reliance on visual cues to initiate nesting activities (consistent with social facilitation behavior). Altogether, the timing of nesting in P. unifilis may be shaped by a combination of environmental factors, moon phase and social facilitation, where visual cues play an important role.

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 nucleotides and this sequence did no match any of the Myxozoa available in the GenBank. Phylogenetic analysis identified the new species as a sister species of Myxidium turturibus , the unique Myxidium species described in a Neotropical turtle. Nevertheless, the SSU rDNA sequences of the new species and M. turturibus have only a 91.5% similarity. This is the first description and molecular study of a Myxozoa in a reptile from Peru. Considering the status of P. unifilis as vulnerable species, the infection by Myxidium parasites is emphasized as possible disease impeller, representing menace to the turtle conservation. [ABSTRACT FROM AUTHOR]

El presente trabajo registra por primera vez para el Perú a Nematophila grandis (Diesing, 1839) Travassos, 1934, en la tortuga de río Podocnemis unifilis «taricaya». Los hospederos fueron colectados en las localidades del Río Putumayo, Samiria, Iquitos (Loreto) y Manu (Madre de Dios). El material identificado pertenece a la Colección Helmintológica del Departamento de Protozoología, Helmintología e Invertebrados Afines del Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos.

Podocnemis expansa e P. unifilis são animais de vida longa, com uma demorada maturação sexual, o que influencia uma baixa taxa de substituição de indivíduos. Suas populações são caracterizadas por uma pequena mortalidade dos animais adultos, mas alta taxa de mortalidade de filhotes e embriões. Sendo a predação natural de ninhos e filhotes um dos fatores mais importantes do baixo sucesso de eclosão dessas espécies. No rio Javaés, os ovos e recém-eclodidos podem ser predados por uma grande diversidade de animais: dentre as aves, urubus (Coragyps atratus e Cathartes aura), carcará (Polyborus plancus), jaburu (Jabiru mycteria); lagartos (Tupinambis teguixin) e mamíferos de pequeno porte, coati (Nasua nasua) e cachorro-do-mato (Cerdocyon thous). Do total anual de desovas de P. unifilis em média 65,98% são predadas, sendo 41,68% de forma total e 24,30% parcialmente. Enquanto que apenas 5,31% das ninhadas de P. expansa são sempre parcialmente predadas. Dentre os predadores aquáticos existem diversos peixes, principalmente piranhas (Serrasalmus nattereri) e jacarés (Melanosuchus niger e Caimam crocodilus). Os predadores das fêmeas de P. unifilis são: jacaré-açu (Melanosuchus niger), onça-pintada (Panthera onca) e onça-parda (Puma concolor). Enquanto que as fêmeas de P. expansa em postura, somente são predadas por P. onca. As fêmeas de P. unifilis em postura são predadas num total médio de 3,93% anualmente, enquanto que para P. expansa a média anual é 5,66% das fêmeas.Podocnemis expansa and P. unifilis long lived with late sexual maturation, which influences a low replacement rate of individuals. Their populations are characterized by low adults mortality, but high mortality of embryos and hatchlings. The natural nest predation is an important factor for hatchling success. In Javaés River, the eggs and hatchlings can be predated by a large number of animals such as birds, vultures (Coragyps atratus and Cathartes aura), carcará (Polyborus plancus), jabiru (Jabiru mycteria); lizards (Tupinambis teguixin) and small mammals, coati (Nasua nasua) and crab-eating-fox (Cerdocyon thous). About 65,98% of nests of P. unifilis are predated (41,68% totally and 24,30% partially). Only 5,31% of P. expansa nests are partially predated. There are many aquatic predators, like carnivorous fish, mainly piranhas (Serrasalmus nattereri) and caimans (Melanosuchus niger e Caimam crocodilus). The predators of P. unifilis females are: black caiman (Melanosuchus niger), jaguar (Panthera onca) and puma (Puma concolor), and of P. expansa females is the P. onca. In average 3,93% of P. unifilis females are predated annually while that to P. expansa the average is 5,66%.

O casco de Podocnemis expansa (tartaruga-da-amazônia) e Podocnemis unifilis (tracajá), os maiores quelônios de água doce da América do Sul, é uma estrutura única que diferencia esse grupo dos vertebrados atuais e está associado a alguns padrões comportamentais. O padrão dos escudos que compõem o casco dos quelônios é bastante uniforme, mas variações já foram descritas e analisadas para um grande número de espécies em todas as famílias existentes atualmente. Averiguou-se a incidência de irregularidades do padrão de escutelação no casco dessas espécies, durante os anos de 1999 a 2003 no rio Javaés, entorno do Parque Nacional do Araguaia e da Área de Proteção Ambiental Bananal/ Cantão, oeste do estado do Tocantins. P. expansa se apresenta como uma espécie mais suscetível à ocorrência de anormalidades no casco em relação a P. unifilis. Sendo que, dos 14.378 filhotes avaliados, (13,32 %) apresentavam irregularidades no padrão de escutelação enquanto que dos 1.329 filhotes de P. unifilis apenas (4,44 %). Em P. expansa, os defeitos ocorreram quase que em sua totalidade na carapaça (98,64 %) e em menor número (83,05 %) em P. unifilis.The shell of Podocnemis expansa (Amazonian giant River turtle) and Podocnemis unifilis (Yellow-spotted Amazon River Turtle), the largest South American turtles, is a unique structure that differentiates them from other known vertebrates; and it is associated with some of their behavioral patterns. Their scute pattern is quite uniform however variations have been described and analyzed for a great number of other species of existing families. In the Javaés River, from 1999 to 2003, we observed an occurrence of abnormalities in their scute pattern. This was in the vicinity of the Araguaia National Park and the Bananal/ Cantão Environment Protected Area, west of Tocantins state. Of the both species, P. expansa is more susceptible to shell abnormalities. Of 14.378 P. expansa hatchlings observed, 13.32 % presented scute pattern abnormalities, while of 1.329 P. unifilis hatchlings, only 4.44 %. The incidence of abnormalities occurred only in the carapace, namely, 98.64% in P. expansa, and 83.05% in P. unifilis.

The article focuses on a study conducted on the nesting behavior of Podocnemis unifilis, a South American yellow-spotted turtle. It reveals that turtles nest during dry-season low water, usually on high sand beaches more than 1.5 meter above water level. It also mentions that predation on nests by crab-eating foxes and caracaras was found intense in daytime during the study.

The purpuse of this study was to investigated the influence of anthropogenic impacts on Podocnemis unifilis nesting on a stretch from Falsino river, with two forest reserves, and one urban area on the Araguari river, state of Amapá, eastern Amazon (Brazil). A total of 180 nests were found, being 89.4 % in the forest reserves and only 10.6 % in urban areas. On Falsino river, we observed a spawning pattern, because the number of nests was correlated to the length and width of the nesting locations. On Araguari river, the P. unifilis nests were generally found in areas with surrounding vegetation up to 5 meters in height, minimum distance of 120 meters from residences and immediately or after places of higher exploration of pebbles. Females from Falsino river had smaller eggs, but the neonates were bigger and with higher body condition index than the neonates from Araguari river. About 80 % of the nests were prey, mostly because of the large collection of eggs for feeding. Furthermore, it was found that adult turtle hunting has been intense. Although one of the areas is in forest reserves, the human impacts were similar to those caused in urban areas, indicating the need to implement protection programs for the conservation of P. unifilis. [ABSTRACT FROM AUTHOR]

We report the effect of predation by the fire ant Solenopsis geminata on nests of the turtle Podocnemis unifilis in the Piagaçu Purus Sustainable Development Reserve, Amazonas, Brazil. During three consecutive breeding seasons (between September and October of 2012, 2013 and 2014), 492 nests were monitored and 95 (19.3%) were predated. Solenopsis geminata was the main predator, accounting for 65.26% (n=62) of the losses. Nest predation by ants was not correlated with soil exposition time. However, all P. unifilis nests predated by S. geminata were entirely covered by vegetation, suggesting that ants may select nests at specific microhabitat conditions. Studies on larger scales, including areas where S. geminata is naturally absent, are needed to develop an adequate management of P. unifilis. [ABSTRACT FROM AUTHOR]

The prevalence and parasitemia of the piroplasm Sauroplasma sp. were evaluated in the Amazon chelonian Podocnemis expansa in Brazil. Samples were collected from 75 chelonians from 3 locations, including a commercial breeding facility, an indigenous subsistence breeding facility, and a wild population. Sauroplasma were found in 72% (54/75) of the chelonians, and the prevalence varied among the sampling sites. No significant correlations were found between the prevalence and the sex and body condition index of the chelonians. The mean parasitemia rate was 44.14/2,000 erythrocytes (2.2%), and no significant correlation was found between the parasitemia and sex and body condition index of the chelonians. These results suggest that the parasite is not pathogenic to P. expansa. No ectoparasites were found in the animals evaluated in the present study; however, due to the aquatic habit of the chelonian, it is likely that the piroplasm is transmitted by leeches and not by ticks, as would be expected for piroplasms. [ABSTRACT FROM AUTHOR]

Population structure, size and sex ratio in Podocnemis unifilis (Testudines, Podocnemididae) in the Guaporé river (RO), northern Brazil.Population structure and sex ratio of Podocnemis unifilis was studied from June to November 1989 and from March to June 1990 in the Guaporé river and its tributaries São Domingos and São Miguel, in the municipality of Costa Marques, Rondônia, Brazil. The margins of these rivers are not altered much by human activities and the water is not polluted in any way. Turtles were captured using 12 fyke nets. Around 1 % of the captured turtles died using this method. The majority of the turtles was captured in the bays andoxbows (55.8%) and when the water level of the river was declining (N=785). The proportion of adults (73.4 %) in the sample was about three times higher than that of juveniles (26.6 %). The distribution of carapace length in males formed a normal curve, while that of females showed no well-defined pattern. The sex ratio of adults in this population was 9.8 males per female.

Data on clutch size and hatching success of P. expansa were gathered for seven beaches traditionally used by the species and re-analyzed statistically by means of regression analysis, of the number of eggs on the number of females (or nests) and of the number of young on the number of eggs. All regressions were linear, passed through the origin and had excellent fits. Average clutch size varied from 75 to 123, and presented geographic differentiation: (i) Rio Orinoco, (ii) Rio Trombetas + Rio Branco and (iii) Rio Juruá + Rio Purus. Average hatching success was ca. 83%. In P. unifilis there was also geographic variation in clutch size, the Iquitos area showing the highest values. Hatching success of P. unifilis was uniformly high: only one sample, from Iquitos, had less than 90% success. The outstanding fit of the clutch size regressions leads one to consider egg volume variability, which was found to be high in both species, in contradiction with current optimal egg size theory.Dados sôbre tamanho da ninhada e viabilidade dos ovos foram colhidos na literatura para 7 praias tradicionalmente usadas por P. expansa para reprodução, e re-analisados por análise de regressão, do número de ovos sobre o número de fêmeas (ou de ninhos) e de filhotes sobre ovos postos. Todas as regressões foram lineares, passando pela origem, e com altíssimos coeficientes de determinação. O tamanho médio da ninhada variou de 75 a 123, e mostrou diferenciação geográfica: (i) Rio Orenoco, (ii) Rio Trombetas + Rio Branco e (iii) Rio Juruá + Rio Purus. A viabilidade média não mostrou diferenciação geográfica, ficando em cerca de 83%. Em P. unifilis também houve diferenciação geográfica, as amostras da região de Iquitos tendo valores muito altos. A viabilidade média foi alta: apenas uma amostra, de Iquitos, teve sucesso inferior a 90%. Os altos valores do coeficiente de determinação levam à consideração do volume dos ovos, que se revelou muito variável em ambas espécies, em contradição com idéias correntes sobre teoria do volume ótimo dos ovos.

We obtained 8 digestive tract of the turtle Podocnemis expansa and 18 of P. unifilis from the Belen market (Iquitos, Peru). Only digeneans were studied and identified. Four species were found: Nematophila grandis (Diesing, 1839) Travassos, 1934, Halltrema avitellina Lent & Freitas, 1939, Podocnemitrema papillosum Alho & Vicente, 1964 and Telorchis hagmanni Lent & Freitas, 1937. Halltrema avitellina, Podocnemitrema papillosum and Telorchis hagmanni are new records from Peru.

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Chelonians are very promising models to explore the role of chemical communication in social contexts. However, it still remains unknown how chemical signals may influence most behavioural patterns in turtles. In this study, we examined whether juvenile yellow-spotted river turtles (Podocnemis unifilis) use chemical cues released into water by other conspecifics to orientate towards them. To test our hypothesis, we compared the behavioural response (i.e., activity level and latency time) of juveniles when exposed to chemical stimuli obtained from other conspecifics (i.e., other juveniles and adult females), as compared to their response in clean water (i.e., the baseline). The results obtained in the study showed that juvenile P. unifilis increased their activity in response to chemical cues of female adult conspecifics. These findings suggest that juvenile turtles may chemically orientate themselves towards adult females during migratory processes. Efficient detection of conspecific chemical cues by juveniles is necessary for particular individuals to aggregate before migrating to habitats with more abundant food resources. Our study provides a framework for future research that should disentangle the role of chemical cues in mass migration of freshwater turtles. [ABSTRACT FROM AUTHOR]