Peltocephalus Research Articles

Gastrointestinal parasites of Peltocephalus dumerilianus (Testudines: Podocnemididae) from Jaú National Park, Brazilian Amazon.

The big-headed Amazon River turtle, Peltocephalus dumerilianus, is endemic to the Orinoco and Amazon River basins. It is a food source for local communities, often unsustainably. Knowledge about P. dumerilianus' parasitological fauna and host-parasite relationships is limited. Thus, ecological aspects of gastrointestinal parasitism in this species were investigated. Helminths were found in the gastrointestinal tract of 21 turtles, morphologically identified, and infection descriptors calculated. All animals harbored helminths: nematodes Ancyracanthus pinnatifidus, Paratractis hystrix, Atractis trematophila, Klossinemella conciliatus indeterminate three Klossinemella species, and digeneans Nematophila grandis, Helicotrema spirale, and Telorchis hagmanni. The highest parasite load occurred in the large intestine, followed by the small intestine and stomach. Shell length directly correlated with parasite burden of heteroxenic helminths, with males having higher burden than females. This is the first record of A. trematophila, K. conciliatus, and T. hagmanni in P. dumerilianus, and new location record for A. trematophila, P. hystrix, N. grandis, H. spirale, and T. hagmanni. Three potentially new Klossinemella species are presented.

Orientatractis bowseri n. sp. (Nematoda: Cosmocercoidea: Atractidae) parasite of Peltocephalus dumerilianus (Schweigger) (Testudines: Podocnemididae) from the Brazilian Amazon.

Peltocephalus dumerilianus (Schweigger) is a diurnal freshwater turtle widely distributed in the Orinoco and Amazon River basins in Brazil, Colombia, Peru, Ecuador, Venezuela, and French Guiana. During a helminthological survey of freshwater turtles from the Brazilian Amazon, numerous nematodes with characteristics of the genus Orientatractis Petter, 1966 were recovered from the stomach of Peltocephalus dumerilianus. These nematodes were different from all congeneric species, and we describe herein. Orientatractis bowseri n. sp. differs from all known species of the genus by having dorsal cuticular projections on the posterior region of the females, distribution of caudal papillae and by having papilla-like ornamentations on the cuticle distributed from the mid-esophagus to the mid portion of the body. This study represents the fourth specie of the genus Orientatractis reported in Brazil, the seventh species of Orientatractis in the Neotropical region, and the third found infecting freshwater turtles in Brazil.

Temporal and Spatial Stability on the Population Structure of Consumed and Illegally Traded Big-Headed Amazon River Turtle in the Negro River Basin, Central Amazon, Brazil

Freshwater turtles are a valuable food resource for riverine human communities and have been historically overharvested throughout all major tropical large river basins, with consequent gradual population decreases. Even species considered to be abundant are declining, and in many cases were brought to a condition of near extinction. The collection of adult females during breeding season on nesting beaches is considered a major factor in population decline and subsequent loss of food sources for humans. There is growing consensus that adult females constitute the category which turtle populations can least afford to lose. In the Negro River Basin, the podocnemidid big-headed Amazon River turtle,Peltocephalus dumerilianus, is heavily exploited for consumption and poached for illegal trade among riverine communities and cities. Between 1997 and 2002 and in 2019, we measured live turtles and carapaces of big-headed turtles in the city of Barcelos and its surroundings, and among the riverine families living in the Jaú National Park. We compared body sizes and sex ratios between areas, periods, and between consumed and traded individuals. We found no differences between areas, even those close to Barcelos and the ones belonging to remote areas where pressure levels are lower. The individuals consumed in Jaú National Park are larger than those poached for illegal trade in both areas. There was an increase in average size between 1997 and 2002. Sex ratio was slightly skewed toward males, which were larger, and did not differ between areas and periods. Results indicate stability on size of harvested populations, which may be supporting current extraction levels. Data suggest this could be related to the absence of adult female capture during nesting for this species. We recommend protection strategies for other Amazon Podocnemidid species that focus on the protection of nesting beaches and surrounding areas where adults occupy, specifically in areas under communal protection.

Biology of the Big-headed Amazon River Turtle, Peltocephalus dumerilianus (Schweigger, 1812) (Testudines, Pleurodira): the basal extant Podocnemididae species

We review the extent and nature of scientific knowledge of the Big-headed Amazon River Turtle, Peltocephalus dumerilianus, covering distribution, morphology, taxonomy, diet, behaviour, reproduction, and ecology. We discuss the phylogenetic position of the species and its evolutionary relationships with the other podocnemidids, comparing morphological, karyological and molecular information. Also, we describe the importance of this species and its relationship with traditional Amazonian communities, including capture techniques, uses, beliefs and taboos. Finally, we comment on the conservation status of the species and the urgent need for additional studies. Besides discussing and reinterpreting published data, we provide new information from recent genetic studies, field activities and captive observations.

Predation by white-fronted capuchin monkeys, Cebus albifrons on eggs of three species of freshwater turtles in Brazilian Amazonia: solitary nests are also depredated

ABSTRACT Although freshwater turtles are well-known for group nesting, most species are solitary nesters, often deploying nest concealment to reduce egg predation risk. Records of predation on such taxa are much less common than on synchronously nesting species, most likely due to the scattered distribution and inconspicuousness of such nests. Here, we report depredation in Jaú National Park, Amazonas, Brazil, by a diurnal generalist Neotropical primate (White-fronted capuchin, Cebus albifrons), on nests of three freshwater turtle species (Kinosternon scorpioides, Peltocephalus dumerilianus, both obligate solitary nesters, and Podocnemis erythrocephala, which does so facultatively). The species involved were identified by distinct characteristics of the eggs and nests (turtles), and impressions of the hands and feet (primates). While the current report shows that nests are subject to predation by generalist species such as white-fronted capuchins, the extent to which this impacts local turtle populations remains unclear. Further studies should address whether or not this is a general phenomenon or the result of a local foraging strategy by the primate concerned. Field-based, preferably long-term, studies are recommended to answer such questions.

Hematologycal and blood biochemistry parameters of captive big-headed amazon river turtles, Peltocephalus dumerilianus (Testudines: Podocnemididae)

The determination of hematological values is used to obtain knowledge about the health conditions of animal species. The big-headed Amazon River turtles, (Peltocephalus dumerilianus)are considered one of the least known testudine species concerning their biology and health status. Herein, we determined the hematological and plasma biochemical parameters of 17 (eight males and nine females) adult P. dumerilianusto provide reference interval values for clinically healthy individuals. We collected the blood samples by puncturing the femoral vein using long heparinized hypodermic syringes. Sexual dimorphism for individuals was determined by external observation of the shape of the plastron. The average values obtained for the ten hematological and biochemical parameters analyzed were red blood cell count = 0.32 million µL-1; hematocrit = 20.6 %; hemoglobin = 8.5 g dL-1; mean corpuscular volume = 681.6 fL; mean corpuscular hemoglobin = 267.8 pg; mean corpuscular hemoglobin concentration = 41.9 g dL-1; glucose = 80.6 mg dL-1, total protein = 4.1 g dL-1, triglycerides = 388.9 mg dL-1, and total cholesterol = 79.3 mg dL-1. Despite the sexual dimorphism evidenced for the species, there was no significant statistical difference between males and females for both hematological and biochemical parameters analyzed herein. Based on these results, the population is considered healthy, with parameter values coinciding with previously reported reference ranges for testudines species in the region. The results obtained in this study can be used for assessing the health status of other Amazonian turtle populations, especially in actions aimed at cultivation strategies, management, and species conservation.

Morphology of the Digestive Tube of the Podocnemididae in the Brazilian Amazon

Abstract: We describe the morphology of the digestive tube of Podocnemis expansa, Podocnemis unifilis, Podocnemis sextuberculata, Podocnemis erythrocephala, and Peltocephalus dumerilianus. The esophagus in these species has two distinct regions: the anterior region has esophageal papillae and the posterior has longitudinal folds. Esophageal glands are absent but goblet cells occur in the mucosa of esophagus. The stomach in P. expansa, P. unifilis, and P. erythrocephala has two regions: the anterior region consists of cardiac and fundic regions and is without glands; the more-posterior pyloric region contains gastric glands that extend into the lamina propria. In P. sextuberculata, the stomach is a J-shape, and in Peltocephalus dumerilianus the stomach is a C-shape with a larger curvature to the left side. The stomachs of these two species have numerous gastric glands in all regions. The small intestine (SI) in all species is a long, coiled tube and has folds and villi that appear different in each region...

The lowest diploid number in Testudines: Banding patterns, telomeric and 45S rDNA FISH in Peltocephalus dumerilianus, 2n = 26 and FN = 52 (Pleurodira, Podocnemididae)

The karyotype of the big-headed Amazon River turtle, Peltocephalus dumerilianus, is characterized based on a sample of seven juveniles from Reserva Biológica do Rio Trombetas, Pará State, Brazil (1°30' S, 56°34' W). Here we present the first results on GTG and CBG-banding patterns, Ag-NOR staining and FISH, with telomeric and 45S rDNA sequences as probes. A cytogenetic comparison with related Podocnemidae is also provided.

Biology and Conservation of the Freshwater Turtles and Tortoises of Peru

Little information has been published on Peruvian chelonians. Here we have compiled the available literature pertaining to Peruvian freshwater turtles and tortoises on four topics: Human consumption and ethnobiology, habitat use, status and abundance, and reproduction. In addition, we provide a map of the regions of Peru showing the number of research records and the number of species that occur in each region. Reproduction was the topic most frequently studied, although investigations were concentrated on only three species (Podocnemis unifilis, P. expansa, P. sextuberculata). The regions where the most studies were implemented are the Departamentos de Loreto and Madre de Dios, with studies tending to be concentrated in the vicinity of Iquitos, the Pacaya-Samiria National Reserve, and Manu National Park and its buffer zone. In general, regions in which more research effort was evident reported more turtle species, which suggests that the least-studied states could have more species, as they share the same types of habitats as the more intensely investigated regions. We identified major gaps in information and suggest future research in the following poorly studied Peruvian regions: Departaments of Junín, San Martín, Tumbes, Huanuco, Amazonas, Cusco, Ayacucho, Puno, Huancavelica, and Cajamarca. The status, distribution, and abundance of Peruvian populations of Podocnemis expansa, P. unifilis, Chelonoidis carbonaria, Peltocephalus dumerilianus, and Mesoclemmys heliostemma are in particular need of study. Conservation priorities are also discussed.

Ciclo ovárico y jerarquía folicular de Peltocephalus dumerilianus (Testudines: Podocnemididae)

Se analizaron cuarenta pares de ovarios de hembras adultas de Peltocephalus dumerilianus (Schweigger 1812), para establecer los cambios morfológicos mensuales producidos durante un año. Se llevaron a cabo exámenes macroscópicos de los oviductos y de los ovarios de especímenes que los habitantes ribereños del municipio de Barcelos, Amazonas, Brasil, utilizaron para su consumo, usando metodológicamente la medida del diámetro y conteo de los folículos ováricos y de los cuerpos lúteos. Los resultados muestran la presencia gradual de folículos acorde con la época reproductiva, resaltando que durante el último tercio del proceso, justo antes de la postura se hacen más evidentes; se analiza la relación existente entre el tamaño de la hembra y la masa ovárica, la cual es estadísticamente significativa (F (10,29)=3,655, p < 0,05). Se hace evidente la existencia de una jerarquía ovario folicular que demuestra que para esta especie solo es posible fisiológicamente una postura por año.

(crocodylia: alligatoridae) como consumidor oportunista de tortugas en su ambiente natural

En el presente trabajo se hicieron observación de depredadores potenciales de quelonios existentes en el medio río Negro, municipio de Barcelos, Amazonas, Brasil. Se trabajó en dos localidades del municipio de Barcelos: Igarapé del río Negro Lodge y Arirá. Para la captura científica de los quelonios se utilizaron mallas y trampas de red, en las cuales además se atrapaban peces y algunos caimanes negros que entraban para comer y que eran registrados visualmente y por la evidencia de daño causado en las tortugas. En general los Crocodylia Rev. Colombiana cienc. Anim. 2(2).2010 ORIGINAL 245 incluyen en su dieta quelonios, siendo Melanosuchus niger (caimán negro) registrado por primera vez para esta área de trabajo como depredador de tortugas: Podocnemis erythrocephala (irapuca) y en especial de Peltocephalus dumerilianus (cabezudo). La relación existente entre depredador y presa en este caso muestra poca documentación, a pesar de existir una amplia variedad de estudios relacionados.

Uses and Taboos of Turtles and Tortoises Along Rio Negro, Amazon Basin

Abstract Chelonians (turtles and tortoises) of the Amazon Basin have constituted a source of food for native populations since pre-Columbian times and have continued to be an important product for subsistence and cash income. Little is known about current levels of exploitation and pressure on natural stocks, despite observations of declining populations of the larger and most valued species. This study investigates how people living in the Negro River area use Amazonian chelonians, including issues of consumption, preferences, restrictions, segmentary taboos, harmfulness, medicinal use, and sale. We conducted interviews with fishing families in the city of Barcelos and in Jau National Park, both located in the Rio Negro basin, in the state of Amazonas, Brazil. All chelonian species are used by these riverine people, especially for food. Peltocephalus dumerilianus is caught year round, whereas the capture of other species is more frequent during the dry season. Terrestrial species are collected whenever f...

Arsenic, Cadmium, Chromium, Lead, Mercury, and Selenium Levels in Blood of Four Species of Turtles from the Amazon in Brazil

Using blood as a method of assessing metal levels in turtles may be useful for populations that are threatened or endangered or are decreasing. In this study the levels of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and selenium (Se) in blood of four species of turtles from the tributaries of the Rio Negro in the Amazon of Brazil were examined. The turtles included the six-tubercled Amazon (river) turtle (Podocnemis sextuberculata), red-headed Amazon (river) turtle (Podocnemis erythrocephala), big-headed Amazon (river) turtle (Peltocephalus dumerilianus), and matamata turtle (Chelus fimbriatus). Blood samples were taken from the vein in the left hind leg of each turtle. There were significant interspecific differences in the sizes of the turtles from the Rio Negro, and in concentrations of Pb, Hg, and Se; the smallest species (red-headed turtles) had the highest levels of Pb in their blood, while Se levels were highest in big-headed turtles and lowest in red-headed turtles. Hg in blood was highest in matamata, intermediate in big-headed, and lowest in the other two turtles. Even though females were significantly larger than males, there were no significant differences in metal levels as a function of gender, and the only relationship of metals to size was for Cd. Variations in metal levels among species suggest that blood may be a useful bioindicator. Metal levels were not high enough to pose a health risk to the turtles or to consumers, such as humans.

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 potential health risk to humans and other receptors that eat them, as well as their potential use as bioindicators. The effect of sex, weight, and carapace length on Hg concentrations in turtle muscle was examined to determine if the levels represent a health risk to riverine people. There was a significant interspecific difference in Hg levels but no differences as a function of size or gender. The highest Hg level was found in Chelus fimbriatus (mean = 432 ppb, standard deviation +/- 196 ppb), followed by Peltocephalus dumerilianus (106 +/- 41 ppb), Podocnemis expansa (62 +/- 49 ppb), P. sextuberculata (61 +/- 40 ppb), P. unilifis (35 +/- 17 ppb), and P. erythrocephala (33.1 +/- 17 ppb). Of the species studied, the piscivorous C. fimbriatus had the highest Hg level. Hg levels in turtles were similar to the levels found in fish from the same basin. Levels of Hg in the muscle of C. fimbriatus are sufficiently high to pose a potential risk to humans who consume them. This study represents the first comparative study of Hg levels in muscle of six species of turtles.

Phylogenetic relationships of the Bauru Group turtles (late Cretaceous of south-central Brazil)

No chelonian of the Bauru Group (Late Cretaceous of south-central Brazil) has so far been included in a numerical cladistic analysis with an explicit taxon-character data matrix. Out of the five taxa formally described from that stratigraphic unit, those based on more complete specimens - Bauruemys elegans, Cambaremys langertoni, and Roxochelys wanderleyi - were considered in a cladistic study of the pro-Podocnemidae Pelomedusoides. The resulting hypothesis of relationships places the specimen known as FR-4922 and Brasilemys josai among Pelomedusoides basal to Podocnemoidea. Within that clade, the Bauru Group taxa lie basal to Podocnemidae. Roxochelys is revealed to be a monophyletic genus, closer to Podocnemidae than the other analyzed Cretaceous forms. Among these, Bauruemys elegans is more derived than Portezueloemys patagonica, while the position of Cambaremys langertoni is ambiguous. Within extant Podocnemidae, a sister group relationship between Peltocephalus dumerilianus and Erymnochelys madagascariensis is proposed.

Turtles of the Tiputini Biodiversity Station with remarks on the diversity and distribution of the Testudines from Ecuador

Ten species of Testudines, from four different families: Chelidae, Kinosternidae, Podocnemididae, and Testudinidae, are reported from the Tiputini Biodiversity Station (Universidad San Francisco de Quito), northeastern Amazonian Ecuador; including the second report from Ecuador of Batrachemys heliostemma. These ten species are sympatric but not completely syntopic, thus I comment on their diversity and habitat preferences patterns. The general distribution of some turtles from Amazonian Ecuador is discussed, providing additional records and distribution maps for Chelus fimbriatus, Platemys platycephala, Batrachemys heliostemma, Batrachemys raniceps, Mesoclemmys gibba, Phrynops geoffroanus, Kinosternon scorpioides, and Geochelone denticulata. The presence of Peltocephalus dumerilianus in Amazonian Ecuador is confirmed; based on re-examination of specimens previously reported by Dr. Gustavo Orcés in 1949. The total Ecuadorian richness of Testudines species includes 31 living taxa, and I provide an annotated list of the turtles and tortoises of mainland and insular Ecuador. Much information is still needed in order to understand the ecological relationships of the Testudines from Ecuador and future research should focus on long-term studies designed to answer several questions about their biology and ecology. Several threats are currently jeopardizing the long-term conservation of turtle populations in Ecuador, and we must increase our knowledge on these amazing animals in order to protect and preserve them.

Haemoproteus (Apicomplexa: Haemoproteidae) of tortoises and turtles.

It is the general opinion that the haemoproteid blood parasites of chelonians belong to the genus Haemoproteus. Different specific names have long been assigned to this parasite in birds, but some past authorities have accepted only a single species, H. metchnikovi, for all those haemoproteids recorded in a wide range of chelonian genera throughout the world. In the present study, a comparison of one such organism in the tortoise Geochelone denticulata with another in the river turtle Peltocephalus dumerilianus, from Amazonian Brazil, has revealed clear morphological differences. These distinguish the parasites from each other, H. metchnikovi and the other named species of chelonian Haemoproteus for which adequate descriptions are available. We have assigned to them the names Haemoproteus geochelonis n.sp. and Haemoproteus peltocephali n.sp.

Eimeria peltocephali n. sp., (Apicomplexa:Eimeriidae) from the freshwater turtle Peltocephalus dumerilianus (Chelonia:Pelomusidae) and Eimeria molossi n. sp., from the bat, Molossus ater (Mammalia:Chiroptera).

The oocyst is described of Eimeria peltocephali n.sp. from faeces of the freshwater turtle Peltocephalus dumerilianus from Barcelos, State of Amazonas, Brazil. Sporulation is exogenous and fully developed oocysts are elongate, ellipsoidal or cylindrical, frequently curved to a banana-shape, 54.4 x 19.1 (37.5-68.7 x 18.7-20.0 microns), shape-index 2.8 (1.8-3.9). The oocyst wall is a single thin, colourless layer about 1 micron thick, with no micropyle. There is a bulky oocyst residuum, at first spherical to ellipsoidal, 19 x 16 (16.2-26.2 x 16-21.5 microns), but becoming dispersed on maturation. There are no polar bodies. The sporocysts, 19.1 x 6.8 (17.5-21.2 x 6.2-7.5 microns), shape-index 2.8 (2.3-3.2), are usually disposed in pairs at each end of the oocyst, and bear an inconspicuous Stieda body in the form of a flat cap. The sporozoites are elongate and slightly curved around the residuum. No refractile bodies were seen. Eimeria molossi n.sp., is described from the molossid bat Molossus ater. Sporulation is exogenous and the mature oocysts are predominantly broadly ellipsoidal, 23.4 x 17.5 (18-30 x 15-22.5 microns), shape-index 1.3 (1-1.6). The oocyst wall is about 2 microns thick, and of three layers: an inner thin, colourless one and two outer layers which are thicker, yellowish-brown, prominently striated and in close apposition. There is no micropyle or oocyst residuum, but one and occasionally two polar bodies are usually present. Sporocysts are ellipsoidal, 10.2 x 7.5 (10-12.5 x 7.5 microns), shape-index 1.4 (1.3-1.7) with an inconspicuous Stieda body. Endogenous stages are described in the epithelial cells of the small intestine.

Diet of the Pelomedusid Turtle Peltocephalus dumerilianus in the Venezuelan Amazon

Diet of the Pelomedusid Turtle Peltocephalus dumerilianus in the Venezuelan Amazon