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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.

Peltocephalus dumerilianus Schweigger 1812:300 Holotype: Formerly in the MNHN, but apparently now lost; no paratypes designated. Fretey (1977:111) believed that the holotype of Emys dumeriliana was MNHN 7893, which he and Williams (1954) identified as Podocnemis unifilis, supposedly making Emys tracaxa Spix (1824:6) the next available name (e.g., Hoogmoed & Gruber, 1983:345). However, Pritchard & Trebbau (1984:89) showed that MNHN 7893 was a Podocnemis expansa, and not the holotype of dumerilianus, and Hoogmoed & Gruber (1983:345) further clarified the synonymy of tracaxa and macrocephala. Finally, MNHN 8634 designated neotype by Bour (2006a:29, and photographed therein). Emys macrocephala Spix 1824:5 Syntypes (3): RMNH 6164 (illustrated in the original description, Pl. IV; Hoogmoed & Gruber 1983:347) and ZSM 15/0 and 17/0 (Franzen & Glaw 2007:207). RMNH 6164 designated lectotype by Hoogmoed and Gruber (1983:347); discussed by Pritchard & Trebbau (1984:89) and Hoogmoed et al. (2010:25–26). Emys tracaxa Spix 1824:6 Syntypes (number uncertain, but one illustrated in the original description, Pl. V): only known syntype is ZSM 16/0, which was designated lectotype by Hoogmoed & Gruber (1983:347); see further comments in Pritchard & Trebbau (1984:89) and Franzen & Glaw (2007:207)., Published as part of Iverson, John B., 2022, A review of Chelonian type specimens (order Testudines), pp. 1-85 in Megataxa 7 (1) on page 14, DOI: 10.11646/megataxa.7.1.1, http://zenodo.org/record/5964441, {"references":["Schweigger, A. F. (1812) Prodromus monographiae Cheloniorum. Konigsberger Archiv fur Naturwissenschaft und Mathematik, 1, 271 - 368, 406 - 462.","Fretey, J. (1977) Les cheloniens de Guyane francaise. 1. Etude preliminaire. Thesis, University of Paris. 202 pp.","Williams, E. E. (1954) A key and description of the living species of the genus Podocnemis (sensu Boulenger) (Testudines, Pelomedusidae). Bulletin of the Museum of Comparative Zoology, 111 (8), 279 - 295.","Spix, J. B. (1824) Animalia Nova sive Species Novae Testudinum et Ranarum. Monachii, 53 pp.","Hoogmoed, M. S. & Gruber, U. (1983) Spix and Wagler type specimens of reptiles and amphibians in the Natural History Musea in Munich (Germany) and Leiden (The Netherlands). Spixiana Supplement, 9, 319 - 415.","Pritchard, P. C. H. & Trebbau, P. (1984) The Turtles of Venezuela. SocietyfortheStudyofAmphibiansandReptiles, Contributions in Herpetology, 2, 1 - 403.","Bour, R. (2006 a) Types of Podocnemidae in the Museum National d'Histoire Naturelle. Emys, 13 (1), 27 - 40.","Franzen, M. & Glaw, F. (2007) Type catalog of reptiles in the Zoologische Staatssammlung Munchen. Spixiana, 30, 201 - 274.","Hoogmoed, M. S., Gasso Miracle, M. E. & van den Hoek Ostende, L. W. (2010) Type specimens of recent and fossil Testudines and Crocodylia in the collections of the Netherlands Centre for Biodiversity Naturalis, Leiden, the Netherlands. Zoologische Mededelingen Leiden, 84, 1 - 41."]}

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 of17 (eight males and nine females) adult P. dumerilianus to 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. RESUMEN La determinación de valores hematológicos se ha utilizado para conocer las condiciones sanitarias de algunas especies animales. La tortuga cabezona del río Amazonas, Peltocephalus dumerilianus, se considera una de las especies de testudines menos conocidas en relación a su biología y estado de salud. Aquí, determinamos los parámetros bioquímicos hematológicos y plasmáticos de 17 adultos (ocho machos y nueve hembras) de P. dumerilianus con el fin de proporcionar valores de intervalo de referencia sobre los individuos clínicamente sanos. Recolectamos las muestras de sangre perforando la vena femoral con jeringas hipodérmicas largas heparinizadas. El dimorfismo sexual de los individuos se determinó mediante la observación externa de la forma del plastrón. Los valores medios obtenidos para los diez parámetros hematológicos y bioquímicos analizados fueron: recuento de glóbulos rojos = 0,32 millones μL-1; hematocrito = 20,6 %; hemoglobina = 8,5 g dL-1; volumen corpuscular medio = 681,6 fL; hemoglobina corpuscular media = 267,8 pg; concentración media de hemoglobina corpuscular = 41,9 g dL-1; glucosa = 80,6 mg dL-1, proteína total = 4,1 g dL-1, triglicéridos = 388,9 mg dL-1 y colesterol total = 79,3 mg dL-1. A pesar del dimorfismo sexual evidente para la especie, no hubo diferencia estadística significativa entre machos y hembras para los parámetros hematológicos y bioquímicos analizados aquí. Con base en estos resultados, la población se considera saludable y los valores de los parámetros coinciden con los rangos de referencia reportados previamente de las especies de testudines en la región. Los resultados obtenidos en este estudio pueden utilizarse en la evaluación del estado de salud de otras poblaciones de tortugas amazónicas, considerando especialmente aquellas acciones dirigidas al manejo, conservación y estrategias de cultivo de la especie.

The largest extinct turtle from South America had males with horned shells., Despite being among the largest turtles that ever lived, the biology and systematics of Stupendemys geographicus remain largely unknown because of scant, fragmentary finds. We describe exceptional specimens and new localities of S. geographicus from the Miocene of Venezuela and Colombia. We document the largest shell reported for any extant or extinct turtle, with a carapace length of 2.40 m and estimated mass of 1.145 kg, almost 100 times the size of its closest living relative, the Amazon river turtle Peltocephalus dumerilianus, and twice that of the largest extant turtle, the marine leatherback Dermochelys coriacea. The new specimens greatly increase knowledge of the biology and evolution of this iconic species. Our findings suggest the existence of a single giant turtle species across the northern Neotropics, but with two shell morphotypes, suggestive of sexual dimorphism. Bite marks and punctured bones indicate interactions with large caimans that also inhabited the northern Neotropics.

This book chapter is the first literature specifically covering the turtles of the igapo environments of the Amazon. The flooding pulse of the igapo and its peculiar chemistry play a crucial role in turtle ecology, remarkably different from any other environments in the Amazon. Discussed inside this chapter is the definition of the igapo and the particular ecology and life of five turtle species most common in this environment: red-headed Amazon River turtle (Podocnemis erythrocephala), yellow-spotted Amazon River turtle (Podocnemis unifilis), giant South American river turtle (Podocnemis expansa), big-headed sideneck turtle (Peltocephalus dumerilianus), and matamata (Chelus fimbriata). These turtles have been historically exploited by human beings causing most of these turtles to be currently listed at some level of endangerment by the International Union for Conservation of Nature (IUCN). They are also protected from international trade by CITES. How the economic development of the Amazon affected the turtles, including covering the most relevant threats and conservation management advice for each species, can also be found in this chapter. Finally, the end of this chapter explores how the unique chemistry of the igapo promotes the uptake of mercury (Hg) by turtles in igapo more efficiently than any other environment of the Amazon. Information in this chapter highlights the need for more direct application from the government agencies to protect these turtle species, through direct research and appropriate conservation in the igapo. The conservation measures provided in this chapter offer the protection turtles need so that populations levels will be maintained. So, turtles can still perform their ecologically functional duties of recycling plant protoplasm to animal matter to feed the predators of the igapo.

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...

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.

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...

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 bio-indicator. Metal levels were not high enough to pose a health risk to the turtles or to consumers, such as humans.

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.

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.

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.

O estudo da movimentação dos indivíduos é importante para compreender a história de vida dos animais e para fomentar estratégias de manejo e conservação das espécies. A movimentação de Peltocephalus dumelirianus teve relação significativa com a temperatura da água e com os estágios do ciclo hidrológico na qual os indivíduos se movimentam mais durante a vazante do rio Trombetas e menos durante a seca. O tamanho da área de uso e a movimentação dos indivíduos não mostraram diferenças entre os sexos e o comprimento da carapaça não influenciou os resultados. P. dumerilianus apresentou uma área de uso restrita durante o período de estudo e se conclui que para a manutenção da espécie é extremamente necessário a preservação do habitat. The study of individual’s movements is important to understand the life history of the animals and to promote strategies for management and conservation of species. Peltocephalus dumelirianus’s movements had a significant relationship with the water temperature and the hydrological cycle stages in which individuals move more during the ebb of the Trombetas river and less during drought. The size of land use and movement of individuals showed no differences between the sexes and the carapace length did not influence the results. P. dumerilianus showed a restricted area of use during the period of study and it is concluded that the maintenance of species is very necessary to preserve the habitat.

El presente trabajo analiza aspectos de alimentación en medio natural de la tortuga, Peltocephalus dumerilianus (Testudines: Podocnemididae; cabezón), a partir de muestras de contenidos alimenticios tomados de estómago e intestino grueso de ejemplares utilizados para consumo por los habitantes ribereños de la comunidad de São Louis, en el medio río Negro, municipio de Barcelos (Amazonas), Brasil. Se documenta que la especie es omnívora, oportunista y generalista, consume preferiblemente vegetales, con predominancia de semillas y frutos de palmeras, además, se registraron otros productos que incluyen materia animal de diversos taxones. This study analyzed aspects of the natural feeding of Peltocephalus dumerilianus (Testudines: Podocnemididae; big headed Amazon river turtle) by inspection of samples taken from stomachs and large intestines of individuals consumed as a protein source by people living along the middle Río Negro river, in the Municipality of Barcelos (Amazon), Brazil. The results showed that this species is an opportunist, omnivore, and generalist, preferring plant material, particularly palm fruits and seeds; in addition, the consumption of diverse animal matter of different taxa was documented.

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. Forty pairs of ovaries of mature female Peltocephalus dumerilianus (Schweigger 1812) were analyzed, to establish the morphologic monthly changes that take place during one year; we examined macroscopically the oviducts and the ovaries of specimens that the riverside inhabitants of the municipality of Barcelos, Amazons, Brazil, used for their consumption. We measured the diameter and recorded the number of enlarged ovarian follicles and corpora lutea. The results show the gradual enlargement of follicles in agreement with the reproductive period, observing that during the last third of the process; just before oviposition they become more evident. The positive relationship between the size of the female and the ovarian mass, is statistically significant (F (10.29)=3.655, p < 0.05). Follicullar sizes suggest that this species nests only once a year.

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.

Forty pairs of ovaries of mature female Peltocephalus dumerilianus (Schweigger 1812) were analyzed, to establish the morphologic monthly changes that take place during one year; we examined macroscopically the oviducts and the ovaries of specimens that the riverside inhabitants of the municipality of Barcelos, Amazons, Brazil, used for their consumption. We measured the diameter and recorded the number of enlarged ovarian follicles and corpora lutea. The results show the gradual enlargement of follicles in agreement with the reproductive period, observing that during the last third of the process; just before oviposition they become more evident. The positive relationship between the size of the female and the ovarian mass, is statistically significant (F (10.29)=3.655, p < 0.05). Follicullar sizes suggest that this species nests only once a year. 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.

Objetivo. Analizar los comportamientos de alimentación bajo diferentes condiciones de temperatura en un grupo de neonatos de Peltocephalus dumerilianus (Testudines Podocnemididae). Materiales y Métodos. Los individuos experimentales fueron obtenidos mediante incubación en el laboratorio, se dividieron en 5 grupos al azar. Durante 2 meses con tres repeticiones a la semana se hicieron pruebas de temperatura utilizando dentro de las bandejas calentadores eléctricos, con registro continuo de temperatura mediante termómetro digital - 10 a + 60°C (± 0.1°C), procurando mantener un ritmo constante de incremento equivalente a 0,25°C cada 10 minutos, hasta llegar a la temperatura seleccionada, que fue mantenida por 60 minutos en cada ensayo. Las temperaturas seleccionadas para cada ensayo, fueron: 26°C, 30°C, 34°C, 38°C y ambiente que fue de 26,8°C en promedio. Fueron evaluados los siguientes parámetros: duración en minutos de la ingesta, tiempo de inicio de comportamientos agonísticos, presencia de dos tipos de despliegues característicos: morder y disputa por alimento. Resultados. En general todos los parámetros fueron significativos, a mayor temperatura el tiempo de ingestión fue mayor, a menor temperatura el volumen de consumo fue menor, a menor temperatura el inicio de los despliegues agonísticos fue mayor y se mantuvo una relación inversamente proporcional. Conclusiones. Los resultados mostraron que existe relación directamente proporcional entre la temperatura ambiental y los procesos de alimentación, además que se relacionaron con aspectos básicos del comportamiento lo cual se manifestó en los despliegues agonísticos observados. Objective. To analyze the feeding behavior of 50 Peltocephalus dumerilianus hatchlings (Testudines Podocnemididae) under different temperature conditions in laboratory. Materials and methods. The individuals for this experiment were obtained by incubation in the laboratory. They were divided randomly into 5 groups. Temperature trials were conducted for 2 months with 3 repetitions per week, using electric heaters. Temperatures were recorded continuously using a digital thermometer - 10 to + 60°C (± 0.1°C). Temperatures were increased 0.25°C every 10 minutes until reaching the selected temperature, which was then maintained for 60 minutes for each test. The temperatures selected for tests, were 26°C, 30°C, 34°C, 38°C, with an ambient temperature of 26.8°C. We evaluated: feeding duration (in minutes), consumption (in volume), the time which turtles began agonistic behavior, and two characteristic displays: biting and disputes over food. Results. In general all parameters were significant, the higher the temperature the longer the time of ingestion; the lower the temperature the lower the consumption volume; the lower the temperature the greater the time to initiation of agonistic behavior, demonstrating an inverse relationship. Conclusions. There was a direct relationship between environmental temperature and feeding processes. Temperature was also related to basic aspects of behavior during agonistic displays.

A presente tese analisa e discute aspectos relacionados à ecologia e à conservação de Peltocephalus dumerilianus (Testudines, Podocnemididae), circunscrita à demarcação de uma área representativa do Município de Barcelos, Amazonas, Brasil. Os locais de coleta da informação biológica foram dois tributários do médio rio Negro: rio Itu e rio Cumicurí. Estudaram-se os aspectos de utilização nas comunidades de São Louis, Baturité, Daracúa y Tomar. Analisam-se os componentes da dieta alimentar durante um ciclo anual, tendo como base os conteúdos de tratos digestivos de exemplares capturados, na área de estudo, pelos ribeirinhos para seu consumo. Determina-se o caráter onívoro e oportunista da espécie. Apresenta-se também informação biológica dos aspectos reprodutivos, fundamentando-se a pesquisa no ciclo ovárico anual, desova em meio natural, desova induzida e incubação no laboratório. Assim, reafirma-se a sexotermodependência da espécie. Apresentam-se os dados morfométricos das capturas experimentais conduzidas durante dois anos contínuos e, mediante o método de captura/recaptura estabelecem-se aspectos importantes de dinâmica populacional para as duas áreas específicas de trabalho. Determina-se, igualmente aplicando-se telemetria, durante um ano contínuo, o uso de habitat por sexo. No aspecto socioeconômico, estabelece-se uma tendência cultural associada ao consumo de quelônios na área de trabalho; os dados obtidos indicam o declínio populacional das espécies de quelônios de maior preferência histórica; igualmente permitem evidenciar a constante caça e crescente comercialização de Peltocephalus dumerilianus (cabeçudo) e um processo de captura para subsistência que esgota os estoques naturais existentes, que envolve a troca das espécies preferidas por outras em função do declínio populacional. The present thesis analyses and discusses aspects related to ecology and conservation of Peltocephalus dumerilianus (Testudines Podocnemididae), within a geographic area that includes a representative zone of the Muncipality of Barcelos, Amazonas, Brazil. The localities of biological and ecological information collected includes two tributaries of the medium Rio Negro: Itú and Cuimicurí rivers; Human use of the species was studied in the communities of São Louis, Baturité, Daracuá and Tomar. The nutritional components of the diet during a annual cycle were analyzed, from the digestive tract contents of individuals captured for consumption by the people inhabitanting the study area. This species was found to be an opportunistic omnivore. Data are also presented on the female reproductive cycle: annual ovarian cycle, egg laying in nature, induced ovoposition, and laboratory incubation reaffirming sex thermo-dependence in this species. Morphometric and mark and recapture data of the turtles captured during a two year continuous study was used to study the population dynamics in the research area. Habitat use was determined by a one year continuous telemetry study. Socioeconomic use was analyzed and discussed, the surveys show a cultural tendency associated with the consumption of turtles in the study area. All data combined indicate the population declination of turtles of greater historic preference; consequently the increasing hunting and commercialization of P. dumerilianus (bigheaded river turtle) is a dynamic process that demonstrates the related natural stock exhaustion taking place today.

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. Diez especies de Testudines, de cuatro familias diferentes: Chelidae, Kinosternidae, Podocnemididae, y Testudinidae, son reportadas de la Estación de Biodiversidad Tiputini (Universidad San Francisco de Quito), en la Amazonía Nororiental de Ecuador; incluyendo el segundo reporte para Ecuador de Batrachemys heliostemma. Estas diez especies son simpátricas pero no completamente sintópicas, por lo que comento sobre sus patrones de diversidad y preferencias de hábitat. La distribución general de algunas especies de tortugas de la Amazonía de Ecuador es discutida, proveyendo registros adicionales y mapas de distribución para Chelus fimbriatus, Platemys platycephala, Batrachemys heliostemma, Batrachemys raniceps, Mesoclemmys gibba, Phrynops geoffroanus, Kinosternon scorpioides, y Geochelone denticulata. La presencia de Peltocephalus dumerilianus en la Amazonía de Ecuador es confirmada; basada en la reexaminación de especímenes previamente reportados por el Dr. Gustavo Orcés en 1949. La riqueza total de especies de tortugas en Ecuador incluye 31 taxa vivientes; proveo una lista anotada de las especies de tortugas de Ecuador continental e insular. Mucha información es aún requerida para poder comprender las relaciones ecológicas de los Testudines de Ecuador e investigaciones futuras deberían enfocarse en estudios a largo plazo diseñados para responder a varias preguntas sobre su biología y ecología. Algunos peligros amenazan la conservación a largo plazo de las poblaciones de tortugas de Ecuador y debemos incrementar nuestro conocimiento sobre estos sorprendentes animales para poder protegerlos y conservarlos.

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.

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.

Stomach contents of 54 Peltocephalus dumerilianus from the Yagua and Atacavi rivers, Amazonas State, Venezuela, were obtained by stomach flushing. Fruits and seeds, fish, and aquatic plants were the most common food items in the diet; invertebrates and algae also were eaten. The most common plant species in the diet were Mauritia flexuosa, Montrichardia arborescens, Parinari campestris, and Thurnia polycephala. The proportion of animal matter ingested by P dumerilianus was the highest recorded among South American pelomedusid turtles. Diet composition was not significantly affected by sex or body size. Significant differences in diet were found between turtles from the two rivers, mainly because fruits and seeds were more diverse in diets of turtles from Atacavi River. RESUMEN.-Contenidos estomacales de 54 ejemplares de Peltocephalus dumerilianus ("cabez6n"), provenientes de los canios Yagua y Atacavi, Estado Amazonas, Venezuela, fueron obtenidos por medio de lavados en vivo del tracto digestivo. Frutas y semillas, peces y plantas acuaticas predominaron en la composici6n de la dieta. Invertebrados y algas fueron igualmente consumidos por esta tortuga. Las especies de plantas mAs comunes en la dieta fueron Mauritia flexuosa, Montrichardia arborescens, Parinari campestris y Thurnia polycephala. La proporci6n de material animal ingerido por I? dumerilianus es la mas alta registrada para tortugas de la familia Pelomedusidae en Sur America. La composici6n de la dieta no fue significativamente diferente entre sexos o clases de tamafno. Diferencias significativas en la dieta fueron encontradas entre las tortugas provenientes de los dos caiios, principalmente como resultado de una mayor diversidad de frutos y semillas en la dieta de las tortugas del caano Atacavi en comparaci6n a las tortugas del canfo Yagua. Peltocephalus dumerilianus ("cabez6n" in Venezuela) is one of the least studied of the South American Pelomedusidae despite the fact that it represents an important food resource for people living in Amazonia (Smith, 1979; Pritchard and Trebbau, 1984; Perez-Eman, 1990). Fragmentary information on distribution, habitat, and sexual dimorphism was compiled by Pritchard and Trebbau (1984). Similarly, some data on reproduction and behavior are available from Colombia and Brazil (Medem, 1960, 1983; Vogt et al., 1994). The diet of this species is poorly known. Seeds, and leaves of weeds, grasses, and herbs were found in one stomach sample from Colombia (Pritchard and Trebbau, 1984). Euterpe palm fruits were present in stomachs from P dumerilianus of southern Venezuela (J. Hall, pers. comm., in Pritchard and Trebbau, 1984). Despite these records, however, morphological characteristics of this species suggest it is likely a bottom-dwelling predator (Neill, 1965; Pritchard, 1979). Given the importance of P dumerilianus as a food resource for many people and the conser3 Present Address: Department of Biology, University of Missouri-St. Louis, 8001 Natural Bridge Rd., St. Louis, Missouri 63121-4499, USA. vation problems that may develop as a consequence of overharvesting, it is important to learn more about its natural history. PerezEman (1990) conducted a study on the biology, ecology, and human use of this turtle in the Venezuelan Amazonia. Information obtained on the diet of this turtle from two river systems forms the basis of this paper. MATERIALS AND METHODS Study Areas.-This study was conducted in the Yagua and Atacavi rivers of Amazonas State, Venezuela (between 3?00'-4'00'N and 66?30'67030'W, altitude 100-120 m). Both rivers are black water rivers, with a high concentration of humic acids and a low pH (Foldats, 1962). The mean annual temperature is above 24?C with little fluctuation throughout the year (Ewel et al., 1976; Paolillo and Cerda, 1983). Rainfall is high, with an annual average of more than 3000 mm; the dry season typically lasts from two to three months (December to February) (Paolillo and Cerda, 1983). Typical components of the vegetation in areas subject to flooding are some Apocynaceae (Mollongum laxum, Malouetia sp., Parahancornia negroensis), and Annonaceae (Tetrameranthus sp.). Also present are Caesalpinaceae (Macrolobium, Swartzia) and Mimosaceae (Inga); Arecaceae This content downloaded from 157.55.39.195 on Thu, 14 Apr 2016 05:10:28 UTC All use subject to http://about.jstor.org/terms J. PERtZ-EMAN AND A. PAOLILLO O. TABLE 1A. Distribution of turtles analyzed for diet information by sex (Indet = indeterminate), locality, and capture technique. Yagua River Atacavi River Total Hand Trap Hand Trap Hand Trap Males 2 12 7 5 9 17 Females 0 8 9 5 9 13 Indet 0 1 5 0 5 1 Total 2 21 21 10 23 31 (palms) such as Mauritia sp., Leopoldinia pulchra, and Mauritiella aculeata, are abundant along both rivers; tall, species-rich riparian forests grow on Ultisol and Oxisol soils. Near the headwaters of the Atacavi River are shrubby and flooded plains, characterized by Rapateaceae and Cyperaceae and by large meadows of Thumiaceae (Thurnia polycephala), typical of black water rivers. The open vegetation areas are flooded from 9-10 mo each year by overflow from the rivers. Capture Techniques and Measurements.-Ninetytwo turtles were captured, 41 from Yagua River during January 1990 (dry season) and 51 in Atacavi River from February to April 1990 (end of dry season and beginning of the rainy season). Turtles were captured by hand (N = 39) or by using traps of indigenous design baited with dead fish (N = 53). Turtles were marked by notching marginal scutes and released at the capture site. Sex, body weight, and straight-line carapace length were recorded for each turtle captured. Sex determination followed Pritchard and Trebbau (1984) and previous observations of turtles in museums. Five size classes, based on carapace length, were defined: 1:140-200 mm; II: 201-260 mm; 111:261-320 mm; IV:321-380 mm; and V:381-440 mm. Stomach Analyses.-Stomach contents were obtained by stomach flushing (Legler, 1977) and contents were preserved in 5-10% formalin. We sorted and identified food materials using a dissecting microscope and reference collections. Food items were classified into seven groups: aquatic plants, fruits and seeds, algae, fishes, invertebrates, miscellaneous (stones, ectoparasites, dry leaves and stems), and unidentified material. We recorded frequency of occurrence of each food item excluding empty stomachs. As more than one food item appeared in several stomach contents, the frequency of occurrence of all food items combined may exceed one hundred percent. Percentage of total volume (based on water displacement) for each food item was recorded for turtles captured by hand (N = 23). A total list of food items consumed by P dumerilianus was compiled using stomach TABLE lB. Distribution of turtles analyzed for diet information by size class (I: 140-200 mm, II: 201-260 mm, III: 261-320 mm, IV: 321-380 mm, V: 381-440 mm), locality, and capture technique. Yagua River Atacavi River Total Hand Trap Hand Trap Hand Trap Class I 0 0 4 0 4 0 Class II 0 4 6 2 6 6 Class III I 11 5 6 6 17 Class IV 1 6 5 2 6 8 Class V 0 0 1 0 1 0 Total 2 21 21 10 23 31 contents (N = 54), remaining food items in the stomachs after flushing (N = 4), intestinal contents of sacrificed turtles (N = 7), and information obtained from indigenous people (Table 2). Chi-square tests were used to compare the diets (i.e., frequency of occurrence) between sex, size classes, and localities. Unless otherwise noted, comparisons are based on 54 turtles from which stomach contents were obtained (see Tables la, lb for sample sizes by category). Occurrence of individual food items was compared only when the item appeared more than three times in the diet.