Academic literature on the topic 'Freshwater turtles'

China has one of the world's most diverse freshwater turtle faunas but is also a major consumer of freshwater turtles. In the 1980s over-collecting, illegal trade and habitat destruction increased dramatically, pushing almost all Chinese turtles towards extinction. Despite the critical status of Chinese turtles little has been done to quantify and evaluate the impact of illegal activities on wild populations. We used a combination of market surveys and questionnaires to examine the illegal trade and conservation status of native freshwater turtles in Nanmao, Hainan Province, from February to August 2003. We found a total of 245 collected freshwater turtles comprising eight species. These data indicate that Nanmao has a rich freshwater turtle fauna that is being affected heavily by illegal poaching. No effective measures have been taken to protect the few remaining wild turtle populations. The main factors that lead to illegal trade include the cultural belief that turtles are a viable food/medicine product, lack of conservation awareness, poaching of turtles as a supplement to income, and poor law enforcement. Possible conservation strategies are discussed.

Hyperphalangy is a rare condition in extant aquatic turtles, and mainly limited to soft-shelled turtles. Here we report a new freshwater turtle,Jeholochelys lingyuanensisgen. et sp. nov. from the Early Cretaceous Jehol Biota of western Liaoning, China. This new turtle is characterized by a hyperphalangy condition with one additional phalanx in pedal digit V, rather than the primitive condition (phalangeal formula: 2-3-3-3-3) of crown turtles.J. lingyuanensisis recovered with other coexisting turtles in the family Sinemydidae in the phylogenetic analysis. This discovery further confirms that hyperphalangy occurred multiple times in the early evolutionary history of the crown turtles. Hyperphalangy is possibly a homoplasy inJeholochelysand the soft-shelled turtles to adapt to the aquatic environments.

Freshwater turtles symbolize a key component of biodiversity in aquatic ecosystems. Of the 356 living species of turtles and tortoises in the world, 34 species are recorded from India. The number of freshwater turtle and tortoise species found in the state of Goa, however, is debatable. No study specific to the Goa region has been carried out on freshwater turtles. Therefore, baseline data on diversity and distribution of freshwater turtles is scanty. The present study was conducted to address this lacuna in knowledge, which will further aid in identifying threats to the population of freshwater turtles and in devising appropriate methods for their conservation. The diversity and distribution of freshwater turtles was investigated in 186 sites in Goa from June 2012 to May 2015. A total of 337 specimens of two native and one introduced species of freshwater turtles belonging to three families—Trionychidae (Indian Flap-shell Turtle Lissemys puncata), Geomydidae (Indian Black Turtle Melanochelys trijuga) and Emydidae (Red-eared Slider Trachemys scripta elegans)— were identified. Melanochelys trijuga (52.23%) was the most widely and abundantly distributed species, and was recorded from 132 sites. L. punctata (46.88%) was recorded from 113 sites, while T. scripta elegans (0.89%) was rare and was recorded from only two sites. While Melanochelys trijuga is generalized in habitat selection, making it the widely distributed species in the State of Goa, L. punctata is more specific in habitat selection thus restricting its range to coastal, middle-level plateau and the foothills of Western Ghats.

Dispersal of freshwater mussels (order Unionida) is primarily as glochidia on the fins and gills of host fish. Adult mussels are more sessile, generally moving short distances (<2 m/week) along lake and river beds. Between 2007 and 2016, we observed seven instances of adult Eastern Elliptio (Elliptio complanata) and one instance of a fingernail clam (Sphaerium sp.) attached to the feet of freshwater turtles in streams and ponds of New England, United States. Observations included five instances of mussels attached to Wood Turtles (Glyptemys insculpta) in Maine and Massachusetts, one instance of a mussel attached to the fingernail of an Eastern Painted Turtle (Chrysemys picta) in Massachusetts, one instance of a mussel attached to a Snapping Turtle (Chelydra serpentina) in Massachusetts, and one instance of a fingernail clam attached to the fingernail of an Eastern Painted Turtle in Massachusetts. We suggest that Eastern Elliptio may be susceptible to transport by freshwater turtles foraging in mussel beds and that transport of adult mussels by freshwater turtles could result in otherwise atypical long-distance, upstream, or overland dispersal between waterbodies.

Laterality has been found in a variety of reptiles. In turtles, one important behaviour is the righting response. Here, we studied laterality of righting response of two species of freshwater turtles, the Painted Turtle (Chrysemys picta) and the Eastern Musk Turtle (Sternotherus odoratus). We found evidence of individual-level laterality in righting response inC. picta, but notS. odoratus. Neither species showed evidence of population-level laterality in righting response. Our results suggest that there is variation in the extent of laterality of righting response in turtles. Possible explanations for variation in laterality of righting response in turtles include shell shape and use of terrestrial habitats. However, more species of turtles need to be examined to demonstrate any general patterns in laterality of righting response in turtles.

Abstract Turtles are linked to energetic food webs as both consumers of plants and animals and prey for many species. Turtle biomass in freshwater systems can be an order of magnitude greater than that of endotherms. Therefore, declines in freshwater turtle populations can change energy transfer in freshwater systems. Here we report on a mark–recapture study at a lake and adjacent borrow pit in a relict tract of bottomland hardwood forest in the Mississippi River floodplain in southeast Missouri, which was designed to gather baseline data, including sex ratio, size structure, and population size, density, and biomass, for the freshwater turtle population. Using a variety of capture methods, we captured seven species of freshwater turtles (snapping turtle Chelydra serpentina; red-eared slider Trachemys scripta; southern painted turtle Chrysemys dorsalis; river cooter Pseudemys concinna; false map turtle Graptemys pseudogeographica; eastern musk turtle Sternotherus odoratus; spiny softshell Apalone spinifera) comprising four families (Chelydridae, Emydidae, Kinosternidae, Trinoychidae). With the exception of red-eared sliders, nearly all individuals captured were adults. Most turtles were captured by baited hoop-nets, and this was the only capture method that caught all seven species. The unbaited fyke net was very successful in the borrow pit, but only captured four of the seven species. Basking traps and deep-water crawfish nets had minimal success. Red-eared sliders had the greatest population estimate (2,675), density (205/ha), and biomass (178 kg/ha). Two species exhibited a sex-ratio bias: snapping turtles C. serpentina in favor of males, and spiny softshells A. spinifera in favor of females.

Conservation authorities invest heavily in the restoration and/or creation of wetlands to counteract the destruction of habitat caused by urbanization. Monitoring the colonization of these new wetlands is critical to an adaptive management process. We conducted a turtle mark-recapture survey in a 250 ha artificially created wetland complex in a large North American city (Toronto, Ontario). We found that two of Ontario’s eight native turtle species (Snapping turtle (SN), Chelydra serpentina, and Midland Painted (MP) turtle, Chrysemys picta marginata) were abundant and both were confirmed nesting. The Blanding’s turtle (Emydoidea blandingii) was present but not well established. Species richness and turtle density were not equally distributed throughout the wetland complex. We noted SN almost exclusively populated one water body, while other areas of the wetland had a varying representation of both species. The sex ratios of both SN and MP turtles were 1:1. We tracked the movement of Snapping and Blanding’s turtles and found that most turtles explored at least two water bodies in the park, that females explored more water bodies than males, and that 95% of turtles showed fidelity to individual overwintering wetlands. We performed DNA analysis of two Blanding’s turtles found in the created wetlands and could not assign these turtles to any known profiled populations. The genetic data suggest that the turtles probably belong to a remnant local population. We discuss the implications of our results for connectivity of artificial wetlands and the importance of the whole wetland complex to this turtle assemblage.

Soft shell turtles are among the most threatened groups of freshwater animals that are in need of urgent conservation attention. In Kerala (South India), two species of freshwater turtles, the Indian black turtle or Indian pond terrapin, Melanochelys trijuga coronata (Schweigger, 1812) and the Indian Flap-shelled turtle Lissemys punctata punctata (Lacépède, 1788) are exploited from Vembanad lake and associated wetlands in Punnamada to meet the demand from local restaurants and toddy shops. Eight hundred and forty three individuals belonging to the two species (499 pond terrapins and 344 flap-shelled turtle) were observed during a field survey conducted in 2007 at Punnamada. Despite being listed at the highest level in the Indian wildlife protection act, very little law enforcement takes place and turtles are exploited and traded regularly. Collection and trade have also become an important component of the local livelihoods in Punnamada, with the involvement of around five full-time and 25 part-time collectors. Details of the collection, marketing, economics and management of the freshwater turtles in Punnamada are discussed.

The distribution and diversity of turtles now reflect the lengthy and complex evolution of the taxonomy, which represents an old group of tetrapod vertebrates in terms of evolutionary history. Freshwater turtles represent the majority of the 365 species, and they mostly live in tropical and subtropical regions. Emydidae diversity hotspots can be found in Southeast North America, as can Geoemydidae and Trionychidae in the Indo-Malayan area. While Pelomedusidae are mostly found in Africa, Chelidae are primarily found in the Neotropics and Australia. Most species of the genus are endemic to a particular region or even to a single location. The majority of freshwater turtles suffer varied degrees of threat, mostly from habitat changes and collection. With the use of morphological and molecular data, the majority of phylogenetic trees for different turtle species have been generated using DNA techniques and procedures. The complete mitochondrial DNA (mtDNA), dehydrogenase subunit 4 (ND4), cytochrome b (Cyt b), carapacial ridge (CR), and cytochrome c oxidase subunit I (CO I) genes of freshwater turtles were sequenced by using universal PCR and long-PCR methods. Along with CR sequences of freshwater turtles, the composition and structure of the control region of diverse species were compared and analysed. Functional domains in the regulatory area, as well as their conserved sequences, were determined based on sequence similarities to other turtles. The mitochondrial regulatory regions and flanking sequences of diverse freshwater turtle species were recovered using Long-PCR and gene-specific primers. To clarify the genetic links between the fresh water turtle species that share the same habitat type, a tree was created based on Cytochrome b sequencing data and the PCR- Restriction fragment length polymorphism (RFLP) pattern. Keywords: Complex evolution, Phylogenetics, Phylogenomics, Tetrapod vertebrates

AbstractExperiments with Pelomedusa subrufa, a widespread African freshwater turtle, showed that this species consumed large quantities of tadpoles. Tadpoles preyed upon, comprised between 0.05 and 21.55% of the turtle's biomass. This demonstrated that Pelomedusa subrufa was neither gape limited nor did it ignore very small prey. Tadpoles with an ovoid body shape (Hemisus marmoratus, Hyperolius nitidulus, Ptychadena maccarthyensis), which shared, under natural conditions, the pond bottom microhabitat with the turtles, were more threatened than the robust tall-finned Kassina tadpoles that lived in the middle of the water column. The translucent, slow swimming Phrynomantis microps tadpole occurred in larger ponds and preferred the upper water column in deeper parts of the pond. This species was especially at risk in ponds with reduced water levels. Turtles, in contrast to fish or dragonfly larvae, are capable of migrating to other ponds. They therefore might have a profound regional influence on tadpole communities in ephemeral savanna ponds.

Thesis (Ph. D.)--School of Biological Sciences, Faculty of Science, University of Sydney, 2005.
Title from title screen (viewed 13 January 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Includes bibliographical references. Also issued in print.

An unusual turtle fauna from Lightning Ridge, New South Wales (Albian) reveals that Australian turtles had a more extensive Mesozoic history than previously indicated. Reevaluation of several primitive groups provides novel information on turtle evolution in the southern hemisphere. Seven turtle taxa are identified at Lightning Ridge. Two are Testudines indet. and two indeterminate chelid groups are evinced by isolated elements. Three new taxa are assigned to the new family Spoochelyidae in the superfamily Meiolanoidea. Spoochelys ormondea n. fam., gen. et sp., Sunflashemys bartondracketti n. gen. et sp. and Opalania baagiwayamba n. gen. et sp. are predominantly land-living turtles with high-domed shells and short manus and pes. The sister-group relationship with the Meiolaniidae, supported by a suite of cranial and postcranial synapomorphies, increases the stratigraphic range of the horned turtles by around ~ 50 my. Primitive structures in Spoochelys (postparietal, supratemporal and interpterygoid vacuity), occur with derived features that are variably developed across Triassic and Jurassic turtles. Phylogenetic analysis precariously resolves the meiolanoids as sister group to a clade containing Palaeochersis and Proterochersis. Limited pleurodiran attributes suggest that meiolanoids may be pleurodiromorphs, closer to primitive pleurodires than to cryptodires. As basal ‘side-necked’ turtles, the Lightning Ridge meiolanoids permit first insights into cranial and postcranial progressions in pleurodiran stem taxa. Evidence of diverse meiolanoids in Early Cretaceous Australia and ancient radiations of meiolanoid-like turtles in southern Pangea, suggest that the horned turtles are a Triassic group and that the dichotomy between Pleurodira and Cryptodira occurred well before the Late Triassic. Early Cretaceous chelids at Lightning Ridge occur at higher palaeolatitude than in South America. The temporal range of Australian chelids is extended by ~ 50 my, demonstrating that chelids had a Jurassic history in Australia, with broad diversifications across the polar supercontinent. The palaeoecological setting of Lightning Ridge is comprehensively described for the first time. Diverse invertebrates and vertebrates include terrestrial, freshwater aquatic and rare marine forms that are anomalous at this near-polar palaeolatitude (~65-70oS). The anachronistic occurrence in Early Cretaceous Australia of distinctive radiations of ‘Triassic-type’ turtles, and other relic groups, implies prolonged intervals of biogeographic isolation in the eastern provinces of Pangea.

Doctor of Philosophy (PhD)
Over 85% of Australia’s population live in urban areas and many turtle populations occur on Australia’s east coast where urban development is particularly concentrated. In the state of NSW, over half of the freshwater coastal wetlands have been highly modified or completely destroyed, and urban freshwater creeks often have only a narrow strip of weedy bushland left along their banks. Even though habitat degradation may result in declines in density and distribution of turtle populations, there are few data on Australian freshwater turtles in urban areas. In addition to extreme habitat alteration, urban waterways are innundated with anthropogenic contaminants from sources including wet weather surface runoff and industrial and sewage discharges. Pollutants can impact all systems of the body with potentially severe effects on reproduction and survival that can result in deterioration of animal populations. Turtles are particularly susceptible to anthropogenic contaminants due to their intimate contact with the aquatic environment, an often high trophic level, their ability to accumulate toxins, and their longevity. For almost all contaminants, the degree of accumulation in and effect on reptile species is unknown. Sublethal effects in field situations are particularly poorly studied and have never been documented in pleurodiran turtles. As a pioneering work in Australian reptile ecotoxicology, this thesis takes a broad approach, but focuses primarily on immunotoxicity and reproductive toxicity – two areas that greatly impact the size and continuance of animal populations. The aim of the thesis is to provide baseline data on haematology, cellular immunology and tissue metal concentrations for freshwater turtles in Sydney – data which were lacking for all Australian turtle species prior to this study. After initial assessment of the distribution and density of freshwater turtles in Sydney, the study examines the potential for Sydney’s turtles as sentinel species for measuring the effects of pollution on haematology, cellular immunity, and parasite loads; and considers the relationships between urban metal pollution and reproductive variables. The relative suitability of non-lethally sampled tissues (blood, carapace, egg) for use in biomonitoring is also assessed. Three species of Australian freshwater turtles were found in the Sydney region, with Chelodina longicollis occurring naturally in the area, and populations of Emydura macquarii and Elseya latisternum likely to have originated from translocated individuals. The North American turtle Trachemys scripta elegans was not encountered during this study despite concerns that it was establishing in the Sydney area. Chelodina longicollis populations were widespread, although poor recruitmment was indicated by low capture rates and comparatively low percentage of juveniles at some sites. Not so widespread, Emydura macquarii was present in much larger numbers than C. longicollis and with a high juvenile component in some areas of southeastern Sydney. I provide information on erythrocyte and leucocyte parameters in C. longicollis over a range of sites, pollution conditions, and seasons. In C. longicollis, numbers of lymphocytes, heterophils and eosinophils varied over sites, but not due to pollution from sewage treatment plant outfalls. There was significant temporal variation in erythrocyte, lymphocyte, eosinophil, heterophil, and basophil number, the heterophil:lymphocyte ratio, and haematocrit, but not consistently among sites. Future studies should ensure simultaneous sampling across sites for comparative purposes. Similarly, turtle populations downstream of sewage treatment plant outfalls showed no consistent difference in number, body condition, blood haemogregarine load, or leech (haemogregarine vector) load from upstream populations. Leech (Helobdella papillornata, with some Placobdella sp.) load and haemogregarine numbers increase dramatically once C. longicollis reach a carapace of 110 mm. The number of leeches on turtles varied across season, year, and site. Turtles with large numbers of leeches had reduced haematocrit, but the presence of leeches had no other correlations with haematological parameters. Haemogregarine numbers did not change across season or year, and were not correlated with haematological variables. The hypothesis that pollutants lead to an increase in normal blood protozoa due to reduced immunity thus was not supported. The concentration of metals in C. longicollis and E. macquarii carapace and in lagoon sediments varied significantly over four urban and four national park sites, but not based on this split. Pollution in periurban areas, such as illegal dumping of toxic wastes and atmospheric deposition of pollutants, means that each site must be classified separately as to degree of metal pollution. There was little or no affect of species, size, sex, or gravidity on metal concentrations in the carapace of adult turtles. Emydura macquarii had higher concentrations of blood Fe than C. longicollis from a different site, but this is possibly due to an increase in haemoglobin resulting from the site’s low aquatic oxygen concentration rather than any increased environmental exposure. Chelid turtles in Sydney do not show much promise as a biomonitoring tool. Carapace analysis is largely discounted as a potential tool for metal biomonitoring due to poor correlations between potentially toxic metals in non-lethally samplable tissues (carapace, claw) and internal organs (liver, kidney) or bone (femur). However, carapace metal concentrations still potentially reflect long-term metal presence or different dietary exposures as evidenced by the significant variation in concentrations over sites. A rare correlation was found for concentrations of aquatic Pb and carapace Pb, and a correlation was also found for concentrations of blood Pb and carapace Pb in E. macquarii. Thus any potential for tissue biomonitoring seems to lie with this highly ecotoxicologically relevant metal. Although two other ecotoxicologically relevent metals, Cu and Se, were significantly higher in egg contents of C. longicollis compared to E. macquarii, these elements are also essential and a lack of baseline values means it is not known if this simply reflects natural taxonomic variation. Ni, a metal of toxicological concern in sea turtles, was not present in egg contents, and only variably present in eggshell. The absence of Pb from eggs, despite its presence in many maternal tissues, suggests that selective metal uptake into eggs may be protective of toxic elements, rather than eggs serving as a maternal method of toxic metal elimination as has been previously suggested. The paucity of toxic metal detection in eggs renders them unlikely tissues for biomonitoring. The maternal tissue or tissues or environmental source from which egg metals originate remains obscure, although a significant negative effect of maternal carapace concentrations of Ca and Mg on eggshell thickness in E. macquarii indicates that there may be mobilisation of Ca and Mg from the carapace for eggshell formation. The only metal whose eggshell concentration correlated with eggshell thickness was Mg, indicating that ecotoxic metals previously associated with eggshell thinning are not problematic in the Sydney chelids. As with North American turtles living at polluted sites, none of the chelid hatchlings were found to have any overt abnormalities. Hatching success was poor and hatching mass low for eggs of both C. longicollis and E. macquarii, although results from natural nests are required to determine whether or not this was an outcome of hormonally-induced oviposition and artificial incubation. It is difficult to interpret metal concentrations found in the soft tissues, calcified tissues, and eggs of chelonians due to the paucity of comparative data, and much more research is required on tissue metal concentrations before patterns will emerge. This especially applies to pleurodires for which no previous information is available. From comparisons with the limited data available for other freshwater turtles, marine turtles, and other aquatic reptiles, it does not appear that Sydney’s turtle populations have unusually high metal concentrations in tissues. Exclusion of toxic metals such as Pb from the egg may also be protective to the developing embryo. An ability to live in polluted habitats, while limiting the accumulation of toxic contaminants, may be one key to their persistence in urban waterways from which other freshwater fauna have disappeared. Reproductive impacts such as low embryo survival and small hatchling weights require more rigorous examination, but may have less effect on these animals which have such naturally high egg and hatchling mortality. Although it was generally hard to demonstrate biochemical, physiological or population impacts of contaminants, C. longicollis from a site with severe sewage pollution did display unusual alterations in a number of haematological variables, body condition, and carapace bone structure. Despite this, the population was large and had a comparatively high ratio of juveniles. Additionally, the adverse haematological alterations appeared reversible. Thus, successful populations in Sydney probably are more dependent on basic ecological needs being met, than on low levels of environmental contaminants. The ongoing persistence of chelid populations in Sydney is likely to be dependent to some extent on their opportunistic diets, which generally make animals less vulnerable to habitat modification and the reduction in prey item diversity following pollution (Mason 1996, Allanson & Georges 1999), with a further benefit possibly bestowed at some sites on E. macquarii by its omnivory.

This chapter assesses the extralimital colonization of the Pacific Northwest by turtles that are native to the eastern United States. There are two native turtles in the Pacific Northwest: the Western pond turtle and the Western painted turtle. Today, many introduced or extralimital species of turtles are present, which may outcompete or displace native turtles. There is a lack of published evidence of this interaction in the Pacific Northwest; however, there is a growing body of negative impact reported of sliders on native turtles in Europe and California. Some suggested impacts include native turtles avoiding basking sites with sliders, competition for food sources, disease transmission, and fitness. The chapter then considers how the presence and abundance of non-native turtles in the Pacific Northwest run counter to restrictions on selling them regionally.

Theodore Roosevelt National Park (THRO) in western North Dakota was established for its historical connections with President Theodore Roosevelt. It contains not only historical and cultural resources, but abundant natural resources as well. Among these is one of the best geological and paleontological records of the Paleocene Epoch (66 to 56 million years ago) of any park in the National Park System. The Paleocene Epoch is of great scientific interest due to the great mass extinction that occurred at its opening (the Cretaceous–Paleogene extinction event), and the unusual climatic event that began at the end of the epoch (the Paleocene–Eocene Thermal Maximum, an anomalous global temperature spike). It is during the Paleocene that mammals began to diversify and move into the large-bodied niches vacated by dinosaurs. The rocks exposed at THRO preserve the latter part of the Paleocene, when mammals were proliferating and crocodiles were the largest predators. Western North Dakota was warmer and wetter with swampy forests; today these are preserved as the “petrified forests” that are one of THRO’s notable features. Despite abundant fossil resources, THRO has not historically been a scene of significant paleontological exploration. For example, the fossil forests have only had one published scientific description, and that report focused on the associated paleosols (“fossil soils”). The widespread petrified wood of the area has been known since at least the 19th century and was considered significant enough to be a tourist draw in the decades leading up to the establishment of THRO in 1947. Paleontologists occasionally collected and described fossil specimens from the park over the next few decades, but the true extent of paleontological resources was not realized until a joint North Dakota Geological Survey–NPS investigation under John Hoganson and Johnathan Campbell between 1994–1996. This survey uncovered 400 paleontological localities within the park representing a variety of plant, invertebrate, vertebrate, and trace fossils. Limited investigation and occasional collection of noteworthy specimens took place over the next two decades. In 2020, a new two-year initiative to further document the park’s paleontological resources began. This inventory, which was the basis for this report, identified another 158 fossil localities, some yielding taxa not recorded by the previous survey. Additional specimens were collected from the surface, among them a partial skeleton of a choristodere (an extinct aquatic reptile), dental material of two mammal taxa not previously recorded at THRO, and the first bird track found at the park. The inventory also provided an assessment of an area scheduled for ground-disturbing maintenance. This inventory is intended to inform future paleontological resource research, management, protection, and interpretation at THRO. THRO’s bedrock geology is dominated by two Paleocene rock formations: the Bullion Creek Formation and the overlying Sentinel Butte Formation of the Fort Union Group. Weathering of these formations has produced the distinctive banded badlands seen in THRO today. These two formations were deposited under very different conditions than the current conditions of western North Dakota. In the Paleocene, the region was warm and wet, with a landscape dominated by swamps, lakes, and rivers. Great forests now represented by petrified wood grew throughout the area. Freshwater mollusks, fish, amphibians (including giant salamanders), turtles, choristoderes, and crocodilians abounded in the ancient wetlands, while a variety of mammals representing either extinct lineages or the early forebearers of modern groups inhabited the land. There is little representation of the next 56 million years at THRO. The only evidence we have of events in the park for most of these millions of years is isolated Neogene lag deposits and terrace gravel. Quaternary surficial deposits have yielded a few fossils...