Turtle - Science topic

The overall diving patterns appear to be relatively consistent between subadults and adults.

But aged adults with larger cloaca and muscle mass which is exposed to water are lesser frequent due to cloacal respiration. Usually biotic and abiotic factors are also responsible for frequent visits and ethological conditions are also a factor and it may change due to abiotic and physiological conditions.

There is no definitive comparative data, the greater variability in diving behavior noted in juvenile turtles across species suggests they may be more prone than adults to resurface multiple times between dives for breathing. However, more targeted research directly comparing age classes is needed to confirm any differences in surfacing frequency.

Other factors help in adult turtles due bigger size and adaptations -High concentrations of hemoglobin,

These adaptations allow turtles to maximize their time underwater for activities like foraging, resting, and avoiding predators while still meeting their oxygen requirements and physiological requirements.

Identifying a Miocene freshwater turtle can be tricky! Scientists use special features like the shape of the shell, bones, and teeth to figure out which kind of turtle it is. They often compare it to other known turtle fossils to make a match.

There are no giant long-necked sea turtles, In addition, if it lived in fresh water it would not be a sea turtle. The long-necked turtles all live in tropical or subtropical climates. This is just a silly question.

Muhammad Ulmar is right about this question.

Dear Sir,

It appears that some females possess alae like structures in the Toxocara genus, while others do not. Initially, I thought they might be different species, but it seems they may be the same species. Due to the similarities in the organs they inhabit within their hosts, and other morphological features, I am almost certain they belong to the same species. Do you have any insights at the genus level at least?

Best regards

I would have to see the fluorescence vs cycles curve for each of your standards.

I don't have specific information on the Palawan Forest Turtle's DNA barcoding requirements. However, the number of fresh-hatched eggs needed for DNA analysis can vary based on the species and the specific research methods used. It's best to consult scientific literature or a geneticist specializing in this area for accurate and up-to-date information on this topic.

Thanks Professor for your valuable reply

Dear researcher

As far as our observation abnormality and deformity in organs of juveniles is not reported at our Rushikulya Rookery. If such additional organs emerges, then it could be may be genetic disorder or invasion of new species due to evolution theory. We have not reported such incident so far. Hope this record is a novel finding at your coast, which indicates marine animals is under transformation phase as per the novel evolution theory.

Thanking You

Dear Oleksandr,

check about the ichnogenus Machichnus. Apparently your bite traces fit well on the diagnosis of such ichnotaxon.

All the best,

Heitor

Hi again.

Another good source of information is the journal ZOOLOGIA CABOVERDIANA, in which there are several papers about cetaceans and sea turtles of the Cape Verde Islands; see:

http://www.scvz.org/zoolcv/issue.html

Best regards from the Canary Islands.

Dear Karl,

Interesting question, unfortunately, I could not locate any literature specifically on the impact of kite surfing or electric foils on sea turtles. However, there is some research that suggests that watercrafts, like boats and jet skis, can disturb and even injure sea turtles, and this could be applicable to kite surfing and electric foils as well. This link may be of interest: https://www.google.com/search?q=Maffucci+et+al.%2C+2007-+turtle&client=firefox-b-d&sxsrf=ALiCzsbyQu-_X_DSaAG5P7VshNhP1E7LUQ%3A1672262737201&ei=UbSsY-XgC6nd7_UPkaKh0Ao&ved=0ahUKEwilza-ToJ38AhWp7rsIHRFRCKoQ4dUDCA4&uact=5&oq=Maffucci+et+al.%2C+2007-+turtle&gs_lcp=Cgxnd3Mtd2l6LXNlcnAQAzIFCCEQoAEyBQghEKABOgoIABBHENYEELADOgcIIRCgARAKSgQIQRgASgQIRhgAUOMTWN8rYJs6aAFwAXgAgAH-AogBrBOSAQUyLTQuNJgBAKABAcgBCMABAQ&sclient=gws-wiz-serp

I hope this information is helpful.

Thanks!

You can go for ANOVA, DMRT, box plots, correlation, regression, PCA etc. in Rstudio.

If there is an opportunity to launch the carp, they will quickly destroy the leeches. There are many chemicals in each country. Search for sure you will find. For example, Indalon, Dimethylphthalate

Since the spotted turtle is one of four bog turtles, this article, which contains bibliographical references items, may be helpful in a scientific research project:

"The spotted turtle (Clemmys guttata), the only species of the genus Clemmys, is a small, semi-aquatic turtle that reaches a carapace length of 8–12 cm (3.1–4.7 in)[3] upon adulthood. Their broad, smooth, low dark-colored upper shell, or carapace, ranges in its exact colour from black to a bluish black with a number of tiny yellow round spots. The spotting patterning extends from the head, to the neck and out onto the limbs. Sexually mature males have a concave plastron and a long, thick tail. By contrast, sexually mature females possess a flat plastron and have a tail notable shorter and thinner than mature males. Mature males also have a dark iris and face; females typically have a yellow or orange iris and a similarly coloured face that is distinctly lighter than males. Juveniles appear female-like in this regard and at maturity males begin to develop darker features.

Spotted turtles are aquatic omnivores that inhabit a variety of semi-aquatic or in other words, shallow, fresh-water areas such as flooded forests, marshes, wet meadows, bogs and woodland streams in southern Canada (Ontario) and the eastern US: the eastern Great Lakes and east of the Appalachian Mountains.[4]

Contents

Taxonomy[edit]

The spotted turtle is the only species in the genus Clemmys, which was first named in 1828 by Ferdinand August Maria Franz von Ritgen.[2][5] Johann Gottlob Schneider originally described the species as Testudo guttatai in 1792; however, he is now the authority for the current binomial name, Clemmys guttata.[5] Until recently, the genus Clemmys consisted of four species (bog turtle, spotted turtle, western pond turtle, and the wood turtle). Recent genetic analyses have revealed that the spotted turtle is distinct from the other three species.[6] The bog turtle and the wood turtle were moved to the genus Glyptemys, while the western pond turtle has been renamed Actinemys.[7]

Description[edit]

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Carapace is keelless and contains a varying number of yellow spots

The spotted turtle is small and has a gray to black base color.[8] Its upper shell (carapace) is smooth, does not have a central ridge running down the middle (called a "keel"),[9] and grows to 3.5–12.5 cm (1.4–4.9 in) in length.[10] It is also totally black and contains anywhere from zero to about one hundred yellow spots, which are a defining characteristic of this turtle.[10] Although perhaps inconsequential, it has been found that the left side of the upper shell has more spots than the right.[8] Spots can always be found on the head, neck, and limbs.[11] The bottom shell (plastron) is yellow or orange-yellow and a black spot is present on each section (scute); however, with age, melanism of the plastron increases until the entire surface is black.[9]

The head is black and the upper jaw is notched.[9] On each side of the head is a large orange blotch.[12] Also present are several yellow bands of varying size.[8] Skin on the dorsal side of the turtle is black with sparse yellow spots while skin on the ventral side may be brighter: orange, pink, or red. These lightly pigmented areas do vary geographically [9] and the tail of some individuals has yellow striping.[12] Regarding the geographical variation in spots, southern individuals tend to have smaller and less conspicuous spots than those of individuals from farther north.[8] The spotted turtle's karyotype consists of 50 chromosomes.[9]

Visual differences between male and female turtles develop around the time of sexual maturity. The male spotted turtle has a tan chin, brown eyes, and a long, thick tail. The chin of the female is yellow; she also has orange eyes and a shorter tail than the male. In addition, the bottom shell of males is concave while it is either flat or convex in females. On average, females grow to be slightly larger than males.[9] Also, females have more spots than males (on average).[8]

Hatchlings resemble the adults closely. Consistently, each segment of the upper shell has only one yellow spot.[13]

Distribution[edit]

The spotted turtle ranges from southern Maine, Quebec, and Ontario, south along the eastern US to Florida in the east and central Indiana and Ohio in the west.[9][10] Disjunct populations exist in the Canadian portion of its range and also in central Illinois, central Georgia,[10][14] North Carolina, South Carolina, and Indiana.[15] In Indiana and Illinois, the species is found only in the northern portion of the state but it is found on most of the lower peninsula of Michigan. The highly fragmented distribution of spotted turtles in Ohio only covers the northern two-thirds of the state.[15]

The spotted turtle occupies a variety of habitats including swamps, bogs, fens, marshes, woodland streams, and wet pastures. Also, brackish streams that are influenced by tides can also serve as a home to this turtle[16] in addition to ditches, vernal pools, and sedge meadows.[12] For a habitat to be sufficient for spotted turtle survival it must have areas of soft substrate and at least some aquatic vegetation.[16] An optimum habitat would include shallow and slow-moving waters with soft muddy soil, sedge tussocks, water lilies, sphagnum moss, and cattails.[12] Because it is so often found in areas that contain duckweed, the yellow spots on these turtles may serve as a form of camouflage.[14] The spotted turtle avoids artificial reservoirs and deep, open-water areas.[14]

The spotted turtle can be decidedly terrestrial, spending a good amount of time on land[16] and sometimes basking on patches of grass near its body of water.[17] The females during times of nesting will travel onto land and lay eggs on sunny soil. Nesting also may take place in other terrestrial locations, for instance near man-made dikes or the nest of a muskrat.[12]

Population features[edit]

Although the spotted turtle has been observed in Quebec, no permanent population is known to exist there. However, 104 populations have been discovered in Ontario. Most of these concentrated around Georgian Bay, on the north shore of Lake Erie, and southeastern Ontario. Of the original 104 sites noted, 36 are known to no longer have spotted turtles.[12]

Despite the seemingly large number of populations in Canada, many are not self-sustaining because of the following reasons: the majority of the populations are small, they all have less than 200 individuals, and the areas are all isolated from one another. All told it is estimated that anywhere from 1000 to 2000 spotted turtles live in Canada however, with individual populations ceasing to exist, this number is declining.[12]

The spotted turtle's range overlaps that of many other turtles. It can often be found in the same wetlands as wood turtles, bog turtles, snapping turtles, painted turtles, Blanding's turtles, eastern box turtles, common musk turtles, and eastern mud turtles.[17]

Ecology and behavior[edit]

The spotted turtle is one species whose sex is determined by temperature during embryonic development. Some researchers have claimed that global warming may deleteriously impact population sex ratios.[18]

During the freezing temperatures of winter and the extreme heat of summer, spotted turtles become inactive during environmentally unfavorable conditions. However, the species appears to be relatively tolerant of drought conditions. Spotted turtles do become active very early in the spring, and are often active at relatively cold water temperatures during that season. Activity appears to peak during April and May in the northern part of the range. In the warmest part of the summer (when water temperatures exceed 30 °C), they may aestivate terrestrially or aquatically for long periods of time. During summer dormancy, the turtles may burrow into leaf litter in woodlands or marsh edges or open fields; others remain in muskrat burrows or other aquatic refuges.[19] Litzgus and Brooks (2000) have questioned the common presumption that summer dormancy is an attempt by the turtles to avoid high temperatures; data from Ontario and elsewhere suggests that avoidance of predation and conservation of energy resources may be viable alternate explanations. No matter the explanation for dormancy, the "winter" dormant period may commence in late summer or fall, but in almost every instance after a return to aquatic habitats.[19][20]

Spotted turtles home ranges tend to occupy limited areas of about 0.5 to 3.5 hectares (1.2 to 8.6 acres).[19][20] Note that due to their size, these small turtles are highly vulnerable to predation, particularly during their frequent terrestrial wanderings. Many specimens will show mutilation injuries and scars from past predation attempts. Raccoons (Procyon lotor) are particularly adept at consuming and killing this species. Spotted turtles have been observed to dive into the water and bury themselves in the bottom mud when surprised while basking. Muskrats kill many spotted turtles during the winter dormant period.[19]

Diet[edit]

The spotted turtle is an active hunter: seeking out prey items in the water by pointing its head into aquatic plants.[21] It feeds at temperatures above 14.2 °C (57.6 °F), which in its range corresponds to roughly the middle of March onward until September. It is omnivorous and eats exclusively in the water,[21] consuming plant material including aquatic vegetation, green algae, and in at least one instance, wild cranberries. Animal food includes aquatic insect larvae,[22] worms, slugs, millipedes, spiders,[23] crustaceans, tadpoles, salamanders, and several genera of small fish. These items are consumed alive or dead but always in the water.[22] Some of the insects commonly found in with the spotted turtle's stomach contents are terrestrial, suggesting the turtle moves onto land to hunt.[23] In captivity, these turtles will eat fruits such as cantaloupe and watermelon and fresh and canned fish.[23]

Notes[edit]

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On a log among aquatic vegetation

The spots on spotted turtles vary greatly throughout their range. They can have up to a hundred spots, while some have no spots at all. Spotted turtles shed their scutes in small pieces occasionally resulting in completely smooth shelled specimens. These are very intelligent turtles and have been tested like the wood turtles in mazes and have been proven to have the brain capacity of a mouse. These turtles are only active in the cooler spring months. The spotted turtle is declining throughout eastern North America due to habitat loss and poaching. One study focused specifically on the Southeastern population, and recorded that females had greater shell heights, heavier body masses, and longer plastrons than males.[24] In another study, where radio-telemetry was used, spotted turtle behavior was observed in northeastern America, where distinct seasonal movement patterns revealed that spotted turtles exhibited a positive association in wetlands hosting abundant wood frog egg masses in spring and from spring to late summer, a negative association in forested wetlands was detected.[4] Spotted turtles require frequent terrestrial movements for their diverse habitat requirements which exposes them to potential threats including unsustainable sources of adult mortality such as road kill and illegal collection.[4] Recovery action is necessary to prevent decline of spotted turtles since this species has been determined to have a high risk of extinction in several areas ranging from South Carolina up to Maine in the US and even further north into Ontario, Canada, mitigation requires spatial and temporal shifts in habitat use.[4]

Conservation[edit]

In Canada, the spotted turtle is federally endangered,[12] while in the United States the spotted turtle is currently under review by the Fish and Wildlife Service for protection under the Endangered Species Act.[25] It is listed by the IUCN as endangered,[1] and has "listed" status in many of the states where it occurs. For example, in Indiana the spotted turtle is listed as an endangered species.[26] In the Northeast, it has protective status in five of the six New England states and is listed as a species of special concern in New York.

Habitat destruction and alteration, collection for the pet trade, and other human impacts such as vehicle mortality (cars and mowers) are leading to declines in populations.[22]

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Spotted Turtle Florida

References[edit]

Bibliography[edit]

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Thanks for your answer

Jordan, your question actually only may be addressed by a stability test (spiked samples, freeze them and then store them at different temperatures for some time). Depending on the results of your analysis and the importance of the conclusions you are drawing from them, it might make sense to set up such a test in order to corroborate your results.

On the other hand, if the samples are sterile, I'd be quite confident that no adverse effects have been happening. Are the steroids sensitive to oxygen or modification by enzymes which are released by broken blood cells? Are you observing hemolysis?

If you know the positions of your samples in the fridge, esp. if you are able to identify those which have been thawed, you could plot the results against the sample position/thawing status to check if the thawed samples are producing weird data.

Use can make use of Chi-square statistical test

Agree with the views of Dr Zaal Kikvidze and Dr David Dawson

Thank you! That map is really great. I will be sure to read the whole summary soon.

I would try to identify what matters to your target audience and how the turtles relate, e.g. maybe turtles help maintain a healthy ecosystem that benefits fish preferred by anglers? Obviously it has to be true, but I'd aim for simple, straightforward, and relatable messages that relate directly to the target audience (easier said than done, of course).

From the touristic point of view, that could be more "visible" than an ecological effect (much more important), this could be an answer:

All the best ,Amos

Good Answer Debasis Dhak

Here is a recent 2020 publication on Indonesia gillnet bycatch, published in the journal Endangered Species Research:

I 'll do it. Thanks!

You can use any data you like as long as you have approval. It's good to get in writing from your head of department that it will be sufficient, and definitely obtain copyright so that only you can publish from it, otherwise do not use it. But obtaining your own confidential primary data is best

Hi here are some

Meek, R., & Avery, R. A. (1988). Allometry in Testudo sulcata: a reappraisal. Herpet. J, 1, 246-247.

Smith, L. L., Pedrono, M., Dorazio, R. M., & Bishko, J. (2001). Morphometrics, sexual dimorphism, and growth in the angonoka tortoise (Geochelone yniphora) of western Madagascar. African Journal of Herpetology, 50(1), 9-18.

Seidel, M. E. (1994). Morphometric analysis and taxonomy of cooter and red-bellied turtles in the North American genus Pseudemys (Emydidae). Chelonian Conservation and Biology, 1(2), 117-130.

Ritz, J., Griebeler, E. M., Huber, R., & Clauss, M. (2010). Body size development of captive and free-ranging African spurred tortoises (Geochelone sulcata): high plasticity in reptilian growth rates. The Herpetological Journal, 20(3), 213-216.

Hi Elizabeth, We used telemetry to determine river ranges of female Barbour's map turtles (see attached file). We calculated home ranges in Arc GIS using Home Range Tools and clipped the MCPs and KDEs to the surface area of the creek as determined with sonar mapping, so the ranges were constrained to the creek. Hope this is helpful.

Best,

Lora Smith

Mohd Hairul Mohd Salleh , yes things are progressing,

Last week, Costa Rica to completely ban polystyrene due to environmental impact.

Aaron Baxter has published on diamondback terrapins in estuaries of Texas :

google his names and terrapins for several pdf reports of his studies. Best, PZimba

apply in wwf

I think a Actinozoa

By Don Moll, Professor of Biology Don Moll, Edward O. Moll, Professor of Zoology Edward O Moll

Thanks Santosh Singh . Yes different methods have different issues in detectability that must be considered in the survey design and subsequent analysis.

I was thinking more about - if the number of nests declines over time in the same area it is safe to assume that the population is declining.

If the number of nests increases can this reflect population increase? As females become older they may lay more nests. So to use nests as measure, we need to know the number of nests, eggs per nest and size of eggs (larger turtles lay larger eggs on average)....

Dear Charlotte, what do you need?

I have attached several articles on DNA extraction in fish .

Hi, yes thank you Hector and Dmitry. Our paper "Using growth rates to estimate age of the sea turtle barnacle Chelonibia testudinaria" describes what you're after. Summarising it, we expect that Chelonibia barnacles generally live for about 1 year on loggerhead turtles in eastern Australia, and probably no more than two years, based on growth rates and maximum sizes observed.

Here is a paper on this problematic which may help you.

95% confidence interval = 1.96 x standard error of the constant

Your situation is not uncommon: these programs have different theoretical backgrounds and different assumptions and do not necessarily produce the same answer. One issue is the likely the number of loci: they may not have the resolution to really disentangle population structure.

STRUCTURE is used so extensively that there is ample discussion about its flaws. Problems include sensitivity to family groups ( ) and sampling distribution ( ). I believe there was also a recent paper that suggested STRUCTURE will always predict K=2 will be the most likely pattern. At the same time, DAPC has not been as rigorously tested in the literature, so its limitations are less known.

Couple of suggestions. First, always frame whatever these programs output in the biological context of your study system. Do the patterns of genetic structure and ancestry assignment make sense given what you know? Second, try things like a standard PCA or neighbor-joining tree just to get a sense of the genetic relationships between individuals. Third, could something like IBD or hierarchical population structure be present? Those can throw off clustering methods. Forth, you could use something like MIGRATE or divMigrate to estimate migration rates or even test specific hypotheses of population structure.

Hope this helps. Best of luck!

Das ist leider plausibel. Bleibt noch die Frage, ob Aussgen zu den Umständen der Einbettung möglich sind, weil ein ungewöhnlich großes Stück des Bauchpanzers in die Grube geriet. Häufig sind an der Siedlungsstelle vor allem einzelne Platten von Schildkrötenpanzern, die sich in der ehemaligen Uferzone und im vererdeten Torf über den mesolithischen Schichten finden, welcher neolithische und umgelagerte mesolithische Artefakte enthält.

Friedman test you can ran using spss from analyse - non parametric test then select K repeated sample then select freiedman test

Ha ha Rastko, I have seen you watching them :-) Do you know who did it?

Dear Ira,

valuable Literature dealing with your subject:

Pritchard PCH. Evolution and structure of the turtle shell. In: Wyneken J, Godfrey MH, Bels V eds. Biology of the turtles. 2008;CRC Press 45-83

Nagashima H, Shibata M, Taniguchi M et al. Comparative study of the shell development of hard- and soft-shelled turtles. J Anat 2014; 225: 60–70.

Hirasawa T, Pascual‐Anaya J, Kamezaki N et al. The evolutionary origin of the turtle shell and its dependence on the axial arrest of the embryonic rib cage. J Exp Zoolog B Mol Dev Evol 2015; 324B: 194–207

Cebra-Thomas JA, Tan F, Sistla S et al. How the turtle forms its shell: a paracrine hypothesis of carapace formation. J Exp Zoolog B Mol Dev Evol 2005; 304: 558–569

Rice R, Riccio P, Gilbert SF et al. Emerging from the rib: Resolving the turtle controversies. J Exp Zoolog B Mol Dev Evol 2015; 324B: 208–220

Lyson TR, Bhullar BA, Bever GS et al. Homology of the enigmatic nuchal bone reveals novel reorganization of the shoulder girdle in the evolution of the turtle shell. Evol Dev 2013; 15(5): 317–325

Loredo GA, Brukman A, Harris MP et al. Development of an evolutionarily novel structure: Fibroblast growth factor expression in the carapacial ridge of turtle embryos. J Exp Zool 2001; 291: 274–281

Kuraku S, Usuda R, Kuratani S. Comprehensive survey of carapacial ridge-specific genes in turtle implies co-option of some regulatory genes in carapace evolution. Evol Dev 2005; 7: 3–17

Moustakas JE. Development of the carapacial ridge: implications for the evolution of genetic networks in turtle shell development. Evol Dev 2008; 10: 29–36

Wang Z, Pascual-Anaya J, Zadissa A et al. The draft genomes of soft-shell turtle and green sea turtle yield insights into the development and evolution of the turtle-specific body plan. Nat Genet 2013c; 45: 701–706.

Scheyer TM, Sander PM, Joyce WG et al. A plywood structure in the shell of fossil and living soft-shelled turtles (Trionychidae) and its evolutionary implications. Organ Divers Evol 2007; 7: 136–144

Gilbert SF, Loredo GA, Brukmann A et al. Morphognesis of the turtle shell: the development of a novel structure in tetrapod evolution. Evol Dev 2001; 3(2): 47-58

Hope this helps?!

Best regards, Jean Meyer

For these long term studies we are looking at snapping and painted turtles. We also are looking at wood turtles and impact of headstarting.

We collect all the standard life history metrics, age of first rep, number and frquency and size of offspring, age specific rep, survival, growth, longevity. We also look at sex ration, TDSD, behaviour, nest site selection and dispersal. Really anything that comes up as interesting. My favourite is the interaction between the specis and leeches.

ron

See also, Ferrara, C.R., Vogt, R.C., and Sousa-Lima, R.S. 2013. Turtle vocalizations as the first evidence of posthatching parental care in chelonians. Journal of Comparative Physchology 127:1-9.  This was the first paper describing freshwater turtle vocalizations.

Dear Hamza,

I suggest to you links and attached files in topics.

Mobile Robot TURTLEBOT 2 ROS | Robotnik

Hands-on With TurtleBot 3, a Powerful Little Robot for Learning ROS ...

TurtleBot 2 - Open source personal research robot - Clearpath Robotics

REP 119 -- Specification for TurtleBot Compatible Platforms (ROS.org)

Best regards

IF there are any ways to reduce the bias of the traps by using different collection methods that might provide a different sex ratio. Try using different bait types (or rotating bait types), more intensive sampling, drift fences (fike-nets) into the traps, use of decoys, etc. 

What was your recapture rate? If your male recapture rates are low, you may just be sampling them poorly. 

Dear David,

thank you for your question. Pappochelys shares numerous apomorphies with other stem-turtles, especially Odontochelys. Most of these features have not been published, so it may be wise to wait until the full description is published before considering it in a phylogenetic analysis. Also, I think first-hand study of the material is essential for such phylogenetic work; this said, you are most welcome to study the material in our museum collection once it has been published.

The reason you may find Pappohelys to nest with placodonts may be based on the misunderstandig of the gatralia, which appear superficially similar in placodonts and Pappochelys but at closer sight are entirely different. There are no characters known to us that would support a placement of Pappochelys (and the very similar Odontochelys) with placodonts. If you find turtles to nest with pareiasaurs, it would be interesting to learn about your opinion about the substantial molecular and soft-anatomical evidence that supports a diapsid (archosauromorph) origin of the clade.

I believe the good Dr. Burke is correct in that little to nothing is known. Bob Gatten was one of the main contributors in the 1970s and 1980s. I did work with him at the University of Toledo [Thermal Preference in Snapping Turtles, Chelydra serpentina. Copeia 1980(1):149-152]. Also, perhaps try Vic Hutchinson or Dan Brooks as sources?  Cheers, Gordon

As brought out previously, most Aldabra tortoises (Aldabrachelys) have a nuchal scute (1.34% do not) and Galapagos tortoises (Chelonoidis) do not. The tortoise in the image appears to have a nuchal scute and thus most likely is an Aldabra tortoise.

dynamometer was my first choice but marine turtles, especially green turtle, are hard to fixate. moreover fixing the adults on beach after they laid their eggs, will disturb them too much.

Thanks for your answers Mehdi and Dusan. But it seems that i have to find another way to measure it.

best regards

onur

Hello Olivier! As you may already know, I have several more pictures of Malayemys macrocephala & subtrijuga from different parts of the range.  Please let me know what you are interested in particular (i.e. localities, morphological features, etc.).

Your methodology is going to vary considerably depending on your specific ecological adaptation research question (e.g., sprint speed, climbing ability, body size, sexual size dimorphism, color/patterning, reproductive mode, etc., etc.).  I would first recommend you conduct an extensive literature review of your particular species of interest (or species group) and the particular adaptation you are interested in exploring.  The chances are good that someone else has worked with your study species (or a closely related species) and/or the adaptation you interested in studying.

So for example, you may want to investigate the ecological adaptations of a freshwater turtle species that has populations living in both flowing and non-flowing conditions.  If you look in the literature, turtle populations have adapted to these different flow conditions by evolving different shell shapes; those that live in high flow conditions are more streamlined while those that live in low flow conditions are more robust.  So to answer this question you would want to design a field study to investigate shell morphology (quantify different shell measurements like carapace length, width, and height) at different sites with different flow regimes.  This field study could then be validated by lab studies in a flow-through system to measure swimming efficiency and/or shell drag.  I have attached a great study by Rivera who did just this study.  

There are numerous other papers using similar studies to research ecological adaptations of herpetofauna. Herpetological Conservation and Biology publishes papers like this regularly, and the papers are freely accessible to the public at this web address (www.herpconbio.org).  I hope that this is helpful.

Dear Sivakumaran,

Due to the speed at which climate change is occurring, it is unlikely that marine turtles would be able to genetically adapt to the rapid increase in temperature as they are long-lived species with long generational times. It has been suggested that phenotypic plasticity could aid turtles to adapt to the temperatures in the short-term, giving a longer time span for genetic adaptation. Genetic variations for plastic responses already exist allowing some individuals to tolerate higher temperatures during development. Weber (2011) showed that hatchlings laid in darker sand showed a higher tolerance to higher temperatures than those laid in pale sand, suggesting adaptive phenotypic variation to thermal-tolerance as well as a current divergence. However, due to the temperature dependent sex determination, sex ratio skew is a cause for concern. There has been studies conducted showing variation in the operational sex ratio (proportional to the amount of males in a breeding area) which suggest that there are currently no sex ratio skews (Tedeschi 2014). As females only mate/nest once every 2 to 3 years, and males can mate every year, it is possible that the population can still be sustained even with a sex ratio skew biased to females.

There are contradictory studies on sea turtle’s ability to change the depth of their nests. It is not known whether they are physiologically able to dig a nest depth deep enough to make a significant difference to the temperature. A study by Kamel (2006) in Antigua recorded only a 0.2’C temperature variation between depths, which is unlikely to have a major effect on hatchling development.

Kind regards,

Claire

You have to refer to their original descriptions to find the difference or to study type specimens. All other suggestions - answers you will get here - can be incorrect (or correct, but you will never know this unless you prove it yourself!).

I strongly suspect that different predators can detect turtle nests for different lenghts of time based on their olfactory capabilities.  For this, I believe the citation of Condgon et al. (1987), offered by John Orr (above in this thread), is among the best-quantified. For the background on probably why Walde et al. wood turtles experienced no predation, I'd suggest you contact him (there are likely reasons, but he is the best source for the details). The point raised by Riley and Litzgus (2014), is well-taken:  the late season nest depredation they observed is quite likely due to the presence of renewed nest location cues ... not really addressing the point you are interested in. With all due humility, you may find my recent paper of interest: A Test of Substrate Sweeping as a Strategy to Reduce Raccoon Predation of Freshwater Turtle Nests, with Insights from Supplemental Nests. Chelonian Consevation and Biology 14(1) 64-72.

Make the mark at the top of the egg with a pencil or another non-toxic marker. Transfer the eggs onto a tray filled with damp sand. Place each egg in a depression you make in the sand with your thumb or finger so that the egg does not roll while being transported.

My only observation was of basking yellow-blotched sawbacks (Graptemys flavimaculata) abandoning their basking structure due to a beaver swimming nearby; presumably they used visual cues to detect the beaver and diving into the water was a safer location.  See Selman and Qualls 2011 below (pp. 192-193).

Hi Richard,

thank you very much for your comments and papers (and sorry for my late reply) :)

This discussion really helped with my thought process!

Hello Paul, you can use the rdfEditor (https://bitbucket.org/dotnetrdf/dotnetrdf/wiki/UserGuide/Tools/rdfEditor).

Hello to all

1-H. marginatum

2-H. detritum

3-H. aegyptium

4-H. dromedarii (ventral surface should be confirmed)

different ticks (Hyalomma spp. should be compared with the same age, otherwise misleading).

Regards

Abdigoudarzi

Based on the data we have in several places, the common strategy for marine turtles is as followed. During a nesting season, a female nest several time. Most of the nests from a female are deposited in the same beach but a small fraction (#10%) are deposited in other beaches of the region (bet hedging strategy). To separate between a "colony" beach and an occasional beach, a strategy could be to estimate the proportion of females seen only once for each beaches (corrected of course for the captured probability). If you calculate the ratio (female seen once)/(total number of females) for each beach, the ratio will be around 0.5 for colony beach and around 0.1 for occasional beach (the values could be different for the species/region). You can find a way to estimate the proportion of single nest females in this paper: 

Briane, J.-P., Rivalan, P., Girondot, M., 2007. The inverse problem applied to the Observed Clutch Frequency of Leatherbacks from Yalimapo beach, French Guiana. Chelonian Conservation and Biology 6, 63-69.

Do not hesitate to contact me if you need some advice.

Sincerely

Marc Girondot

As far as I understand this type of research, you should just find a way how visualize migrations, show how let's say feeding sites are connected with nesting sites. In principle, it is possible to find correlation with water temperatures, type of biomes and presence of animals in particular part of ocean. Niche modelling could be also applied to nesting sites in order to predict their distribution. Connectivity of nesting sites and feeding sites and distance might be crucial. I am sure that much is already done with such iconic animals, but I am not familiar with the literature on the topic.