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Lemos-Espinal, Julio A., et Geoffrey R. Smith. « A conservation checklist of the herpetofauna of Morelos, with comparisons with adjoining states ». ZooKeys 941 (16 juin 2020) : 121–44. http://dx.doi.org/10.3897/zookeys.941.52011.
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Despite being one of the smallest states in Mexico, the high diversity of habitats in Morelos has led to the development of a rich biota made up of a mixture of species typical of the Neovolcanic Axis and the Sierra Madre del Sur. However, recent expansion of cities in Morelos is likely to have consequences for the state’s herpetofauna. Here a checklist of the amphibians and reptiles of Morelos is provided with a summary of their conservation status and overlap with its neighboring states. Morelos is home to 139 species of amphibians and reptiles representing 32 families and 75 genera. Twenty-six of the 38 species of amphibians and 70 of the 101 species of reptiles that inhabit Morelos are endemic to Mexico. Fourteen species of amphibians and reptiles from Morelos are IUCN listed (i.e., Vulnerable, Near Threatened, or Endangered), 22 are placed in a protected category by SEMARNAT, and 41 are categorized as high risk by the EVS. The Tropical Deciduous Forest vegetation type hosts the greatest number of amphibian and reptile species in Morelos (84 species). Morelos shares the largest proportion of its herpetofauna with the State of Mexico (79.3%), Puebla (77.0%), and Guerrero (74.8%).
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Xia, Tian, Honghai Zhang, Lei Zhang, Xiufeng Yang, Guolei Sun, Jun Chen, Dajie Xu et Chao Zhao. « Comparative and evolutionary analysis of the reptilian hedgehog gene family (Shh, Dhh, and Ihh) ». PeerJ 7 (30 août 2019) : e7613. http://dx.doi.org/10.7717/peerj.7613.
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The hedgehog signaling pathway plays a vital role in human and animal patterning and cell proliferation during the developmental process. The hedgehog gene family of vertebrate species includes three genes, Shh, Dhh, and Ihh, which possess different functions and expression patterns. Despite the importance of hedgehog genes, genomic evidence of this gene family in reptiles is lacking. In this study, the available genomes of a number of representative reptile species were explored by utilizing adaptive evolutionary analysis methods to characterize the evolutionary patterns of the hedgehog gene family. Altogether, 33 sonic hedgehog (Shh), 25 desert hedgehog (Dhh), and 20 Indian hedgehog (Ihh) genes were obtained from reptiles, and six avian and five mammalian sequences were added to the analysis. The phylogenetic maximum likelihood (ML) tree of the Shh, Dhh, and Ihh genes revealed a similar topology, which is approximately consistent with the traditional taxonomic group. No shared positive selection site was identified by the PAML site model or the three methods in the Data Monkey Server. Branch model and Clade model C analyses revealed that the Dhh and Ihh genes experienced different evolutionary forces in reptiles and other vertebrates, while the Shh gene was not significantly different in terms of selection pressure. The different evolutionary rates of the Dhh and Ihh genes suggest that these genes may be potential contributors to the discrepant sperm and body development of different clades. The different adaptive evolutionary history of the Shh, Dhh, and Ihh genes among reptiles may be due to their different functions in regulating cellular events of development from the embryonic stages to adulthood. Overall, this study has provided meaningful information regarding the evolution of the hedgehog gene family in reptiles and a theoretical foundation for further analyses on the functional and molecular mechanisms that have shaped the reptilian hedgehog genes.
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Sugiarto, Daniel. « PENGEMBANGAN MODUL ANATOMI REPTIL DI DAERAH ALIRAN SUNGAI MAOSPATI MAGETAN UNTUK MENINGKATKAN PEMAHAMAN KONSEP MATA KULIAH STRUKTUR HEWAN DI IKIP PGRI MADIUN ». Florea : Jurnal Biologi dan Pembelajarannya 3, no 1 (20 décembre 2016) : 1. http://dx.doi.org/10.25273/florea.v3i1.781.
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<p>During this time the students learning system, especially on the structure of animals in biology education IKIP PGRI MADIUN. information presented in the form of modules still no or less so difficult to accept students in particular about the material or preparations that are less known as well as local reptile anatomy that is found around the neighborhood students. The aim of developing local reptile anatomy modules in subjects animal structure. Research using 4-D<br />model of development (Define, Design, Develop, Disseminate). Results of development in the form of draft module to be tested and improved understanding of the concept of students. The trial results are obtained material content of the course structure validator experts percentage of 86.66% was obtained animals can be categorized valid (good). The trial results stating that: 1) the modules worth diujicabakan field and very helpful in learning the anatomy of reptiles 2) Students are more familiar with preparations anatomy reptiles as obtained from the student environment and the result of understanding the concept of students with test pre test and posh test through the test T is obtained thitung 15.22> ttable 1,717 or able to enhance student understanding of concepts. Limitations modules developed only compiled on the subject of local reptile anatomy</p>
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Russell, Anthony P., et M. W. J. Ferguson. « The Structure, Development and Evolution of Reptiles ». Copeia 1986, no 3 (4 août 1986) : 841. http://dx.doi.org/10.2307/1444977.
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Cloudsley-Thompson, J. L. « The Structure, Development and Evolution of Reptiles ». Journal of Arid Environments 9, no 2 (septembre 1985) : 185. http://dx.doi.org/10.1016/s0140-1963(18)31500-3.
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Russell, Findlay E. « The structure, development and evolution of reptiles ». Toxicon 23, no 6 (janvier 1985) : 1019. http://dx.doi.org/10.1016/0041-0101(85)90399-x.
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Clulow, John, et Simon Clulow. « Cryopreservation and other assisted reproductive technologies for the conservation of threatened amphibians and reptiles : bringing the ARTs up to speed ». Reproduction, Fertility and Development 28, no 8 (2016) : 1116. http://dx.doi.org/10.1071/rd15466.
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Amphibians and reptiles are experiencing serious declines, with the number of threatened species and extinctions growing rapidly as the modern biodiversity crisis unfolds. For amphibians, the panzootic of chytridiomycosis is a major driver. For reptiles, habitat loss and harvesting from the wild are key threats. Cryopreservation and other assisted reproductive technologies (ARTs) could play a role in slowing the loss of amphibian and reptile biodiversity and managing threatened populations through genome storage and the production of live animals from stored material. These vertebrate classes are at different stages of development in cryopreservation and other ARTs, and each class faces different technical challenges arising from the separate evolutionary end-points of their reproductive biology. For amphibians, the generation of live offspring from cryopreserved spermatozoa has been achieved, but the cryopreservation of oocytes and embryos remains elusive. With reptiles, spermatozoa have been cryopreserved in a few species, but no offspring from cryopreserved spermatozoa have been reported, and the generation of live young from AI has only occurred in a small number of species. Cryopreservation and ARTs are more developed and advanced for amphibians than reptiles. Future work on both groups needs to concentrate on achieving proof of concept examples that demonstrate the use of genome storage and ARTs in successfully recovering threatened species to increase awareness and support for this approach to conservation.
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Turak, Eren, Alex Bush, Jocelyn Dela-Cruz et Megan Powell. « Freshwater Reptile Persistence and Conservation in Cities : Insights from Species Occurrence Records ». Water 12, no 3 (28 février 2020) : 651. http://dx.doi.org/10.3390/w12030651.
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Reptiles are rarely included in urban freshwater biodiversity monitoring and conservation. We explored the global persistence of freshwater dependent turtles, lizards, crocodilians and snakes in cities with a population greater than 100,000 using species occurrence data in online databases from a five-year period (2013–2018). We then used ecological niche models to help identify the locations of suitable habitats for three freshwater reptile species in Sydney, Australia. Our Global analysis showed that sightings of a majority of known species of crocodilians and freshwater turtles were recorded in databases within this 5-year period in contrast to about one in three freshwater lizard species and one in ten freshwater snake species and that freshwater reptiles were observed within 50 km of the center of 40% of the 3525 cities. While global databases hold substantial recent species occurrence records for some regions, they contain very little data for large parts of the world. Modelling showed that potential suitable habitat for the three freshwater species in Sydney was distributed across areas with different levels of urban development. The persistence of populations of freshwater reptiles in and around a large proportion of the world’s cities show that this group can play an important role in urban biodiversity conservation.
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McDowell, Samuel B. « Wide Ranging on Reptiles The Structure, Development and Evolution of Reptiles Mark W. J. Ferguson ». BioScience 36, no 3 (mars 1986) : 206–7. http://dx.doi.org/10.2307/1310325.
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Sun, Bao-Jun, Teng Li, Yi Mu, Jessica K. McGlashan, Arthur Georges, Richard Shine et Wei-Guo Du. « Thyroid hormone modulates offspring sex ratio in a turtle with temperature-dependent sex determination ». Proceedings of the Royal Society B : Biological Sciences 283, no 1841 (26 octobre 2016) : 20161206. http://dx.doi.org/10.1098/rspb.2016.1206.
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The adaptive significance of temperature-dependent sex determination (TSD) has attracted a great deal of research, but the underlying mechanisms by which temperature determines the sex of a developing embryo remain poorly understood. Here, we manipulated the level of a thyroid hormone (TH), triiodothyronine (T 3 ), during embryonic development (by adding excess T 3 to the eggs of the red-eared slider turtle Trachemys scripta , a reptile with TSD), to test two competing hypotheses on the proximate basis for TSD: the developmental rate hypothesis versus the hormone hypothesis . Exogenous TH accelerated embryonic heart rate (and hence metabolic rate), developmental rate, and rates of early post-hatching growth. More importantly, hyperthyroid conditions depressed expression of Cyp19a1 (the gene encoding for aromatase) and levels of oestradiol, and induced more male offspring. This result is contrary to the direction of sex-ratio shift predicted by the developmental rate hypothesis , but consistent with that predicted by the hormone hypothesis . Our results suggest an important role for THs in regulating sex steroid hormones, and therefore, in affecting gonadal sex differentiation in TSD reptiles. Our study has implications for the conservation of TSD reptiles in the context of global change because environmental contaminants may disrupt the activity of THs, and thereby affect offspring sex in TSD reptiles.
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Hulbert, AJ, et PL Else. « Mammalian metabolism : insights from arid zone reptiles. » Australian Mammalogy 26, no 1 (2004) : 111. http://dx.doi.org/10.1071/am04111.
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Mammals, being endotherms have very high metabolic rates compared to ectothermic reptiles. Similarly, small mammals have high rates of mass-specific metabolism compared to larger mammals. This review examines the mechanistic basis of why particular mammal species have a specific metabolic rate. Initial studies compared mammals with arid zone reptile species of the same size and Tb. Mammals have larger internal organs, with more mitochondrial membrane surface area than the reptiles. The cells of mammals are leakier to Na+ ions and their mitochondrial membranes are leakier to H+ ions than in reptile cells. These leakier membranes have membrane lipids that are polyunsaturated and less monounsaturated than their less leaky counterparts. Examination of the cellular basis of allometric variation in metabolism in mammals reveals very similar findings with polyunsaturated membranes associated with the high mass-specific metabolic rates of small mammal species and monounsaturated membranes with low rates of metabolism of large mammals. These findings have resulted in the development of the ?membrane pacemaker? theory of metabolism, which proposes that membrane bilayer composition is regulated in animals and that highly polyunsaturated membranes result in enhanced molecular activity of membrane proteins and in turn this results in an elevated metabolic rate of cells, tissues and consequently whole animals. This theory is also supported by the recent examination of the basis of body-size variation in the metabolic rates of birds. The ?membrane pacemaker? theory of metabolism is currently the only explanation of the mechanisms determining the metabolic rate and thus the cost of living of animals. It has implications for the effect of food habits on metabolism and the relationship between metabolism and lifespan.
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Thigpen, Christopher, Logan Best et Troy Camarata. « Comparative morphology and allometry of select extant cryptodiran turtle kidneys ». Zoomorphology 139, no 1 (28 septembre 2019) : 111–21. http://dx.doi.org/10.1007/s00435-019-00463-3.
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Abstract Reptile, avian, and mammalian species all possess a metanephric kidney to maintain fluid homeostasis. The physiology of the kidney is intimately related to tissue organization and gross morphology, which is dependent upon organ size, animal habitat, and body plan. Reptiles have significant variations in body plan and as a result have differences in visceral organ placement and morphology. One organ that appears to show great morphological variation is the reptilian kidney found in Crocodylia, Testudines, and Squamata (Sauria and Ophidia). However, limited research has been conducted to evaluate and compare kidney morphology in reptiles and more specifically, in turtles. Here we have examined multiple cryptodiran turtle species from the families Chelydridae, Emydidae, Kinosternidae, and Trionychidae. Detailed descriptions of kidney morphology along with comparative allometry are provided. Significant differences in external renal morphology were found between and within turtle families as well as differences in scaling of kidney mass with body mass. Our study provides a foundation for understanding differences in organ development and tissue architecture as well as potential differences in physiology.
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Stets, O. V. « Parasites of panther chameleons (Furcifer pardalis) grown in captivity and brought from the wild ». Journal for Veterinary Medicine, Biotechnology and Biosafety 5, no 4 (10 décembre 2019) : 15–17. http://dx.doi.org/10.36016/jvmbbs-2019-5-4-4.
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Reptile parasites imported from the wild differ from those grown in captivity. Thus, captive-grown reptiles tolerate the process of disadaptation better than imported wild animals, even under proper conditions of keeping and feeding. It should be noted that determining the origin of reptiles is sometimes difficult or impossible. For this, special methods are needed. In this regard, the purpose of research was to confirm or refute the theory, in reptiles from different places of residence, various parasites are found. We studied panther chameleons (Furcifer pardalis) imported from the wild and raised in captivity. To determine the parasites in the laboratory, methods of native smear, sequential washing and flotation were used. 10 species of intestinal parasites were found in panther chameleons imported from the wild, in particular Trematoda gen. sp. 1, Tremaitoda gen. sp. 2, Cestoda gen. sp., Spinicauda freitasi (Olfers, 1919), Hexametra angusticaecoides (Chabaud et Brygoo, 1960), Pharyngodonidae gen. sp., spirurates of the genus Thubunaea sp., larvae of the family Rhabdiasidae gen. sp., flagellates from the series Kinetoplastida gen. sp. and Eimeria sp, with prevalence 87.56%. In panther chameleons grown in captivity only Pharyngodonidae gen. sp. was found, prevalence was 94.05%. It is noted that under appropriate conditions of keeping and feeding in captive panther chameleons, a small number of parasites with a direct development cycle and their insignificant toxic effect on the body can develop
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Novruzov, Nizami Enver, et Sabina Nizami Bunyatova. « Modern state and perspectives of amphibian and reptile synantropisation in anthropocoenosiss of Eastern Azerbaijan ». Samara Journal of Science 6, no 2 (1 juin 2017) : 65–70. http://dx.doi.org/10.17816/snv201762113.
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Three species of amphibians and 21 species of reptiles were found on the investigated anthropogenically transformed territories of the eastern part of Azerbaijan, which was 32% of 75 species representing the herpetofauna of the republic as a whole. A consistent decrease in the abundance and index of species diversity was revealed with an increase in the degree of development of the territory and the level of anthropogenic impact. The ratio of species in anthropocoenosiss varied depending on the size of their areas. The recreational pressing has presumably less influence on the numbers, but more on the species diversity of amphibian and reptile. In less developed areas, their numbers increase due to the presence of background species. The effectiveness of adaptation of some species of amphibians and reptiles is apparently associated with an adequate response to environmental changes brought about by anthropogenic impact on the natural environment. As the research has shown, anthropogenic impacts contributed to the spread and growth of the numbers of 7 species (2 species of amphibians and 5 species of reptiles). For Absheron Peninsula and Gobustan, such species were Bufotes variabilis , Pelophylax ridibundus , Eremias velox , Cyrtopodion caspius , Emys orbicularis , Natrix tessellata , Macrovipera lebetina . During the period of research, all these species were observed practically in all anthropogenic landscapes and now can be considered promising synanthropes for the regions studied.
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SAN-MARTÍN-ÓRDENES, JULIO, SEBASTIÁN MUÑOZ-LEAL, CARLOS F. GARÍN et DANIEL GONZÁLEZ-ACUÑA. « A systematic review of parasites and micropredators of non-avian reptiles (Reptilia=Sauropsida) in Chile ». Zootaxa 4543, no 3 (7 janvier 2019) : 301. http://dx.doi.org/10.11646/zootaxa.4543.3.1.
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Knowledge about the identity of parasites in vertebrates is relevant because of their influence on ecological processes and health of their hosts. This is particularly important for groups of animals currently facing conservation issues, such as reptiles. The diversity of species and supra-specific taxa of microparasites and macroparasites (such as helminths and arthropods) present in non-avian reptiles in Chile was analyzed through a systematic review. A total of 49 scientific documents (thesis projects, abstracts in congresses, book chapters and peer-reviewed articles) concerning parasites, taxonomic descriptions and parasite ecology were included in this review. The suborder Iguania was among the most studied group with 35 native species recognized as hosts of parasites and 39 species of parasites reported up to the category of species or genus. Liolaemus tenuis was the species with the most taxa of recorded parasites (11 taxa, and only three to species level), but Liolaemus chillanensis had the highest number of identified species of parasites. In addition, only one native species of Serpentes, one of Gymnophthalmoidea, and two of Gekkota, as well as some reports of exotic species, were recorded as hosts. Among parasites, Trombidiformes was the richest order with 10 species from the superfamily Pterygosomatoidea and 16 species from Trombiculoidea. Current knowledge about the richness of helminths is very limited and there were only a few records of microparasites. In general, there is an urgent need for the development of collaborative works between specialists in reptile taxonomy and epidemiology in parasitology destined to evaluate the consequences that reptiles and their parasites will suffer due to the ongoing processes of habitat loss, climate change and the still present taxonomic issues of the native reptiles.
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Chuliuk, W. I. « Features of the usage of antibiotics in herpetology ». Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 23, no 101 (5 avril 2021) : 61–66. http://dx.doi.org/10.32718/nvlvet10111.
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The article summarizes the literature data on the frequency and causes of diseases of reptiles, the peculiarities of their infection with bacterial microorganisms, the use of antimicrobial drugs and the development of antibiotic resistance. It should be noted that the use of antibiotics and other antimicrobial drugs in veterinary herpetology has its own characteristics, due primarily to the peculiarities of thermoregulation and metabolism in reptiles, the nature of the pathogenic microflora inherent in these animals. In reptiles, infection with gram-negative microorganisms is more common: enterobacteria (salmonella, Escherichia coli, Proteus) and gram-positive bacteria (staphylococci and streptococci), as well as saprophytes belonging to the group of spore-forming microorganisms. Some species of actinomycetes show quite pronounced pathogenic activity as well. Reptiles suffer from salmonellosis or are salmonella carriers. In such cases, conditions are created for the potential infection of humans with salmonella, most often infecting children and the elderly who come into contact with sick reptiles. Other anthropozoonoses (eschiriosis, leptospirosis, chlamydia, campylobacteriosis, streptococcal and staphylococcal infections, fungal infections, etc.) are dangerous as well. Antibiotics were prescribed to sick reptiles “at the beginning” of the development of veterinary herpetology. The effectiveness of antimicrobial drugs depends on many factors (species, age and sex of reptiles, their physiological state: temperature, metabolic rate, the presence of underlying and comorbidities, the type of bacteria that infect reptiles and their resistance to antibacterial drugs, etc.). Unlike mammals, reptiles have a portal venous system of the kidneys, which is represented by a system of veins, through which much of the venous blood from the back of the body enters the portal vein of the kidneys, which breaks down into a system of capillaries isolated many toxic compounds, including antibiotics. Thus, the portal venous system of the kidneys, together with the portal venous system of the liver play an important role in the metabolism and excretion of most antibiotics. Taking into account the potential nephrotoxicity of antibiotics and the possibility of their rapid excretion from the body (due to the presence of the portal venous system of the kidneys), most herpetologists recommend parenteral administration of drugs to reptiles in the front of the body. Thus, when choosing and using antibacterial drugs for the treatment of infectious diseases of reptiles should take into account a number of morpho-functional features of reptiles, sensitivity of microorganisms to antibiotics, choose the right dose, frequency, method and place of administration, consider the possibility of complications.
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Whittaker, Alexandra L., Brianna Golder-Dewar, Jordyn L. Triggs, Sally L. Sherwen et David J. McLelland. « Identification of Animal-Based Welfare Indicators in Captive Reptiles : A Delphi Consultation Survey ». Animals 11, no 7 (5 juillet 2021) : 2010. http://dx.doi.org/10.3390/ani11072010.
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There is an increasing focus on evidence-based welfare assessment by animal care staff in zoos, along with a strong interest in animal welfare by the zoo-visiting public, to the extent that this can influence their choice of institutions to visit. Regulatory oversight of animal welfare standards continues to strengthen across many jurisdictions. Zoos are increasingly formalizing their practices with the development and refinement of evidence-based welfare assessment tools. There has been a drive for welfare assessment tools to comprise both resource-based and animal-based measures. However, animal-based indicators are not always well characterized, in terms of their nature and whether they infer a positive or negative affective state. This is especially so for reptiles, which are often considered behaviorally inexpressive and are under-researched. In this study, a Delphi consultation approach was used to gather expert opinion on the suitability of potential animal-based indicators of welfare for inclusion in a welfare assessment tool across four families of reptiles: Agamidae, Chelidae, Pythonidae, and Testudinidae. Two rounds of online surveys were conducted eliciting responses from a global group of professionals who work with reptiles. In the first survey, respondents were provided with an author-derived list of potential animal-based indicators for consideration of their validity and practicality as welfare indicators. The indicators were refined for the second survey including only those indicators that were considered valid or practical on the first survey (≥4 on a 5-point Likert scale), and that achieved ≥70% consensus amongst experts. In the second survey, respondents were asked to re-evaluate the reliability and practicality of the indicators and to rank them on these facets. Eight to ten assessment indicators for each family of reptiles were identified from Survey 2. These indicators were often health related, for example, presence of oculo-nasal discharge or wounds. However, some true behavioral indicators were identified, such as showing species-specific interest and alertness. These indicators should now be incorporated into taxon-tailored welfare assessment tools for trial and validation in captive reptile populations. This study provides a next step towards developing reptile-specific animal welfare assessment tools for these often-overlooked animals.
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Jensen, Bjarke, et Vincent M. Christoffels. « Reptiles as a Model System to Study Heart Development ». Cold Spring Harbor Perspectives in Biology 12, no 5 (11 novembre 2019) : a037226. http://dx.doi.org/10.1101/cshperspect.a037226.
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FISK, ALAN, et MARGARET TRIBE. « The development of the amnion and chorion of reptiles ». Proceedings of the Zoological Society of London 119, no 1 (21 août 2009) : 83–114. http://dx.doi.org/10.1111/j.1096-3642.1949.tb00870.x.
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Di-Poï, Nicolas, et Michel C. Milinkovitch. « The anatomical placode in reptile scale morphogenesis indicates shared ancestry among skin appendages in amniotes ». Science Advances 2, no 6 (juin 2016) : e1600708. http://dx.doi.org/10.1126/sciadv.1600708.
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Most mammals, birds, and reptiles are readily recognized by their hairs, feathers, and scales, respectively. However, the lack of fossil intermediate forms between scales and hairs and substantial differences in their morphogenesis and protein composition have fueled the controversy pertaining to their potential common ancestry for decades. Central to this debate is the apparent lack of an “anatomical placode” (that is, a local epidermal thickening characteristic of feathers’ and hairs’ early morphogenesis) in reptile scale development. Hence, scenarios have been proposed for the independent development of the anatomical placode in birds and mammals and parallel co-option of similar signaling pathways for their morphogenesis. Using histological and molecular techniques on developmental series of crocodiles and snakes, as well as of unique wild-type and EDA (ectodysplasin A)–deficient scaleless mutant lizards, we show for the first time that reptiles, including crocodiles and squamates, develop all the characteristics of an anatomical placode: columnar cells with reduced proliferation rate, as well as canonical spatial expression of placode and underlying dermal molecular markers. These results reveal a new evolutionary scenario where hairs, feathers, and scales of extant species are homologous structures inherited, with modification, from their shared reptilian ancestor’s skin appendages already characterized by an anatomical placode and associated signaling molecules.
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Preuschoft, H., H. G. Horn et A. Christian. « Biomechanical reasons for bipedalism in reptiles ». Amphibia-Reptilia 15, no 3 (1994) : 275–84. http://dx.doi.org/10.1163/156853894x00056.
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AbstractBipedal locomotion can be observed in numerous species of recent tetrapodal reptiles which usually have well developed tails and hindlimbs while the forelimbs are considerably shorter and weaker than the hindlimbs. It is commonly used when the reptiles move at the highest possible speeds of locomotion. The different development of the extremities is a common feature among recent reptiles that can be understood as an adaptation to quick acceleration. Additionally it reduces the interference of fore-and hindlimbs at high speeds. We present some biomechanical arguments to show how and why bipedalism can facilitate quick running in recent reptiles in which the hindlimbs are much longer and stronger than the forelimbs. Our main arguments can also be applied to some dinosaurs.
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Clulow, Simon, John Clulow, Ruth Marcec-Greaves, Gina Della Togna et Natalie E. Calatayud. « Common goals, different stages : the state of the ARTs for reptile and amphibian conservation ». Reproduction, Fertility and Development 34, no 5 (11 mars 2022) : i—ix. http://dx.doi.org/10.1071/rdv34n5_fo.
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Amphibians and reptiles are highly threatened vertebrate taxa with large numbers of species threatened with extinction. With so many species at risk, conservation requires the efficient and cost-effective application of all the tools available so that as many species as possible are assisted. Biobanking of genetic material in genetic resource banks (GRBs) in combination with assisted reproductive technologies (ARTs) to retrieve live animals from stored materials are two powerful, complementary tools in the conservation toolbox for arresting and reversing biodiversity decline for both amphibians and reptiles. However, the degree of development of the ARTs and cryopreservation technologies differ markedly between these two groups. These differences are explained in part by different perceptions of the taxa, but also to differing reproductive anatomy and biology between the amphibians and reptiles. Artificial fertilisation with cryopreserved sperm is becoming a more widely developed and utilised technology for amphibians. However, in contrast, artificial insemination with production of live progeny has been reported in few reptiles, and while sperm have been successfully cryopreserved, there are still no reports of the production of live offspring generated from cryopreserved sperm. In both amphibians and reptiles, a focus on sperm cryopreservation and artificial fertilisation or artificial insemination has been at the expense of the development and application of more advanced technologies such as cryopreservation of the female germline and embryonic genome, or the use of sophisticated stem cell/primordial germ cell cryopreservation and transplantation approaches. This review accompanies the publication of ten papers on amphibians and twelve papers on reptiles reporting advances in ARTs and biobanking for the herpetological taxa.
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Park, Soon Yong, Hyeongrok Choi et Jin Woong Chung. « Reptiles as Promising Sources of Medicinal Natural Products for Cancer Therapeutic Drugs ». Pharmaceutics 14, no 4 (16 avril 2022) : 874. http://dx.doi.org/10.3390/pharmaceutics14040874.
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Natural products have historically played an important role as a source of therapeutic drugs for various diseases, and the development of medicinal natural products is still a field with high potential. Although diverse drugs have been developed for incurable diseases for several decades, discovering safe and efficient anticancer drugs remains a formidable challenge. Reptiles, as one source of Asian traditional medicines, are known to possess anticancer properties and have been used for a long time without a clarified scientific background. Recently, it has been reported that extracts, crude peptides, sera, and venom isolated from reptiles could effectively inhibit the survival and proliferation of various cancer cells. In this article, we summarize recent studies applying ingredients derived from reptiles in cancer therapy and discuss the difficulties and prospective development of natural product research.
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Benn, Amelia, David McLelland et Alexandra Whittaker. « A Review of Welfare Assessment Methods in Reptiles, and Preliminary Application of the Welfare Quality® Protocol to the Pygmy Blue-Tongue Skink, Tiliqua adelaidensis, Using Animal-Based Measures ». Animals 9, no 1 (17 janvier 2019) : 27. http://dx.doi.org/10.3390/ani9010027.
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Reptiles are held at wildlife parks and zoos for display and conservation breeding programs and are increasingly being kept as pets. Reliable indicators of welfare for reptiles need to be identified. Current guidelines for the captive management of reptiles utilize resource-based, rather than animal-based indicators; the latter being a more direct reflection of affective state. In this paper we review the literature on welfare assessment methods in reptiles with a focus on animal-based measures. We conclude that, whilst a number of physiological and behavioral indicators of welfare have been applied in reptiles, there is need for further validation of these methods across the diversity of species within the Class. Methods of positive welfare state assessment are comparatively understudied and need elucidation. Finally, we examine some widely-used welfare assessment tools in mammals and explore the application of the Welfare Quality® Protocol to the endangered pygmy blue-tongue skink, Tiliqua adelaidensis. We propose that this framework can form the basis for the development of taxon-specific tools with consideration of species-specific biology.
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Xia, Tian, Lei Zhang, Guolei Sun, Xiufeng Yang et Honghai Zhang. « Genomic evidence of adaptive evolution in the reptilian SOCS gene family ». PeerJ 9 (24 juin 2021) : e11677. http://dx.doi.org/10.7717/peerj.11677.
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The suppressor of the cytokine signaling (SOCS) family of proteins play an essential role in inhibiting cytokine receptor signaling by regulating immune signal pathways. Although SOCS gene functions have been examined extensively, no comprehensive study has been performed on this gene family’s molecular evolution in reptiles. In this study, we identified eight canonical SOCS genes using recently-published reptilian genomes. We used phylogenetic analysis to determine that the SOCS genes had highly conserved evolutionary dynamics that we classified into two types. We identified positive SOCS4 selection signals in whole reptile lineages and SOCS2 selection signals in the crocodilian lineage. Selective pressure analyses using the branch model and Z-test revealed that these genes were under different negative selection pressures compared to reptile lineages. We also concluded that the nature of selection pressure varies across different reptile lineages on SOCS3, and the crocodilian lineage has experienced rapid evolution. Our results may provide a theoretical foundation for further analyses of reptilian SOCS genes’ functional and molecular mechanisms, as well as their roles in reptile growth and development.
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Urbanová, D., et M. Halán. « The Use of Ultrasonography in Diagnostic Imaging of Reptiles ». Folia Veterinaria 60, no 4 (1 décembre 2016) : 51–57. http://dx.doi.org/10.1515/fv-2016-0038.
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Abstract The aim of this study was to obtain new knowledge and show the possibility of the use of ultrasonographic (USG) examinations in reptilian medicine. As reptiles are patients brought to veterinary clinic in smaller numbers, we focused on the indications and limits of this type of examination in individual groups of reptiles. In the period of 2014—2015 we examined by ultrasound, 28 reptiles with the aim to diagnose gravidity, reproductive problems and to determine their gender. At the same time we examined the internal organs and their availability for potential USG examinations. We also investigated: the issues related to fixation and positioning of the patients; selection of suitable examination probes; and the ways of their application to a suitable body area. The experimental part of our study was focused on the examination of the reproductive apparatus of reptiles. We monitored: individual phases of gravidity in selected reptilian species; evaluated development of follicles in ovaries; and the development of eggs after successful mating up to their laying. We described the pathological states of reproductive organs and the suitability of this examination for the determination of gender.
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Biserkov, Vulko, et Aneta Kostadinova. « Development of the plerocercoid I of Ophiotaenia europaea in reptiles ». International Journal for Parasitology 27, no 12 (décembre 1997) : 1513–16. http://dx.doi.org/10.1016/s0020-7519(97)00138-0.
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Blackburn, Daniel G. « Chorioallantoic placentation in squamate reptiles : Structure, function, development, and evolution ». Journal of Experimental Zoology 266, no 5 (1 août 1993) : 414–30. http://dx.doi.org/10.1002/jez.1402660508.
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Jones, Hugh I. « Physalopterine nematodes in Australian reptiles : interactions and patterns of infection ». Australian Journal of Zoology 62, no 2 (2014) : 180. http://dx.doi.org/10.1071/zo13033.
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Spirurid nematodes (family Physalopteridae) are widespread as adults or as encysted larvae in many species of Australian reptiles. Fifteen species of physalopterine nematodes (subfamily Physalopterinae) in the genera Kreisiella, Abbreviata and Skrjabinoptera infect more than 40 species of reptile in the five families Agamidae, Varanidae, Gekkonidae, Scincidae and Elapidae. Four species of nematode are host-species specific, six are host-family specific to varanid lizards, and three to agamid lizards. Larger species of reptile support a higher prevalence and abundance of nematodes, and often support multiple infections with more than one species, with the potential for interspecific competition. Geographic distribution of nematodes is partially limited by host distribution, and by climatic factors, mainly precipitation and temperature. There are strong positive and negative associations between several pairs of nematodes. Two species of nematode with the most pronounced muscular development at the anterior end, Abbreviata tumidocapitis and Abbreviata glebopalmae, only occur concurrently, and in low numbers, with species of nematode without these morphological features, suggesting differences in feeding in the hosts’ stomachs. A combination of host specificity, geographic distribution and habitat, climatic factors and feeding organ morphology are factors that probably reduce the potential for interspecific competition. There is no evidence that concurrent infections affect either prevalence or abundance of nematodes, or cause discernible pathological changes to their hosts.
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YIN, HUI NG, EHWAN NGADI, MD-ZAIRI ZAINAL et MUHAMMAD ABU BAKAR ABDUL-LATIFF. « A NOTE ON THE NEW RECORD OF THE REPTILE FAUNA IN PULAU TINGGI, JOHOR, MALAYSIA ». JOURNAL OF SUSTAINABILITY SCIENCE AND MANAGEMENT 17, no 11 (30 novembre 2022) : 35–44. http://dx.doi.org/10.46754/jssm.2022.11.005.
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Island ecosystem is a fragile ecosystem affected by an ocean climate, which resulting different microclimates, floristic composition and unique habitats. The island’s insularity resulted in the unique composition of animal species, especially reptiles which depend most on the microclimate. Hence, a study on reptile diversity was carried out in Pulau Tinggi, Mersing, Johor from February to October 2019. A previous survey of reptile diversity in Pulau Tinggi was conducted in 2003 and 2006, which recorded 13 and 17 species, respectively and there is an urgent need to update these data. This study used the Visual Encounter Survey (VES) and drift-fenced pitfall traps as the primary sampling methods. 21 species were recorded, which comprise eight families. The Scincidae family recorded the highest number of species, which is five. Meanwhile, Viperidae and Varanidae reported the lowest number of species recorded, one species, respectively. 13 species were reported as new records for Pulau Tinggi, resulting in updated reptile diversity in Pulau Tinggi currently to 32 species based on a comparative literature review with previous studies. These new records indicate that extensive and intensive studies are needed to determine the reptilian diversity in Pulau Tinggi for conservation and management purposes.
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Martín-del-Campo, Rodolfo, Itzel Sifuentes-Romero et Alejandra García-Gasca. « Hox Genes in Reptile Development, Epigenetic Regulation, and Teratogenesis ». Cytogenetic and Genome Research 157, no 1-2 (15 décembre 2018) : 34–45. http://dx.doi.org/10.1159/000495712.
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Reptiles are ancestral organisms presenting a variety of shapes, from the elongated vertebral column of the snake to the turtle dorsalized ribs or retractile neck. Body plans are specified by a conserved group of homeobox-containing genes (Hox genes), which encode transcription factors important in cell fate and vertebral architecture along the anteroposterior axis during embryonic development; thus, dysregulation of these genes may cause congenital malformations, from mild-sublethal to embryonic-lethal. The genetic pool, maternal transfer, and environmental conditions during egg incubation affect development; environmental factors such as temperature, moisture, oxygen, and pollution may alter gene expression by epigenetic mechanisms. Thus, in this review, we present information regarding Hox genes and development in reptiles, including sex determination and teratogenesis. We also present some evidence of epigenetic regulation of Hox genes and the role of the environment in epigenetic modulation of gene expression. So far, the evidence suggests that the molecular instructions encoded by Hox genes to build a snake, a lizard, or a turtle represent the interplay between genome and epigenome after years of evolution, with occasional environmentally induced molecular mistakes leading to abnormal body shapes.
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Curtis, Neil, M. E. H. Jones, S. E. Evans, P. O'Higgins et M. J. Fagan. « Cranial sutures work collectively to distribute strain throughout the reptile skull ». Journal of The Royal Society Interface 10, no 86 (6 septembre 2013) : 20130442. http://dx.doi.org/10.1098/rsif.2013.0442.
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The skull is composed of many bones that come together at sutures. These sutures are important sites of growth, and as growth ceases some become fused while others remain patent. Their mechanical behaviour and how they interact with changing form and loadings to ensure balanced craniofacial development is still poorly understood. Early suture fusion often leads to disfiguring syndromes, thus is it imperative that we understand the function of sutures more clearly. By applying advanced engineering modelling techniques, we reveal for the first time that patent sutures generate a more widely distributed, high level of strain throughout the reptile skull. Without patent sutures, large regions of the skull are only subjected to infrequent low-level strains that could weaken the bone and result in abnormal development. Sutures are therefore not only sites of bone growth, but could also be essential for the modulation of strains necessary for normal growth and development in reptiles.
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Rieppel, Olivier. « Studies on skeleton formation in reptiles. I. The postembryonic development of the skeleton in Cyrtodactylus pubisulcus (Reptilia : Gekkonidae) ». Journal of Zoology 227, no 1 (mai 1992) : 87–100. http://dx.doi.org/10.1111/j.1469-7998.1992.tb04346.x.
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Baynes-Rock, Marcus. « Precious reptiles : Social engagement and placemaking with saltwater crocodiles ». Area 51, no 3 (31 juillet 2018) : 578–85. http://dx.doi.org/10.1111/area.12484.
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Bobrov, V. V. « Herpetological research in Russian nature reserves : Current status and perspectives of development ». SOCIALNO-ECOLOGICHESKIE TECHNOLOGII, no 3. 2018 (2018) : 43–61. http://dx.doi.org/10.31862/2500-2964-2018-3-43-61.
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The article is devoted to the herpetological research of USSR nature reserves that were described in the scientific journal published over 30 years ago. The author proposes some new directions of herpetological research in nature reserves of Russia, in particular, studying of critically significant territories for amphibians and reptiles and the research of invasive species.
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Karim, Aditya K., Rury Eprilurahman, Laksmindra Fitria et Paul J. Kawatu. « Senyawa Bioaktif Herpetofauna pada Penderita Diabetes Mellitus dan Hipertensi : Tinjauan Secara Patofisiologi ». JURNAL BIOLOGI PAPUA 5, no 1 (13 octobre 2018) : 35–43. http://dx.doi.org/10.31957/jbp.521.
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Amphibians and reptiles (herpetofauna groups) produced of many compounds. The herpetofauna and their chemical compounds have been the subject of intense research interest for many years due to their potential in medical application and in lead compound development for new drugs. A number of different types of compounds have been identified from the glandular skin secretions of amphibians and venom or saliva of reptiles. These compounds have been shown to be active against gram-negative and gram-positive bacteria, fungi, enveloped viruses, diabetes mellitus, hypertension and cardiovascular disorder.Key words: Herpetofauna, diabetes mellitus, hypertension, drugs, pathophysiology
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Proshchina, Alexandra, Victoria Gulimova, Anastasia Kharlamova, Yuliya Krivova, Nadezhda Besova, Rustam Berdiev et Sergey Saveliev. « Reproduction and the Early Development of Vertebrates in Space : Problems, Results, Opportunities ». Life 11, no 2 (31 janvier 2021) : 109. http://dx.doi.org/10.3390/life11020109.
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Humans and animals adapt to space flight conditions. However, the adaptive changes of fully formed organisms differ radically from the responses of vertebrate embryos, foetuses, and larvae to space flight. Development is associated with active cell proliferation and the formation of organs and systems. The instability of these processes is well known. Over 20 years has passed since the last systematic experiments on vertebrate reproduction and development in space flight. At the same time, programs are being prepared for the exploration of Mars and the Moon, which justifies further investigations into space flight’s impact on vertebrate development. This review focuses on various aspects of reproduction and early development of vertebrates in space flights. The results of various experiments on fishes, amphibians, reptiles, birds and mammals are described. The experiments in which our team took part and ontogeny of the vertebrate nervous and special sensory systems are considered in more detail. Possible causes of morphological changes are also discussed. Research on evolutionarily and taxonomically different models can advance the understanding of reproduction in microgravity. Reptiles, in particular, geckos, due to their special features, can be a promising object of space developmental biology.
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Pugh, Timothy W. « FLOOD REPTILES, SERPENT TEMPLES, AND THE QUADRIPARTITE UNIVERSE ». Ancient Mesoamerica 12, no 2 (juillet 2001) : 247–58. http://dx.doi.org/10.1017/s0956536101122042.
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Mayapan, Yucatan, Mexico, was the most prominent Maya ceremonial center from the mid-thirteenth to the mid-fifteenth century. The city was a religious center for surrounding Maya populations. Its construction was linked through cyclical reasoning to a chain of antecedent centers, the ultimate link of which lay in creation. In the heart of Mayapan lay its exemplary center, an architectural model of cosmogony composed of five temple assemblages. The central building of each assemblage was a temple decorated with serpent imagery. These five serpent temples were depicted on a mural in Structure Q-80 at Mayapan, with additional symbolism suggesting that each building was tied to a specific elite official, likely the Ajaw B'atab'ob, Jalach Winik, and AjK'in as described in ethnohistoric documents. The serpent temples also depict the primordial flood crocodilian, who was both the world and the world destroyer—hence, a symbol of both order and chaos.
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Gatto, Christopher R., et Richard D. Reina. « A review of the effects of incubation conditions on hatchling phenotypes in non-squamate reptiles ». Journal of Comparative Physiology B 192, no 2 (10 février 2022) : 207–33. http://dx.doi.org/10.1007/s00360-021-01415-4.
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AbstractDeveloping embryos of oviparous reptiles show substantial plasticity in their responses to environmental conditions during incubation, which can include altered sex ratios, morphology, locomotor performance and hatching success. While recent research and reviews have focused on temperature during incubation, emerging evidence suggests other environmental variables are also important in determining hatchling phenotypes. Understanding how the external environment influences development is important for species management and requires identifying how environmental variables exert their effects individually, and how they interact to affect developing embryos. To address this knowledge gap, we review the literature on phenotypic responses in oviparous non-squamate (i.e., turtles, crocodilians and tuataras) reptile hatchlings to temperature, moisture, oxygen concentration and salinity. We examine how these variables influence one another and consider how changes in each variable alters incubation conditions and thus, hatchling phenotypes. We explore how incubation conditions drive variation in hatchling phenotypes and influence adult populations. Finally, we highlight knowledge gaps and suggest future research directions.
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Tolley, Krystal A., Nicolas S. Telford, Buyisile G. Makhubo, R. John Power et Graham J. Alexander. « Filling the gap : Noteworthy herpetological discoveries in North West Province, South Africa ». Zoosystematics and Evolution 99, no 1 (26 janvier 2023) : 101–16. http://dx.doi.org/10.3897/zse.99.90181.
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The North West Province, South Africa, is centrally situated in southern Africa and is characterised by savannah with a mesic, temperate climate in the east and a hot, arid climate in the west. While the eastern region is fairly well-documented for herpetofauna, the arid central and western regions are poorly surveyed. Given that the Province has been targeted by the national government for development of infrastructure, the overall deficiency of biodiversity data could result in impact assessments that are not well-informed. We, therefore, carried out herpetofaunal surveys over two years (2019–2020) in the North West Province to improve knowledge on the distributions of reptiles and amphibians. Our surveys added a total of 578 new records to an earlier baseline of 1340 records. In addition, over 300 records were added to a citizen-science platform in connection with our surveys. As compared to the previous 100 years, our surveys increased the herpetofaunal dataset by 68% in just two years, increased geographic coverage by 20% and brought the total number of species with accurate records for the Province to 102 reptiles and 23 amphibians. We also recorded range extensions for five reptile species and confirmed the presence of Dendroaspis polylepis (Black Mamba) in the west where it had been last recorded in 1996. Our surveys resulted in a significant increase in biodiversity data for the Province and provided a better foundation for spatial planning that accounts for biodiversity and the maintenance of ecological function.
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Guillette, L. J., et Taisen Iguchi. « Contaminant-induced endocrine and reproductive alterations in reptiles ». Pure and Applied Chemistry 75, no 11-12 (1 janvier 2003) : 2275–86. http://dx.doi.org/10.1351/pac200375112275.
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Many chemicals introduced into the environment by humans adversely affect embryonic development and the functioning of the vertebrate reproductive system. It has been hypothesized that many developmental alterations are due to the endocrine-disruptive effects of various environmental contaminants. The endocrine system exhibits an organizational effect on the developing embryo, altering gene expression and dosing. Thus, a disruption of the normal hormonal signals can permanently modify the organization and future functioning of the reproductive and endocrine system. We have worked extensively with contaminant-exposed and reference populations of the American alligator (Alligator mississippiensis) as well as performed a number of experimental studies exposing developing embryos to various persistent and nonpersistent pesticides. Using this species, we have described altered steroidogenesis, circulating hormone levels, and hepatic transformation of androgen and endocrine organ (gonad, thyroid) morphology in juvenile alligators living in polluted environments. Given the adverse observations reported to date, we recommend several important future needs: Further development of "receptor zoos" and other molecular tools that include key reptiles from various major ecosystems, in addition to freshwater ecosystems. Global studies extending the current knowledge base on crocodilians and freshwater turtles to comparable ecosystems on other continents, such as linked studies examining and extending current molecular to population level studies in Florida (USA) to tropical and temporate regions of Africa, Australia, and South America. Further studies of actual exposure, assimilation and excretion of contaminants by ectothermic vertebrates, especially reptiles that occupy high levels of the food chain.
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Blackburn, Daniel G., et Alexander F. Flemming. « Morphology, development, and evolution of fetal membranes and placentation in squamate reptiles ». Journal of Experimental Zoology Part B : Molecular and Developmental Evolution 312B, no 6 (15 septembre 2009) : 579–89. http://dx.doi.org/10.1002/jez.b.21234.
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Ficetola, Gentile Francesco, Mattia Falaschi, Anna Bonardi, Emilio Padoa-Schioppa et Roberto Sindaco. « Biogeographical structure and endemism pattern in reptiles of the Western Palearctic ». Progress in Physical Geography : Earth and Environment 42, no 2 (avril 2018) : 220–36. http://dx.doi.org/10.1177/0309133318765084.
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The analysis of biogeographical structure and patterns of endemism are central topics of biogeography, but require exhaustive distribution data. A lack of accurate broad-scale information on the distribution of reptiles has so far limited the analyses of biogeographical structure. Here we analysed the distribution of reptiles within the broad-sense Western Palearctic to assess biogeographical regionalization using phylogenetic and non-phylogenetic approaches, identified areas of endemism and evaluated the environmental factors promoting community uniqueness and endemism. We gathered distributional records from the literature and from the field, mapping the distribution of all the Western Palearctic reptiles on a 1-degree resolution grid. βsim dissimilarity and hierarchical clustering was used to identify bioregions, analysing data both at the species and at the genus level, and considering phylogenetic dissimilarity. Consensus areas of endemism were identified on the basis of the optimality criterion. We then assessed whether biogeographical structure is related to present-day climate, insularity, orography and velocity of climate change during the Late Quaternary. The genus-level analysis identified five main biogeographical regions within the Western Palearctic, in partial agreement with previous proposals, while the species-level analysis identified more bioregions, largely by dividing the ones identified by genera. Phylogenetic bioregions were generally consistent with the non-phylogenetic ones. The strongest community uniqueness was observed in subtropical warm climates with seasonal precipitation and low productivity. We found nine consensus areas of endemism, mostly in regions with limited velocity of Quaternary climate change and warm subtropical climates. The biogeographical structure of Western Palearctic reptiles is comparable to what has been observed in other vertebrates, with a clear distinction between the Saharo-Arabian-Sindian and Euro-Mediterranean herpetofaunas. Unlike other vertebrates, in reptiles the highest uniqueness and endemism is observed in dry climates, but the velocity of climate change during the Quaternary remains a major driver of endemism across all the vertebrates.
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Trevisan, Giusto, Marina Cinco, Sara Trevisini, Nicola di Meo, Karin Chersi, Maurizio Ruscio, Patrizia Forgione et Serena Bonin. « Borreliae Part 1 : Borrelia Lyme Group and Echidna-Reptile Group ». Biology 10, no 10 (12 octobre 2021) : 1036. http://dx.doi.org/10.3390/biology10101036.
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Borreliae are divided into three groups, namely the Lyme group (LG), the Echidna-Reptile group (REPG) and the Relapsing Fever group (RFG). Currently, only Borrelia of the Lyme and RF groups (not all) cause infection in humans. Borreliae of the Echidna-Reptile group represent a new monophyletic group of spirochaetes, which infect amphibians and reptiles. In addition to a general description of the phylum Spirochaetales, including a brief historical digression on spirochaetosis, in the present review Borreliae of Lyme and Echidna-Reptile groups are described, discussing the ecology with vectors and hosts as well as microbiological features and molecular characterization. Furthermore, differences between LG and RFG are discussed with respect to the clinical manifestations. In humans, LG Borreliae are organotropic and cause erythema migrans in the early phase of the disease, while RFG Borreliae give high spirochaetemia with fever, without the development of erythema migrans. With respect of LG Borreliae, recently Borrelia mayonii, with intermediate characteristics between LG and RFG, has been identified. As part of the LG, it gives erythema migrans but also high spirochaetemia with fever. Hard ticks are vectors for both LG and REPG groups, but in LG they are mostly Ixodes sp. ticks, while in REPG vectors do not belong to that genus.
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Johnston, Sonya D., Sandra Orgeig, Olga V. Lopatko et Christopher B. Daniels. « Development of the pulmonary surfactant system in two oviparous vertebrates ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 278, no 2 (1 février 2000) : R486—R493. http://dx.doi.org/10.1152/ajpregu.2000.278.2.r486.
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In birds and oviparous reptiles, hatching is often a lengthy and exhausting process, which commences with pipping followed by lung clearance and pulmonary ventilation. We examined the composition of pulmonary surfactant in the developing lungs of the chicken, Gallus gallus, and of the bearded dragon, Pogona vitticeps. Lung tissue was collected from chicken embryos at days 14, 16, 18 (prepipped), and 20(postpipped) of incubation and from 1 day and 3 wk posthatch and adult animals. In chickens, surfactant protein A mRNA was detected using Northern blot analysis in lung tissue at all stages sampled, appearing relatively earlier in development compared with placental mammals. Chickens were lavaged at days 16, 18, and 20 of incubation and 1 day posthatch, whereas bearded dragons were lavaged at day 55, days 57–60 (postpipped), and days 58–61 (posthatched). In both species, total phospholipid (PL) from the lavage increased throughout incubation. Disaturated PL (DSP) was not measurable before 16 days of incubation in the chick embryo nor before 55 days in bearded dragons. However, the percentage of DSP/PL increased markedly throughout late development in both species. Because cholesterol (Chol) remained unchanged, the Chol/PL and Chol/DSP ratios decreased in both species. Thus the Chol and PL components are differentially regulated. The lizard surfactant system develops and matures over a relatively shorter time than that of birds and mammals. This probably reflects the highly precocial nature of hatchling reptiles.
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Alibardi, Lorenzo. « Development, comparative morphology and cornification of reptilian claws in relation to claws evolution in tetrapods ». Contributions to Zoology 78, no 1 (18 mai 2009) : 25–42. http://dx.doi.org/10.1163/18759866-07801003.
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The development of claws in different reptiles and their cornification are analyzed using histological, ultrastructural and autoradiographic methods. Claws develop at the tip of digits in relation to the growth of the terminal phalanx and appear as modified scales. The apical epidermis of digit becomes thickened and is associated with a mesenchymal condensation or a dense mesenchyme. The dorsal side of the digit becomes the unguis while the ventral side becomes the sub-unguis. The corneous layer in the unguis is thicker than in the sub-unguis and accumulates hard-keratin while corneocytes remain separated or partially fused. Bundles of hard-keratin tend to accumulate in parallel orientation with respect to the surface and are directed toward the claw tip. The sub-unguis is formed by a softer corneous material and by a much thinner hard-keratin layer. Autoradiography after tritiated thymidine and histidine injection indicates that the growth of reptilian claws occurs along the entire epidermis of the claw. A proximal matrix zone for cell proliferation like in mammalian nails and claws is therefore absent in claws of reptiles. This observation indicates that the pattern of growth of reptilian and probably avian claws is different from that of mammals.
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Paladino, Frank V., et James R. Spotila. « Does the Physiology of Large Living Reptiles Provide Insights into the Evolution of Endothermy and Paleophysiology of Extinct Dinosaurs ? » Paleontological Society Special Publications 7 (1994) : 261–74. http://dx.doi.org/10.1017/s2475262200009576.
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Our studies using American alligators, Alligator mississippiensis, green turtles, Chelonia mydas, and leatherback turtles, Dermochelys coriacea, have provided insights into the physiology of large extant and extinct reptiles. Respiratory and metabolic physiology studies indicate that many living large reptiles exhibit heat conservation adaptations and mechanisms which allow them to maintain constant warm body temperatures in cold environments with low “reptilian” metabolism. For example, leatherback turtles which are found in the oceans as far north as the Arctic Circle can maintain constant body temperatures above 25° C while water temperatures are below 7° C. This dramatic ability to maintain warm temperatures in cold, highly conductive water, that would quickly cause hypothermia and kill most endotherms, is made possible by a mechanism we describe as gigantothermy. Gigantothermy is the ability to maintain constant warm body temperatures with low energy consumption, control of peripheral circulation and extensive insulation due to large body size.The muscles of leatherbacks show a fiber type unlike the specialized, endothermic heater organs of modern fish Scombroidei (tunas, billfish, bonitos, butterfly mackerel and relatives) that have evolved specialized “endotherm like” red muscle to maintain regional endothermy. The primitive large reptiles like leatherbacks do not show the specialization in muscle fiber type nor do the enzyme activities indicate the emergence or evolution of endothermy or a high rate of energy consumption. Yet leatherbacks can migrate over 70 km per day in the open ocean and dive to depths deeper than 1000 m on a regular basis.Collectively these physiological studies on large living reptiles support the concept that dinosaurs, especially the larger more spectacular species, were able to maintain high body temperatures, be very active, move great distances quickly, as well as exhibit complex behavior such as communal nesting and nest building without evolving endothermy or high levels of energy consumption. The physiology of large living reptiles indicates that it is not necessary to attribute heretical ideas to explain the paleophysiology and capabilities of dinosaurs. As reptiles they were fully capable of complex and spectacular behaviors such as long and rapid migrations and surviving the cold. All evolutionary indications suggest that large size would provide a negative selection pressure for the development of endothermy especially in equable and or tropical climates.
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Guillette, L. J., D. H. Dubois et A. Cree. « Prostaglandins, oviducal function, and parturient behavior in nonmammalian vertebrates ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 260, no 5 (1 mai 1991) : R854—R861. http://dx.doi.org/10.1152/ajpregu.1991.260.5.r854.
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Extensive data show that in mammals and birds, prostaglandins (PGs) are associated with ovulation, luteal function, oviposition, and parturition, and that also in mammals they are associated with birth-related behavior and sexual receptivity. In mammals and birds, the ability of PGs to stimulate oviducal contractions varies regionally along the oviduct (i.e., there is a functional cervix or uterovaginal region that acts to retain eggs or embryos in utero during shelling or embryonic development). Furthermore, at least in mammals, there is neural control over oviducal contractions. In reptiles, PGs stimulate oviducal contractions, and these contractions may be overridden by neural control. No data are available on whether PGs stimulate oviducal contractions in amphibians or whether there is a functional cervix in amphibians or reptiles. We suggest that in ancestral amphibians with oviparity and external fertilization, eggs moved rapidly through the oviduct after ovulation and that ovarian and oviducal PGF served as an endocrine hormone coordinating oviducal contractions and central nervous system-controlled oviposition behavior. Furthermore, we hypothesize that there was little or no neural control over oviducal contractions and no functional cervix. These conditions may still exist in present-day oviparous amphibians. In contrast, we suggest that modern-day oviparous reptiles have evolved a functional cervix and neural control over PG-induced uterine contractions, allowing egg passage to be blocked and thus the development of egg retention. These characteristics may be viewed as exaptations for the evolution of viviparity.
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Aboitiz, Francisco, Daniver Morales et Juan Montiel. « The evolutionary origin of the mammalian isocortex : Towards an integrated developmental and functional approach ». Behavioral and Brain Sciences 26, no 5 (octobre 2003) : 535–52. http://dx.doi.org/10.1017/s0140525x03000128.
Texte intégralRésumé :
The isocortex is a distinctive feature of mammalian brains, which has no clear counterpart in the cerebral hemispheres of other amniotes. This paper speculates on the evolutionary processes giving rise to the isocortex. As a first step, we intend to identify what structure may be ancestral to the isocortex in the reptilian brain. Then, it is necessary to account for the transformations (developmental, connectional, and functional) of this ancestral structure, which resulted in the origin of the isocortex. One long-held perspective argues that part of the isocortex derives from the ventral pallium of reptiles, whereas another view proposes that the isocortex originated mostly from the dorsal pallium. We consider that, at this point, evidence tends to favor correspondence of the isocortex with the dorsal cortex of reptiles. In any case, the isocortex may have originated partly as a consequence of an overall “dorsalizing” effect (that is, an expansion of the territories expressing dorsal-specific genes) during pallial development. Furthermore, expansion of the dorsal pallium may have been driven by selective pressures favoring the development of associative networks between the dorsal cortex, the olfactory cortex, and the hippocampus, which participated in spatial or episodic memory in the early mammals. In this context, sensory projections that in reptiles end in the ventral pallium, are observed to terminate in the isocortex (dorsal pallium) of mammals, perhaps owing to their participation in these associative networks.
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Gasso, V. Y., A. M. Hahut et S. V. Yermolenko. « Biochemical parameters in the blood of grass snakes (Natrix natrix) in ecosystems under varying degrees of anthropogenic influence ». Visnyk of Dnipropetrovsk University. Biology, medicine 7, no 2 (28 septembre 2016) : 127–31. http://dx.doi.org/10.15421/021623.
Texte intégralRésumé :
The grass snake Natrix natrix (Linnaeus, 1758) is a partly hygrophilous species, distributed throughoutUkraine. This snake may be considered as a test object for environmental biomonitoring. Modern biochemical methods make it possible to obtain new scientific data on the effects of anthropogenic pressure on reptiles. Blood is a sensitive and informative indicator of the condition of an organism as it responds quickly to most changes in exogenous and endogenous factors, and reflects negative influences on both individual and, indirectly, populations. Changes in biochemical parameters may be used as biomarkers of the state of health of reptiles in ecosystems under varying degrees of anthropogenic pressure. Due the increase in anthropogenic influence the development and introduction of new methods of perceptual research, collection of up-to-date information and development of a database of reptile biochemical parameters have become an urgent priority. We collected mature individuals of the grass snake in floodplain ecosystems on the right bank of the Dnieper River in Dnipropetrovsk city. Grass snakes from floodplain habitats on the left bank of theSamaraRiver (O.L. Belgard Prysamarskii International Biosphere Station, Novomoskovsk district, Dnipropetrovsk province) were studied as the control specimens. Our study demonstrated statistically significant differences between snakes from the study sites in the amount of albumin, urea and urea nitrogen, and inorganic phosphorus, as well as in alanine aminotransferase (ALT) and alkaline phosphatise (AP) activity. The amount of albumin in the blood serum of specimens from the anthropogenically transformed areas was significantly lower (by 25%) than in that of the snakes caught in the control habitats. Decrease of the albumin concentration usually indicates abnormal processes in the kidneys and liver. According to the changes observed in the concentration of albumin, a corresponding increase in the albumin to globulin ratio by about 30% was found. A statistically significant increase in alkaline phosphatase activity may demonstrate negative physiological changes in tissues of the liver and bones. Increased activities of ALT and AP indicate certain changes in the physiological condition of the liver of snakes from the anthropogenically transformed site. Other studied parameters did not exceed the limits found for different species of reptiles. Significant differences between certain biochemical parameters in the serum of snakes from the studied regions may reflect pathological processes in the grass snakes from transformed ecosystems, mainly in their liver and kidneys. The results can be used in future studies as benchmarks for assessing the condition of the organism of this species in the conditions of anthropogenic stress.