| description and life-cycle of three new species of dingularis n.g. (digena: plagiorchiida), parasites of australian freshwater turtles. | dingularus n.g. is proposed to accommodate three new species, d. anfracticirrus, d. pearsoni and d. megapharynx, within the plagiorchiida. dingularus is closely related to the plagiorchiidae, despite the unusual excretory systems of the three species. adult worms were parasitic in the intestines of freshwater turtles, chelodina expansa (d. pearsoni and d. megapharynx) and emydura macquarii (d. anfracticirrus), and appeared to be host-specific. the three species had similar, three-host, aquatic l ... | 1999 | 10619067 |
| hemoprotozoa of freshwater turtles in queensland. | blood smears from 27 turtles (15 emydura signata, nine elseya latisternum, and three chelodina longicollis) from southeastern queensland (australia) were examined for infections by hemoprotozoan parasites between january and june 1999. infections were found in 26 (96%) of the turtles. twenty five (93%) were infected with the adeleorin coccidian haemogregarina clelandi, eight (30%) with the hemosporidian haemoproteus chelodinae, 11 (41%) with the kinetoplastid flagellate trypanosoma chelodinae, a ... | 2001 | 11272486 |
| phylogenetic relationships of hepatozoon (haemogregarina) boigae, hepatozoon sp., haemogregarina clelandi and haemoproteus chelodina from australian reptiles to other apicomplexa based on cladistic analyses of ultrastructural and life-cycle characters. | the phylogeny of representative haemozoan species of the phylum apicomplexa was reconstructed by cladistic analyses of ultrastructural and life-cycle characteristics. the analysis incorporated 4 apicomplexans previously not included in phylogenetic reconstructions: haemogregarina clelandi from the brisbane river tortoise (emydura signata), hepatozoon sp. from the slaty grey snake (stegonotus cucullatus), hepatozoon (haemogregarina) boigae from the brown tree snake (boiga irregularis), and haemop ... | 2003 | 12866793 |
| structure and similarity of helminth communities of six species of australian turtles. | patterns of infracommunity structure and infra- and component community similarity were examined for helminths of 6 species of turtles, each collected from a single locality in australia in 1993 and 1994. elseya latisternum (n = 11) and emydura kreffti (n = 16) were collected from northern queensland, emydura macquarii macquarii (n = 11) from southern queensland, emydura macquarii dhara (n = 11) and chelodina longicollis (n = 11) from northern new south wales, and chelodina oblonga (n = 5) from ... | 2008 | 18576816 |
| an xx/xy heteromorphic sex chromosome system in the australian chelid turtle emydura macquarii: a new piece in the puzzle of sex chromosome evolution in turtles. | chromosomal sex determination is the prevalent system found in animals but is rare among turtles. in fact, heteromorphic sex chromosomes are known in only seven of the turtles possessing genotypic sex determination (gsd), two of which correspond to cryptic sex microchromosomes detectable only with high-resolution cytogenetic techniques. sex chromosomes were undetected in previous studies of emydura macquarii, a gsd side-necked turtle. using comparative genomic hybridization (cgh) and gtg-banding ... | 2008 | 18679815 |
| two new species of camallanus (nematoda: camallanidae) from freshwater turtles in queensland, australia. | we describe 2 new species of camallanus (nematoda: camallanidae) from freshwater turtles collected in queensland, australia: camallanus nithoggi n. sp. from elseya latisternum (gray) and camallanus waelhreow n. sp. from emydura krefftii (gray), emydura macquarrii (gray), and em. macquarrii dharra cann. the only camallanus sp. previously reported from turtles is c. chelonius baker, 1983 (all other species in the family have been transferred to serpinema). the 2 new species described here differ f ... | 2008 | 19127966 |
| biochemical and hematological reference intervals for krefft's turtles emydura macquarii krefftii from the burnett river catchment, australia. | biochemical and hematological reference intervals have not previously been reported for emydura macquarii krefftii. in 2009, 56 e. m. krefftii were captured by hand from the burnett catchment, clinically assessed to determine health status and blood sampled. reference intervals were calculated from the 35 clinically healthy turtles using techniques established in other chelonid species. aberrant blood results were identified from the 21 clinically unhealthy turtles. low numbers of observed cases ... | 2011 | 21797034 |
| phylogenetic relationships of trypanosoma chelodina and trypanosoma binneyi from australian tortoises and platypuses inferred from small subunit rrna analyses. | trypanosome infections are often difficult to detect by conventional microscopy and their pleomorphy often confounds differential diagnosis. molecular techniques are now being used to diagnose infections and to determine phylogenetic relationships between species. complete small subunit rrna gene sequences were determined for isolates of trypanosoma chelodina from the brisbane river tortoise (emydura signata), the saw-shelled tortoise (elseya latisternum), and the eastern snake-necked tortoise ( ... | 2001 | 11719959 |
| patterns of metabolism in embryonic reptiles. | vo2 of eggs of the turtle emydura macquarii, the crocodilian alligator mississipiensis, and the tuatara sphenodon punctatus, were measured throughout incubation. e. macquarii and a. mississipiensis, species in which hatching synchrony may be important, show a decline in vo2 prior to hatching ('peaked' pattern). this is similar to the pattern shown by ratite birds, where the decline period may be variable and facilitates hatching synchrony. the same interpretation is used here for reptiles. hatch ... | 1989 | 2749027 |
| identifying critical habitat for australian freshwater turtles in a large regulated floodplain: implications for environmental water management. | freshwater turtles face many threats, including habitat loss and river regulation reducing occupancy and contributing to population decline. limited knowledge of hydrological conditions required to maintain viable turtle populations in large floodplain wetlands hinders effective adaptive management of environmental water in regulated rivers. we surveyed three turtle species over 4 years across the lower murrumbidgee river floodplain, a large wetland complex with a long history of water resource ... | 2017 | 28280912 |
| amplification of microsatellite repeat motifs is associated with the evolutionary differentiation and heterochromatinization of sex chromosomes in sauropsida. | the sex chromosomes in sauropsida (reptiles and birds) have evolved independently many times. they show astonishing diversity in morphology ranging from cryptic to highly differentiated sex chromosomes with male (xx/xy) and female heterogamety (zz/zw). comparing such diverse sex chromosome systems thus provides unparalleled opportunities to capture evolution of morphologically differentiated sex chromosomes in action. here, we describe chromosomal mapping of 18 microsatellite repeat motifs in ei ... | 2016 | 26194100 |
| reproductive investment compromises maternal health in three species of freshwater turtle. | life-history theory predicts that a trade-off in the allocation of resources between different physiological systems exists because resources are finite. as a result, females investing heavily in reproduction may compromise their future health. we used hematology, serum biochemistry, mass, and morphometric measurements as indicators of physiological health state to investigate whether reproductive investment altered subsequent maternal health in three australian freshwater turtles: the oblong tu ... | 2014 | 24769705 |
| hematologic and serum biochemical values of gravid freshwater australian chelonians. | hematologic and serum biochemical analyses were performed on 30 wild-caught, gravid, australian freshwater chelonians. species sampled were western long-necked turtles (chelodina oblonga; n = 13), common long-necked turtles (chelodina longicollis; n = 8), and murray river turtles (emydura macquarii; n = 9). turtles were obtained from lake goolellal in perth, western australia (c. oblonga), and lake coranderrk in healesville, victoria (c. longicollis and e. macquarii). all turtles were considered ... | 2012 | 22493107 |
| delimiting species in recent radiations. | despite considerable effort from the systematics community, delimiting species boundaries in recent radiations remains a daunting challenge. we argue that genealogical approaches, although sometimes useful, may not solve this important problem, because recently derived species often have not had sufficient time to achieve monophyly. instead, we suggest that population genetic approaches that rely on large sets of informative markers like single nucleotide polymorphisms (snps) provide an alternat ... | 2007 | 18066926 |
| thyroid hormones reduce incubation period without developmental or metabolic costs in murray river short-necked turtles (emydura macquarii). | metabolic processes are affected by both temperature and thyroid hormones in ectothermic vertebrates. temperature is the major determinant of incubation length in oviparous vertebrates, but turtles can also alter developmental rate independent of temperature. temperature gradients within natural nests cause different developmental rates of turtle embryos within nests. despite temperature-induced reductions in developmental rate, cooler-incubated neonates often hatch synchronously with warmer sib ... | 2017 | 28051941 |
| salinity tolerances of two australian freshwater turtles, chelodina expansa and emydura macquarii (testudinata: chelidae). | freshwater biota experience physiological challenges in regions affected by salinization, but often the effects on particular species are poorly understood. freshwater turtles are of particular concern as they appear to have limited ability to cope with environmental conditions that are hyperosmotic to their body fluids. here, we determined the physiological responses of two australian freshwater chelid turtles, emydura macquarii and chelodina expansa, exposed to freshwater (0‰) and brackish wat ... | 2016 | 27757236 |
| microscopic and immunohistochemical study on the cornification of the developing beak in the turtle emydura macquarii. | the development and cornification of the ramphoteca (beak) in turtles are not known. the microscopic aspects of beak formation have been analyzed in the pleurodirian turtle emydura macquarii using histological, immunocytochemical and ultrastructural methods. at embryonic stage 15 the maxillar beak is originated from discontinuous placodes (one frontal and two oral) formed in the epidermis above and below the mouth that later merge into the epidermis of the beak. the mandibular beak is formed by ... | 2016 | 27418151 |
| herpesvirus in a captive australian krefft's river turtle (emydura macquarii krefftii). | a mature, captive krefft's river turtle (emydura macquarii krefftii) was presented with severe proliferative and ulcerative lesions of the skin and shell. the areas were biopsied and histopathological examination demonstrated orthokeratotic hyperkeratosis with keratinocytes containing eosinophilic intranuclear inclusions. molecular diagnostics confirmed the presence of a herpesvirus in the affected tissues. | 2015 | 25622710 |
| influence of drainage divides versus arid corridors on genetic structure and demography of a widespread freshwater turtle, emydura macquarii krefftii, from australia. | the influence of pleistocene climatic cycles on southern hemisphere biotas is not yet well understood. australia's eastern coastal margin provides an ideal setting for examining the relative influence of landscape development, sea level fluctuation, and cyclic climatic aridity on the evolution of freshwater biodiversity. we examined the impact of climatic oscillations and physical biogeographic barriers on the evolutionary history of the wide-ranging krefft's river turtle (emydura macquarii kref ... | 2014 | 25035802 |
| metabolic circadian rhythms in embryonic turtles. | oviparous species are model organisms for investigating embryonic development of endogenous physiological circadian rhythms without the influence of maternal biorhythms. recent studies have demonstrated that heart rates and metabolic rates of embryonic turtles are not constant or always maximal and can be altered in response to the presence of embryos at a more advanced stage of development within the nest. a first step in understanding the physiological mechanisms underpinning these responses i ... | 2013 | 23652198 |
| embryonic communication in the nest: metabolic responses of reptilian embryos to developmental rates of siblings. | incubation temperature affects developmental rates and defines many phenotypes and fitness characteristics of reptilian embryos. in turtles, eggs are deposited in layers within the nest, such that thermal gradients create independent developmental conditions for each egg. despite differences in developmental rate, several studies have revealed unexpected synchronicity in hatching, however, the mechanisms through which synchrony are achieved may be different between species. here, we examine the ... | 2012 | 22130606 |
| counterintuitive density-dependent growth in a long-lived vertebrate after removal of nest predators. | examining the phenotypic and genetic underpinnings of life-history variation in long-lived organisms is central to the study of life-history evolution. juvenile growth and survival are often density dependent in reptiles, and theory predicts the evolution of slow growth in response to low resources (resource-limiting hypothesis), such as under densely populated conditions. however, rapid growth is predicted when exceeding some critical body size reduces the risk of mortality (mortality hypothesi ... | 2006 | 17249235 |
| helminth assemblages of the turtle emydura macquarii (pleurodira: chelidae) queensland, australia. | the helminth fauna of 76 emydura macquarii from 3 river systems in central and northern queensland was examined. eleven species were found, including 2 nematodes, 6 trematodes, 1 aspidogastrean, 1 cestode, and 1 monogenean. analysis of helminth diversity showed that the fitzroy and ross river turtles had communities of comparable diversity, but the helminth communities in proserpine river turtles were much less diverse. the helminth communities in all localities were dominated by trematodes. pol ... | 2006 | 16629335 |
| description of buckarootrema goodmani n. g., n. sp. (digenea: pronocephalidae), a parasite of the freshwater turtle emydura macquarii (gray, 1830) (pleurodira: chelidae) from queensland, australia, and a phylogenetic analysis of the genera of the pronocephalidae looss, 1902. | buckarootrema goodmani n. g., n. sp. is described from the small intestine of the murray turtle, emydura macquarii (gray, 1830), from the vicinity of warwick, queensland, australia. the distinctive taxonomic features include the vitellarium, which consists of 2 compact masses directly anterior to and occasionally overlapping the testes; the uterus with extensive pre- and postovarian coils; intestinal ceca with small, medial diverticula that terminate anterior to or at the anterior margin of the ... | 2001 | 11695376 |
| life-cycle and biology of sychnocotyle kholo n.g., n. sp. (trematoda : aspidogastrea) in emydura macquarii (pleurodira : chelidae) from southern queensland, australia. | sychnocotyle kholo n. g., n. sp. (aspidogastrea: aspidogastridae) is described from the small intestine of the freshwater turtle emydura macquarii (pleurodira: chelidae). the new genus is distinguished from other aspidogastrids by the possession of the following suite of characters: no cirrus-sac; no hermaphroditic duct; four rows of alveoli on the ventral disc but no prominent papillae; laurer's canal opening to the exterior. eggs hatched to cotylocidia within 37-41 days at 17-24 degrees c. the ... | 1999 | 10613529 |
| epidermal differentiation during carapace and plastron formation in the embryonic turtle emydura macquarii. | as part of a large comparative study on the development of reptilian skin, we provide the first ultrastructural description of differentiation of the epidermis of the carapace and plastron in the chelonia, using the australian pleurodiran turtle emydura macquarii as a model. the epidermis is initially composed of an external flat peridermis and a basal layer of cuboidal cells. during differentiation, the peridermis darkens, flakes off and is partially lost before hatching. four to 6 layers of fl ... | 1999 | 10445822 |
| the diet and digestive energetics of an australian short-necked turtle, emydura macquarii. | we described the diet of emydura macquarii, an omnivorous turtle from south-eastern australia, compared its digestive performance on diets of fish or plants at two temperatures, and related how both diet and temperature affect its food selection in nature. filamentous algae constituted 61% of the stomach content of e. macquarii. the turtles rarely fed on motile prey, but selected carrion from the lagoon bottom and terrestrial insects (diptera, hymenoptera and coleoptera) trapped on the surface o ... | 1998 | 10048187 |
| uterotrema australispinosa n. gen., n. sp. (digenea: spirorchidae), a parasite of a freshwater turtle emydura macquarii from southern queensland, australia. | uterotrema australispinosa n. gen., n. sp. from the heart of the murray river turtle emydura macquarii (pleurodira: chelidae) is distinguished from other members of the spirorchidae by the presence of a voluminous uterus; a single, lobed testis occupying the posterior quarter of the body; linear rows of 5-6 spines arranged along the lateral margins of the hindbody from the posterior rim of the acetabulum to the posterior end of the body; and the posterior end ventrally curved with a dorsal clust ... | 1994 | 7799141 |
| influence of the hydric environment on water exchange and hatchlings of rigid-shelled turtle eggs. | to examine the possible influence of incubation substrate water potential on rigid-shelled chelonian eggs and hatchlings, rigid-shelled eggs from four clutches of brisbane river turtle (emydura signata) were incubated buried in vermiculite at water potentials of approximately -100, -350, and -850 kpa, and patterns of egg mass change and hatchling attributes were examined. all eggs hatched successfully, and there was no apparent effect of water potential on incubation period, fresh hatchling mass ... | 2013 | 19115963 |
| temperature and the respiratory properties of whole blood in two reptiles, pogona barbata and emydura signata. | we investigated the capacity of two reptiles, an agamid lizard pogona barbata and a chelid turtle emydura signata, to compensate for the effects of temperature by making changes in their whole blood respiratory properties. this was accomplished by measuring the p50 (at 10, 20 and 30 degrees c), hematocrit (hct), haemoglobin concentration ([hb]) and mean cell haemoglobin concentration (mchc) in field acclimatised and laboratory acclimated individuals. the acute effect of temperature on p50 in p. ... | 2006 | 16406640 |
| composition and energy density of eggs from two species of freshwater turtle with twofold ranges in egg size. | lipid, protein, ash, carbohydrate and water content and energy density of eggs were measured from different clutches over a range of egg size in two species of freshwater turtle. dry egg contents consisted of protein (54-60%), lipid (25-31%) and ash (5-6%) while carbohydrate was found to be negligible (<1%). albumen consisted principally of water ( approximately 98%), and the dry component was composed of protein (47-51%), ash (19-26%) and lipid (18-21%), but contributed only a small amount ( ap ... | 2003 | 12507616 |
| effects of incubation temperature on the energetics of embryonic development and hatchling morphology in the brisbane river turtle emydura signata. | incubation temperature and the amount of water taken up by eggs from the substrate during incubation affects hatchling size and morphology in many oviparous reptiles. the brisbane river turtle emydura signata lays hard-shelled eggs and hatchling mass was unaffected by the amount of water gained or lost during incubation. constant temperature incubation of eggs at 24 degrees c, 26 degrees c, 28 degrees c and 31 degrees c had no effect on hatchling mass, yolk-free hatchling mass, residual yolk mas ... | 1998 | 9706707 |
| incubation of turtle eggs at different temperatures: do embryos compensate for temperature during development? | freshwater turtle eggs are normally subjected to fluctuations in incubation temperature during natural incubation. because of this, developing embryos may make physiological adjustments to growth and metabolism in response to incubation at different temperatures. i tested this hypothesis by incubating eggs of the brisbane river turtle emydura signata under four different temperature regimes, constant temperatures of 24 degrees c and 31 degrees c throughout incubation, and two swapped-temperature ... | 2004 | 9472809 |
| serological survey of australian native reptiles for exposure to ranavirus. | ranaviruses have been isolated from many ectothermic vertebrates, and serological surveys of both amphibians and reptiles have shown the presence of ranaviral antibodies in a proportion of these populations. an enzyme-linked immunosorbent assay (elisa) was developed to measure serum antibodies against ranavirus in australian reptiles. the elisa was validated with serum from challenge trials with bohle iridovirus (biv) in 6 reptilian species. a preliminary sero-survey of northern queensland ripar ... | 2017 | 29160216 |
| conservation implications of turtle declines in australia's murray river system. | conservation requires rapid action to be effective, which is often difficult because of funding limitations, political constraints, and limited data. turtles are among the world's most endangered vertebrate taxa, with almost half of 356 species threatened with extinction. in australia's murray river, nest predation by invasive foxes (vulpes vulpes) was predicted to drive turtle declines in the 1980s. we assessed populations of the broad-shelled turtle (chelodina expansa), eastern long-necked tur ... | 2019 | 30760813 |
| prey-switching does not protect a generalist turtle from bioenergetic consequences when its preferred food is scarce. | optimal foraging theory explains how animals make foraging decisions based on the availability, nutritional content, and handling times of different food types. generalists solve this problem by consuming a variety of food types, and alter their diets with relative ease. specialists eat few food types, and may starve if those food types are not available. we integrated stable isotope analyses with previously-published stomach contents and environmental data to investigate how the foraging ecolog ... | 2020 | 32070322 |
| cutaneous lesions in freshwater turtles (emydura macquarii krefftii and myuchelys latisternum) in a rainforest creek in north queensland, australia. | freshwater turtles inhabit most rivers and creeks on the east coast of australia, but some species are only found in specific catchments, which makes them vulnerable to extinction. during annual fieldtrips to alligator creek, north queensland, the resident population of myuchelys latisternum and emydura macquarii krefftii in a natural pond, just outside bowling green national park, have been surveyed for a number of years and demographic data recorded against tagged turtles. rounded, cutaneous l ... | 2020 | 32083109 |
| cell proliferation, adhesion, and differentiation of keratinocytes in the developing beak and egg-tooth of the turtle emydura macquarii. | the development of the beak in turtles is poorly known. beak development has been analyzed by immunofluorescent methods for studying cell proliferation and localization of specific proteins. the flat two-layered epidermis covering the turtle embryo at mid stage of development becomes columnar in the oral region and is associated with an increase of mesenchymal density as in placodes. using 5brdu, an intense cell proliferation is observed in the oral and epidermal cells covering the maxilla and m ... | 2020 | 32533364 |
| microbiome diversity and composition varies across body areas in a freshwater turtle. | there is increasing recognition that microbiomes are important for host health and ecology, and understanding host microbiomes is important for planning appropriate conservation strategies. however, microbiome data are lacking for many taxa, including turtles. to further our understanding of the interactions between aquatic microbiomes and their hosts, we used next generation sequencing technology to examine the microbiomes of the krefft's river turtle (emydura macquarii krefftii). we examined t ... | 2020 | 32213245 |
| dose-dependent morbidity of freshwater turtle hatchlings, emydura macquarii krefftii, inoculated with ranavirus isolate (bohle iridovirus, iridoviridae). | ranaviral infections cause mass die-offs in wild and captive turtle populations. two experimental studies were performed to first determine the susceptibility of an australian turtle species (emydura macquarii krefftii) to different routes of infection and second examine the effect of viral titre on the morbidity in hatchlings. all inoculation routes (intracoelomic, intramuscular and oral) produced disease, but the clinical signs, histopathology and time to onset of disease varied with the route ... | 2019 | 31483246 |
| genomewide snp markers breathe new life into phylogeography and species delimitation for the problematic short-necked turtles (chelidae: emydura) of eastern australia. | understanding the evolutionary history of diversifying lineages and the delineation of evolutionarily significant units and species remains major challenges for evolutionary biology. low-cost representational sampling of the genome for single nucleotide polymorphisms shows great potential at the temporal scales that are typically the focus of species delimitation and phylogeography. we apply these markers to a case study of a freshwater turtle, emydura macquarii, whose systematics has so far def ... | 2018 | 30403418 |