Water Dragons Research Articles

Intellagama lesueurii (Gray, 1831), the correct binomial combination for the Australian Eastern Water Dragon (Sauria, Agamidae)

The Eastern Water Dragon is a large, conspicuous agamid, well known to many inhabitants of eastern Australia. It was first described in the scientific literature as Lophura lesueurii by Gray (1831). Gray’s allocation of this taxon to his earlier genus Lophura Gray, 1827, created for the species Lacerta lophura Shaw, 1802, does not mention that Cuvier (1829) had erected Istiurus for amboinensis Schlosser, 1768, which Cuvier treated as a senior synonym of lophura. Cuvier considered the generic name Lophura to be too similar to Lophyrus Latreille, 1802, a genus of conifer sawflies belonging to the family Diprionidae, hence the need for a new genus. Both Gray and Cuvier were evidently unaware that Lophura was unavailable as this name had already been assigned to a genus of phasianid birds (Fleming 1822). The Eastern Water Dragon has subsequently appeared in the taxonomic literature under the following synonyms: Iguana paramatensis Fitzinger, 1843; Amphibolurus maculiferus Girard, 1857; Amphibolurus heterurus Peters, 1866 and Amphibolurus branchialis De Vis, 1884. The combination Physignathus lesueurii was first used in 1845 by Gray in his Catalogue of the Specimens of Lizards in the British Museum and has been in use ever since. The only other generic name proposed for this taxon is Intellagama Wells and Wellington, 1985, by which the authors implied its distinctiveness from the other member of Physignathus, the Chinese Water Dragon P. cocincinus Cuvier, 1829. However, as their description provided no evidence to demonstrate that Australian water dragons are generically distinct from their foreign congener, this name has not been adopted by subsequent authors, and has been informally treated as a synonym of Physignathus.

Isolation and characterisation of novel microsatellite and mitochondrial DNA markers for the Eastern Water Dragon (Physignathus lesueurii)

Habitat fragmentation as a result of urbanisation is a growing problem for native lizard species. The Eastern Water Dragon (Physignathus lesueurii) is a social arboreal agamid lizard, native to Australia. This species represents an ideal model species to investigate the effect of urbanisation because of their prominent abundance in the urban landscape. Here we describe the isolation and characterisation of a novel set of 74 di-, tri-, and tetramicrosatellites from which 18 were selected and optimised into two multiplexes. The 18 microsatellites generated a total 148 alleles across the two populations. The number of alleles per locus varied from 2 to 18 alleles and measures of Ho and He varied from 0.395 to 0.877 and from 0.441 to 0.880, respectively. We also present primers for four novel mitochondrial DNA (mtDNA) markers. The combined length of the four mtDNA marker pairs was 2,528 bp which included 15 nucleotides changes. In comparison to threatened species, which are generally characterised by small population sizes, the Eastern Water Dragon represents an ideal model species to investigate the effect of urbanisation on their behavioural ecology and connectivity patterns among populations.

Cerebral Xanthomatosis in Three Green Water Dragons (Physignathus cocincinus)

Cerebral xanthomatosis was diagnosed in three female green water dragons (Physignathus cocincinus), all of which presented with progressive neurologic signs. No antemortem evidence for xanthomatosis was identified, but on postmortem examination cholesterol granulomas, composed of cholesterol clefts surrounded by macrophages and multinucleated giant cells, were found in the forebrain of each animal and were associated with significant displacement and pressure on the adjacent brain. Although the cause of xanthomatosis in these animals is unknown, nutrition and trauma may be involved in the pathogenesis of this condition. Cerebrum, cholesterol, green water dragon, Physignathus cocincinus, xanthoma.

Superficial lizards in cold climates: Nest site choice along an elevational gradient

AbstractEmbryonic conditions may limit the distributions of egg‐laying ectotherms, and recent research suggests that nesting mothers of wide‐ranging species may use a number of factors to compensate for differing climates. However, while variation in temporal factors across environmental gradients are common or pervasive (i.e. seasonal timing of nesting), similar evidence for spatial factors is rare (e.g. aspect, openness and depth of nest sites). I tested the idea that a wide‐ranging lizard, the Australia water dragon (Physignathus lesueurii), uses nest depth to counter climate differences along a temperature cline at their cold‐end range margin. Two measures of nest depth were significantly, inversely related to elevation across six populations spanning 700 m. Elevation explained 83–86% of the variation in nest depth. These findings support a thermal compensatory mechanism for this pattern, although soil moisture compensation is plausible. My results directly support a recent, untested prediction that the evolution of viviparity in reptiles is preceded by a behavioural shift towards increasingly superficial nest sites in cold climates, followed by selection for increased egg retention to avoid temperature extremes. However, in the present study egg desiccation rates increased with increasing elevation in a dry year, suggesting that increased egg retention may evolve in response to lethal hydric conditions, rather than lethal temperatures. When considered alongside recent research, the present study indicates that water dragons possess several mechanisms for adjusting to climate change.

Telemetry tagging methods for some freshwater reptiles

Reptiles are often ignored or under-studied in freshwater systems. An understanding of their biology and thus their role in aquatic communities can be greatly advanced by studies using radio telemetry. In turn, the value of radio telemetry for research depends on the availability of suitable and reliable methods of attaching or implanting radio transmitters. The present study describes transmitter attachment and implantation techniques for selected freshwater reptiles, including the eastern and northern long-necked turtles (Chelodina longicollis and Chelodina rugosa, respectively), the pig-nosed turtle (Carettochelys insculpta), Mertens’ water monitor (Varanus mertensi) and the water dragon (Physignathus lesueurii). The effectiveness of the methods for each species is described and the potential pitfalls and challenges of each method are discussed. The literature abounds with techniques for attachment and implantation techniques, and the methods used in the present study are not wholly novel. The aim, however, is to provide detailed summaries, in one paper, of effective methods for attachment and implantation of radio-tags for freshwater reptiles with a diversity of sizes, shapes and attachment surfaces. Despite the focus on Australian freshwater reptiles, these methods are applicable to aquatic reptiles worldwide.

Phylogeny of Australasian agamid lizards based on nuclear and mitochondrial genes: implications for morphological evolution and biogeography

Recent mtDNA phylogenies of Australasian agamid lizards are highly incongruent with existing morphological views. To resolve this discrepancy we sequenced two nuclear gene regions, c-mos and brain-derived neurotrophic factor (BDNF). These were highly concordant with each other and the mtDNA phylogeny, but not the morphology. A combined molecular analysis reveals substantial hidden support (additional phylogenetic signal that emerges only when the data sets interact in a combined analysis). Bayesian posteriors, and a partitioned bootstrap procedure introduced here, indicate strong support for most nodes. The resultant tree implies extensive morphological homoplasy, with many genera emerging as non-monophyletic (Amphibolurus, Rankinia, Ctenophorus, Physignathus, Diporiphora). The water and forest dragons (Physignathus and Hypsilurus) form a paraphyletic basal assemblage to the more derived Australian forms such as Amphibolurus and Ctenophorus, which include almost all the xeric taxa. However, the thorny devil Moloch horridus is a basal lineage and not closely related to the other arid forms. Tree topology, inferred divergence dates, palaeogeographical and palaeoclimatic data are all consistent with Miocene immigration into Australia from the north by mesic forest ecomorphs, followed by initial diversification in mesic habitats before radiation into xeric habitats facilitated by increasing aridity. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 343–358.

Basking in the Australian water dragon Physignathus lesueurii; why do alpha males not respond to operative temperatures in the same way as adults and sub-adults?

AbstractObservations have been made on the behaviour of the Australian water dragon Physignathus lesueurii in southeast Australia. Physical models that explore the thermal environment at a similar spatial level as real lizards were related to ontogenetic changes in lizard behaviour. Current theory predicts that a heliotherm will bask in open locations to optimise heating rates in order to attain target body temperatures as quickly as possible. Movement to shaded or partially shaded areas then maintains thermal stability. Regression equations of basking intensity in relation to operative temperatures were employed to test this theory. The behaviour of adults, which were not alpha males, and sub adults was in agreement with the prediction, but the behaviour of alpha males was not: the regression coefficient did not differ significantly from 0. In general, sub adult lizards were more active and fed more often than larger lizards although this relationship changed with different times of the day. The results suggest differing costs for thermoregulation for different size classes, particularly in alpha males where territory defence has a key role.

Hues of a dragon's belly: morphological correlates of ventral coloration in water dragons

AbstractSexual dichromatism is common in lizards, and may play an important role in sex recognition and mating systems. Nonetheless, relatively few published papers provide quantitative analyses of colour, deal with Australian taxa or are based on large‐bodied species. Water dragons Physignathus lesueurii (Agamidae) from eastern Australia are very large (upto 1 m total length) and sexually dichromatic, with conspicuous red ventral coloration in adult males. We quantified coloration in three ventral regions (throat, chest and abdomen) of males and females using a spectroradiometer and looked for associations of colour with sex and with morphological traits predicted to correlate with fitness (body size, body condition, relative head size and asymmetry of femoral pores). Among adult males, larger individuals showed less red on the abdomen than did smaller animals, and males with relatively large heads had darker, less red abdomens than did males with smaller heads. Among adult females, larger animals had darker chests, and less red on the abdomen and chest, than did smaller females. The similarity in these trends between the sexes, and the location of the sexually dichromatic and size‐sensitive colours in an area (under the abdomen) where they presumably are not visible to other lizards cast doubt on their utility as sexual or dominance signals. Hence, although we documented significant sex and body‐size effects on ventral coloration, our results suggest that ventral colours in water dragons do not function in sex‐specific displays.

SalmonellaKingabwa Infections and Lizard Contact, United States, 2005

To the Editor: Nontyphoidal Salmonella infections cause an estimated 1.4 million illnesses and 400 deaths in the United States annually (1). Among the >2,500 Salmonella serotypes, Salmonella enterica serotype Kingabwa rarely causes human illness. This serotype was first reported in a patient in the Belgian Congo in 1953 (2). From 1995 through 2004, only 30 human illnesses caused by S. Kingabwa were reported to the National Salmonella Surveillance System (3). No common source for S. Kingabwa human illnesses has been previously identified. We recently investigated an outbreak of S. Kingabwa infections associated with 2 lizard species: the water dragon and the bearded dragon. Eighteen isolates of S. Kingabwa (antigenic formula: I 43:y:1,5) were received by PulseNet, the National Molecular Subtyping Network for Foodborne Disease Surveillance, from 2001 through 2005. When digested with restriction enzyme XbaI and subtyped by pulsed-field gel electrophoreisis (PFGE), 13 isolates produced a single, indistinguishable pattern (KINX01.0001). Of these, 1 (8%) was isolated in 2001, 4 (31%) were isolated in 2002, 2 (15%) were isolated in 2004, and 6 (46%) were isolated in 2005. We defined a case as illness during 2005 caused by S. Kingabwa that matched pattern KINX01.0001 by PFGE. Of the 9 S. Kingabwa isolates received by PulseNet in 2005, 6 matched KINX01.0001. Antimicrobial drug susceptibility of 3 isolates was determined by the National Antimicrobial Resistance Monitoring System (NARMS) for Enteric Bacteria at the Centers for Disease Control and Prevention (CDC), and the isolates were susceptible to each of 15 antimicrobial agents tested. The 6 patients in the 2005 outbreak did not know each other and resided in 5 states: Maine (2 patients), Arizona, California, Idaho, and Ohio. Illness onset dates were in June, July, August, October (2 patients), and November 2005. Of the 6 patients, 4 (67%) were ≤1 year old (range <1–53 years), 4 were male, 2 were hospitalized, and none died. Interviews with patients or their parents or guardians conducted during routine public health surveillance collected information on specific food items, water sources, restaurant venues, travel history, and animal contact. No common food or environmental source was identified. However, 4 (67%) of the 6 patients had known exposure to lizards: 3 water dragons (Physignathus cocincinus, Figure) and 1 bearded dragon (Pogona sp.). Of these 4 patients, 3 had >1 lizard in their own household as pets; the other patient was exposed to a lizard when visiting a family member. The 2 patients who did not recall lizard exposure might represent patients with background cases unrelated to lizards. Single cultures of the 2 lizards available for testing in February 2006 did not yield S. Kingabwa, which could mean that they did not carry this rare Salmonella serotype. However, this does not exclude lizards as the source of these illnesses because lizards intermittently shed salmonellae (4). Figure Water dragon (Physignathus cocincinus). Three of the patients with Salmonella Kingabwa infections were exposed to this reptile species. Photo credit: Robert Lawton, rklawton@LawtonPhotos.com. The lizards had been purchased from local pet shops and a traveling reptile show. Shipments of reptiles were mixed together at points of sale, and numerous distributors and importers were used, so determining the origin of individual reptiles was not feasible. However, water dragons and bearded dragons are imported into the United States from Asia and Australia and are rarely bred domestically. Two thirds of the patients in this outbreak had documented exposure to 1 of 2 lizard species, and half of the patients had pet lizards in their homes. In 2001, the estimated number of households with lizards was 545,000, which represents ≈0.5% of all American households (5). Using a standard binomial model, the probability of finding at least 3 of 6 persons chosen at random to be lizard owners is 0.000002. To our knowledge, this is the first investigation to identify a strong association between the rare serotype S. Kingabwa and lizards and the first instance of which we are aware that a serotype has been associated with a particular species of lizard dispersed in homes across the United States. The association between reptile exposure and human salmonellosis is well-established (6–8). CDC has published recommendations for reducing the risk for infection from reptiles (http://www.cdc.gov/healthypets/animals/reptiles.htm); these include thoroughly washing hands with soap and water after handling reptiles or their cages and keeping reptiles out of food preparation areas. The young age of most patients in this outbreak supports the recommendation that reptiles should not be allowed in households with children <5 years of age.

Trophic relationships between neighbouring White-bellied Sea-Eagles (Haliaeetus leucogaster) and Wedge-tailed Eagles (Aquila audax) breeding on rivers and dams near Canberra

The diet of the White-bellied Sea-Eagle (Haliaeetus leucogaster) in Australia is poorly known, especially inland. The diet of the Wedge-tailed Eagle (Aquila audax) is better known, but the overlap in prey used by the two eagles has not been studied. In four inland territories of White-bellied Sea-Eagles, and five territories of Wedge-tailed Eagles nesting close to them (range 1.6-5.1 km apart) between July 2002 and December 2004, we identified 116 and 118 prey items from nests of White-bellied Sea-Eagles and Wedge-tailed Eagles respectively. There was little overlap between the diets, and that of Wedge-tailed Eagles was similar to that reported elsewhere. In addition to fish, White- bellied Sea-Eagles specialised in aquatic birds, such as cormorants, grebes or ducks, and aquatic reptiles, such as turtles or water dragons, but tended to avoid terrestrial birds and reptiles, such as ravens and skinks, or mammals such as European Rabbits (Oryctolagus cuniculus) and macropods that were the main prey of nearby Wedge-tailed Eagles. Though food niche breadth was almost identical for the two eagles, Wedge-tailed Eagles captured significantly larger prey, as indicated by the geometric mean prey weight. Our results indicate that closely located breeding pairs of riparian Wedge-tailed Eagles and White-bellied Sea-Eagles were not competing for food, owing to the differences in foraging preferences, at least during the breeding season. We found no evidence to support the claim that the spread of rabbits assisted the increase of breeding numbers of White-bellied Sea-Eagles.

Characterizing the Hematologic and Plasma Chemistry Profiles of Captive Chinese Water Dragons, Physignathus cocincinus

Twenty-six (one to six years of age) Chinese water dragons, Physignathus cocincinus, from two different captive populations, Massachusetts (MA) and Mississippi (MS), were selected for this study. The lizards were given a thorough examination, and a blood sample was collected for a complete blood count (CBC) and plasma biochemistry. Whole blood was stored in both lithium heparin and Ca- EDTA; Ca-EDTA was considered the superior anticoagulant based on multiple paired samples. The packed cell volume (PCV) for the water dragons was 32 - 40%. The lymphocyte was the most common cell found on the CBC. There were significant differences in the plasma uric acid (MS: 2.3; MA 6.0; p=0.001) and phosphorus (MS: 5.7, MA:7.1; p=0.04) concentrations between the two populations. Younger dragons ( 3 yr: 2.3, p=0.01) than dragons > 3 yr of age. There were no significant differences in the bio- chemistries based on the origin (wild-caught vs. captive bred) of the lizards or between genders. Overall, the dragons in this study were clinically healthy, and the reference range established from these two pop- ulations may be used as a basis for comparison in clinical cases.

The Thai Water Dragon, Physignathus cocincinus

ABSTRACT The Thai water dragon, Physignathus cocincinus, originates from India and eastern Asia. This arboreal, diurnal lizard grows to 90 cm and is a popular pet, requiring tropical environments of 25 – 35° C (77 – 95° F) and 60- 90% humidity. Basking light and heat sources, and broad spectrum lighting are essential, as is a varied and balanced insectivorous diet. Captive breeding is common with the average clutch of 8 to 12 eggs taking 60 - 101 d to incubate at 28 - 30°C (82 - 86 °F). Common diseases encountered in captivity include secondary nutritional hyperparathyroidism (nutritional metabolic bone disease) with and without concomitant pathologic fractures, dystocia, abscesses, digit, and tail trauma, obesity, rostral abrasions, stomatitis, and gingivitis.

Clinical Differentiation of Chinese Water Dragon, Physignathus spp., Leukocytes

Clinical Differentiation of Chinese Water Dragon, Physignathus spp., Leukocytes

Inclusions in the erythrocytes of eastern water dragons (Physignathus lesueurii)

Inclusions in the erythrocytes of eastern water dragons (Physignathus lesueurii)

Estimate of the population structure of the estern water dragon, Physignathus lesueurii (Reptilia : Agamidae), along riverside habitat

A population of eastern water dragons, Physignathus lesueurii, was investigated along 1.5km of the Gloucester River in central eastern New South Wales from November 1989 to December 1992. Dragons were caught in all months from September to April, but not in June. In all, 373 dragons were marked and 69 of these were recaptured on one or more occasions. Females are ovigarous in late October, November and December. Only about one third of females have palpable eggs during these months. Hatchlings enter the population in February and March at 4.5g, with a snout-vent length (SVL) of 53mm. In the next season they are 19.5g (SVL 80mm). The dragons grow rapidly for four years to reach adult size. Growth rates are fastest during the first year at 2.25mm SVL per month or 1.25 g per month. The Jolley-Seber population estimate for adult females was 103 +/-49 in the study site or 69 per km of river. Estimates for males and for the total population could not be calculated because individuals were not equally catchable (Leslie's test for equal catchability). However, theoretical considerations place the density of adult dragons at 138-215 per km of river. The largest male was 304mm SVL, 54mm longer than the next-largest water dragon reported. One male was heavier than 1000g. The largest female was 230mm SVL and the heaviest was 490g, or approximately half the mass of the heaviest male. Adult males and adult females have the same proportion of broken tails. Water dragons are fairly sedentary, with an average distance of 76m (range 0-785m) between captures.

Divinity and Salvation: The Great Goddesses of China

Though Chinese mythology and religion have been dominated by male gods and masters, the presence of female divinities has always been a part of Chinese folk belief. These various divinities, usually identified with the feminine principle of moist, dark, receptive nature, constitute a somewhat obscure pantheon of water sprites, dragon ladies, snake queens, moon-goddesses, and rulers of heaven and earth. Among them may be recognized four divinities whose collective popularity extends from ancient times to the present. These four are Niigua -& #fi, the ancient Zhou dynasty creatress; Xiwangmu EEB, the Queen Mother of the West; Guanyin as, the Goddess of Mercy; and Tianhou *G, the Empress of Heaven. These four divinities have an interesting and significant relationship with each other, indicative of the dynamic social and cultural history of China. Collectively, they represent the presence of the feminine element, divinized to the highest degree, in an almost unbroken continuity of spiritual potency and significance for both the masses of China, as well as for various religious and ~olitical groups. It is the purpose of this paper to discuss these four figures and to show how their interrelationship has developed in the face of a dominant male religious and political environment. The basic difference between the religious environment of classical and post-classical China might best be characterized as the difference between a warring hegemony of hereditary Chinese warlords and a central bureaucracy, dominated by a structured hierarchy of nonhereditary officials (BODDE 1961, 369). By the end of the Han Dynasty (220 c.E.), the spiritual hierarchy began to resemble, at least officially, the actual structure of the imperial order. Subsequently, the Han

The effect of temperature on bimodal gas exchange and the respiratory exchange ratio in the water dragon, Physignathus lesueurii

1. 1. Oxygen consumption and carbon dioxide output of a semi-aquatic lizard, Physignathus lesueurii were measured over a range of temperatures and the contribution of the skin as a respiratory surface was assessed. 2. 2. Both total oxygen consumption and total CO 2 output increased logarithmically with temperature: log V ̇ o 2 = −1.97 + 0.028T log V ̇ co 2 = −2.01 + 0.019T 3. 3. Cutaneous oxygen uptake contributed little to total oxygen uptake. 4. 4. Fifteen percent of CO 2 output was eliminated through the skin at 25°C, and this percentage decreased with increasing temperature. 5. 5. R E decreased with increasing temperature: R E = 1.02 — 0.018 T.

Time constants of heating and cooling in the eastern water dragon, Physignathus lesueruii and some generalizations about heating and cooling in reptiles

1. 1.|In keeping with other reptiles, core temperature of the lizard Physignathus lesueurii responds more rapidly to a step function increase in temperature than to a corresponding decrease. 2. 2.|Observations on twelve species (five families) of non-Chelonian reptiles heating and cooling in air and water show that strongly predictable relationships exist between thermal time constants and body size. Chelonia show a different pattern. 3. 3.|These observations are compared with the predictions of a simple model which, although not sufficiently complex to simulate physiological changes, provides insight into the relative importance of the physical and biological factors which underlie the observed relationships.