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Literatur und Schriften
ZOFFER, D. & T. MAZORLIG (1998): Bearded & Frilled Dragons. – T.F.H. Publications, USA. 64 S.
Kragenechse / Frilled Lizard ANONYM (1958): Frilled Lizard (Chlamydosaurus kingi). – Turtox News, 36: 192. ARESTÉ, M. & J.L. FARRIOLS (2000): Chlamydosaurus kingii Kragenechse. – Reptilia, Münster, 5 (1): 47-50. BEDFORD, G.S., CHRISTIAN, K.A. & A.D. GRIFFITHS (1993): Preliminary investigations on the reproduction of the Frillneck Lizard Chlamydosaurus kingii in the Northern Territory. – In: Lunney, D. & D. Ayers (eds.): Herpetology in Australia. – Transactions of the Royal Zoological Society of New South Wales. 414 S. BEDDARD, F.-E. (1905): A contribution to the anatomy of the frilled lizard (Chlamydosaurus kingii) and some other Agamidae. – Proceedings of the Zoological Society, London, 75 (1): 9-22. BENDER, E. (1956): Chlamydosaurus in Deutschland. – Die Aquar. Terrar. Z., Stuttgart, 9 (6): 166. BOGERT, C.M. (1957): The lizard with the frightening frill. – Nat. Hist. N.Y., 66: 98-99. BOULENGER, G,A. (1895): Remarks on the value of certain cranial characters employed by Prof. Cope for distinguishing lizards from snakes. - Ann. Mag. nat. Hist. (6) 16: 366-367. BROOK, B.W. & A.D. GRIFFITHS (2004): Frillneck lizard (Chlamydosaurus kingii) in northern Australia: determining optimal fire-management regimes. - In: Akcakaya, H.R.; Burgman, M.A.; Kindvall, O.; Wood, C.C.; Sjogren-Gulve, P.; Hatfield, J.S.; McCarthy, M.A. (eds.): Species conservation and management: case studies. Oxford University Press, Oxford, New York, etc.: 312-325. BUSH, B. (1985): On the distribution of two north Australian agamid lizards, Chelosania brunnea Gray and Chlamydosaurus kingii [Clamydosaurus kingii] Gray. – West. Aust. Nat., 16 (2-3): 53. CAMERON, E. (1983): Frilled lizard Chlamydosaurus kingii. – Aust. Nat. Hist., 21 (3): 99-102. CHRISTIAN.K.A. & G.S. BEDFORD (1995): Seasonal changes in thermoregulation by the frillneck lizard, Chlamydosaurus kingii, in tropical Australia. – Ecology, 76: 124-132. CHRISTIAN, K.A. & G.S. BEDFORD (1995): Physiological consequences of filarial parasitres in the frillneck lizard, Chlamydosaurus kingii, in northern Australia. – Canadian Hournal of Zoology, 73 (12): 2302-2306. CHRISTIAN, K., BEDFORD, G. & A. GRIFFITHS (1995): Frillneck lizard morphology: comparisons between sexes and sites. – Journal of Herpetology, 29 (4): 576-583. CHRISTIAN, K. & B. GREEN (1994): Seasonal energetics and water turnover of the frillneck lizard, Chlamydosaurus kingii, in the wet-dry tropics of Australia. – Herpetologica, 50 (3): 274-281. The field metabolic rates and water fluxes of frillneck lizards, Chlamydosaurus kingii, were studied in the field during three seasons. In the wet season, energy expenditure and water influx rates were relatively high (83.7 kJ kg-' day-' and 27.5 ml H2O kg-' day-', respectively), but they declined substantially during early dry (22.8 kJ kg-' day-' and 13.6 ml H2O kg-' day-') and dry (23.3 kJ kg-' day-' and 5.6 ml H2O kg-' day-') seasons. Dry season values represent a 77% reduction in energy expenditure and an 80% reduction in water flux. During the wet and early dry seasons, the lizards gained small amounts of mass (0.14 and 0.16% mass day-'), but during the dry season, they lost mass at a rate of 0.06% mass day-'. During the dry half of the year, the lizards are much less active, and they remain perched in trees. This represents a relatively exposed site for a period of inactivity in a warm climate, but frillneck lizards are nevertheless able to maintain rates of water flux and energy expenditure that are similar to over-wintering lizards and lizards in underground
We observed adult-like display behavior in newly hatched frillneck lizards, Chlamydosaurus kingii, including hand waving and erection of the frill. Hatchlings were placed together in groups of four for a week at a time and a measure of dominance was scored with respect to gaining access to a basking site. In most cases, the hatchlings were ordered non-randomly with respect to the optimum basking site, suggesting a hierarchy among the lizards. Plasma androgen concentrations were measured in hatchlings and lizards of both sexes of age classes ranging from hatchlings to three or more years old. Hatchling dominance was not related to plasma androgen concentrations, sex, or body size, but there was a positive correlation between dominance and mass gained over the six weeks of observations. Plasma androgen concentrations were low in all age and sex groups except adult males three or more years old, although two-year-old males had slightly elevated concentrations. A few (8%) two year old males had scars, presumably from intraspecific fights, but many (46%) males three or more years old had scars. No females or males younger than two years old were scarred.
FRAPPELL, P.B. & J.P. MORTOLA (1998): Passive body movement and gas exchange in the frilled lizard (Chlamydosaurus kingii) and goanna (Varanus gouldii). - J. Exp. Biol., 201 (15): 2307-2311. The saccular lung in lizards is large and highly compliant compared with mammalian lungs, and these properties led us to question to what extent body movements could affect pulmonary gas exchange and the partial pressure of arterial blood gases. Specimens of two species of lizards, the frilled lizard (Chlamydosaurus kingii, approximately 600g body mass) and the goanna (Varanus gouldii, approximately 1400mass), were anaesthetised, maintained at approximately 36°C and mechanically hyperventilated to lower the arterial partial pressure of carbon dioxide (PaCO·) to below apnoeic threshold. Respiratory system compliance (Crs) averaged 0.112mlkg-1Pa-1 (goanna) and 0.173mlkg-1Pa-1 (frilled lizard), which is approximately 7–11 times the predicted value for a mammal of similar body mass. Mechanical ventilation was interrupted, and the changes in PaCO· and PaO· were monitored over the following 10 min as the animal was either left immobile or subjected to imposed lateral body movements. During the post-hyperventilation apnoea, PaCO· increased whereas PaO· did not always fall, sometimes even increasing, suggesting a reduction in the importance of pulmonary shunts. No significant differences were detected in the time course of changes in arterial blood gas levels or heart rate between runs with or without body movement. We conclude that in these species of lizards, despite the high Crs, lateral chest wall movements neither hinder nor favour pulmonary gas exchange. The demography and home range of a population of frillneck lizards, Chlamydosaurus kingii, were examined from 1992 to 1994, in Kakadu National Park, Northern Territory, Australia. Lizards were studied using radiotelemetry and mark-recapture techniques. Reproduction occurred between November and April each year, coinciding with monsoonal conditions. R eproductivea ctivityw as highest in the first three months of the wet season. Females reached sexual maturity at 18 months of age. Males grew faster than females. Minimum longevity in the field was four years for females and six years for males. The population structure was constant at three sites, and the sex ratio exhibited a strong male bias. Density of frillneck lizards in Eucalyptuos pen forest varied from 0.13 to 0.78 ha-1. Males have larger dry-season home ranges (mean = 1.96 ± 0.57 ha) than females (mean = 0.63 ± 0.12 ha). No seasonal difference was evident in size of home range for either male or female lizards. No correlation was evident between snout-vent length and home range for either sex. This suggests that the home ranges of frillneck lizards were not determined by either food resources or body size but possibly related to social behavior. Arid-adapted agamids exhibit broad similarity in timing of the reproductive season, whereas factors such as growth and age at sexual maturity differ with body size and environmental conditions. Abstract: HAUSCHILD, A. (1997): Mit Stehkragen und Peitschenschwanz: Kragenechsen. – Reptilia, Münster, 2 (4): 56-60. Geographical variants of the Frill-necked Lizard Chlamydosaurus kingii Gray, 1825 have been recognized for many years including within the pet trade in Europe and the USA. In spite of this, there has been no recognition of the various taxonomic units beyond the single described species. Taking a conservative position, this paper reviews the monotypic genus and formally names two new subspecies, namely Chlamydosaurus kingii pughae subsp. nov. from New Guinea and Chlamydosaurus kingi mickpughi from eastern Queensland. Abstract: Animal coloration has evolved in contexts such as communication, camouflage, and thermoregulation. Most studies of animal coloration focus on its adaptive benefits, whereas its underlying mechanisms have received less attention despite their potential influence on adaptive benefits. In fish and reptiles, for example, colour variation from yellow to red can be produced by carotenoid and/or pteridine pigments, which differ dramatically in the way they are obtained (carotenoids through diet and pteridines synthesized de novo). Hence, potential adaptive benefits could differ greatly depending on the relative contribution to coloration of different pigments. In the present study, we investigate the mechanisms underlying colour variation in the frill of the Australian frillneck lizard (Sauropsida: Chlamydosaurus kingii). Frill colour varies between populations across the species’ range (red, orange, yellow or white). We argue that this geographical variation results from different concentrations of carotenoids and pteridines in the frill. Frill carotenoid concentrations were lower in eastern populations (yellow and white forms), and pteridines were present only in the red and orange forms, thereby explaining their redder hues. The observed geographical variation in frill carotenoids suggests variation in carotenoid availability across the species’ range, which is backed up by the finding that plasma carotenoid concentrations were higher in the red (western) compared to the yellow (eastern) form. Although no correlations were found between individual colour measurements, frill pigments and plasma carotenoids, our results suggest that selective pressures vary across the species’ range and we speculate that predation pressures and/or intrasexual signalling context differ between forms. The spectacular threat display of the savannah specialist Australo-Papuan frilled lizards has made them one of the world’s most iconic reptiles. They are increasingly used as a model system for research in evolutionary biology and ecology but little is known of their population structure. Their distribution across northern Australia and southern New Guinea also provides an opportunity to examine biogeographic patterns as they relate to the large-scale movement of savannah habitat during the Plio/Pleistocene and the associated increase in aridity. We generated sequence data for one mitochondrial and four nuclear DANN loci (5052 base pairs) for 83 frilled lizards sampled throughout their range. We also quantified body proportion variation for 279 individuals. Phylogenetic analyses based on maximum likelihood and Bayesian species-tree methods revealed three shallow clades that replace each other across the monsoon tropics. We found the expected pattern of male biased sexual size dimorphism in both maximum body size and head size but there was no sexual dimorphism in overall body shape or in frill size, relative to head size, supporting the hypothesis that the frill is used primarily as a threat display rather than a sexual display. The genetic clades are broadly consistent with known clinal variation in frill color that gradually shifts from west to east (red, orange, yellow/white) but otherwise show little morphological differentiation in body proportion measures. The biogeographic breaks between clades occur at the Carpentaria Gap and the lowlands surrounding the Ord River, and our ecological niche modeling predicts lower habitat suitability for C. kingii in these regions. While this biogeographic pattern is consistent with numerous other taxonomic groups in northern Australia, the overall low genetic diversity in frilled lizards across the entire monsoon tropics and southern New Guinea contrasts starkly to patterns seen in other terrestrial vertebrates. Extremely low intra-clade genetic diversity over vast geographic areas is indicative of recent gene flow that would likely have been facilitated by widespread savannah during interglacials, or alternatively may reflect population bottlenecks induced by extreme aridity during Pleistocene glacials. The shallow divergence between Australian and New Guinean samples is consistent with recent connectivity between Australia and New Guinea that would have been possible via a savannah corridor across the Torres Strait. Based on our molecular and morphological data, we do not support taxonomic recognition of any of the frilled lizard clades and instead consider C. kingii a single species with shallow phylogeographic structure and clinal variation in frill color. Abstract: Abstract: Inhalt: SHINE, R. & R. LAMBECK (1989): Ecology of frillneck lizards, Chlamydosaurus kingii (Agamidae), in tropical Australia. – Aust. Wildl. Res., 16: 491-500. Mitochondrial DNA (mtDNA) is the traditional workhorse for reconstructing evolutionary events. The frequent use of mtDNA in such analyses derives from the apparent simplicity of its inheritance: maternal and lacking bi-parental recombination. However, in hybrid zones, the reproductive barriers are often not completely developed, resulting in the breakdown of male mitochondrial elimination mechanisms, leading to leakage of paternal mitochondria and transient heteroplasmy, resulting in an increased possibility of recombination. Despite the widespread occurrence of heteroplasmy and the presence of the molecular machinery necessary for recombination, we know of no documented example of recombination of mtDNA in any terrestrial wild vertebrate population. By sequencing the entire mitochondrial genome (16 761 bp), we present evidence for mitochondrial recombination in the hybrid zone of two mitochondrial haplotypes in the Australian frillneck lizard (Chlamydosaurus kingii). By using both mitochondrial and nuclear multiloci markers, we explored population genetic structure, gene flow and sex-specific dispersal of frillneck lizards (Chlamydosaurus kingii) sampled at three locations, separated by 10 to 50 km, in a homogenous savannah woodland in tropical Australia. Apart from a recombinant lizard, the mitochondrial analyses revealed two nonoverlapping haplotypes/populations, while the nuclear markers showed that the frillneck lizards represented three separate clusters/populations. Due to the small population size of the mtDNA, fixation may occur via founder effects and/or drift. We therefore suggest that either of these two processes, or a combination of the two, are the most likely causes of the discordant results obtained from the mitochondrial and the nuclear markers. In contrast to the nonoverlapping mitochondrial haplotypes, in 12 out of 74 lizards, mixed nuclear genotypes were observed, hence revealing a limited nuclear gene flow. Although gene flow should ultimately result in a blending of the populations, we propose that the distinct nuclear population structure is maintained by frequent fires resulting in local bottlenecks, and concomitant spatial separation of the frillneck lizard populations. Limited mark–recapture data and the difference in distribution of the mitochondrial and nuclear markers suggest that the mixed nuclear genotypes were caused by juvenile male-biased dispersal. UJVÁRI, B., SHINE, R. & T. MADSEN (2011): Detecting the impact of invasive species on native fauna: cane toads (Bufo marinus), frillneck lizards (Chlamydosaurus kingii) and the importance of spatial replication. – Aust. Ecol., 36 (2): 126-130. An understanding of which native species are severely impacted by an anthropogenic change (such as the arrival of an invasive species) and which are not is critical to prioritizing conservation efforts. However, it is difficult to detect such impacts if the native taxa exhibit strong stochastic variations in abundance; a ‘natural’ population decline might be wrongly interpreted as an impact of the invader. Frillneck lizards (Chlamydosaurus kingii) are large iconic Australian agamids, and have been reported to decline following the invasion of toxic cane toads. We monitored three populations of the species in the savanna woodland of tropical Australia over a 7-year period bracketing toad arrival. One population crashed, one remained stable and one increased. Hence, studies on any single population might have inferred that cane toads have negative, negligible or positive effects on frillneck lizards. With the benefit of spatial replication, and in combination with observations of prey choice by captive lizards, our data suggest that invasive cane toads have had little or no effect on frillneck abundance. Here a prototype biomimetic robot is presented that imitates the shape and motion of a frilled lizard. The robot’s upper body posture can be controlled using the air resistance generated by the frill around the neck during running. Several experiments were conducted to determine the range of motion of the robot. A fan experiment showed that the robot could adjust the angle of the upper body at intervals of at least 5° to 10° up to 35°. The robot was able to control the angle of its upper body to an accuracy of about 1° while running. Thus, the robot controlled its upper body angle using the membrane around its neck. This is the first robot to use air to control the upper body posture. |
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