Academic literature on the topic 'Tiliqua Rugosa'

We examined whether Australian varanids as a group are more aerobic than other lizards. The standard metabolic rate (SMR) and maximal oxygen consumption (V-O2max) were measured for four species of varanid lizards and the skink Tiliqua rugosa at 35 degrees C. These were compared to each other and to the V-O2max of the iguanid lizard Cyclura nubila by analysis of covariance with body mass as a covariate. There were no differences with respect to SMR, but the V-O2max of the lizards fell into three groups: Varanus rosenbergi, V. gouldii and V. panoptes had higher aerobic capacities than V. mertensi and Cyclura nubila, and Tiliqua rugosa had a V-O2max lower than the other species. There is no simple relationship between V-O2max and the time these lizards spend in natural activity. The summer SMRs of V. rosenbergi and T. rugosa were significantly higher than during other seasons. The V-O2max of V. rosenbergi was higher in summer than in other seasons, but T. rugosa showed no seasonal differences in V-O2max. These results indicate that the SMRs of the varanids were similar to those of other lizards, and, despite generalisations in the literature, not all varanid lizards have high aerobic capacities. Varanid lizards may be as physiologically diverse as other lizard families.

We report the development of 48 anonymous nuclear loci from the Australian skink Tiliqua rugosa using 454 sequencing. These loci amplified across a Western Australian lineage (47 loci), a ‘northern’ lineage (48 loci) and a ‘southern’ lineage (46 loci). We further tested amplification for the related T. adelaidensis and Egernia stokesii where 37 and 34 loci amplified respectively. The loci showed variability within T. rugosa (22 polymorphic loci) and at least 27 loci also exhibited variation among the three species, highlighting the usefulness of these markers for phylogenetic, phylogeographic and population genetic analyses in T. rugosa and related species.

Nonmammalian vertebrates possess some unusual features in their hormonal systems/ when compared to mammals. As a consequence, they can make an important contribution in investigations concerning the fundamental mechanisms operating in endocrinology. Such studies concerning androgens include inter alia their effects on developmental aspects in the brain of birds and related singing behaviour; the role of neural enzymes in reproductive processes in fish; and the relation between androgens and the stages of spermatogenesis in amphibia, The present thesis examines the biochemistry of androgens in the Australian lizard Tiliqua rugosa. The major compounds studied were testosterone and epitestosterone, which are known to be present in high concentrations in the plasma of the male animal. Previous investigations are expanded, particularly in the areas of steroid identification and testicular biosynthesis. In addition, preliminary studies on the metabolism in the brain (and other tissues) and plasma protein binding are reported. The presence of epitestosterone as a major free androgen in the plasma of the male lizard was confirmed. Other steroids were found in the sulphate fraction. Testosterone sulphate was the most rigorously identified compound, while some evidence was also found for the presence of conjugated 5-androstene-3β,17-diols, etiocholanolone and dehydroepiandrosterone (DHA). Epitestosterone does not appear to be extensively conjugated in this animal. Steroids were not found to be conjugated as glucuronides. The identification studies employed a novel method of electrochemical detection of steroids. This technique was investigated and extended in the current thesis. Biosynthetic studies were carried out on androgen interconversions in the testis, in vitro. The major enzyme activities detected were 17α-arid 17β-oxidoreductases (17α-OR and l7β-OR) and 3β-hydroxysteroid dehydrogenase (3β-HSD)/isonerase. No evidence was found for the presence of a steroid-17-epimerase that would directly interconvert testosterone and epitestosterone. The 17-oxidoreductases were found to be dependent on the cofactor NBDFH. Testosterone appears to be formed mainly via the 4-ene pathway, whereas epitestosterone is formed from both the 4- and 5-ene routes. The compound 5-androstene-3β, 17α-diol was found to be an intermediate in the synthesis of epitestosterone from DHA. Temperature was found to significantly affect 17α-OR activity (maximum at 32°C). In contrast,17β-OR activity was independent of this factor in the testis. Androgen metabolism in the testis was found to be regulated by cofactors, temperature and season. The major enzyme activities found in the male brain were 17α- and 17β-OR. 3βHSD/isomerase was not found; however a low activity of 5α-reductase was identified. Aromatase activity was not positively identified, but preliminary results suggest that it may be present at low levels. The 17-oxidoreductases were widespread throughout the brain. The 17α-OR was significantly lower in the forebrain than other brain sections. The 170-OR activity did not vary significantly throughout the organ, although there was a trend for its activity to be higher in the midbrain region (containing the hypothalamus in these sections). The concentration of endogenous steroids in brain tissue was estimated by radioimmunoassay. Epitestosterone was found throughout the organ structure, whereas testosterone was found mainly in the midbrain (containing hypothalamic regions in these sections). Correlations between enzyme activities and steroid concentrations in brain regions suggested that the main function of 17α-OR is to produce epitestosterone, whereas the 17β-OR may catalyse a more reversible reaction in vivo. Temperature was found to significantly affect both 17α- and 17β-OR activities in the brain. In contrast to the testis, the maximum activity of the brain enzymes occurred at 37°C. The level of 17α-OR activity in the male lizard (100 nmol/g tissue/h) is the highest reported for this enzyme in vertebrates. Both activities were found to be quantitatively similar in the whole brain homogenates of male and female animals, and did not vary seasonally when examined in the male. The 17-oxidoreductases were also found in most other tissues in T.rugosa, including epididymis, adrenal, kidney and liver (but not blood). This suggests that the high activities of both 17α-OR and 17β-OR are dominant features of the steroid system in this animal. The formation of 11-oxygenated compounds was found in the adrenal, in addition to the formation of polar metabolites in the kidney and liver (possibly polyhydroxylated and conjugated steroids). A preliminary investigation into the plasma binding of androgens was carried out. The insults suggest that there are several binding sites for testosterone; one with high affinity and low capacity; the other with low affinity and high capacity. Binding experiments were carried out at 32°C. At this temperature, specific binding was greater than at 25 or 37°C. From the results of competition studies it was suggested that epitestosterone (with a K(i)= 3 X 10 (-6)M for testosterone binding) regulates the binding of testosterone (K(i)=10(-7)M) and hence the concentrations of the latter steroid as a free compound in plasma. In general, the study has shown that the biochemistry of androgens in the reptile T.rugosa is largely similar to that found in other vertebrates. The major difference is a greatly increased activity of 17α-OR, which causes a higher concentration of 17α-compounds to be present in the tissues of this lizard. The physiological roles for epitestosterone are not yet clear. However it appears from this study that this steroid regulates testosterone concentrations in several tissues by either steroidogenic or binding mechanisms. Several major influences on this regulation include temperature, availability of cofactors and seasonal effects.

Ticks are haematophagous arthropods and major vectors of pathogenic microorganisms. In Australia, over 74 species of ticks have been described, of which 13 are known to parasitise reptiles. While only three tick borne diseases are formally recognised, Rickettsia honei, the causative agent of Flinders Island spotted fever, has been long associated with the reptile tick, Bothriocroton hydrosauri, despite this tick rarely reported to parasitise people. More recently, a novel Rickettsia species, Rickettsia gravesii, was reported in the ornate kangaroo tick (a common human biting tick), Amblyomma triguttatum, on Barrow Island in Western Australia. In addition, a number of overseas tick-associated microbes (taxa of interest) have been identified in Australian human-biting ticks using an advanced molecular technique, next generation sequencing (NGS). Therefore, the aims of this study were to morphologically and molecularly identify ticks that parasitise reptiles, specifically the bobtail lizard, Tiliqua rugosa, and to employ NGS to profile the bacterial 16S rRNA gene (16S) within the ticks. The taxa identified would then be phylogenetically compared to known taxa of interest. A total of 306 ticks from Western Australia were morphologically identified and 30 were removed from the data set and the remaining 276 included all developmental stages comprising males 43.1% (n=119); nymphs 40.6% (n=112); females 15.2% (n=42) and three larvae (1.1%). Using Australian-specific morphological keys, ticks were identified as A. albolimbatum. To provide more accurate species identification, molecular barcoding of the cytochrome C oxidase 1 (CO1) gene was employed on 17 nymphal and two larval ticks, along with Northern and Southern WA A. albolimbatum ticks as representative specimens. However, only one nymph (5.8%) and two larvae (100%) generated clean chromatograms and all were identified as A. albolimbatum; the two larvae were genetically identical to the Southern representative sample and the nymph more genetically similar to the Northern representative sample (0.48% genetic difference). The genetic distance between the two A. albolimbatum sequences was 4.79%. A total of 116 ticks and six controls were processed for 16S metabarcoding to profile the bacterial communities. A total of 9,706,920 reads were generated using an Illumina V3 600 cycle run on the MiSeq platform. A final quality filtered data set consisted of 4,823,227 reads, with a total of 1,385 zero operational taxonomic units (ZOTUs) generated. The bacterial diversity of the ticks was observed to be statistically different between life stage, with males exhibiting the highest diversity. The bacterial microbiome of the tick samples was dominated by the phylum Proteobacteria (90.94%) and also included Actinobacteria (3.81%) and Firmicutes (3.71%). Interestingly, orders Rickettsiales and Legionellales, which contain known taxa of interest, were identified. BLAST analysis of ZOTUs associated with taxa of interest revealed the most abundant ZOTU as Rickettsia endosymbiont (100% similarity; GenBank accession MK00580); ZOTU2 was 99% genetically similar to Francisella hispaniensis (GenBank accession KT28184); while ZOTU10 and ZOTU19 were most closely related to a Spotted Fever Rickettsia raoultii (99.7% similarity; GenBank accession MK30454) and Coxiella burnetii (100% similarity; GenBank accession LC464975), respectively. Importantly, while R. raoultii does not exist in Australia, literature supports that species delimitation for Rickettsia cannot be based on 16S alone and requires a multi-loci approach. Therefore, the Rickettsia identified in this study may in fact represent a novel endemic species. However, the presence of C. burnetii is intriguing and represents the first evidence within A. albolimbatum ticks supported by phylogenetic analysis. While ticks are rarely implemented in the zoonotic transmission of C burnetii, further research is required to investigate the vector competency of this tick and to determine if reptiles, particularly T. rugosa, are viable reservoirs for this bacterium and determine if reptiles pose a risk to wildlife carers. Overall, this study provides new molecular data for A. albolimbatum and requires further research to investigate the validity of the Northern and Southern morphotypes identified. Furthermore, for the first time in Australia, this study presents the bacterial communities within the bobtail tick, A. albolimbatum, and showcases a rich diversity of microbes, including endosymbionts and known tick-associated pathogens.

Australia’s native reptile, the Shingleback lizard (Tiliqua rugosa) is under threat from a variety of causes including a newly discovered Nidovirus(1). This flu has caused an influx of Shinglebacks into rehabilitation centres, demonstrating upper respiratory tract infections (URTI). Therefore, understanding other factors that can impact on the progression of this infection is extremely important for the conservation of the Shingleback lizard population. Such factors include the effects of co-infections, which are composed of two or more pathogens working synergistically or antagonistically against each other. Interactions seen in co-infections tend to cause enhancement of pathogenesis(3). In this study we investigated the association between gastro-intestinal (GI) parasites and the Nidovirus within the Tiliqua rugosa population. The main aims and hypothesis of this study is to investigate if any association exists between the abundance and diversity of individual parasitic loads, with the presence/absence of the novel Tiliqua rugosa Nidovirus. This will be completed by three objectives, (i) obtaining baseline data on the prevalence of infection, (ii) confirming the proportion of animals infected by coinfections and (iii) examine any possible relationship seen in co-infected Shingleback lizards. Samples were collected from Shingleback lizards entering Native ARC Rehabilitation Centre and Kanyana Wildlife Rehabilitation Centre. Oral swabs were taken for virology analysis which was completed through polymerase chain reaction (PCR) technology. Faecal samples were collected when naturally produced and were analysed at Murdoch University laboratories, through malachite stained faecal smear(4) and zinc sulphate faecal flotation techniques(5). There were three main findings from this study. First, prevalence of infection was relatively high, with 73 % of Shinglebacks infected with at least one species of gastro-intestinal parasite and 58.1% of Shinglebacks infected with the T. rugosa Nidovirus. Secondly, co-infections with gastro-intestinal parasites and Nidovirus were common; 48.4% of Shinglebacks carried both parasitic and viral infections, while 26% had only parasitic infections and 9% had only viral infections. Finally, evidence was found corroborating my initial hypothesis that the major clinical signs of viral infection, discharge from the eyes or nose, were enhanced in Shinglebacks which were co-infected with the virus and gastro-intestinal parasites. This study suggests that the Nidovirus seen in the Tiliqua rugosa population is part of the multi dynamic route of disease seen in reptiles(6), in particular an emerging pattern between co infection with GI parasites suggest synergistic interaction may be a possible factor in the progression of pathogenesis in this viral infection. Therefore, possible immunological enhancement of the virus or/and the parasites may be seen within an individual host. It is not clear yet if this enhancement of infection is caused due to the immunosuppressive characteristics of the virus or due to high parasitic abundance causing immunological stress on the hosts. This is the first comprehensive study of gastrointestinal parasitism in wild populations of Tiliqua rugosa and the first study of co-infections of gastro-intestinal parasites and Nidovirus. This paper will allow a clearer understanding of natural co-infections, synergistic and/or antagonistic relations between pathogens and the potential cause of pathogenesis.

Bobtail lizards (Tiliqua rugosa) are native to Western Australia. Haematological evaluation is useful for health assessment: the only previous study of the haematology of this species sampled just six lizards (Canfield and Shea, 1988). The main aim of this study was to produce reference intervals for bobtail haematology. Over the summers of 2011/12 and 2012/13, heparinised venous blood was collected from 46 clinically healthy, captive adult bobtails in Perth. Complete blood counts and blood smear evaluations were performed. Cytochemical stains, transmission electron microscopy, and bone marrow cytology and histology facilitated further characterisation of the blood cells. Reference intervals with 90% confidence intervals were determined using Reference Value Advisor freeware (Geffré et al., 2011). The packed cell volume (PCV) was 0.10-0.44L/L (n=40). Total plasma protein by refractometry was 36-74g/L (n=39). Haemoglobin was 20-154g/L (n=32). The manual red and white blood cell counts were 0.28-1.03x1012/L (n=38) and 2.75-30.76 x109/L (n=39), respectively. Blood cell morphology was similar to that of other lizards - except the eosinophils which were uniformly vacuolated. A 200 cell leukocyte differential count was performed on each smear (n=46). Heterophils predominated (27-88%), with fewer lymphocytes (0-34%) and monocytes (1-27%), occasional eosinophils (0-22%) and basophils (0-20%). Thrombocytes were frequently clumped or present as bare nuclei. Slight polychromasia (0-7%) was typically present (n=45). Many reference intervals were wide, particularly PCV, haemoglobin and white blood cell count. This was not unexpected as reptile haematology is influenced by many preanalytical factors. Smears from 13 bobtails contained haemogregarine parasites, identified as probable Hemolivia species. There was evidence that this infection caused mild erythrocyte pathology. The reference intervals were applied to the haematology of seven bobtails hospitalised with upper respiratory tract disease. Six bobtails possessed haematological evidence of inflammation. Thus the reference intervals appear to be clinically useful for the haematological assessment of captive bobtail lizards.

Bobtail lizards, Tiliqua rugosa, have been studied extensively in South Australia, with the majority of studies focusing on the population near Mt Mary. There is a substantial lack of literature from other localities, including Perth, Western Australia, as well as on the impact urbanization is having on this species. This study aimed to gain an insight on the spatial ecology and habitat use of bobtails local to the Perth region. Lizards held small home ranges (mean 1.4ha) that did not differ between urban and peri-urban locations. There was no significant correlation between home range size and remnant bushland patch size nor were there any associations between home range and lizard morphometrics. Home range did overlap between individuals inhabiting the same reserve. Several lizards were preferentially selecting microhabitat composition at locations where they were observed inactive and using these habitat as a refuge. However there was not one particular variable that was responsible for this significant difference but cover at several levels; namely leaf litter, canopy, low shrub, and grass trees were important. This represents their flexibility in utilizing a range of different microhabitat structures, both for refuge and when active. The bobtail lizards were recorded reaching their optimum body temperature between 12pm to 3pm for most of the year regardless of the season. Flexibility in microhabitat use as well as their ability to maintain small home ranges while rarely moving beyond the bushland patch boundary is likely why they are adapted to urban living. Due to their flexibility and ability to maintain their home range within small reserves it is important to ensure a variety of vegetation and habitat structures are available for the lizards to seek shelter under. Given that the lizards were rarely moving outside of their reserve boundaries, in order to prevent them crossing roads and potentially getting struck by cars, leaving a border around the edge of the reserve with no vegetation to encourage them to stay with the sheltered reserve.

The present study examined the home range and microhabitat selection by Tiliqua rugosa and Egernia napoleonis in the jarrah forest of southwest Western Australia. The aim of the study was to compare the microhabitats used by T. rugosa with the microhabitats used by E. napoleonis and discuss why T. rugosa was located in rehabilitated bauxite mined areas, whereas E. napoleonis was not. The overall objective of the present study was to identify methods which may be incorporated into the management of rehabilitated bauxite mined areas operated by Alcoa World Alumina Australia, to accelerate the return of T. rugosa and E. napoleonis. A total of five Tiliqua rugosa and eight Egernia napoleonis were radio tracked from October 2005 until January 2006. The 100% home range average of T. rugosa was significantly larger than that of E. napoleonis. There was no significant difference in 50% Core home range average between the two species. The home range of T. rugosa was made up of native jarrah forest and rehabilitated mined areas. E. napoleonis were only found in native jarrah forest. The microhabitats significantly selected by Tiliqua rugosa in the native jarrah forest and rehabilitated mined areas were shrubs and leaf litter. In the native jarrah forest spikey and dome-shaped shrubs were significantly selected, but when in the rehabilitated mined areas spikey shrubs were significantly selected, which was probably due to the scarcity of dome-shaped shrubs in the rehabilitated areas. The selected microhabitats of Egernia napoleonis were logs and trees. The Eucalyptus marginata logs selected by Egernia napoleonis had a mean diameter of 42 ± 2lcm, whilst the Corymbia calophylla logs had a mean diameter of 48 ± 6cm. E. napoleonis did not differentiate between tree species of log. Common characteristics of logs selected by E. napoleonis were the presence of cracks, hollows, and some degree of fire damage. In the present study no logs were located in rehabilitated mined areas. The trees selected by Egernia napoleonis were significantly larger than a random selection of those found in native jarrah forest or those found in rehabilitated mined areas. Eucalyptus marginata selected by E. napoleonis had an average diameter at breast height of 73 ± 16cm whilst Corymbia calophylla had an average diameter at breast height of 58± 15cm. Species of tree were not differentiated by E. napoleonis. Both microhabitat structures (logs and large trees) selected by Egernia napoleonis were unable to be located in rehabilitated mined areas. The spikey shrubs and leaf litter microhabitats selected by Tiliqua rugosa were present in native jarrah forest and rehabilitated mined areas. The present study has shown that a lack of suitable microhabitats was reducing the occurrence of E. napoleonis in rehabilitated mined areas. Methods to help rectify this problem are discussed.

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Includes bibliographies.
3 v. : ill. ; 30 cm.
The aim of this thesis is to provide a comprehensive study of the cytology, innervation and blood supply of the pineal complex in Tiliqua rugosa, a large desert dwelling skink (family: Scincidae), commonly known as the sleepy or stumpy-tailed lizard. The study complements the physiological work already reported and expands the knowledge of the epithalamic region in lizards. Various histological techniques, at both light and electron microscopic levels, are utilised.
Thesis (Ph.D.)--University of Adelaide, Dept. of Anatomy and Histology, 1997