No description available.

The display repertoires of three sibling species of Anolis lizards, were quantitatively analyzed and described. These species are distributed along Haiti's western coast with no major geographic barriers separating their populations. Anolis websteri is the northernmost species, Anolis caudalis is centrally located, and Anolis brevirostris is the southernmost species. Except for contrasting dewlap color at the species contact zones, they are identical in physical appearance. Behavioral mechanisms have been implicated in the reproductive isolation of the species. Because the head bob displays consistently incorporate the dewlap and are important in anoline communication, they may be the focal point of this isolation. This study documents a species-unique display repertoire for each of the siblings and thereby supports this hypothesis. Analysis of 736 head bob displays revealed that each species possesses one stereotyped Type A display and one to three stereotyped B displays (A. caudalis, one; A. brevirostris, two; A. websteri, three). Each species' A display resembled that of its siblings, however, discriminant analysis procedure clearly discriminated between the three species' A displays. This procedure also demonstrated differences between the Type B displays. The six kinds of Type B displays in the combined repertoires were considered derived from one B display pattern. An interpretation of the evolutionary sequence of these patterns is provided in a cladogram in which the A. caudalis display was considered the outgroup. The cladogram shows the three displays of A. websteri are the most apomorphic and the two displays of A. brevirostris the most plesiomorphic. / Master of Science

A study of the lizard Sceloporus undulatus, conducted 1981-82 at an abandoned coal mine in Virginia, was designed to determine whether home range size, home range overlap, and patterns of behavior reflected the requirements of polygyny. The lizards were seen most often on the piles of debris that characterized the study site. Home range size was most strongly influenced by the debris pile size. Mean home range sizes (MCP, N≥5) were 69.3 m² and 59.9 m² for adult males and females, respectively, when data for all debris piles were pooled. The average overlap of home ranges for both study areas and for both years was 32% among adult females and 56% between adult males and females. No overlap among adult males was observed. Adult males usually associated with more than one female. Display frequency (push-ups) and total distance moved during 20 min observation periods were higher for adult males than adult females. Jiggling (rapid head nodding) was observed only in males. The frequencies of other behaviors (e. g. prey capture) did not differ between the sexes. Only one activity, substrate licking by males, seemed to decrease significantly as a function of date. Male home range owners interacted socially with females during the post-reproductive period. This behavior may increase a male's mating success the following spring, as most adult males that appeared on the study site during the mating season in 1982 had been home range owners in 1981. / M.S.

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: Thermal ecology is a central theme in reptilian biology because of the thermodynamic rate dependence of virtually all biological processes in these ectothermic animals. Thermoregulation includes active processes (with associated energetic costs related to altered behaviour and physiology) functioning to maintain body temperatures within a preferred temperature range, so that the majority of physiological functions occurs optimally, despite natural variation in the animal’s thermal habitat. The recent development of quantitative thermal indices now allows researchers to describe the thermal habitat and thermoregulatory functioning of an ectotherm within its environment from a cost-benefit perspective. The use of such quantitative biophysical approaches to reptile thermal ecology studies is however limited in the African context. Cordylus cataphractus is one of the best studied cordylids, and exhibits various characteristics atypical for the family, such as permanent group-living, seasonally lowered surface activity, a low resting metabolic rate and large fat bodies. These characteristics are generally thought to be associated with groupliving in a semi-arid habitat, yet, the possible links to thermal ecology remains unexplored. The objectives of the current study was: firstly, to characterize the preferred temperature range (Tp) of C. cataphractus through the use of ecologically realistic laboratory thermal gradients; secondly, to explore seasonal and geographical variation in thermal preference, by comparing Tp among individuals captured from a coastal and inland population and during different seasons (autumn and spring); thirdly, to describe the thermal habitat of a C. cataphractus population during summer, autumn, winter and spring and to then relate these findings to the seasonal activity patterns reported in literature for the species; fourthly, to describe the seasonal patterns of thermoregulation (during summer, autumn, winter and spring) in a C. cataphractus population through quantitative thermoregulatory indices; fifthly, to assess geographic variation in the thermal habitat and IV associated patterns of thermoregulation in C. cataphractus among a coastal population (western range limit) and an inland population (eastern range limit). The thermal habitat of C. cataphractus was described by measuring operative environmental temperatures (Te) with hollow copper lizard models placed around rocks according to the natural surface movement patterns of the species. Variation in thermal habitat quality was subsequently calculated (de = |Te – Tp|) and averaged. Field body temperatures (Tb) of lizards were measured with dorsally attached miniature temperature loggers. Thermoregulatory indices were calculated from Te, Tb and Tp, describing: thermoregulatory accuracy, the effectiveness of thermoregulation and thermal exploitation for each population (coastal and inland) for the respective sampling periods. The preferred body temperature range of C. cataphractus is the lowest recorded among cordylids to date (mean Tp = 29.8oC) and was conserved among different populations and within these populations among seasons, despite the fact that environmental temperatures are known to vary geographically and seasonally. Thermal habitat quality varied significantly at micro spatial scale around rocks in the coastal population. Since C. cataphractus males are territorial, competition for thermal habitat quality around rocks may therefore occur. Such effects will be a function of the time of year since the variability in thermal habitat quality among rock aspects (around rocks) varied seasonally. Thermal habitat quality of crevices varied among seasons and was typically higher in the open, outside rock crevices, during the cooler winter and spring periods, whereas in summer and autumn the crevice environments were more favourable. Thermal habitat quality was high in crevices during autumn, suggesting that the observed repressed surface activity of C. cataphractus described for the time is not necessarily, as previously thought, only due to food constraints. Moreover, in contrast to earlier reports, the current results (Tb versus Te) indicate that individuals emerged from crevices in summer. The geographical assessment indicated that lizards from the coastal population, with generally larger groups, thermoregulated more successfully than those from the inland population. The higher thermoregulatory success in the coastal population occurred in spite of the fact that thermal habitat quality was significantly lower at the coastal locality. The higher thermoregulatory success in the coastal population was likely due to reduced predation risk associated with increased group-size. The seasonal trends in thermoregulation at the coastal and inland population corresponded to the patterns predicted by the cost-benefit model of thermoregulation, accuracy of thermoregulation and the effectiveness of thermal exploitation being higher during the thermally more favourable autumn. / AFRIKAANSE OPSOMMING: Uittreksel Termiese ekologie is ‘n sentrale tema in reptiel-biologie as gevolg van die termodinamies tempo-afhanklikheid van feitlik alle biologiese prosesse in hierdie ektotermiese diere. Termoregulering sluit aktiewe prosesse (wat lei tot energie-koste in terme van gedrag en fisiologie) in om liggaamstemperature binne ‘n vasgestelde voorkeurtemperatuur-reeks te handhaaf sodat fisiologiese prosesse optimaal kan geskied te midde van natuurlike variasie in die dier se termiese omgewing. Die onlangse ontwikkeling van kwantitatiewe funksionele termiese indekse stel navorsers nou in staat om die werklike termiese omgewing en die funksionering van die ektoterm binne sy omgewing te beskryf en uit ‘n koste (energie)- voordeel oogpunt te verstaan. Die gebruik van hierdie biofisiese koste-voordeel benadering in reptiel termoreguleringstudies is egter beperk in die Afrika-konteks. Cordylus cataphractus is een van die bes bestudeerde lede van familie Cordylidae, en vertoon verskeie eienskappe ongewoon vir hierdie groep akkedisse, soos groeplewendheid, beperkte seisoenale aktiwiteit buite hul skeure, ‘n relatiewe lae rustende metaboliese tempo en relatiewe groot vetliggame. Hierdie unieke eienskappe is al deur navorsers gekoppel aan die groeplewe lewensstrategie. Die potensiële koppeling van die termiese ekologie en die spesifieke lewensstrategie van C. cataphractus benodig verdere studie. Die doelwitte van hierdie studie was eerstens: om die voorkeurtemperatuur-reeks (Tp) van C. cataphractus te bepaal deur van ekologies-realistiese termiese gradiënte in die laboratorium gebruik te maak; tweedens: om geografiese en seisoenale variasie in Tp te ondersoek deur individue te gebruik wat uit binnelandse en kus-populasies, tydens verskillende seisoene, herfs en lente versamel is; derdens: om die termiese omgewing, meer spesifiek die variasie in termiese kwaliteit, binne die habitat van C. cataphractus populasie in verskillende seisoene, somer, herfs, winter en lente, te moduleer en met die gedokumenteerde aktiwiteitspatrone in verband te bring; vierdens: om die seisoenale temoreguleringspatrone (tydens somer, herfs, winter en lente) van C. cataphractus populasie te beskryf; vyfdens: om geografiese variasie in die termiese habitat en geassosieerde termoreguleringspatrone tussen kus-populasie (westelike VII verspreidingsgrens) en binneland-populasie (oostelike verspreidingsgrens) te bestudeer. Die kwaliteit van die termiese habitat van C. cataphractus is bepaal deur hol koper-modelle van akkedisse (operatiewe temperatuur modelle (Te)) te plaas rondom rotse in ooreenstemming met die natuurlike bewegingspatrone van die akkedisse. Die termiese kwaliteit is gevolglik afgelei (de = |Te – Tp|) en gemiddeldes bereken. Die liggaamstemperature (Tb) van vrylopende akkedisse in die veld is met dorsaal-gemonteerde miniatuur temperatuur “data-loggers” gemeet. Termiese indekse (deur Te, Tb en Tp te gebruik) is bereken om die akkuraatheid en effektiwiteit van termoregulering, sowel as termiese benutting van die omgewing vir beide populasies (kus en binneland) tydens verskillende seisoene te beraam. Die voorkeurtemperatuur-reeks van C. cataphractus is die laagste gedokumenteerde temperature vir enige lid van die familie Cordylidae tot op hede bestudeer (gemiddeld van Tp = 29.8oC), en het ten spyte van die feit dat omgewingstemperature wissel op geografiese en seisoenale vlakke, min gevarieer tussen die twee populasies asook tydens verskillende seisoene binne die populasies. Die termiese kwaliteit het beduidend gevarieer tussen seisoene en binne die mikroruimtelike omgewing rondom rotse in die kus-populasie. Aangesien C. cataphractus mannetjies territoriaal is, word die aanname gemaak dat kompetisie vir ‘n ruimtelike posisie ook ‘n termiese koste mag hê aangesien daar beduidende variasie in de om die rotse was. Variasie in termiese kwaliteit rondom rotse was verder ook funksie van die tyd van die jaar (seisoene). Die termiese kwaliteit van skeure het gevarieer tussen seisoene, en termiese kondisies/toestande was oor die algemeen meer gunstig buite die rots-skeure tydens die koeler winter en lente tydperke, terwyl skeure termies meer gunstig was in die somer en herfs maande. Termiese habitat kwaliteit van skeure was besonders hoog gedurende die herfs, en die voorspelling is dus dat die verlaagde oppervlak-aktiwiteit wat gedurende hierdie tyd van die jaar vir C. cataphractus gedokumenteer is nie noodwendig funksie van beperkte voedselbeskikbaarheid is nie. Teenstrydig met gepubliseerde aktiwiteitsrekords dui die resultate (Tb teenoor Te) verder daarop dat individue wel uit skeure kom tydens die warm somer seisoen. Die geografiese ondersoek het gewys dat akkedisse van die kus-populasie (wat gewoonlik uit groter groepe bestaan), meer akkuraat getermoreguleer het as akkedisse van die binneland-populasie. Die hoër akkuraatheid van termoregulering in die kus-populasie is bewerkstellig ten spyte van die feit dat die termiese kwaliteit beduidend laer was as die van die binneland-populasie. Die hoër termoreguleringsakkuraatheid in die kus-populasie kan waarskynlik toegeskryf word aan laer predasie-risiko geassosieer met groter groepe. Die seisoenale variasie-patroon van termoregulering kan verklaar word deur die koste-voordeel model van termoregulering, waarvolgens die akkuraatheid van termoregulering sowel as termiese benutting hoër is tydens periodes van hoë termiese kwaliteit (i.e. herfs).

South Africa is well known for its many, important fossil bearing deposits of Plio-Pleistocene age. Many of these sites contain abundant remains of extinct and extant animals including hominins. Non-herpetological fauna have been used to reconstruct important information about past environments and for chronological data. This study tried a different method; using herpefauna to establish past environments of Cooper’s Cave. Herpetological fauna potentially have numerous advantages in their use for such questions, including typically limited ranging behaviors, and specific temperature requirements. Despite these advantages only a few studies have even mentioned the presence of squamate fauna in the fossil assemblages of these sites. This study has demonstrated that herpefauna exists, in reasonable levels of abundance and with adequate preservation within the fossil record of the dolomitic region now known as the Cradle of Humankind. It has also demonstrated for the first time the presence of a relative abundance of herpefauna at numbers far greater than any previous study has recognized. The present study was however, handicapped in not being able to fully utilize the material at hand to interpret past environments, owing to the lack of comparative material needed to move beyond the family or generic level in most cases with any degree of confidence. However, Agamids and Pseudocordylids were described to generic level. However, the many shortcomings that this work highlighted should not be seen as reason not to pursue the study of herpefauna, but to improve present comparative collections and collecting methods around the fossils themselves.

Learning in reptiles has been studied with a variety of methods and included numerous species. However, research on learning in lizards has generally focused on spatial memory and has used only a few species. No research has specifically investigated and documented the use of visual discrimination in monitor lizards. The ability of monitor lizards (Varanus spp.) to discriminate between visual stimuli was investigated. Subjects were tested on acquisition and two reversals of a discrimination task between black and white stimuli. A food-choice procedure was used to determine if consistent rankings of food items could be determined using a multiple-stimulus choice procedure. The functional value of the rankings was assessed using a progressive ratio technique. The subjects formed stable food preferences, which were reflected in increased response requirement completed for preferred items and subjects did successfully learn the initial discrimination task and the following reversals.

This research project examined the role of environmental time cues and circadian rhythms in mediating seasonal adjustments in the body temperature and locomotoractivity patterns in the Australian sleepy lizard, Tiliqua rugosa (Gray 1827). The first component of this study investigated whether daily rhythms of behavioural thermoregulation and locomotor activity that T. rugosa displays in the field are endogenous circadian rhythms. In each season, there was significant variation in each of these rhythms in lizards released on laboratory thermal gradients under prevailing light-dark (LD) cycles. Both rhythms persisted when lizards were released in constant darkness (DD) and exhibited the same free-running period suggesting a single circadian pacemaker drives both rhythms. The first component of this study revealed that seasonal changes in the expression of daily behavioural thermoregulatory and locomotor activity rhythms are mediated by the circadian system in T. rugosa. The second component of this project comprised three experiments that determined the relative importance of 24 h LD and temperature cycles (TCs) in entraining the locomotor activity rhythm. In the first experiment, lizards were held under LD 12:12 and were subjected to either a TC of 33:15C in phase with the LD cycle or a reversed TC. Following LD 12:12, lizards were maintained under the same TCs but were subjected to DD. Activity was restricted to the thermophase in LD irrespective of the lighting regime and during the period of DD that followed, suggesting entrainment by the TC. In the second experiment, lizards were held under LD 12.5:11.5 and were subjected to one of three treatments; (1) constant 30C, (2) normal TC (30:20C), or (3) reversed TC. Following LD, all lizards were subjected to DD and constant 30C. Post-entrainment free-run records revealed that LD cycles and TCs both entrain locomotor activity rhythms of T. rugosa. Although there was large variation in the phasing of the rhythm in relation to the LD cycle in reversed TC lizards, TCs presented in phase with the LD cycle most accurately synchronised the rhythm to the photocycle. In the third experiment, lizards were held in DD at constant 30C before being subjected to a further period of DD and one of four treatments; (1) normal TC (06:00 h to 18:00 h thermophase), (2) delayed TC (12:00 h to 00:00 h thermophase), (3) advanced TC (00:00 h to 12:00 h thermophase) or (4) control (no TC, constant 30C). While control lizards continued to free-run in DD at constant temperature, locomotor rhythms of lizards subjected to TCs rapidly entrained to TCs irrespective of whether TCs were phase advanced or delayed by 6 h. The results of this experiment excluded the possibility that masking effects were responsible for locomotor responses of lizards to TCs. This study demonstrated that seasonal changes in the expression of this species‟ daily behavioural thermoregulatory and locomotor rhythms are mediated by a circadian system that is sensitive to both light and temperature. The sensitivity of the circadian system to temperature, in particular, may allow T. rugosa to restrict its activity to times of the year that are thermally favourable. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1521959 / Thesis(Ph.D.)-- University of Adelaide, School of Medical Sciences, 2010

Thesis (Env. Mgt.(Hons.))--University of Adelaide, Dept. of Environmental Science and Management, 1998. / Bibliography: leaves 52-58.

The thermal environment exerts a strong influence on many aspectsof squamate life history. Environmental temperatures constrain daily activity time, fecundity, growth rate, and also influences hatchling phenotype. Cold nest temperatures can slow the development of eggs deposited in the soil, cause developmental abnormalities or result in mortality of embryos.

Thesis (MSc)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: An understanding of the phylogeography and evolutionary processes involved in speciation is essential for the conservation and management of any particular species. To investigate the phylogeographic patterns in Agama atra from the Cape Fold Mountains (CFM), 98 individuals from 38 geographically close localities were analysed. In addition, to understand the phylogeographic associations between the CFM populations and the rest of Southern Africa, 18 specimens from 12 localities outside the CFM were also included. A total of 988 characters derived from two mitochondrial DNA fragments (control region and ND2) revealed 59 distinct haplotypes in the CFM. Parsimony, Bayesian and maximum likelihood analyses revealed four distinct clades associated with geography within the CFM. These clades were supported by a haplotype network and were defined as the Cape Peninsula clade, the Limietberg clade, the northern CFM clade and the central CFM clade. Analysis of molecular variance confirmed the high degree of genetic structure within the CFM, with more than 75% of genetic variation found among the geographic areas. SAMOVA and nested clade analysis (NCA) suggest that the central CFM clade may be more diverse than detected by the networks and the phylogenetic analyses. The processes that caused the four distinct genetic groups in the CFM are not yet clear. Using a speculative molecular clock estimate, the main cladogenesis of A. atra within the CFM took place, approximately ~6.5 - 9 MYA. This dating coincides well with the documented Miocene-Pliocene climate fluctuations which might have contributed towards the isolation among lineages. The genetic structure found in A. atra is also markedly congruent with what has been found in other taxa such as Mesamphisopus spesies, Potamonautes brincki, and Pedioplanis burchelli and this would further support vicariance as a main isolating factor here. / AFRIKAANSE OPSOMMING: ‘n Goeie begrip van die filogeografie en die evolusionêre gebeurtenisse wat verband hou met spesiasie is belangrik vir die bewaring en bestuur van enige spesie. Om die filogeografiese patrone in Agama atra van die Kaapse Plooiberge (KPB) te ontleed, was 98 individue van 38 nabygeleë lokaliteite geanaliseer. Tesame met bogenoemde monsters was 18 individue van 12 lokaliteite van buite die KPB ook geanaliseer om die filogeografiese verwantskappe tussen die KPB bevolkings en die res van Suidelike Afrika te ondersoek. Uit ‘n totaal van 988 karakters verkry uit twee mitochondriale DNS fragmente (die kontrole gebied en ND2) is 59 haplotipes gevind. Parsimonie en modelgebaseerde filogenetiese analises dui daarop dat vier groepe geassosieer met geografie binne die KPB voorkom. Die groepe word geondersteun deur ‘n haplotipe netwerk en word soos volg gedefinieer: ‘n Kaapse Peninsula groep, ‘n Limietberg groep, ‘n noordelike KPB groep en ‘n sentrale KPB groep. Analises van molekulêre variansie (AMOVA) bevestig die hoë graad van genetiese struktuur binne die KPB, met meer as 75% genetiese variasie gevind tussen die geografiese areas. SAMOVA en gesetelde groep analises (“NCA”) stel voor dat die sentrale KPB groep dalk meer variasie vertoon as wat die netwerk en filogenetiese analises vertoon. Die prosesse wat die vier genetiese groepe tot stand gebring het is nog nie bekend nie. Volgens ‘n spekulatiewe molekulêre klok berekening het die hoof kladogenese van A. atra binne die KPB ongeveer ~6.5 - 9 miljoen jaar (MJ) gelede plaasgevind. Hierdie datering stem goed ooreen met die gedokumenteerde Mioseen-Plioseen klimaat veranderinge wat isolasie van die groepe kon bewerkstellig het. Die genetiese struktuur van A. atra in the KPB is ook gevind in ander taksa soos Mesamphisopus spesies, Potamonautes brincki, en Pedioplanis burchelli en bevestig dus dat vikariansie hier die hoof faktor vir isolasie is.