Long‐distance geneflow and habitat specificity of the rock‐dwelling coppertail skink,Ctenotus taeniolatus

Rock boulders or ‘bush‐rocks’ provide essential habitat for many organisms and there has been interest in rehabilitating areas denuded of rock with artificial substitutes. We examine whether the density and size of bush rock influences the density of the coppertail skink (Ctenotus taeniolatus). The success of habitat rehabilitation is contingent on dispersal of rock‐dwelling organisms into areas that have been remediated. To gauge the likelihood of this we characterize geneflow of coppertail skinks among discrete patches of rocky habitat associated with ridge tops. We genotyped 154 individuals from seven localities at six microsatellite DNA loci and from a subset of these individuals we obtained sequence data from the mitochondrial ND4 region. Our field survey established that lizard density was positively associated with the availability of suitably sized bush‐rock (P < 0.001), highlighting the importance of maintaining this habitat element, or replacing it where it has been lost. Despite the presence of habitat features that might be presumed as barriers to dispersal for coppertail skinks, such as intervening gullies and dense vegetation, our genetic data demonstrated high levels of geneflow among rocky ridge tops. Levels of partitioning estimated by global F_ST were significant but low for both microsatellite (F_ST = 0.020) and mitochondrial data (F_ST = 0.113). Spatial autocorrelation of genotypic similarity supports our conclusion of regular longer‐distance geneflow, and we infer lower levels of dispersal in juveniles than in adults. This study suggests that dispersal of coppertail skinks can be sufficient to naturally colonize areas of restored habitat.     

Food and foraging behaviour of the lizard,Ctenotus taeniolatus

A sample of 261 Ctenotus taeniolatus revealed that this species of skink is principally insectivorous, the most common foods being lepidopteran and coleopteran larvae, orthopterans and formicids. The occurrence of these foods in the diet followed seasonal patterns. The prey of adults and juveniles did not differ qualitatively, although adults were capable of eating a greater diversity of prey sizes than juveniles. Lizards used both sit-and-wait and active foraging strategies, with adults and juveniles exhibiting these behaviours in different ratios.     

Recolonization of regenerating open forest by terrestrial lizards following sand mining

The terrestrial lizard fauna of a regenerating mining path situated in open forest on coastal sand dunes was surveyed by pitfall trapping. The regeneration age of the series of chronosequence plots used ranged from 3.9 to 15.9 years. No lizards were recorded on plots less than 5.9 years old. Only four species of lizard were regularly found on the mining path. The skink Ctenotus robustus was the first colonizer and attained peak abundance and biomass after 9 years’ regeneration. Amphibolurus muricatus and Ctenotus taeniolatus were less abundant than C. robustus and did not appear on the mining path until 9 to 11 years’ regeneration. The abundance of C. taeniolatus continued to increase up to the oldest age class (16 years). Linear multiple regression analysis showed that sparse patchy vegetation in the 0–1 m layer and the amount of live shrub cover jointly accounted for 72% of the variance in abundance and 68% of variance in biomass for C. robustus. Fifty percent of the variance in C. taeniolatus abundance was explained by the proportion of plant species endemic to forest, regeneration age and the patchiness in understorey vegetation height. However, 67% of C. taeniolatus biomass was accounted for by plant species richness, plant species diversity, and the proportion of endemic forest and heath plant species. Some lizard species recorded from the surrounding forest were not found on the mining path. Lizards appear to recolonize revegetated areas more slowly than some other animal groups; this ‘sensitivity’ implies that they can act as important ‘indicator species’ of successful regeneration in disturbed areas. The non-linear response with time of some habitat variables makes it difficult to predict the time required for the complete rehabilitation of the mining path; however, it seems likely that a period well in excess of 20 years may be necessary before the lizard fauna on the mining path reaches premined levels.     

Too hot to handle? Balancing increased trapability with capture mortality in hot weather pitfall trapping

Trapping at air temperatures close to, or exceeding, critical thermal maxima is important for comprehensive sampling of vertebrate assemblages and collection of sufficient data for impact assessment. However, pitfall trapping on hot days also potentially exposes trapped animals to stress or death through overheating or desiccation. We investigate causes of mortality from 14 305 captures over a 22‐year pitfall trap study in arid South Australia and compared mortality rates with maximum temperatures, solar radiation and rainfall. Overall mortality rate was 3.2% with chewing by rodents and handling accidents the most influential cause of death recorded. The highest mortality rates were experienced by the tiny skink, Lerista labialis, which was difficult to detect in traps each day and hence problematic to assess the effect of weather variables on capture mortality. For all other abundant species, high maximum temperature was only a significant explanatory variable for increased death rates of the house mouse Mus domesticus, and increased solar radiation was positively related to capture mortality for the house mouse, the frog Neobatrachus sudelli and the small skink Ctenotus schomburgkii. However, capture rates for these taxa and eight other common species would have been significantly lower if trapping did not occur on days of 40 °C or more. We conclude that trapping in hot weather is both desirable and justifiable and suggest techniques for further reducing mortality rates in pitfall studies.     

Molecular evidence for hybridization between two Australian desert skinks, Ctenotus leonhardii and Ctenotus quattuordecimlineatus (Scincidae: Squamata)

Australian scincid lizards in the genus Ctenotus constitute the most diverse vertebrate radiation in Australia. However, the evolutionary processes that have generated this diversity remain elusive, in part because both interspecific phylogenetic relationships and phylogeographic structure within Ctenotus species remain poorly known. Here we use nucleotide sequences from a mitochondrial locus and two nuclear introns to investigate broad-scale phylogeographic patterns within Ctenotus leonhardii and C. quattuordecimlineatus, two geographically widespread species of skinks that were found to have a surprisingly close genetic relationship in a previous molecular phylogenetic study. We demonstrate that the apparent close relationship between these ecologically and phenotypically distinct taxa is attributable to mitochondrial introgression from C. quattuordecimlineatus to C. leonhardii. In the western deserts, Ctenotus leonhardii individuals carry mtDNA lineages that are derived from C. quattuordecimlineatus mtDNA lineages from that geographic region. Coalescent simulations indicate that this pattern is unlikely to have resulted from incomplete lineage sorting, implicating introgressive hybridization as the cause of this regional gene-tree discordance.     

Isolation of polymorphic tetranucleotide microsatellite markers for the skink Mabuya affinis

We isolated 10 polymorphic microsatellite markers for the skink Mabuya affinis from genomic libraries enriched for (AAGG)_n and (AAAG)_n repetitive elements. The number of alleles ranged from eight to 13 per locus with the observed heterozygosity ranging from 0.60 to 0.92. These markers will be useful for analysis of questions concerning population genetic structure and models of speciation.     

Physiological diving adaptations of the australian water skink Sphenomorphus quoyii

• 1.1. Both the small riparian skink Sphenomorphus quoyii and its completely terrestrial relative Ctenotus robustus respond to forced submergence with instantaneous bradycardia.
• 2.2. The strength of the bradycardia was affected by water temperature and fear. Dives into hot (30°C) water produced weak and erratic bradycardia compared to dives into cold (19.5°C) water. For S. quoyii the strongest bradycardia occurred when submergence took place in water at a lower temperature than the pre-dive body temperature.
• 3.3. Upon emergence both species of skink exhibited elevated heart rates and breathing rates while heating from 19.5 to 30°C, compared to heating at rest. The increased heart and breathing rates probably act to replenish depleted oxygen stores and remove any lactate. Increased heart and ventilation rates are not indicators of physiological thermoregulation in this case.
• 4.4. Both lizard species exhibited higher heart rates and ventilation frequencies during heating than cooling.
• 5.5. Compared to its terrestrial relative, S. quoyii does not appear to possess any major thermoregulatory, ventilatory or cardiovascular adaptations to diving. However, very small reptiles may be generally preadapted to use the water to avoid predators.

     

Distributions of lizard species across edges delimiting open‐forest and sand‐mined areas

Abstract The distributions of lizards across habitat edges delimiting open‐forest and regenerating sand‐mined areas as a function of distance from the edge were studied at Tomago, New South Wales, Australia. Pitfall‐trapping was used to survey lizards across the northern edges of four forest fragments, to determine if lizards displayed characteristic responses across the edge, and whether these could be explained by the different habitat conditions. At each site, 11 equally spaced drift fences (each parallel to the edge) were arranged in a transect running perpendicular to the edge, and stretching 50 m into each habitat type. Captures of Amphibolurus muricatus (Agamidae) decreased substantially across the edge from the mine‐path to the forest so that it was identified as a mine‐path specialist lizard species. Captures of two skink species decreased across the mine‐path before reaching the edge, and were not caught (Ctenotus taeniolatus) or were seldom caught (Ctenotus robustus) in the forest, so they were identified as mine‐path specialist, edge avoiding, lizard species. Captures of Lampropholis delicata (Scincidae) increased across edges into the forest, consistent with the expectation for a forest specialist. Regression analyses indicated the responses to edges of three lizard species (A. muricatus, C. robustus and C. taeniolatus) were negatively correlated with canopy cover (probably due to its influence on temperature, as captures of A. muricatus and C. robustus were also correlated positively with mean daily temperature). In addition, the response of C. robustus correlated negatively with a vegetation factor (dense, even vegetation in the first 50 cm from ground level). The response of L. delicata correlated positively with understorey height. We have identified edge response strategies for four species of lizards across edges delimiting temperate open‐forest and mined areas, and identified habitat and microclimate variables that may have driven these responses.     

Parapharyngodon ocalaensis n. sp. (Nematoda: Pharyngodonidae) from the sand skink,Neoseps reynoldsi (Scincidae), of Florida

Parapharyngodon ocalaensis n. sp. (Nematoda: Pharyngodonidae) from the large intestine of a sand skink Neoseps reynoldsi collected in Florida is described and illustrated. Parapharyngodon ocalaensis n. sp. represents the 31st species assigned to the genus and the third from the Nearctic Realm. It is distinguished from the other 2 North American species by the presence in the male of 3 pairs of caudal papillae and smooth cloacal lips.     

Rapid Recovery of an Urban Remnant Reptile Community following Summer Wildfire

Reptiles in urban remnants are threatened with extinction by increased fire frequency, habitat fragmentation caused by urban development, and competition and predation from exotic species. Understanding how urban reptiles respond to and recover from such disturbances is key to their conservation. We monitored the recovery of an urban reptile community for five years following a summer wildfire at Kings Park in Perth, Western Australia, using pitfall trapping at five burnt and five unburnt sites. The reptile community recovered rapidly following the fire. Unburnt sites initially had higher species richness and total abundance, but burnt sites rapidly converged, recording a similar total abundance to unburnt areas within two years, and a similar richness within three years. The leaf-litter inhabiting skink Hemiergis quadrilineata was strongly associated with longer unburnt sites and may be responding to the loss of leaf litter following the fire. Six rarely-captured species were also strongly associated with unburnt areas and were rarely or never recorded at burnt sites, whereas two other rarely-captured species were associated with burnt sites. We also found that one lizard species, Ctenotus fallens, had a smaller average body length in burnt sites compared to unburnt sites for four out of the five years of monitoring. Our study indicates that fire management that homogenises large areas of habitat through frequent burning may threaten some species due to their preference for longer unburnt habitat. Careful management of fire may be needed to maximise habitat suitability within the urban landscape.     

Feeling the pressure at home: Predator activity at the burrow entrance of an endangered arid‐zone skink

Habitat modification and invasive species are among the most important contemporary drivers of biodiversity loss. These two threatening processes are often studied independently and few studies have focused on how they interact to influence species declines. Here we assess the predation pressure placed on the threatened great desert skink (Liopholis kintorei) and how this interacts with fire‐induced habitat modifications. We collected daily track data of potential predators for 1 month at 30 great desert skink burrow‐systems where vegetation cover varied significantly after experimental burns. We used these data to evaluate potential predation pressure at the burrow‐system and assess whether fire influenced predator pressure. We supplemented this analysis by documenting predation via the inspection of large mammalian predator scats collected from great desert skink habitat. The level of feral cat activity at a burrow‐system entrance was significantly higher than that of any other potential predator, however fire had no effect on the visitation rates of feral cats, dingoes or large snakes to great desert skink burrow‐systems. The remains of great desert skink were found significantly more frequently in feral cat scats, compared to fox and dingo scats. We provide the first direct evidence that feral cats are a significant predator for great desert skink, thus supporting the hypothesis that feral cat predation is a key threatening process. Feral cat activity was not influenced by small‐scale experimental burns, however, this does not preclude an effect of larger scale fires and we recommend further research exploring this possible interaction.     

New species of Raillietnema (Nematoda: Cosmocercidae) in Carlia mysi (Squamata: Scincidae) from Papua New Guinea

Raillietnema nanus n. sp. from the intestines of the skink Carlia mysi (Scincidae) from Morobe Province, Paupa New Guinea, is described and illustrated. It is the 23rd species assigned to the genus and first species of Raillietnema to be reported from the Australian biogeographical realm. It is the ninth species with a lizard type host and is distinguished from other species by its short body length, small egg size, and number of caudal papillae in the male. An initial parasite list of R. nanus and the nematode Physalopteroides milnensis is established for C. mysi.     

Phylogeography of the endangered Otago skink, Oligosoma otagense: population structure, hybridisation and genetic diversity in captive populations

Climatic cooling and substantial tectonic activity since the late Miocene have had a pronounced influence on the evolutionary history of the fauna of New Zealand's South Island. However, many species have recently experienced dramatic range reductions due to habitat fragmentation and the introduction of mammalian predators and competitors. These anthropogenic impacts have been particularly severe in the tussock grasslands of the Otago region. The Otago skink (Oligosoma otagense), endemic to the region, is one of the most critically endangered vertebrates in New Zealand. We use mitochondrial DNA sequence data to investigate the evolutionary history of the Otago skink, examine its population genetic structure, and assess the level of genetic diversity in the individuals in the captive breeding program. Our data indicate that the Otago skink diverged from its closest relatives in the Miocene, consistent with the commencement of tectonic uplift of the Southern Alps. However, there is evidence for past introgression with the scree skink (O. waimatense) in the northern Otago-southern Canterbury region. The remnant populations in eastern Otago and western Otago are estimated to have diverged in the mid-Pliocene, with no haplotypes shared between these two regions. This divergence accounts for 95% of the genetic diversity in the species. Within both regions there is strong genetic structure among populations, although shared haplotypes are generally evident between adjacent localities. Although substantial genetic diversity is present in the captive population, all individuals originate from the eastern region and the majority had haplotypes that were not evident in the intensively managed populations at Macraes Flat. Our data indicate that eastern and western populations should continue to be regarded as separate management units. Knowledge of the genetic diversity of the breeding stock will act to inform the captive management of the Otago skink and contribute to a key recovery action for the species.     

Detection and analysis of six lizard adenoviruses by consensus primer PCR provides further evidence of a reptilian origin for the atadenoviruses

A consensus nested-PCR method was designed for investigation of the DNA polymerase gene of adenoviruses. Gene fragments were amplified and sequenced from six novel adenoviruses from seven lizard species, including four species from which adenoviruses had not previously been reported. Host species included Gila monster, leopard gecko, fat-tail gecko, blue-tongued skink, Tokay gecko, bearded dragon, and mountain chameleon. This is the first sequence information from lizard adenoviruses. Phylogenetic analysis indicated that these viruses belong to the genus Atadenovirus, supporting the reptilian origin of atadenoviruses. This PCR method may be useful for obtaining templates for initial sequencing of novel adenoviruses.     

Disturbance effects from fire and mining produce different lizard communities in eastern Australian forests

The lizard fauna of sand‐mined dunes of the central coast of New South Wales, Australia has been shown to be dominated by Ctenotus robustus and Ctenotus taeniolatus (Scincidae), with relative abundance changing with time since mining. However, there is little published information on how this lizard fauna compares to that of the undisturbed open forest that previously grew on these sites. Here, existing data are added to in order to produce a longer chronosequence of times since sand‐mining (4, 8, 14 and 20 years) than has been examined previously. The new data are compared to those from unmined forests. Ctenotus robustus and C. taeniolatus dominated lizard captures on mined areas, with peak abundances at 8 and 14 years, respectively. Lampropholis guichenoti (Scincidae) was at low abundance until 20 years post‐mining and L. delicata was present only at 20 years post‐mining. Unmined forest burned 4, 8 or 14 years ago had a significantly different lizard community from that of sand‐mined areas. Ctenotus robustus and C. taeniolatus were absent from unmined forest at all post‐fire periods. Lampropholis guichenoti and Lampropholis delicata were numerically dominant in forest, with increasing abundance of L. guichenoti with time since fire. Thus the composition of the lizard community on these coastal dunes is not solely determined by time since disturbance per se. Comparisons of sites on the basis of accumulated leaf litter showed a significant relationship between Lampropholis abundance and litter density. On sand‐mined sites and forested sites with similar leaf litter densities, the abundances of L. guichenoti were similar. As Ctenotus were absent from unmined forest, we could not compare their distribution in unmined and mined areas. However, negative correlations of Ctenotus abundance with canopy cover and understorey vegetation density offer a possible explanation for the absence of these species from forest.     

Characterization of six polymorphic microsatellite loci isolated from Hymenocallis coronaria (J. LeConte) Kunth (Amaryllidaceae)

Microsatellite loci were isolated from the allotetraploid aquatic plant Hymenocallis coronaria. A repeat‐enriched genomic library was constructed and primer pairs designed, resulting in six polymorphic loci. A total of 230 individuals were genotyped, and allelic richness per locus ranged from three to 11, while observed heterozygosity ranged from 0.017 to 0.570. Some amplified products were excised from agarose gel and sequenced to confirm primer specificity and mutation model. These are the first microsatellite markers developed for any member of this genus, and cross‐amplification was successful with the only other member of the genus tested and with a member of the related genus Zephyranthes.     

Diet and prey selection of sympatric tropical skinks

Most skinks are opportunistic predators, taking available prey from the environment as it is encountered. Variation in their diet composition is thought to reflect differences in prey abundance in the environment. We studied diet composition and prey selection in a community of three sympatric skink species (genus Carlia) in northern Australia by comparing contents of skink stomachs with arthropod prey available in their habitat. Carlia were entirely carnivorous and fed on a range of arthropod prey. We found high overlap in diet and prey size among the three species and between the wet and dry seasons, but found that skinks generally focused their foraging efforts on prey types and prey sizes that were not abundant in the habitat. Spiders (Aranea), orthopterans, blattarians, isopods and termites (Isoptera) were important prey of skinks, but these arthropods were rarely trapped in the environment. Skinks also frequently consumed large‐bodied prey, despite the higher relative abundance of small prey in the environment. Skinks were more selective in their foraging and diet than previously assumed. Selection of prey by consumers is a fundamental ecological process, important to consumers for maintaining energy requirements to grow and reproduce, but equally important to the community dynamics of the prey consumed.     

Isospora viridanae N. Sp., an Intranuclear Coccidian Parasite from the Canarian Skink, Chalcides viridanus (Lacertilia: Scincidae)

A caryotropic species of coccidium, Isospora viridanae n. sp. (Apicomplexa: Eimeriidae). has been found as a parasite in the Canarian skink, Chalcides viridanus Gravenhorst, 1851, from Tenerife, Spain, and is described here as a new species. Fully sporulaled oocysts of Isospora viridanae are spherical and measure 21.6 (1 7.6–23.4) nm in diameter. Mtcropyle, oocyst residuum and polar granule are ali absent. Oocysts of this coccidian, with a smooth bilayered wall, contain 2 ovoid sporocysts 13.2 (11.7–14.0) by 9.5 8.2–10 5) μm. A sporocyst residuum is present as well as a Stieda body and a substieda body. Most oocysts are found to be at the beginning of sporulanon when excreted and show 2 spherical sporoblasts. Sporulation is completed within 24 to 48 h at 23 × 2°C Sporozoites are 13–14 μm long and are about 2.5–3 μ m wide. Endogenous stages of schizogony and gamogony develop in the nuclei of epithelial cells from the small intestine of the skink. Comparisons with other species of the genus found in lacertilian hosts indicate that it is a new species.     

Subhabitat variability: A key to the high reptile diversity in chenopod shrublands

Abstract The herpetofauna of one hectare of chenopod shrubland near Roxby Downs in arid South Australia was studied from January 1991 until June 1993. The subhabitat preferences of 27 reptile species and one frog species were investigated by analysing capture rates, from more than 1800 captures in 401 pit traps. Although the site was characterized by relatively uniform cover of the dominant plant species Atriplex vesicaria, significant variation occurred in rock cover, and in edaphic and floristic features. Ctenophorus fordi, Ctenotus brooksi and Lerista labialis were strongly associated with sandy regions while Tympanocryptis intima, Diplodactylus tessellatus and Ctenotus strauchii were largely restricted to rocky subhabitats. Ctenotus leonhardii was strongly associated with a high density of Maireana species. Subhabitat preference of some of these species could be explained by the defence strategies they employed. Several species such as Ctenophorus nuchalis, Pogona vitticeps, Tympanocryptis lineata, Diplodactylus stenodactylus, Rhynchoedura ornata, Menetia greyii and Neobatrachus centralis were subhabitat generalists within the study site. The biological appropriateness of using a smaller number of subhabitat groupings, rather than the square root of the number of study sites, was confirmed in this study. Five subhabitat groups yielded meaningful preference data for more species than did 10 or 20 groups, and did not lose resolution achieved through higher level clustering.     

Partitioning of temporal activity among desert lizards in relation to prey availability and temperature

Partitioning of activity time within ecological communities potentially reduces interspecific competition and increases the number of species that can coexist. We investigated temporal activity in a highly diverse lizard assemblage in the Simpson Desert, central Australia, to determine the degree of partitioning that occurs. Three periods were defined, daytime (sunrise to sunset), early night (sunset to midnight) and late night (midnight to sunrise), and live captures of lizards were tallied for each period during two sampling months (September and November 2007). We also quantified the activity times of potential invertebrate prey and measured ambient temperatures during the different time periods to investigate any associations between these factors and lizard activity. Some 77% of captures of 13 lizard species were made by day, with Ctenotus pantherinus, Egernia inornata (Scincidae) and Nephrurus levis (Gekkonidae) the only species showing extended nocturnal activity. Activity of both species of skink was recorded at temperatures 4°C lower than those for agamid and varanid lizards early in the night, and at temperatures as low as 18–20°C. Surface‐active invertebrates differed in composition between time periods and were less abundant during the late night period in the drier of the two sample months (September), but were distributed equally over time in the other month. Termites were active in subterranean galleries at night in September and mostly by day in November, but available at all times on surface/subsurface baits. We conclude that activity is distributed unevenly within this lizard assemblage, with partitioning facilitated by the ready availability of invertebrate prey and by lizards having relatively broad temperature tolerances that, in some cases, permit opportunistic exploitation of resources beyond usual times of activity.