Zealand Skinks Research Articles

Interference competition following a recent invasion of plague skinks (Lampropholis delicata) into a nationally critical native skink population

Context Invasive species can threaten native species through exploitative and interference competition if they occupy similar ecological niches. The invasive plague skink (Lampropholis delicata) has been accidently introduced to New Zealand, Lord Howe Island, and the Hawaiian Islands. Resource usage overlaps between plague skinks and several New Zealand skinks, suggesting the potential for exploitative and interference competition. However, no competitive mechanism or population impact has been identified. In 2014–15, plague skinks colonised Bream Head Scenic Reserve, Northland, New Zealand, where they overlap in occupancy and habitat with the ‘Nationally Critical’ kakerakau skink (Oligosoma kakerakau). Aims We investigated intra- and interspecific interference competition between kakerakau and plague skinks in the wild. Methods We recorded naturally occurring encounters and quantified aggression at a short-lived resource (sun-basking sites). Key results Behavioural interactions were observed in 72% of all encounters with similar proportions of encounters resulting in agonistic interactions between intraspecific kakerakau skink encounters and interspecific kakerakau-plague encounters. Although kakerakau skinks and plague skinks reacted equally aggressively in an interspecific interaction, kakerakau skinks behaved significantly more aggressively in an interaction with a plague skink than with a conspecific. Juvenile kakerakau skinks were more likely than adults to exhibit submissive behaviours such as fleeing during interspecific interactions. Conclusions This is the first evidence of interference competition occurring between plague skinks and a native skink. Our study suggests that kakerakau skinks, particularly juveniles, may experience competitive exclusion at important resources. Implications Our findings indicate that plague skinks may pose a threat to native skink populations when habitat use overlaps.

Wind of change: a diurnal skink thermoregulates between cooler set-points and for an increased amount of time in the presence of wind.

ABSTRACTWind has the potential to dramatically alter the thermal landscape of habitats, and consequently, to affect how ectotherms thermoregulate. However, few studies have directly assessed if wind alters thermoregulation by ectotherms. We compared the thermoregulation of a heliothermic New Zealand skink under three treatments: no wind, wind at 2 m s−1 and wind at 6 m s−1. We provided captive skinks with housing in which their preferred body temperature was only achievable inside a wind tunnel. During experimental treatments with wind, airflow was generated through the wind tunnel while the maximum available operative temperature remained consistent among treatments. Skinks were able to move in and out of the wind tunnel. Using thermal bio-loggers, we recorded near-continuous skin temperatures of skinks over 90 min. Contrary to our expectations, more skinks tended to thermoregulate in the two wind treatments compared with the treatments without wind (P=0.062) and of the skinks that did thermoregulate, those in the two wind treatments thermoregulated for significantly longer than those in the treatment without wind. The set-point temperatures that skinks thermoregulated between became significantly cooler as windspeed increased, despite skinks having access to the same operative temperatures. Overall, our study suggests that wind has the potential to significantly change the temperatures selected by lizards, even when comparable temperatures are available; wind is therefore an important environmental parameter to consider when studying the thermal ecology of ectotherms, including in the context of climate change.

Modelling three‐dimensional space to design prey refuges using video game software

AbstractRefuges can be ecologically important, allowing access only to some species or individuals and providing prey protection from predators. Creation of refuges can be used to protect threatened species from introduced predators, which can have large negative impacts that are difficult to attenuate via other means. To design refuges for conservation purposes, refuge accessibility to different species must be understood. Traditional techniques are not adequate to measure or describe complex three‐dimensional spaces which are often important refuges. We designed a novel predictive method for modeling three‐dimensional refuge space using video game software that simulates real‐world physics (Unity, PhysX). We use the study system of endemic New Zealand skinks (Oligosoma spp.), their introduced predators, house mice (Mus musculus), and the habitat of interstitial spaces within rock piles to demonstrate how this modeling technique can be used to inform design of habitat enhancement for conservation. We used video game software to model realistic rock piles and measure their interstitial spaces, and found that the spaces we predicted matched those we measured in real rock piles using computed tomography (CT) scanning. We used information about the sizes of gaps accessible to skinks and mice and the results of our modeling to determine the optimal size of rocks to create refuges which would protect skinks from mice. We determined the ideal rock size to be those with graded diameters of 20–40 mm. The approach we developed could be used to describe interstitial spaces in habitats as they naturally occur, or it could be applied to design habitats to benefit particular species.

Pregnancy reduces critical thermal maximum, but not voluntary thermal maximum, in a viviparous skink

Upper thermal limits are commonly measured in ectotherms; however, the effects of life-history stages, and in particular pregnancy in viviparous species, are rarely considered. In this study, we examined whether two measures of upper thermal tolerance varied among life-history stages in a viviparous New Zealand skink (Oligosoma maccanni). First, we measured voluntary thermal maxima (VTmax) and critical thermal maxima (CTmax) for four groups: late-pregnant females, newly postpartum females, males, and neonates. Second, we examined whether exposing skinks to their CTmax in late pregnancy affected success of pregnancies or size and performance of offspring. We found that both VTmax and CTmax differed among the four groups, although only CTmax differed enough to detect specific pairwise differences. Pregnant skinks and neonates had a significantly lower CTmax than postpartum skinks, and pregnant skinks also had a lower CTmax than males. Effect sizes were very large between groups, where CTmax differed significantly, and borderline large for VTmax between male and neonate skinks and between postpartum and pregnant females. Pregnancy success, and the size and sprint speed of resulting neonates were not affected by thermal-tolerance tests on late-pregnant females. The reduction in CTmax we observed in pregnant skinks could indicate that at high temperatures, pregnant skinks do not have the same ability to keep up with oxygen demands as non-pregnant skinks-possibly reflecting reduced ventilation capacity simultaneous with high oxygen demands from embryos as well as maternal tissues. These findings are consistent with some studies, showing that reduced oxygen availability can reduce thermal tolerance in reptiles.

Lizards in the suburbs: a single-garden study of a small endemic New Zealand skink (Oligosoma aeneum)

ABSTRACTDetailed investigations of ecology and life history of lizards in New Zealand/Aotearoa are needed to inform their conservation and management. An early demographic study of copper skinks (Oligosoma aeneum) in a suburban garden was undertaken in Lower Hutt using mark–recapture methods, sampling weekly from March 1971 to December 1973. Oligosoma aeneum were seen on 1372 occasions, with 972 captures of 169 individuals. The maximum snout–vent length was 66 mm, 33% of skinks had complete tails, and colour differences suggested sexual signalling and warrant further study. Most captures occurred over November–March, with fewest over June–August. The estimated spring/summer population size in the garden (± SEM) was 83.6 (± 9.4) skinks, and the annual survival rate (± SEM) was 38.0% (± 16.0%). This is one of the few New Zealand lizard studies that have extended through all months of the year and it adds to limited information on lizard populations in suburban areas.

A new species of scincid lizard in the genus Oligosoma (Reptilia: Scincidae) from the mid-Canterbury high country, New Zealand.

New Zealand has a diverse, endemic skink fauna, which is recognised as the most species rich skink assemblage of any cool temperate region on earth. All native New Zealand skink species are assigned to a single genus, Oligosoma Girard. A new species of Oligosoma is described from screes in montane tussock grassland in the mid-Canterbury high country, New Zealand, where it is currently known from four sites on two mountain ranges. The new species (Oligosoma hoparatea sp. nov.) can be distinguished from all congeners by a combination of mid-body scale row and lamellae counts, scale morphologies, and a bold striped pattern with smooth-edged, dark lateral bands. It is part of the O. longipes Patterson species complex, and occurs in sympatry with its closest relative, O. aff. longipes 'southern'. The species is currently highly threatened, and is listed as Nationally Critical in New Zealand. Predation by a suite of introduced mammals is assumed to be a major threat to its survival.

Hidden conservation vulnerability within a cryptic species complex: taxonomic revision of the spotted skink (Oligosoma lineoocellatum; Reptilia: Scincidae) <br />from New Zealand

The diverse skink fauna of New Zealand comprises 40 described species within the single genus Oligosoma Girard, 1857. Cryptic species are common among New Zealand skinks, leaving numerous species undescribed. We used molecular phylogeny together with morphological analyses to distinguish four species in the spotted skink, Oligosoma lineoocellatum (Duméril & Duméril 1851), species complex. These are O. lineoocellatum sensu stricto, which is confined to the centre of the South Island, O. prasinum sp. nov. from the Lake Tekapo region, O. elium sp. nov. from the northern half of the South Island, and O. kokowai sp. nov. from the northern South Island, Cook Strait, and the North Island. Despite significant genetic differences, the morphological similarity of these species made it challenging to resolve their taxonomic identity. Three of the four species previously recognised as a single, widespread taxon are now recognised as threatened with extinction by a combination of invasive predatory mammals and land use change.

A review of the parasitic mites of New Zealand skinks and geckos with new host records

ABSTRACTDespite a general awareness of mites parasitic on New Zealand native lizards, they have received little attention. In total, eight species have been described to infect New Zealand lizards; however, many of the records are decades old and are opportunistic encounters rather than focused surveys. This article reviews existing knowledge of these mites with particular focus given to identifying known distributional ranges and host species parasitised. To complement the literature review, a modest survey of the mite fauna of New Zealand lizards was conducted. Mites were collected from 10 lizard species from five different locations. Four mite species (Neotrombicula naultini, Ne. sphenodonti, Microtrombicula hoplodactyla and Odontacarus lygosomae) were recovered and identified. The study expands the known ranges of Ne. naultini, M. hoplodactyla and Odontacarus mites and provides a new host record for M. hoplodactyla. Importantly, this study highlights that our documentation of these mites is limited and incomplete.

Genetic diversity and gene flow in a rare New Zealand skink despite fragmented habitat in a volcanic landscape

Anthropogenic habitat fragmentation often restricts gene flow and results in small populations that are at risk of inbreeding. However, some endangered species naturally occupy patchy habitat where local population extinction and recolonization are normal. We investigated population fragmentation in the range-restricted New Zealand small-scaled skink (Oligosoma microlepis), documenting changes in habitat occupancy and analyzing mitochondrial, microsatellite, and morphological variation sampled across the geographical range of the species (approximately 100 km2). Small-scaled skinks have a strong preference for rocky outcrops that exist in a mosaic of other habitat types. A metapopulation structure was indicated by both local extinction and colonization of new sites. We found relatively high mtDNA nucleotide site diversity within this narrow range (π = 0.004; 16S), evidence of inter-patch gene flow, and no statistical support for inbreeding. Gene flow was limited by geographical distance, although the existence of pasture between habitat patches apparently has not prevented skink dispersal. Generalized linear models indicated an association between body size and location suggesting a local environmental influence on phenotype. Prior to human-induced habitat modification, native forest probably separated preferred sites and, less than 2000 years ago, volcanic activity devastated much of the area currently occupied by O. microlepis. This skink appears able to re-establish populations if other human-linked factors such as agricultural intensification and introduced predators are limited. Although in contrast to expectations for a scarce and localized species living in a highly modified landscape, this lizard may have previously adapted to a dynamic, mosaic environment mediated by volcanism.

A retrospective approach to testing the DNA barcoding method.

A decade ago, DNA barcoding was proposed as a standardised method for identifying existing species and speeding the discovery of new species. Yet, despite its numerous successes across a range of taxa, its frequent failures have brought into question its accuracy as a short-cut taxonomic method. We use a retrospective approach, applying the method to the classification of New Zealand skinks as it stood in 1977 (primarily based upon morphological characters), and compare it to the current taxonomy reached using both morphological and molecular approaches. For the 1977 dataset, DNA barcoding had moderate-high success in identifying specimens (78-98%), and correctly flagging specimens that have since been confirmed as distinct taxa (77-100%). But most matching methods failed to detect the species complexes that were present in 1977. For the current dataset, there was moderate-high success in identifying specimens (53-99%). For both datasets, the capacity to discover new species was dependent on the methodological approach used. Species delimitation in New Zealand skinks was hindered by the absence of either a local or global barcoding gap, a result of recent speciation events and hybridisation. Whilst DNA barcoding is potentially useful for specimen identification and species discovery in New Zealand skinks, its error rate could hinder the progress of documenting biodiversity in this group. We suggest that integrated taxonomic approaches are more effective at discovering and describing biodiversity.

Taxonomic revision of the ornate skink (Oligosoma ornatum; Reptilia: Scincidae) species complex from northern New Zealand.

Although the New Zealand skink fauna is known to be highly diverse, a substantial proportion of the recognised species remain undescribed. We completed a taxonomic revision of the ornate skink (Oligosoma ornatum (Gray, 1843)) as a previous molecular study indicated that it represented a species complex. As part of this work we have resolved some nomenclatural issues involving this species and a similar species, O. aeneum (Girard, 1857). A new skink species, Oligosoma roimata sp. nov., is described from the Poor Knights Islands, off the northeast coast of the North Island of New Zealand. This species is diagnosed by a range of morphological characters and genetic differentiation from O. ornatum. The conservation status of the new taxon appears to be of concern as it is endemic to the Poor Knights Islands and has rarely been seen over the past two decades.

Phylogeography and taxonomic revision of the New Zealand cryptic skink (Oligosoma inconspicuum; Reptilia: Scincidae) species complex

The New Zealand skink fauna is highly diverse and contains numerous cryptic, undescribed or hitherto undiscovered species. We completed a taxonomic revision of the cryptic skink (Oligosoma inconspicuum) species complex using molecular (550 bp of the ND2 mitochondrial gene) and morphological analyses. Four new species are described, with each diagnosable by a range of morphological characters and genetic differentiation from several closely related species: O. inconspicuum (sensu stricto), O. notosaurus, O. maccanni, O. stenotis and O. grande. Oligosoma tekakahu sp. nov. is restricted to Chalky Island in Fiordland, and is most closely related to O. inconspicuum and O. notosaurus. The other three new species are restricted to particular mountainous regions in central and western Otago (O. burganae sp. nov., Lammermoor and Rock and Pillar Ranges; O. toka sp. nov., Nevis Valley; O. repens sp. nov., Eyre Mountains) and are most closely related to O. stenotis and O. grande. We also re-described O. inconspicuum. Two proposed new taxa, the ‘Big Bay’ skink and ‘Mahogany’ skink, were found to represent Westland/Fiordland populations of O. inconspicuum rather than distinct taxa. We discuss the evolutionary and phylogeographic implications of cryptic and ‘anti-cryptic’ species within the O. inconspicuum species complex, and suggest that morphologically aberrant populations are the result of local adaptation to novel selective regimes.

Case 3510Cyclodina aeneaGirard, 1857 (currentlyOligosoma aeneum; Reptilia, Squamata, scincidae): proposed conservation of the specific name and suppression of the senior subjective synonymTiliqua ornataGray, 1843 (currentlyOligosoma ornatumGray, 1843)

The purpose of this application, under Article 75.6 of the Code, is to conserve the specific name of the name Oligosoma aeneum (Girard, 1857), widely used for a species of New Zealand skink, commonly known as the copper skink. We have found Tiliqua ornata Gray, 1843 (currently Oligosoma ornatum) to be a senior subjective synonym and the oldest available name for this species. The name Oligosoma ornatum has been incorrectly applied since 1977 to a similar but larger sympatric species, commonly known as the ornate skink, and prior to 1977 was in use for a third species, now identified as the brown skink, Oligosoma zelandicum (Gray, 1843). With various generic name changes the name Oligosoma ornatum has been in widespread usage for the larger ornate skink and Oligosoma aeneum for the smaller copper skink, for more than 30 years. Application of the specific name Oligosoma ornatum to a third species within 35 years will cause extreme confusion and inaccuracy of recording of biological data and conservation status. The Commission is requested to maintain the use of the junior synonym Oligosoma aeneum as a nomen protectum and suppress the name Oligosoma ornatum as a nomen oblitum.

Origin, diversification, and systematics of the New Zealand skink fauna (Reptilia: Scincidae)

The diverse scincid lizard fauna of the largely submerged subcontinent of Zealandia (which incorporates New Zealand, New Caledonia, Lord Howe Island, Norfolk Island, and the Chatham Islands) forms a monophyletic lineage within the Eugongylus group of skinks. We use 4062 bp of mitochondrial (ND2, ND4, Cytochrome b, 12SrRNA, 16SrRNA) and nuclear (Rag-1) DNA sequence data to recover a molecular phylogeny for the New Zealand skink fauna, and investigate the origin and diversification of skinks in New Zealand. Our phylogeny includes 32 of the 33 extant described New Zealand skink species ( Cyclodina and Oligosoma), the Lord Howe Island skink ( C. lichenigera), and representatives from several New Caledonian genera. Neighbour-joining, Maximum Parsimony, Maximum Likelihood, and Bayesian phylogenetic analyses are used to demonstrate that the New Zealand skink species form a single monophyletic lineage, with C. lichenigera representing a closely related sister lineage to the New Zealand radiation. Our relaxed molecular clock analyses indicate that skinks colonised New Zealand in the early Miocene (16–22.6 mya), shortly after the ‘Oligocene drowning’ event (∼25 mya). We propose that skinks reached New Zealand from New Caledonia via long-distance overwater dispersal, with C. lichenigera persisting on volcanic islands along the Lord Howe Rise and Norfolk Ridge. Eight major genetic clades are evident within the New Zealand skink fauna, with the divergences among these clades during the early to mid-Miocene resulting in distinct open habitat, forest, and coastal radiations. Subsequent diversification in the late Miocene–Pliocene appears to coincide with tectonic activity along the Alpine Fault and the uplift of the Southern Alps. We were unable to resolve the phylogenetic affinities of O. suteri, New Zealand’s only native oviparous skink. We use the phylogeny and topology tests to resolve several taxonomic issues and assess the taxonomic status of several suspected undescribed taxa. We complete a generic revision for the New Zealand skink fauna, placing C. lichenigera and all native New Zealand species into a single genus.

Comparative phylogeography reveals pre-decline population structure of New Zealand Cyclodina (Reptilia: Scincidae) species

We examined the comparative phylogeography of all species within the endemic New Zealand skink genus Cyclodina to gain insight into the influence of historical processes on the biogeography of the North Island fauna. Until 1‐2 kya, six Cyclodina species occurred sympatrically across the North Island of New Zealand. However, most species have undergone dramatic distributional declines subsequent to the introduction of mammals and the arrival of humans. We compare the phylogeographic patterns evident in Cyclodina species in three biogeographic categories: widespread species (Cyclodina aenea, Cyclodina ornata), North Island disjunct relics (Cyclodina macgregori, Cyclodina whitakeri), and northeastern island relics (Cyclodina alani, Cyclodina oliveri, Cyclodina townsi). Mitochondrial DNA (ND2) sequence data was obtained from across the entire range of each Cyclodina species. We used Neighbour-joining, maximum likelihood and Bayesian methods to examine the phylogeographic patterns present in each species. Phylogeographic patterns varied among species in different biogeographic categories. Substantial phylogeographic structure was evident in the two widespread species (C. aenea, C. ornata), with Pliocene and Pleistocene divergences between clades evident. Divergences among island groups in the three northeastern island relic species (C. alani, C. oliveri, C. townsi) occurred during the late Pliocene‐Pleistocene. By contrast, relatively shallow structure, indicative of late Pleistocene divergences, was present in the two North Island disjunct species (C. macgregori, C. whitakeri). The results strongly suggest that the Poor Knights Islands population of C. ornata represents a new species. We suggest that the contrasting phylogeographic patterns exhibited by Cyclodina species in different biogeographic categories might be related to body size, ecology, and habitat preferences. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95, 388‐408. ADDITIONAL KEYWORDS: lizard ‐ mitochondrial DNA ‐ ND2 ‐ Pleistocene glacial cycle ‐ skink ‐ topology tests ‐ volcanic activity.

Phylogeography of two New Zealand lizards: McCann’s skink ( Oligosoma maccanni) and the brown skink ( O. zelandicum)

The New Zealand skink fauna has proven to be an ideal taxonomic group in which to examine the impact of climatic and geological processes on the evolution of the New Zealand biota since the Pliocene. Here we examine the phylogeography of McCann’s skink ( Oligosoma maccanni) in order to gain insight into the relative contribution of Pliocene and Pleistocene processes on patterns of genetic structure in the South Island biota, and investigate the phylogeography of the brown skink ( O. zelandicum) to examine whether Cook Strait landbridges facilitated geneflow between the North and South Islands in the late-Pleistocene. We obtained mitochondrial DNA sequence data (ND2 and ND4; 1282 bp) from across the range of both species. We examined the phylogeographic patterns evident in each species using Neighbour-Joining, Maximum Likelihood and Bayesian methods. We found substantial phylogeographic structure within O. maccanni, with seven distinct clades identified. Divergences among clades are estimated to have occurred during the Pliocene. Populations in the Otago/Southland region (south of the Waitaki River valley) formed a well-supported lineage within O. maccanni. A substantial genetic break was evident between populations in east and west Otago, either side of the Nevis-Cardrona fault system, while north-south genetic breaks were evident within the Canterbury region. Within-clade divergences in O. maccanni appear to have occurred during the mid- to late-Pleistocene. Shimodaira–Hasegawa topology tests indicated that the ‘Garston’ skink is not genetically distinct from O. maccanni. There was only relatively minor phylogeographic structure within O. zelandicum, with divergences among populations occurring during the mid- to late-Pleistocene. Our genetic data supports a single colonisation of the North Island by O. zelandicum from the South Island, with the estimated timing of this event (0.46 mya) consistent with the initial formation of Cook Strait.

Community‐wide character displacement in New Zealand skinks

AbstractAim To test for community‐wide character displacement in New Zealand skinks.Location Four small islands in the New Zealand archipelago.Methods (1) We conducted a field experiment on a single island to evaluate whether prey size selection is correlated with lizard body size. We pitfall trapped 69 skinks from three species, measured several aspects of their morphology and presented each animal with a variety of different‐sized prey in a food choice experiment. (2) We tested whether the morphological characteristics associated with prey size selection were evenly partitioned in four island skink communities using null models.Results Prey size selection was associated with skink morphology; larger skinks consumed larger prey. Null model analyses showed support for evenly displaced body sizes on one island, weak support on one island and no support on two islands.Main conclusions Results showed mixed support for community‐wide character displacement in New Zealand skinks. Differences in body sizes appear to reflect the use of different‐sized prey. Even differentiation in body sizes on one island suggests that species coexistence is facilitated by interspecific differences in prey size selection. However, little support was found on other islands, suggesting that other factors, such as interspecific differences in habitat selection and/or diurnal activity patterns, may interact with differences in prey size selection to promote coexistence among New Zealand skinks.

Attempting to Manage Complex Predator‐Prey Interactions Fails to Avert Imminent Extinction of a Threatened New Zealand Skink Population

Abstract: The current primary threats to biodiversity on a global scale are species invasions and habitat modification. Management of vulnerable populations often involves a lengthy sequence of 1) research to identify threats and recommend management strategies, 2) active management, and 3) results monitoring to assess effectiveness of management. The last mainland population of the large, endemic New Zealand skink (Whitaker's skink [Cyclodina whitakeri]) provides an opportunity to test this process in a system where the synergistic effects between invasive species (introduced rodents and grasses) have predicted outcomes. A low abundance of Whitaker's skink at the Pukerua Bay Scientific Reserve in the 1980s prompted management recommendations to remove grazing stock and revegetate the site to simultaneously restore habitat and provide protection against introduced mammalian predators. Since Whitaker's skink have low detectability, it was recommended that sympatric copper skink (C. aenea) be used an indicator species of management effectiveness. Grazing stock were removed in 1987, but efforts to revegetate the site were ineffective. Long‐term monitoring (1984‐2006) of the Whitaker's skink population and 4 other sympatric lizard species within a 336‐m2 area at the site resulted in 1,693 lizard captures over 7,597 trap days. Whitaker's skink represented 2.8% of all captures in 1984‐1988, but declined relative to other species to represent only 0.2% of captures in 2000‐2006 (representing 2 individuals). Congeneric copper skink showed a similar decline with capture rates also approaching zero by 2006. Removing grazing stock did not result in an increased abundance of Whitaker's skink or copper skink through improved habitat quality, as was intended by the management recommendation. Instead, reduced grazing has allowed introduced seeding grasses to proliferate, which may have led to periodic rodent irruptions, supporting a guild of introduced mammalian predators and depleting populations of Whitaker's skink and copper skink. In this instance, attempted protection may have driven a vulnerable population towards extinction. We recommend investigating the feasibility of constructing a mammal‐proof fence around the core Whitaker's skink habitat, as the last remaining management option to salvage the population.

Chromosomes of New Zealand Skinks, Genus Oligosoma

Karyotypes from the New Zealand skinks Oligosoma nigriplantare nigriplantare, Oligosoma nigriplantare polychroma, and Oligosoma microlepis are presented. All have a chromosome complement of 30, and there are no sex-related heteromorphisms. Comparisons with the other New Zealand skink genus, Cyclodina, and the Mauritius skink Leiolopisma telfairi, indicate Oligosoma and Leiolopisma share a common karyotype and that the Cyclodina karyotype is derived from Oligosoma.

Microsatellite DNA markers for New Zealand skinks

Reptiles are a prominent part of the faunal diversity of New Zealand, but most species have suffered major range declines or extinctions in the past 2000 years. Nearly fifty percent of species (26 of 62) are now threatened or restricted to offshore islands and eight are subject to recovery programs (Towns and Daugherty 1994; Towns et al. 2001). Most declines can be attributed to loss or modification of habitat and predation by introduced mammals. Previous genetic studies of New Zealand reptiles have increased the number of recognised species (e.g. Daugherty et al. 1990), but provided little autecological or population-level genetic information that could be applied to management. Here we present the first microsatellite DNA markers to be developed for a New Zealand lizard. We are using these markers to study dispersal in the grand skink, Oligosoma grande, a large rock-dwelling lizard endemic to sub-alpine grasslands in southern New Zealand. This formerly widespread species now has a restricted range, and is listed as ‘vulnerable’ under IUCN criteria (HiltonTaylor 2000).