Publications

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composition of the cloacal gland secretion of tuatara, sphenodon punctatus.the lipophilic content of the cloacal gland secretion of the tuatara (sphenodon punctatus) was investigated. gc/ei-ms analysis of ch2cl2 extracts of the secretions revealed triacylglycerols as major glandular constituents. twelve major medium-chain fatty acids were found to be conjugated to glycerol in different combinations, resulting in complex mixtures. these acids were identified by transesterification and subsequent derivatization of natural samples, and their structures were verified by sy ...200919180453
dentary tooth shape in sphenodon and its fossil relatives (diapsida: lepidosauria: rhynchocephalia).today rhynchocephalia, the sister tax-on to squamata (snakes, lizards and amphisbaenians), is only represented by the tuatara (sphenodon) of new zealand. however, for much of the mesozoic, the group was speciose and globally distributed. historically, the rhynchocephalia were considered to be homogenous and unspecialized but new fossils and new research are overturning this view. as well as differences in body size, body proportions, habit (aquatic vs. terrestrial), and skull structure, their te ...200919828962
timing of organogenesis support basal position of turtles in the amniote tree of life.the phylogenetic position of turtles is the most disputed aspect in the reconstruction of the land vertebrate tree of life. this controversy has arisen after many different kinds and revisions of investigations of molecular and morphological data. three main hypotheses of living sister-groups of turtles have resulted from them: all reptiles, crocodiles + birds or squamates + tuatara. although embryology has played a major role in morphological studies of vertebrate phylogeny, data on development ...200919389226
influence of major histocompatibility complex genotype on mating success in a free-ranging reptile population.major histocompatibility complex (mhc) genes are highly polymorphic components of the vertebrate immune system, which play a key role in pathogen resistance. mhc genes may also function as odour-related cues for mate choice, thus ensuring optimal mhc diversity in offspring. mhc-associated mate choice has been demonstrated in some fish, bird and mammal species but it is not known whether this is a general vertebrate phenomenon. we investigated whether mhc-associated mate choice occurs in a wild p ...200919324833
evolutionary, behavioural and molecular ecology must meet to achieve long-term conservation goals.founder populations in reintroduction programmes can experience a genetic bottleneck simply because of their small size. the influence of reproductive skew brought on by polygynous or polyandrous mating systems in these populations can exacerbate already difficult conservation genetic problems, such as inbreeding depression and loss of adaptive potential. without an understanding of reproductive skew in a target species, and the effect it can have on genetic diversity retained over generations, ...200919761487
how do reproductive skew and founder group size affect genetic diversity in reintroduced populations?reduced genetic diversity can result in short-term decreases in fitness and reduced adaptive potential, which may lead to an increased extinction risk. therefore, maintaining genetic variation is important for the short- and long-term success of reintroduced populations. here, we evaluate how founder group size and variance in male reproductive success influence the long-term maintenance of genetic diversity after reintroduction. we used microsatellite data to quantify the loss of heterozygosity ...200919732338
a sphenodontine (rhynchocephalia) from the miocene of new zealand and palaeobiogeography of the tuatara (sphenodon).jaws and dentition closely resembling those of the extant tuatara (sphenodon) are described from the manuherikia group (early miocene; 19-16 million years ago, mya) of central otago, new zealand. this material is significant in bridging a gap of nearly 70 million years in the rhynchocephalian fossil record between the late pleistocene of new zealand and the late cretaceous of argentina. it provides the first pre-pleistocene record of rhynchocephalia in new zealand, a finding consistent with the ...200919203920
discrimination of flicker frequency rates in the reptile tuatara (sphenodon ).by investigating the mechanisms that underlie the perception of environmental cues, we may begin to understand how the sensory system governs behavioral responses. this is the first empirical study to examine learning and visual sensitivity in a reptile species, the tuatara (sphenodon punctatus). we established a non-intrusive psychophysical method by employing an instrumental paradigm in order to examine discrimination learning and the ability to distinguish different flicker frequencies in the ...200919089401
a survey of the husbandry of captive tuatara (sphenodon spp.) in relation to factors implicated in nutritional secondary hyperparathyroidism.to examine selected aspects of the diet and husbandry of captive tuatara (sphenodon spp.) in new zealand, in order to develop recommendations on provision of ultraviolet b light and diet, to reduce the incidence of nutritional secondary hyperparathyroidism (nshp).200919966899
microstructure of dental hard tissues and bone in the tuatara dentary, sphenodon punctatus (diapsida: lepidosauria: rhynchocephalia).the tuatara, sphenodon, is a small reptile currently restricted to islands off the coast of new zealand where it feeds mainly on arthropods. a widely held misconception is that 'sphenodon does not have real teeth' and instead possesses 'serrations on the jaw bone'. one hatchling and one adult dentary were examined under sem. two longitudinal ground sections 100-microm thick were prepared through a lower canine tooth and its supporting tissues. there was clear evidence of aprismatic enamel (priml ...200919828975
the evolutionary rate of tuatara revisited. 200918976831
on the relative roles of selection and genetic drift in shaping mhc variation.genes of the major histocompatibility complex (mhc) have provided some of the clearest examples of how natural selection generates discordances between adaptive and neutral variation in natural populations. the type and intensity of selection as well as the strength of genetic drift are believed to be important in shaping the resulting pattern of mhc diversity. however, evaluating the relative contribution of multiple microevolutionary forces is challenging, and empirical studies have reported c ...201020854274
genetic diversity and differentiation at mhc genes in island populations of tuatara (sphenodon spp.).neutral genetic markers are commonly used to understand the effects of fragmentation and population bottlenecks on genetic variation in threatened species. although neutral markers are useful for inferring population history, the analysis of functional genes is required to determine the significance of any observed geographical differences in variation. the genes of the major histocompatibility complex (mhc) are well-known examples of genes of adaptive significance and are particularly relevant ...201020723045
transitional fossils and the origin of turtles.the origin of turtles is one of the most contentious issues in systematics with three currently viable hypotheses: turtles as the extant sister to (i) the crocodile-bird clade, (ii) the lizard-tuatara clade, or (iii) diapsida (a clade composed of (i) and (ii)). we reanalysed a recent dataset that allied turtles with the lizard-tuatara clade and found that the inclusion of the stem turtle proganochelys quenstedti and the 'parareptile' eunotosaurus africanus results in a single overriding morpholo ...201020534602
the evolution of the lepidosaurian lower temporal bar: new perspectives from the late cretaceous of south china.until recently, it was considered axiomatic that the skull of lizards and snakes arose from that of a diapsid ancestor by loss of the lower temporal bar. the presence of the bar in the living new zealand tuatara, sphenodon, was thus considered primitive, corroborating its status as a 'living fossil'. a combination of new fossils and rigorous phylogeny has demonstrated unequivocally that the absence of the bar is the primitive lepidosaurian condition, prompting questions as to its function. here ...201019324758
the constrictor dorsalis musculature and basipterygoid articulation in sphenodon.the constrictor internus dorsalis (cid) trigeminal muscles in vertebrates lie between the braincase and the palatoquadrate bar, and in reptiles they are believed to function in the relative movements between braincase and maxillary segment known as kinesis. in amniote taxa, the presence of a synovial basipterygoid articulation (bpa) correlates with presence of the cid. previous descriptions of the cid in the tuatara sphenodon (rhynchocephalia) are inconsistent regarding presence, size and direct ...201019806656
the pineal eye of the tuatara. 201015850819
unravelling causality from correlations: revealing the impacts of endemic ectoparasites on a protected species (tuatara).understanding the impacts of endemic parasites on protected hosts is an essential element of conservation management. however, where manipulative experiments are unethical, causality cannot be inferred from observational correlative studies. instead, we used an experimental structure to explore temporal associations between body condition of a protected reptile, the tuatara (sphenodon punctatus) and infestation with ectoparasites (ticks and mites). we surveyed tuatara in a mark-recapture study o ...201019835646
a cold-adapted reptile becomes a more effective thermoregulator in a thermally challenging environment.thermoregulation is of great importance for the survival and fitness of ectotherms as physiological functions are optimized within a narrow range of body temperature (t(b)). the precision with which reptiles thermoregulate has been proposed to be related to the thermal quality of their environments. although a number of studies have looked at the effect of thermal constraints imposed by diel, seasonal and altitudinal variation on thermoregulatory strategies, few have addressed this question in a ...201020140685
the first cytogenetic map of the tuatara, sphenodon punctatus.tuatara, sphenodon punctatus, is the last survivor of the distinctive reptilian order rhynchocephalia and is a species of extraordinary zoological interest, yet only recently have genomic analyses been undertaken. the karyotype consists of 28 macrochromosomes and 8 microchromosomes. a bacterial artificial chromosome (bac) library constructed for this species has allowed the first characterization of the tuatara genome. sequence analysis of 11 fully sequenced bac clones (approximately 0.03% cover ...201020299781
endangered species hold clues to human evolution.we report that 18 conserved, and by extension functional, elements in the human genome are the result of retroposon insertions that are evolving under purifying selection in mammals. we show evidence that 1 of the 18 elements regulates the expression of asxl3 during development by encoding an alternatively spliced exon that causes nonsense-mediated decay of the transcript. the retroposon that gave rise to these functional elements was quickly inactivated in the mammalian ancestor, and all traces ...201020332163
developmental stages and molecular phylogeny of hepatozoon tuatarae, a parasite infecting the new zealand tuatara, sphenodon punctatus and the tick, amblyomma sphenodonti.the developmental stages of hepatozoon tuatarae were elucidated in both the tuatara host, sphenodon punctatus and the tick, amblyomma sphenodonti. pcr amplicons from a. sphenodonti samples identified dna matching h. tuatarae. dissection of tick samples showed oogenesis and sporogony occurring in the haemocoel of a. sphenodonti with the average mature oocyst size being 236 x 228 microm. partial sequence data of the parasite's small subunit ribosomal gene, obtained by pcr, was used for phylogeneti ...201020451526
social network structure and parasite infection patterns in a territorial reptile, the tuatara (sphenodon punctatus).we investigated whether the parasite load of an individual could be predicted by its position in a social network. specifically, we derived social networks in a solitary, territorial reptile (the tuatara, sphenodon punctatus), with links based on the sharing of space, not necessarily synchronously, in overlapping territories. tuatara are infected by ectoparasitic ticks (amblyomma sphenodonti), mites (neotrombicula spp.) and a blood parasite (hepatozoon tuatarae) which is transmitted by the tick. ...201020637210
ecology and dynamics of the blood parasite, hepatozoon tuatarae (apicomplexa), in tuatara (sphenodon punctatus) on stephens island, new zealand.we explored infection patterns and temporal dynamics of the protozoan blood parasite hepatozoon tuatarae (apicomplexa) infecting the tuatara (sphenodon punctatus), a protected reptile living on stephens island, new zealand. in march 2006, we surveyed tuatara in five study sites to examine spatial variation in infection prevalence, and four times, from may 2005 to november 2006, we recaptured marked individuals within three study sites to examine the temporal dynamics of infection. we also examin ...201121270002
segregating variation for temperature-dependent sex determination in a lizard.temperature-dependent sex determination (tsd) was first reported in 1966 in an african lizard. it has since been shown that tsd occurs in some fish, several lizards, tuataras, numerous turtles and all crocodilians. extreme temperatures can also cause sex reversal in several amphibians and lizards with genotypic sex determination. research in tsd species indicates that estrogen signaling is important for ovary development and that orthologs of mammalian genes have a function in gonad differentiat ...201120700140
deleterious mutations of a claw keratin in multiple taxa of reptiles.we have recently shown that homologs of mammalian hair keratins are expressed in the claws of the green anole lizard, anolis carolinensis. to test whether reptilian hair keratin homologs are functionally associated with claws, we investigated the conservation of the prototypical reptilian hair keratin homolog, hard acidic keratin 1 (ha1), in representative species from all main clades of reptiles. a complete cdna of ha1 was cloned from the claw-forming epidermis of the lacertid lizard podarcis s ...201121181402
functional relationship between skull form and feeding mechanics in sphenodon, and implications for diapsid skull development.the vertebrate skull evolved to protect the brain and sense organs, but with the appearance of jaws and associated forces there was a remarkable structural diversification. this suggests that the evolution of skull form may be linked to these forces, but an important area of debate is whether bone in the skull is minimised with respect to these forces, or whether skulls are mechanically "over-designed" and constrained by phylogeny and development. mechanical analysis of diapsid reptile skulls co ...201122216358
structure and compositional characteristics of caniniform dental enamel in the tuatara sphenodon punctatus (lepidosauria: rhynchocephalia).the evolution of dental tissues in relation to tooth function is poorly understood in non-mammalian vertebrates. we studied the dentition of sphenodon punctatus, the sole remaining member of the order rhynchocephalia in this light.201121721336
the structural basis of the filament-matrix texture in the avian/reptilian group of hard β-keratins.avian hard keratin has a filament-matrix texture in which the filaments contain a helical array of twisted β-sheets and the matrix has unusually high concentrations of cysteine, glycine, and tyrosine. x-ray diffraction studies have established that similar filaments exist in the hard keratins of crocodiles, turtles, tuataras, lizards and snakes. here, the relationship between amino acid sequence and the filament-matrix texture is explored in a wide variety of avian and reptilian hard keratins. u ...201120869443
environmentally cued hatching in reptiles.evidence is accumulating for the widespread occurrence of environmentally cued hatching (ech) in animals, but its diversity and distribution across taxa are unknown. herein i review three types of ech in reptiles: early hatching, delayed hatching, and synchronous hatching. ech is currently known from 43 species, including turtles, crocodilians, lizards, snakes, tuatara, and possibly worm lizards. early hatching caused by physical disturbance (e.g., vibrations) is the most commonly reported ech a ...201121659393
immunolocalization of keratin-associated beta-proteins (beta-keratins) in scales of the reptiles sphenodon punctatus indicates that different beta-proteins are present in beta- and alpha-layers.the present ultrastructural immunocytochemical study analyzes the localization of keratin-associated beta-proteins (beta-keratins) in the epidermis of the ancient reptile sphenodon punctatus, a relict species adapted to mid-cold conditions. the epidermis comprises two main layers, indicated as beta- and alpha-keratin layers. the beta-layer contains small beta-proteins (beta-keratins) identified by using three different antibodies while the alpha-layer is poorly or not labeled for these proteins. ...201222817772
shearing mechanics and the influence of a flexible symphysis during oral food processing in sphenodon (lepidosauria: rhynchocephalia).the new zealand tuatara, sphenodon, has a specialized feeding system in which the teeth of the lower jaw close between two upper tooth rows before sliding forward to slice food apart like a draw cut saw. this shearing action is unique amongst living amniotes but has been compared with the chewing power stroke of mammals. we investigated details of the jaw movement using multibody dynamics analysis of an anatomically accurate three-dimensional computer model constructed from computed tomography s ...201222644955
micrornas support a turtle + lizard clade.despite much interest in amniote systematics, the origin of turtles remains elusive. traditional morphological phylogenetic analyses place turtles outside diapsida-amniotes whose ancestor had two fenestrae in the temporal region of the skull (among the living forms the tuatara, lizards, birds and crocodilians)-and allied with some unfenestrate-skulled (anapsid) taxa. nonetheless, some morphological analyses place turtles within diapsida, allied with lepidosauria (tuatara and lizards). most molec ...201221775315
tuatara. 201223218010
an inordinate fondness for eukaryotic diversity.why do some groups of organisms, like beetles, have so many species, and others, like the tuataras, so few? this classic question in evolutionary biology has a deep history and has been studied using both fossils and phylogenetic trees. phylogeny-based studies have focused on tree balance, which compares the number of species across clades of the same age in the tree. these studies have suggested that rates of speciation and extinction vary tremendously across the tree of life. in this issue, ra ...201222952431
phylogenomic analyses support the position of turtles as the sister group of birds and crocodiles (archosauria).the morphological peculiarities of turtles have, for a long time, impeded their accurate placement in the phylogeny of amniotes. molecular data used to address this major evolutionary question have so far been limited to a handful of markers and/or taxa. these studies have supported conflicting topologies, positioning turtles as either the sister group to all other reptiles, to lepidosaurs (tuatara, lizards and snakes), to archosaurs (birds and crocodiles), or to crocodilians. genome-scale data ...201222839781
securing the demographic and genetic future of tuatara through assisted colonization.climate change poses a particular threat to species with fragmented distributions and little or no capacity to migrate. assisted colonization, moving species into regions where they have not previously occurred, aims to establish populations where they are expected to survive as climatic envelopes shift. however, adaptation to the source environment may affect whether species successfully establish in new regions. assisted colonization has spurred debate among conservation biologists and ecologi ...201222827440
more than 1000 ultraconserved elements provide evidence that turtles are the sister group of archosaurs.we present the first genomic-scale analysis addressing the phylogenetic position of turtles, using over 1000 loci from representatives of all major reptile lineages including tuatara. previously, studies of morphological traits positioned turtles either at the base of the reptile tree or with lizards, snakes and tuatara (lepidosaurs), whereas molecular analyses typically allied turtles with crocodiles and birds (archosaurs). a recent analysis of shared microrna families found that turtles are mo ...201222593086
de novo sequence assembly and characterisation of a partial transcriptome for an evolutionarily distinct reptile, the tuatara (sphenodon punctatus).the tuatara (sphenodon punctatus) is a species of extraordinary zoological interest, being the only surviving member of an entire order of reptiles which diverged early in amniote evolution. in addition to their unique phylogenetic placement, many aspects of tuatara biology, including temperature-dependent sex determination, cold adaptation and extreme longevity have the potential to inform studies of genome evolution and development. despite increasing interest in the tuatara genome, genomic re ...201222938396
tooth and cranial disparity in the fossil relatives of sphenodon (rhynchocephalia) dispute the persistent 'living fossil' label.the tuatara (sphenodon punctatus) is the only living representative of rhynchocephalia, a group of small vertebrates that originated about 250 million years ago. the tuatara has been referred to as a living fossil; however, the group to which it belongs included a much greater diversity of forms in the mesozoic. we explore the morphological diversity of rhynchocephalia and stem lepidosaur relatives (sphenodon plus 13 fossil relatives) by employing a combination of geometric morphometrics and com ...201222905810
considering extinction of dependent species during translocation, ex situ conservation, and assisted migration of threatened hosts.translocation, introduction, reintroduction, and assisted migrations are species conservation strategies that are attracting increasing attention, especially in the face of climate change. however, preventing the extinction of the suite of dependent species whose host species are threatened is seldom considered, and the effects on dependent species of moving threatened hosts are unclear. there is no published guidance on how to decide whether to move species, given this uncertainty. we examined ...201222443127
intra-genomic gc heterogeneity in sauropsids: evolutionary insights from cdna mapping and gc(3) profiling in snake.extant sauropsids (reptiles and birds) are divided into two major lineages, the lineage of testudines (turtles) and archosauria (crocodilians and birds) and the lineage of lepidosauria (tuatara, lizards, worm lizards and snakes). karyotypes of these sauropsidan groups generally consist of macrochromosomes and microchromosomes. in chicken, microchromosomes exhibit a higher gc-content than macrochromosomes. to examine the pattern of intra-genomic gc heterogeneity in lepidosaurian genomes, we const ...201223140509
[prehistoric eyes: ophthalmosaurus and the tuatara]. 201223623026
molecular characterization of reptile pathogens currently known as members of the chrysosporium anamorph of nannizziopsis vriesii complex and relationship with some human-associated isolates.in recent years, the chrysosporium anamorph of nannizziopsis vriesii (canv), chrysosporium guarroi, chrysosporium ophiodiicola, and chrysosporium species have been reported as the causes of dermal or deep lesions in reptiles. these infections are contagious and often fatal and affect both captive and wild animals. forty-nine canv isolates from reptiles and six isolates from human sources were compared with n. vriesii based on their cultural characteristics and dna sequence data. analyses of the ...201323926168
using genes as characters and a parsimony analysis to explore the phylogenetic position of turtles.the phylogenetic position of turtles within the vertebrate tree of life remains controversial. conflicting conclusions from different studies are likely a consequence of systematic error in the tree construction process, rather than random error from small amounts of data. using genomic data, we evaluate the phylogenetic position of turtles with both conventional concatenated data analysis and a "genes as characters" approach. two datasets were constructed, one with seven species (human, opossum ...201324278129
cornification in reptilian epidermis occurs through the deposition of keratin-associated beta-proteins (beta-keratins) onto a scaffold of intermediate filament keratins.the isolation of genes for alpha-keratins and keratin-associated beta-proteins (formerly beta-keratins) has allowed the production of epitope-specific antibodies for localizing these proteins during the process of cornification epidermis of reptilian sauropsids. the antibodies are directed toward proteins in the alpha-keratin range (40-70 kda) or beta-protein range (10-30 kda) of most reptilian sauropsids. the ultrastructural immunogold study shows the localization of acidic alpha-proteins in su ...201323065677
how to decide whether to move species threatened by climate change.introducing species to areas outside their historical range to secure their future under climate change is a controversial strategy for preventing extinction. while the debate over the wisdom of this strategy continues, such introductions are already taking place. previous frameworks for analysing the decision to introduce have lacked a quantifiable management objective and mathematically rigorous problem formulation. here we develop the first rigorous quantitative framework for deciding whether ...201324146778
integration of molecules and new fossils supports a triassic origin for lepidosauria (lizards, snakes, and tuatara).lepidosauria (lizards, snakes, tuatara) is a globally distributed and ecologically important group of over 9,000 reptile species. the earliest fossil records are currently restricted to the late triassic and often dated to 227 million years ago (mya). as these early records include taxa that are relatively derived in their morphology (e.g. brachyrhinodon), an earlier unknown history of lepidosauria is implied. however, molecular age estimates for lepidosauria have been problematic; dates for the ...201324063680
granulocytes of reptilian sauropsids contain beta-defensin-like peptides: a comparative ultrastructural survey.the ability of lizards to withstand infections after wounding or amputation of the tail or limbs has suggested the presence of antimicrobial peptides in their tissues. previous studies on the lizard anolis carolinensis have identified several beta-defensin-like peptides that may potentially be involved in protection from infections. the present ultrastructural immunocytochemical study has analyzed tissues in different reptilian species in order to localize the cellular source of one of the more ...201323553853
global taxonomic diversity of living reptiles.reptiles are one of the most ecologically and evolutionarily remarkable groups of living organisms, having successfully colonized most of the planet, including the oceans and some of the harshest and more environmentally unstable ecosystems on earth. here, based on a complete dataset of all the world's diversity of living reptiles, we analyse lineage taxonomic richness both within and among clades, at different levels of the phylogenetic hierarchy. we also analyse the historical tendencies in th ...201323544091
reptiles.most small children can tell you that 'reptiles' are the snakes, lizards, crocodiles, and turtles (perhaps with the dinosaurs thrown in) - suggesting that it's easy to tell the difference between reptiles and other animals. unfortunately, evolutionary biologists struggle with the same task, because phylogenetic analysis tells us loud and clear that these different types of what we loosely call 'reptiles' are not particularly closely related to each other (figure 1). on the evolutionary tree, som ...201323518049
absence of cooperative haemoglobin-oxygen binding in sphenodon, a reptilian relict from the triassic.it is generally accepted that the sigmoidal nature of the haemoglobin-oxygen dissociation curve (odc) is necessary for efficient oxygen transport in terrestrial vertebrates because it allows large volumes of oxygen to be bound or released for relatively small changes in the partial pressure of oxygen (po2) in the blood. furthermore, the amount of oxygen to tissues is increased by hydrogen ions produced from the dissociation of carbon dioxide in solution. the generality of these key features of c ...20136646231
unidirectional pulmonary airflow patterns in the savannah monitor lizard.the unidirectional airflow patterns in the lungs of birds have long been considered a unique and specialized trait associated with the oxygen demands of flying, their endothermic metabolism and unusual pulmonary architecture. however, the discovery of similar flow patterns in the lungs of crocodilians indicates that this character is probably ancestral for all archosaurs--the group that includes extant birds and crocodilians as well as their extinct relatives, such as pterosaurs and dinosaurs. u ...201424336209
immunoreactivity to the pre-core box antibody shows that most glycine-rich beta-proteins accumulate in lepidosaurian beta-layer and in the corneous layer of crocodilian and turtle epidermis.the differentiation of the corneous layers of reptilian epidermis has been analyzed by ultrastructural immunocytochemistry using specific antibodies against the conserved pre-core box region of their keratin-associated beta-proteins (kabetaps, formerly indicated as beta-keratins) and silver-intensification. the epitope analysis in the sequences of different reptilian kabetaps indicates that this antibody recognizes mainly glycine-rich beta-proteins in lizards and snakes. the immunoreactivity of ...201424246129
amino acid sequence homologies in the hard keratins of birds and reptiles, and their implications for molecular structure and physical properties.avian and reptilian epidermal appendages such as feathers, claws and scales exhibit a filament-matrix texture. previous studies have established that both components reside within the same single-chain molecule. in the present study the homology in a wide range of aligned sequences is used to gain insights into the structure and function of the molecular segments associated with the filament and with the matrix. the notion that all molecules contain a β-rich 34-residue segment associated with th ...201425448888
micromechanical characterization of prismless enamel in the tuatara, sphenodon punctatus.dental enamel - a naturally occurring biocomposite of mineral and protein - has evolved from a simple prismless to an advanced prismatic structure over millions of years. exploring the mechanical function of its structural features with differing characteristics is of great importance for evolutionary developmental studies as well as for material scientists seeking to model the mechanical performance of biological materials. in this study, mechanical properties of prismless tuatara sphenodon pun ...201425146675
unusual change in activity pattern at cool temperature in a reptile (sphenodon punctatus).animals that can be active both during day and night offer unique opportunities to identify factors that influence activity pattern. by experimental manipulations of temperatures under constant photoperiod, we aimed to determine if emergence, activity and thermoregulatory behaviour of juvenile tuatara (sphenodon punctatus) varied at different temperatures (20°c, 12°c and 5°c). to help clarify its activity pattern, we compared tuatara with two lizard species endemic of the south island of new zea ...201424802147
the youngest south american rhynchocephalian, a survivor of the k/pg extinction.rhynchocephalian lepidosaurs, though once widespread worldwide, are represented today only by the tuatara (sphenodon) of new zealand. after their apparent early cretaceous extinction in laurasia, they survived in southern continents. in south america, they are represented by different lineages of late cretaceous eupropalinal forms until their disappearance by the cretaceous/palaeogene (k/pg) boundary. we describe here the only unambiguous palaeogene rhynchocephalian from south america; this new ...201425143041
sex ratio bias and extinction risk in an isolated population of tuatara (sphenodon punctatus).understanding the mechanisms underlying population declines is critical for preventing the extinction of endangered populations. positive feedbacks can hasten the process of collapse and create an 'extinction vortex,' particularly in small, isolated populations. we provide a case study of a male-biased sex ratio creating the conditions for extinction in a natural population of tuatara (sphenodon punctatus) on north brother island in the cook strait of new zealand. we combine data from long term ...201424714691
modulation of corticosterone secretion in tuatara (sphenodon punctatus): evidence of a dampened stress response in gravid females.baseline and stress response glucocorticoid (gc) secretion can be modulated by individuals to support activities and physiological functions connected with reproduction (migration, mating, oviposition and/or parturition, care of young). corticosterone (cort) is the primary gc in reptiles and, in accordance with other vertebrates, an adrenocortical stress response is observed. modulation of cort secretion occurs in several reptile species, such that elevated baseline cort concentration and/or a d ...201424713446
understanding publication bias in reintroduction biology by assessing translocations of new zealand's herpetofauna.the intentional translocation of animals is an important tool for species conservation and ecosystem restoration, but reported success rates are low, particularly for threatened and endangered species. publication bias further distorts success rates because the results of successful translocations may be more likely to be published than failed translocations. we conducted the first comprehensive review of all published and unpublished translocations of herpetofauna in new zealand to assess publi ...201424606604
a novel hypothesis for the adaptive maintenance of environmental sex determination in a turtle.temperature-dependent sex determination (tsd) is widespread in reptiles, yet its adaptive significance and mechanisms for its maintenance remain obscure and controversial. comparative analyses identify an ancient origin of tsd in turtles, crocodiles and tuatara, suggesting that this trait should be advantageous in order to persist. based on this assumption, researchers primarily, and with minimal success, have employed a model to examine sex-specific variation in hatchling phenotypes and fitness ...201425009063
investigating kleptothermy: a reptile-seabird association with thermal benefits.studies on interspecific interactions between vertebrates based on thermal benefits are poorly represented in the literature. ecologists know little about a category of thermoregulation termed kleptothermy. we provide evidence that a close association between a medium-sized reptile (tuatara, sphenodon punctatus) and a small seabird (fairy prion, pachyptila turtur) enables the reptile to maintain higher-than-average body temperatures. this is the first multiyear data set to reveal that the presen ...201424642539
reptile reservoirs and seasonal variation in the environmental presence of salmonella in an island ecosystem, stephens island, new zealand.a wide variety of salmonella serotypes occurs within reptilian hosts, but their ecology is poorly understood. we collected cloacal swabs from tuatara (sphenodon punctatus), fairy prions (pachyptila turtur), and skinks (oligosoma spp.) on stephens island, new zealand, to screen for salmonella. soil samples were also collected from inside burrows of tuatara and fairy prions and tested for salmonella. we sampled repeatedly from october 2009 to october 2011. cloacal swabs were collected from 620 tua ...201424807185
antimicrobial peptides in reptiles.reptiles are among the oldest known amniotes and are highly diverse in their morphology and ecological niches. these animals have an evolutionarily ancient innate-immune system that is of great interest to scientists trying to identify new and useful antimicrobial peptides. significant work in the last decade in the fields of biochemistry, proteomics and genomics has begun to reveal the complexity of reptilian antimicrobial peptides. here, the current knowledge about antimicrobial peptides in re ...201424918867
reptilian transcriptomes v2.0: an extensive resource for sauropsida genomics and transcriptomics.despite the availability of deep-sequencing techniques, genomic and transcriptomic data remain unevenly distributed across phylogenetic groups. for example, reptiles are poorly represented in sequence databases, hindering functional evolutionary and developmental studies in these lineages substantially more diverse than mammals. in addition, different studies use different assembly and annotation protocols, inhibiting meaningful comparisons. here, we present the "reptilian transcriptomes databas ...201526133641
investigation of mortalities associated with salmonella spp. infection in wildlife on tiritiri matangi island in the hauraki gulf of new zealand.salmonellosis was suspected as the cause of death in eight wild animals on tiritiri matangi island, in the hauraki gulf of new zealand, between november and september 2011, including three hihi (notiomystis cincta), a tuatara (sphenodon punctatus), a masked lapwing (vanellus miles novaehollandiae), and a saddleback (philesturnus carunculatus). an outbreak investigation to identify the source and distribution of infection was undertaken over the summer of 2011-2012.201525482376
complete mitochondrial genomes of tuatara endemic to different islands of new zealand.tuatara are the sister taxon to the squamata (including lizards and snakes) and are regarded as the most distinctive surviving reptilian genus. they are currently inhabits on offshore islands around new zealand and have been recognized as a species in need of active conservation management. in this study, we report a total number of five nearly complete mitochondrial genomes, which were sequenced by sanger and next generation dna sequencing methods. our phylogenomic analysis revealed distinct cl ...201524156717
resurrecting embryos of the tuatara, sphenodon punctatus, to resolve vertebrate phallus evolution.the breadth of anatomical and functional diversity among amniote external genitalia has led to uncertainty about the evolutionary origins of the phallus. in several lineages, including the tuatara, sphenodon punctatus, adults lack an intromittent phallus, raising the possibility that the amniote ancestor lacked external genitalia and reproduced using cloacal apposition. accordingly, a phallus may have evolved multiple times in amniotes. however, similarities in development across amniote externa ...201526510679
major histocompatibility complex genes map to two chromosomes in an evolutionarily ancient reptile, the tuatara sphenodon punctatus.major histocompatibility complex (mhc) genes are a central component of the vertebrate immune system and usually exist in a single genomic region. however, considerable differences in mhc organization and size exist between different vertebrate lineages. reptiles occupy a key evolutionary position for understanding how variation in mhc structure evolved in vertebrates, but information on the structure of the mhc region in reptiles is limited. in this study, we investigate the organization and cy ...201525953959
distance-dependent patterns of molecular divergences in tuatara mitogenomes.population genetic models predict that populations that are geographically close to each other are expected to be genetically more similar to each other compared to those that are widely separate. however the patterns of relationships between geographic distance and molecular divergences at neutral and constrained regions of the genome are unclear. we attempted to clarify this relationship by sequencing complete mitochondrial genomes of the relic species tuatara (sphenodon punctatus) from ten of ...201525731894
moving house: long-term dynamics of corticosterone secretion are unaltered in translocated populations of a rare reptile (the tuatara, sphenodon punctatus).translocations are an important conservation tool used to restore at-risk species to their historical range. unavoidable procedures during translocations, such as habitat disturbance, capture, handling, processing, captivity, transport and release to a novel environment, have the potential to be stressful for most species. in this study, we examined acute and chronic stress (through the measurement of the glucocorticoid corticosterone) in a rare reptile (the tuatara, sphenodon punctatus). we fou ...201527293699
presence of antibodies to salmonella in tuatara (sphenodon punctatus) sera.colonisation of a host by pathogenic microorganisms is a near constant threat to the health of all vertebrates and most species have evolved an efficient adaptive immune response which produces antibodies following exposure to a specific antigen. the strength of this response can be influenced by many factors including sex and season. tuatara are exposed to salmonella through contact with infected skinks and soil; however, no gastrointestinal colonisation of tuatara with salmonella has been foun ...201526264523
electrocardiographic observations on the tuatara, sphenodon punctatus. 20154400097
ticks imported to europe with exotic reptiles.it is known that traded exotic animals carry with them an immense number of associated symbionts, including parasites. reptiles are no exception. most of the imported reptiles originate from tropical countries and their possibility to carry potentially dangerous pathogens is high. according to cites, europe is currently the main reptile importer in the world. despite this, there is no review or analysis available for the risk related to the importation of tick-borne diseases with traded reptile ...201525913453
anatomy, morphology and evolution of the patella in squamate lizards and tuatara (sphenodon punctatus).the patella (kneecap) is the largest and best-known of the sesamoid bones, postulated to confer biomechanical advantages including increasing joint leverage and reinforcing the tendon against compression. it has evolved several times independently in amniotes, but despite apparently widespread occurrence in lizards, the patella remains poorly characterised in this group and is, as yet, completely undescribed in their nearest extant relative sphenodon (rhynchocephalia). through radiography, osteo ...201626740056
evolution: one penis after all.amniote penises come in many shapes but are missing from the basal tuatara. this has been taken as evidence for multiple evolutionary origins of the penis. now, genital swellings have been found in tuatara embryos, arguing for a single origin.201626766229
detection of paranannizziopsis australasiensis in tuatara (sphenodon punctatus) using fungal culture and a generic fungal pcr.to describe the methods used at the animal health laboratory (ahl, ministry for primary industries) to identify paranannizziopsis australasiensis.201627079795
prevalence of klebsiella oxytoca in anolis carolensis of louisiana.klebsiella oxytoca is a gram-negative bacterium that can be found throughout the environment as well as on mucosal membranes of mammals including humans. this bacterium is responsible for a variety of infections in humans including nosocomial infections resulting in hospital outbreaks. reptiles including snakes, tuataras, and turtles have been shown to harbor this bacterium, and previous studies have shown that pet reptiles are a potential source for dissemination of pathogenic bacteria. green a ...201627779443
evolution of the hippocampus in reptiles and birds.although the hippocampus is structurally quite different among reptiles, birds, and mammals, its function in spatial memory is said to be highly conserved. this is surprising, given that structural differences generally reflect functional differences. here i review this enigma in some detail, identifying several evolutionary changes in hippocampal cytoarchitecture and connectivity. i recognize a lepidosaurid pattern of hippocampal organization (in lizards, snakes, and the tuatara sphenodon) that ...201625982694
dermatomycosis caused by paranannizziopsis australasiensis in five tuatara (sphenodon punctatus) and a coastal bearded dragon (pogona barbata) in a zoological collection in new zealand.health monitoring of tuatara (sphenodon punctatus) at auckland zoo between 2001 and 2009 showed that 58/93 tuatara had been affected by dermatitis of unknown origin. from 2011 onwards, cases of suspected fungal dermatitis underwent extensive diagnostic investigations.201627074995
what was the ancestral sex-determining mechanism in amniote vertebrates?amniote vertebrates, the group consisting of mammals and reptiles including birds, possess various mechanisms of sex determination. under environmental sex determination (esd), the sex of individuals depends on the environmental conditions occurring during their development and therefore there are no sexual differences present in their genotypes. alternatively, through the mode of genotypic sex determination (gsd), sex is determined by a sex-specific genotype, i.e. by the combination of sex chro ...201625424152
developmental and evolutionary origins of the amniote phallus.an intromittent phallus is used for sperm transfer in most amniote taxa; however, there is extensive variation in external genital morphology within and among the major amniote clades. amniote phalluses vary in number (paired, single, or rudimentary), spermatic canal morphology (closed tube or open sulcus), and mode of transition between resting and tumescent states (inflation, rotation, eversion, or muscle relaxation). in a phylogenetic context, these varying adult anatomies preclude a clear in ...201627549197
sesamoid bones in tuatara (sphenodon punctatus) investigated with x-ray microtomography, and implications for sesamoid evolution in lepidosauria.sesamoids bones are small intra-tendinous (or ligamentous) ossifications found near joints and are often variable between individuals. related bones, lunulae, are found within the menisci of certain joints. several studies have described sesamoids and lunulae in lizards and their close relatives (squamata) as potentially useful characters in phylogenetic analysis, but their status in the extant outgroup to squamata, tuatara (sphenodon), remains unclear. sphenodon is the only living rhynchocephal ...201727882577
microanatomy and life history in palaeopleurosaurus (rhynchocephalia: pleurosauridae) from the early jurassic of germany.the tuatara (sphenodon punctatus) from new zealand is often-erroneously-identified as a 'living fossil', although it is the lone survivor of a large, successful radiation of rhynchocephalia, sister taxon to squamates (lizards and snakes), that thrived through the mesozoic and cenozoic and experienced an intricate evolution of life histories and feeding habits. within rhynchocephalia, only pleurosauridae are thought to be marine and piscivorous. here, we present bone histological data of the jura ...201728005148
interspecies differences in plasma concentrations of 25-hydroxyvitamin d3 and dermal vitamin d synthesis of kiwi (apteryx mantelli), tuatara (sphenodon punctatus), and new zealand sea lions (phocarctos hookeri).vitamin d plays a central role in calcium homeostasis of most vertebrates, and is obtained in different species through diet, dermal synthesis, or a combination of both. the aim of this study was to determine the predominant routes of vitamin d synthesis in three disparate species, brown kiwi (apteryx mantelli), tuatara (sphenodon punctatus), and new zealand sea lions (phocarctos hookeri). we surveyed plasma concentrations of 25-hydroxyvitamin d2 and d3, analysed environmental conditions and lif ...201728755031
temperature selection by juvenile tuatara (sphenodon punctatus) is not influenced by temperatures experienced as embryos.most reptiles thermoregulate to achieve body temperatures needed for biological processes, such as digestion and growth. temperatures experienced during embryogenesis may also influence post-hatching growth rate, potentially through influencing post-hatching choice of temperatures. we investigated in laboratory settings whether embryonic temperatures (constant 18°c, 21°c and 22°c) influence selected body temperatures (tsel) of juvenile tuatara (sphenodon punctatus), providing a possible mechanis ...201729037392
bite force in the horned frog (ceratophrys cranwelli) with implications for extinct giant frogs.of the nearly 6,800 extant frog species, most have weak jaws that play only a minor role in prey capture. south american horned frogs (ceratophrys) are a notable exception. aggressive and able to consume vertebrates their own size, these "hopping heads" use a vice-like grip of their jaws to restrain and immobilize prey. using a longitudinal experimental design, we quantified the ontogenetic profile of bite-force performance in post-metamorphic ceratophrys cranwelli. regression slopes indicate po ...201728931936
glucocorticoids in tuatara (sphenodon punctatus): some influential factors, and applications in conservation management.glucocorticoid (gc) hormones promote basic life processes, regulate life-history transitions, and help individuals cope with challenges and stressors, thereby playing an important fitness role. here, we review recent evidence for several factors that influence plasma concentrations of corticosterone (cort), the main gc in tuatara (sphenodon punctatus), and discuss the application of cort as a physiological tool to monitor conservation efforts. observational studies show an association between co ...201726673869
unraveling the influences of climate change in lepidosauria (reptilia).in recent decades, changes in climate have caused impacts on natural and human systems on all continents and across the oceans and many species have shifted their geographic ranges, seasonal activities, migration patterns, abundances and interactions in response to these changes. projections of future climate change are uncertain, but the earth's warming is likely to exceed 4.8 °c by the end of 21th century. the vulnerability of a population, species, group or system due to climate change is a f ...201830509664
two new genera of hard ticks, robertsicus n. gen. and archaeocroton n. gen., and the solution to the mystery of hoogstraal's and kaufman's "primitive" tick from the carpathian mountains.we establish two new monotypic genera, robertsicus n. gen. and archaeocroton n. gen., based on two enigmatic species of amblyomma. robertsicus, with the type species r. elaphensis (price, 1959) n. comb., is proposed for amblyomma       elaphense, the tick of the trans-pecos rat-snake of the chihuahuan desert of mexico and southeastern usa (parts of arizona, west texas and new mexico). archaeocroton, with the type species ar. sphenodonti (dumbleton, 1943) n. comb., is proposed for amblyomma sphen ...201830486049
thermoregulation of a temperate reptile in a forested habitat.a major focus in zoology is to understand the phenotypic responses of animals to environmental variation. this is particularly important when dealing with ectotherms in a thermally heterogenous environment. we measured body temperatures of a free-ranging, medium sized temperate reptile, the tuatara, sphenodon punctatus, to investigate its thermal opportunities and the degree to which the animal actively regulates its body temperature. we found high variation in body temperature between individua ...201829500060
the only known jawed vertebrate with four eyes and the bauplan of the pineal complex.the pineal and parapineal organs are dorsal outpocketings of the vertebrate diencephalon that play key roles in orientation and in circadian and annual cycles. lampreys are four eyed in that both the pineal and parapineal form eyelike photosensory structures, but the pineal is the dominant or sole median photosensory structure in most lower vertebrate clades. the pineal complex has been thought to evolve in a single direction by losing photosensory and augmenting secretory function in the transi ...201829614279
cystatin immunoreactivity in cornifying layers of the epidermis suggests a role in the formation of the epidermal barrier in amniotes.the presence and localization of cystatin, a cysteine protease inhibitor involved in barrier formation in human and mice epidermis, has been studied in the epidermis of piscine and terrestrial vertebrates using a mouse monoclonal antibody. cystatin has been localized by immunostaining in the pre-corneous and corneous layers of monotreme, marsupial and placental mammals, and sparsely in the thin corneous layer of birds. cystatin-immunolabeling is present in the pre-corneous and corneous layer of ...201829503061
behavioral variation in nesting phenology may offset sex-ratio bias in tuatara.the nest environment for eggs of reptiles has lifelong implications for offspring performance and success, and, ultimately, for population viability and species distributions. however, understanding the various abiotic and biotic drivers of nesting is complex, particularly regarding variation in nesting behavior of females and consequences for sex ratios in species with temperature-dependent sex determination (tsd). we investigated how nest construction and nesting phenology affect the incubatio ...201829939491
an exploration of differences in the scaling of life history traits with body mass within reptiles and between amniotes.allometric relationships linking species characteristics to body size or mass (scaling) are important in biology. however, studies on the scaling of life history traits in the reptiles (the nonavian reptilia) are rather scarce, especially for the clades crocodilia, testudines, and rhynchocephalia (single extant species, the tuatara). previous studies on the scaling of reptilian life history traits indicated that they differ from those seen in the other amniotes (mammals and birds), but so far mo ...201829938067
effects of warm temperatures on metabolic rate and evaporative water loss in tuatara, a cool-climate rhynchocephalian survivor.the thermal sensitivity of physiological rates is a key characteristic of organisms. for tuatara (sphenodon punctatus), the last surviving member of the reptilian order rhynchocephalia and an unusually cold-tolerant reptile, we aimed to clarify responses in indices of metabolic rate (oxygen consumption [[formula: see text]] and carbon dioxide production [[formula: see text]]) as well as rates of total evaporative water loss (tewl) to temperatures at the warmer end of the known tolerated range; c ...201829863954
patterns of developmental plasticity in response to incubation temperature in reptiles.early life environments shape phenotypic development in important ways that can lead to long-lasting effects on phenotype and fitness. in reptiles, one aspect of the early environment that impacts development is temperature (termed 'thermal developmental plasticity'). indeed, the thermal environment during incubation is known to influence morphological, physiological, and behavioral traits, some of which have important consequences for many ecological and evolutionary processes. despite this, fe ...201829806741
a comparative study of eggshells of gekkota with morphological, chemical compositional and crystallographic approaches and its evolutionary implications.the gekkota is an important clade in the evolution of calcified eggshells in that some of its families lay rigid eggshells like archosaurs. however, the fundamental differences and similarities between the mechanism of rigid eggshell formation of the gekkota and archosauria have not been investigated thoroughly due to the lack of knowledge of gekkotan eggshells. here, we report for the first time a comprehensive analysis of morphological, chemical compositional, and crystallographic features of ...201829933400
neutron scanning reveals unexpected complexity in the enamel thickness of an herbivorous jurassic reptile.eilenodontines are one of the oldest radiation of herbivorous lepidosaurs (snakes, lizards and tuatara) characterized by batteries of wide teeth with thick enamel that bear mammal-like wear facets. unlike most reptiles, eilenodontines have limited tooth replacement, making dental longevity particularly important to them. we use both x-ray and neutron computed tomography to examine a fossil tooth from the eilenodontine eilenodon (late jurassic, usa). of the two approaches, neutron tomography was ...201829899156
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