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    Mammal-related Cryptosporidium infections in endemic reptiles of New Zealand.
    (Springer Nature, 2023-05-01) Garcia-R JC; Pita AB; Velathanthiri N; Pas A; Hayman DTS
    New Zealand's endemic reptile fauna is highly threatened and pathogens causing infectious diseases may be a significant risk to already endangered species. Here, we investigate Cryptosporidium infection in captive endemic New Zealand reptiles. We found two mammal-related Cryptosporidium species (C. hominis and C. parvum) and six subtypes from three gp60 families (Ib, Ig and IIa) in 12 individuals of captive endemic Tuatara, Otago and Grand skinks, and Jewelled and Rough geckos. Cryptosporidium serpentis was identified in two Jewelled geckos using 18S. In New Zealand, C. hominis and C. parvum are associated with infections in humans and introduced domestic animals but have also been recently found in wildlife. Our finding of Cryptosporidium infection in endemic reptiles can help inform strategies to monitor the conservation of species and manage potential introductions of pathogens to in-situ and ex-situ populations.
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    An investigation of vitamin D metabolism in kiwi (Apteryx mantelli), tuatara (Sphenodon punctatus) and New Zealand sea lion (Phocarctos hookeri) and the relationship of vitamin D metabolism with their life history characteristics : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Studies at Massey University, Turitea, Palmerston North, New Zealand
    (Massey University, 2016) Kale, Madhumita Sanjay
    Vitamin D, a fat-soluble vitamin, has a wide range of functions in vertebrates. The aim of the study was to determine if the evolutionary history of different animal species affects their predominant route of vitamin D metabolism. The species chosen in this study were Brown kiwi (Apteryx mantelli) for their nocturnalism, tuatara (Sphenodon punctatus) for their diurnal sun basking nature and New Zealand sea lion (Phocarctos hookeri), as a marine mammal species. A survey of plasma or serum concentrations of 25-hydroxyvitamin D2 (25(OH)D2) and 25-hydroxyvitamin D3 (25(OH)D3) in kiwi, tuatara and New Zealand sea lion and analysed the ability of skin to produce vitamin D3 in response to UV exposure from post mortem samples of these three species. Assessment of morepork (Ninox novaseelandiae) skin was also carried out as an additional example of a nocturnal species. Wild kiwi had lower plasma 25(OH)D3 concentrations than captive kiwi and this variation was most likely of dietary origin. The low concentrations of plasma 25(OH)D3 in wild kiwi in their natural habitat, suggest that these minimal levels are sufficient to fulfill their vitamin D requirements in the body or they utilise calcium independent of vitamin D. Captive diets for kiwi may be over-supplemented with vitamin D. In contrast to this finding, the skin of both kiwi and morepork was able to produce small but measureable amounts of vitamin D3 in response to UV exposure. This result was unexpected, considering their nocturnal nature and the overall pattern of vitamin D metabolism in the kiwi is still unclear. Vitamin D metabolism in tuatara suggests that both dietary and dermal pathways are important. The survey of plasma 25(OH)D3 concentrations in captive tuatara showed variation between the five zoological institutions, which was correlated to the variation in the dietary vitamin D provided between captive institutions. However, analysis of tuatara skin showed that tuatara had a strong ability to synthesise vitamin D dermally, indicating that it is an important route of vitamin D metabolism in tuatara. New Zealand sea lion showed overall higher serum 25(OH)D3 concentrations than kiwi and tuatara, which might be attributed to the high UV-B radiation exposure they receive in their natural habitat. New Zealand sea lion skin also had comparatively higher vitamin D concentrations both prior to and in response to UV exposure, which shows that dermal route of vitamin D is an important route of metabolism in these marine mammals.
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    Is there sex-specific DNA in the tuatara, a reptile with temperature-dependent sex determination?: a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Ecology at Massey University
    (Massey University, 1999) Quinn, Alex
    It is widely viewed that there is a dichotomy of sex-determining mechanisms within the reptiles: species either exhibit genotypic sex determination or temperature-dependent sex determination (TSD). However, very few species have been examined for both modes. Although it is often considered that the two mechanisms are mutually exclusive, there is evidence that there may be a weak genetic sex-determining mechanism in species in which the primary sex-determining mode is temperature-dependent sex determination. This infers that some TSD individuals may be sex-reversed; that is, their sexual genotype is discordant with their sexual phenotype. This hypothesis of an underlying genotypic system may also be linked to the question of the evolution of sex-determination within the reptiles. The discovery of sex-specific DNA within a TSD reptile could suggest that genotypic sex determination is ancestral and TSD has evolved many times over within independent reptile lineages. This study tested the hypothesis that there is a genetic component to sex determination in TSD species. This was accomplished by searching for sex-specific DNA in the tuatara, a reptile with temperature-dependent sex determination, using two different molecular genetic techniques. The major undertaking of the experimental programme was the completion of a comprehensive minisatellite DNA profiling survey. This incorporated 14 restriction enzymes and five different polycore DNA probes; in total, 66 different probe/enzyme combinations were tested for tuatara genomic DNA. None of the DNA profiles revealed sex-specific fragments. Furthermore, a significant difference in mean fragment numbers for males and females was not detected for any of the probe/enzyme combinations. In addition, a RAPD analysis was conducted in a search for a molecular sex marker in the tuatara. A total of 27 random-sequence oligonucleotide primers were used to successfully amplify anonymous products from the genomic DNA of male and female tuatara. Again, no sex-specific fragments were detected. Thus, evidence of sex-specific genetic differences in the tuatara was not found. This result fails to refute the null hypothesis that there are underlying sexual genotypes in the tuatara. This finding may reflect the absence of genetic sex differences in the tuatara. Alternatively, it might also be the result of accidental inclusion of sex-reversed individuals within the analyses, a situation which could have obscured the sex-specific nature of any sex-linked fragments. It would appear that the key to solving the question of sex-specific DNA within TSD reptiles such as the tuatara lies with the problem of ensuring sex-reversed individuals are excluded from molecular analysis.