Contribution à l’histologie des glandes nasales externes de Sphenodon punctatus Gray (Reptilia, Rhynchocephalia)

1973 ◽  
Vol 84 (3) ◽  
pp. 452-464
Author(s):  
M. Gabe ◽  
H. Saint Girons
Keyword(s):  
Sphenodon Punctatus

scholarly journals Evidence of two deeply divergent co-existing mitochondrial genomes in the Tuatara reveals an extremely complex genomic organization

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
J. Robert Macey ◽  
Stephan Pabinger ◽  
Charles G. Barbieri ◽  
Ella S. Buring ◽  
Vanessa L. Gonzalez ◽  
...  
Keyword(s):  
Genomic Organization ◽  
Phylogenetic Analyses ◽  
Genomic Polymorphism ◽  
Sequencing Technologies ◽  
Cold Tolerant ◽  
Long Read ◽  
Sphenodon Punctatus ◽  
Nucleotide Divergence ◽  
Mitochondrial Heteroplasmy ◽  
Transmembrane Regions

AbstractAnimal mitochondrial genomic polymorphism occurs as low-level mitochondrial heteroplasmy and deeply divergent co-existing molecules. The latter is rare, known only in bivalvian mollusks. Here we show two deeply divergent co-existing mt-genomes in a vertebrate through genomic sequencing of the Tuatara (Sphenodon punctatus), the sole-representative of an ancient reptilian Order. The two molecules, revealed using a combination of short-read and long-read sequencing technologies, differ by 10.4% nucleotide divergence. A single long-read covers an entire mt-molecule for both strands. Phylogenetic analyses suggest a 7–8 million-year divergence between genomes. Contrary to earlier reports, all 37 genes typical of animal mitochondria, with drastic gene rearrangements, are confirmed for both mt-genomes. Also unique to vertebrates, concerted evolution drives three near-identical putative Control Region non-coding blocks. Evidence of positive selection at sites linked to metabolically important transmembrane regions of encoded proteins suggests these two mt-genomes may confer an adaptive advantage for an unusually cold-tolerant reptile.

Thermal sensitivity of reptilian melatonin rhythms: "cold" tuatara vs. "warm" skink

1989 ◽  
Vol 256 (5) ◽  
pp. R1160-R1163 ◽  
Author(s):  
B. T. Firth ◽  
M. B. Thompson ◽  
D. J. Kennaway ◽  
I. Belan
Keyword(s):  
Environmental Conditions ◽  
Thermal Sensitivity ◽  
Cold Temperature ◽  
Daily Rhythm ◽  
Threshold Temperature ◽  
Daily Rhythms ◽  
Thermoregulatory Behavior ◽  
Lower Amplitude ◽  
Sphenodon Punctatus ◽  
Reptilian Species

Daily rhythms in plasma melatonin levels were compared in two ecologically diverse reptilian species under natural environmental conditions in autumn. The nocturnal, cold temperature-adapted tuatara (Sphenodon punctatus) had a melatonin rhythm of much lower amplitude than did the diurnal desert-adapted sleepy lizard (Tiliqua rugosa). Experiments in controlled laboratory environments showed that, although both species are capable of attaining a comparable melatonin peak (approximately 750 pmol/l), the threshold temperature at which a significant daily rhythm occurs is approximately 15 degrees C in S. punctatus compared with approximately 25 degrees C in T. rugosa. This difference probably reflects the disparate thermoregulatory adaptations of the two species, S. punctatus favoring mean activity temperatures of 11.5 degrees C and T. rugosa, 32.5 degrees C. In ectotherms such as reptiles, therefore, species-typical thermoregulatory behavior may provide thermal cues that interact with photoperiod to provide the appropriate melatonin signal for the regulation of annual physiological cycles.

scholarly journals Corticosterone secretion in tuatara (Sphenodon punctatus): Influential factors and conservation applications

2021 ◽  
Author(s):  
◽  
Lindsay Erin Anderson
Keyword(s):  
Breeding Season ◽  
Physiological Stress ◽  
Population Variation ◽  
Monitoring Tool ◽  
Extrinsic Factors ◽  
Corticosterone Secretion ◽  
Wide Range ◽  
Sphenodon Punctatus ◽  
Gravid Females

<p>Animals are regularly exposed to environmental, social and physiological challenges. In reaction to these challenges, individuals adjust their physiology and behaviour to maintain essential processes and optimise fitness. The most widely used indicators of physiological stress in vertebrates are glucocorticoid hormones (corticosterone (CORT) or cortisol), which are commonly referred to as ‘stress hormones’. The use of CORT as a tool to understand how individuals respond to natural or human-caused challenges is central to stress physiology research. Here, I investigated intrinsic and extrinsic factors associated with CORT secretion, CORT secretion as an indicator of physiological response to challenges/stressors, and the value of CORT secretion as conservation tool in an iconic protected reptile (the tuatara, Sphenodon punctatus).  A capture-restraint time series revealed a significant CORT response over a 24 h period in male and female (non-gravid and gravid) tuatara. Baseline CORT and the CORT response to capture and restraint (i.e. a standardised capture-stress protocol) were similar between sexes; however, female reproductive condition was correlated with CORT secretion in that higher baseline CORT and a lower CORT response were observed in gravid females. An observational study incorporating data across a wide range of ambient temperatures (from four island sites) confirmed that body temperature (Tb) is positively correlated with baseline CORT in gravid females only, and revealed a positive correlation between the CORT response and higher Tb in all adults. A supporting experimental study showed that acute ambient temperature increase (in which mean Tb reached 21.4±0.4°C) elicits a significant CORT response to capture-restraint in gravid females. These results confirmed that gravid females are not secreting CORT maximally during nesting, but actively modulate secretion. An inter-island comparison of CORT secretion (for four populations) revealed that baseline CORT secretion was similar among populations during the non-breeding and breeding seasons; however, the CORT response to capture-restraint varied significantly among populations. Inter-population variation in testosterone (T) was observed in males (but not females) and was positively linked with increased baseline CORT from the non-breeding season to the breeding season, suggesting male reproductive activity may drive seasonal change of baseline CORT. Significant correlations were observed between the CORT response to capture-restraint (but not baseline CORT) and habitat elements of latitude, tuatara density and seabird abundance and 2) demogenetic factors of sex ratio and genetic diversity. The measurement of CORT as a physiological monitoring tool indicated that short- and long- term dynamics of CORT secretion in tuatara are not altered through translocation to a new island, as the acute CORT response remained stable throughout exposure to cumulative stressors and long-term dynamics of CORT secretion in translocated populations simultaneously mirrored those in source populations.  These findings deliver the most detailed study of CORT secretion patterns in tuatara to date. Moreover, as the first study to apply CORT secretion data as an conservation physiology monitoring tool in tuatara, these results serve as a baseline reference for future research and monitoring of conservation efforts.</p>

scholarly journals Unravelling causality from correlations: revealing the impacts of endemic ectoparasites on a protected species (tuatara)

Parasitology ◽  
2009 ◽  
Vol 137 (2) ◽  
pp. 275-286 ◽  
Author(s):  
STEPHANIE S. GODFREY ◽  
JENNIFER A. MOORE ◽  
NICOLA J. NELSON ◽  
C. MICHAEL BULL
Keyword(s):  
Body Condition ◽  
Conservation Management ◽  
Essential Element ◽  
The Body ◽  
Protected Species ◽  
Manipulative Experiments ◽  
Sphenodon Punctatus ◽  
Correlative Studies ◽  
Experimental Structure

SUMMARYUnderstanding 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 on Stephens Island (New Zealand), which encompassed the pre-peak, peak and post-peak infestation periods for each ectoparasite. Tick loads during the peak infestation period were negatively related to body condition of tuatara. Body condition before the peak was not related to subsequent infestation rates; however, tick loads in the peak were negatively related to subsequent changes in body condition. Mite loads during the peak infestation period were not correlated with body condition of tuatara. Body condition before the peak had no effect on subsequent mite infestation rates, but mite loads of small males during the peak were negatively related to subsequent changes in body condition. Our results suggest that both ectoparasites reduce the body condition of tuatara, which has implications for the long-term conservation management of this host and its parasites.

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