The kiwi of all skinks: an unusual egg size in a species of Madascincus (Squamata: Scincidae) from eastern Madagascar

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Adjustment of the reproductive activity of vulnerable lizard phymaturus williamsi at high altitudes

In environments with cold climates, reproduction of lizards is restricted to short seasonal periods of activity, from mid-spring to early autumn. We studied the reproductive biology of Phymaturus williamsi (William’s Andean Lizard), a vulnerable and viviparous lizard from the palluma phylogenetic group of genus Phymaturus, endemic to rocky outcrops in cold environments in the Andes of San Juan, Argentina. We determined adult size, male and female reproductive cycles, litter size, mean annual reproductive output, and the relationship between gonadal cycles, fat bodies, and climatic variables. The shortest reproductive male and female were 87.2 mm and 86.4 mm SVL, respectively. The litter size per female was of one or two offspring every two years, and the mean annual reproductive output was 0.95 offspring/female/year. Births occurred from late summer to early autumn. Males exhibited an annual postnuptial cycle, with spermatogenesis beginning in mid-spring, spermiogenesis occurring in summer and autumn, and sperm stored during brumation through early spring when mating occurs. The male post-nuptial cycle is common in species of the patagonicus group, but not in the palluma group, as is P. williamsi. Nevertheless, the biennial female cycle is common in the palluma group, and results from the adjustment of the reproductive activity to the physiological and environmental constraints of the harsh and cold climatic conditions prevailing at high altitudes in the Andes. The knowledge of the reproductive traits of the vulnerable P. williamsi has direct relevance for the development of conservation strategies, as this information is fundamental for population viability analyses.Fil: Castro, Susana Alejandra. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Boretto, Jorgelina Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Blanco, Graciela Mirta. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; ArgentinaFil: Acosta, Juan Carlos. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentin

Exotic Reptiles in the Pet Trade: Are They a Threat to New Zealand?

Worldwide, invasive species are associated with severe ecological and economic impacts. As a group, reptiles are very successful invaders and in some areas where they have established they are responsible for the decline of native fauna and economic disruptions, whilst also posing a threat to human health. Due to its biogeographical isolation and unique evolutionary history, New Zealand is highly susceptible to invasive species. Importation of reptiles into New Zealand is illegal, however over a dozen species of exotic reptile are legally present in captivity and their risk of establishment is unknown. This study investigates their establishment potential and possible impacts by considering 1) the amount of trade and propagule pressure of species, 2) the degree of climate match between their native range and New Zealand, 3) areas that may be suitable for establishment based on physiological models of incubation and development, 4) their ability to transfer pathogens to native fauna and humans, and 5) overall establishment risk. The red-eared slider (Trachemys scripta elegans; RES) is the most common and easily obtained exotic reptile pet in New Zealand, with over 800 sales per annum. The RES is also the species most regularly released into the wild. Climate matching models in this study were developed to minimise false-negative predictions, to generate a suitability score irrespective of the prevalence of species records (allowing species to be easily compared to one another), and incorporated a weighted multimodel average prediction based on the relative importance of climatic variables to each species. These correlative models indicated that the blotched blue-tongue skink (Tiliqua nigrolutea) had the highest degree of climate match with parts of New Zealand, while the common blue-tongue skink (T. scincoides) had the highest proportion of land area predicted to be suitable for establishment. The other 10 species generally had both low climate match scores and limited areas within New Zealand predicted to be suitable. Mechanistic models focus upon environmental influences on physiological processes of a species, such as development and growth. Degree-day models, combined with soil measurements in potential reptile nesting sites in New Zealand, were utilised to determine if environmental conditions were suitable for the successful reproduction of oviparous exotic reptiles. These models predicted that the New Zealand environment meets the minimum thermal requirements for the incubation of eggs of RES, snake-neck turtles (Chelodina longicollis), and Reeves turtles (Chinemys reevesii). While prevalence of Salmonella in exotic reptiles is higher than that of native reptiles, it is considerably lower than that of exotic reptiles overseas. All serovars identified in this study had been previously reported both in humans and reptiles in New Zealand. The overall risk assessment for 12 species of exotic reptile kept in captivity in New Zealand indicates that blotched blue-tongue skinks and RES pose the highest establishment risk. Blotched blue-tongue skinks are allegedly only present in zoos. Therefore, based on propagule pressure, RES pose the highest establishment risk and efforts should focus on minimising release events and removing feral individuals from the New Zealand environment. In summary, at least eight species of exotic reptile legally traded within New Zealand are predicted to be capable of surviving in a portion of the New Zealand environment and at least three species have the potential to successfully breed in warmer microclimates. However, further research involving climatic tolerances and breeding potential (i.e., soil moisture content, juvenile survival, sex ratio, and predicted climate change) is recommended. Public education and possible regulations imposed on the New Zealand exotic reptile trade may prevent introductions of these species into the local environment and still allow selected species to be enjoyed by the New Zealand public. The methods developed in this study may be easily applied to other species and other geographic regions, allowing investigation into the establishment risk of alien species. This may help guide control and management efforts and help stem the tide of the growing problem of invasive species

Reproductive cycle of the house gecko, Hemidactylus flaviviridis, in Oman in relation to morphological and ultrastructural changes and plasma steroid concentrations with reference to localisation of progesterone receptors

In Oman, a comprehensive study of the annual reproductive cycles of male and female house geckos, Hemidactylus flaviviridis was conducted. Circulating testosterone (T), oestradiol (E2) and progesterone (P) concentrations were measured using a sensitive HPLC-MS/MS detection technique. Data were collected from a natural population over two consecutive seasons. The annual patterns of circulating concentrations of T, E2 and P were measured for both sexes. In males, peak plasma T, E2 and P concentrations occurred in the active phase, coinciding with the stages of spermatogenesis, courtship and mating, but gradually declined in the second half of the mating period with a significant drop in the quiescent phase, coinciding with testicular regression. In females, elevated plasma E2 and T concentrations in the active phase were associated with vitellogenesis and mating. Plasma E2 concentrations decreased significantly during the quiescent phase, coinciding with follicular regression. Plasma P concentrations were elevated during gravidity but fell significantly prior to oviposition. The plasma steroid concentrations were related to the steroidogenic ultrastructural features and expression of progesterone receptors (PR) throughout the reproductive cycle. The steroidogenic ultrastructural features were characterized by the presence of smooth endoplasmic reticulum (SER) in the form of cisternal whorls and tubular cisternae, presence of swollen vesiculated mitochondria and association between SER, mitochondria, and lipid droplets. In the male, the rise in the three plasma steroid concentrations during the active phase was closely associated with the development of the ultrastructural features and strong PR expression in Leydig and Sertoli cells. During the quiescent phase, there was a significant decline in plasma steroid concentrations, undeveloped steroidogenic features and weakly expressed PR. In the female, the appearance of the steroidogenic ultrastructural features in the preovulatory and lutein granulosa cells was correlated with the significant rise in the three steroid concentrations and the strong expression of PR. As the steroid concentrations declined, the granulosa cells underwent general degeneration and disruption of the ultrastructural steroidogenic features. These detailed findings are the first to be reported for this species in the Arabian Peninsula. Based on histological and gross morphological observations, the house gecko ovulates two eggs at a time, one from each ovary. This is followed by a second two egg clutch, suggesting that this species lays two clutches of eggs annually, each clutch containing two eggs. The comprehensive data obtained from this study may be of some value for comparison with reproductive cycles of other closely related species in this region. In addition, conservation awareness for the protection of this widely distributed species may be beneficial for the protection of other wildlife.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Can Assisted Reproductive Technologies Help Conserve 300 Million Years of Evolution? A First Attempt at Developing These Technologies for Male Reptiles

Biodiversity loss is the most critical environmental problem threatening ecosystem, animal, and human health today. Increases in extinction rates have been observed over the past 50 years, with reptile losses occurring twelve times faster than traditional extinction rates. This demonstrated biodiversity loss is secondary to climate change, habitat destruction, infectious disease, invasive species, poaching, and unsustainable trade. Approximately 20% of all reptiles are threatened with extinction and population declines are approaching rates similar to the current amphibian extinction crisis. Preventing the extinction of reptiles will require humans to acknowledge these losses and develop plans to preserve these evolutionary sentinel species. Assisted reproductive technologies (ART) are well developed in a handful of species, and these technologies have become integral parts of conservation programs for threatened and endangered species. The creation of functional and sustainable reproductive assistance programs for reptiles using ART will strengthen our conservation capacity. Combining ART with an understanding of reproductive physiology will enable scientists to capture genetic material from different animals housed at different institutions, overcoming reproductive barriers. Subsequent gamete transport will reduce the need to transport animals from stressful or dangerous environments for breeding. Additionally, these gametes could be stored indefinitely to preserve genetic diversity. The goal of this research was to systematically apply ART to male reptiles. Semen was safely and successfully collected from veiled (Chamaeleo calyptratus) and panther chameleons (Furcifer pardalis) using electroejaculation. The annual reproductive cycles of these two chameleons were characterized under captive conditions, and both species follow season breeding cycles. Human chorionic gonadotropin can be used to increase circulating plasma testosterone concentrations in veiled chameleons. Short-term cooled semen storage can be done in red-eared sliders (Trachemys scripta elegans) and diamondback water snakes (Nerodia fasciata) using Ham’s F10, INRA 96, and sperm washing buffer; green anole (Anolis carolinensis) semen could not be stored using these same extenders. Red-eared slider turtle spermatozoa motility was lost following cryopreservation, but plasma membrane integrity remained. Reptile survival is dependent on how we plan today. ART will help us develop programs to preserve the genetics of these sentinel animals

The global diversity and distribution of lizard clutch sizes

Aim Clutch size is a key life‐history trait. In lizards, it ranges over two orders of magnitude. The global drivers of spatial and phylogenetic variation in clutch have been extensively studied in birds, but such tests in other organisms are lacking. To test the generality of latitudinal gradients in clutch size, and their putative drivers, we present the first global‐scale analysis of clutch sizes across lizard taxa. Location Global. Time period Recent. Major taxa studied Lizards (Reptilia, Squamata, Sauria). Methods We analysed clutch‐size data for over 3,900 lizard species, using phylogenetic generalized least‐square regression to study the relationships between clutch sizes and environmental (temperature, precipitation, seasonality, primary productivity, insularity) and ecological factors (body mass, insularity, activity times, and microhabitat use). Results Larger clutches are laid at higher latitudes and in more productive and seasonal environments. Insular taxa lay smaller clutches on average. Temperature and precipitation per se are unrelated to clutch sizes. In Africa, patterns differ from those on other continents. Lineages laying small fixed clutches are restricted to low latitudes. Main conclusions We suggest that the constraint imposed by a short activity season, coupled with abundant resources, is the main driver of large‐clutch evolution at high latitudes and in highly seasonal regions. We hypothesize that such conditions – which are unsuitable for species constrained to laying multiple small clutches – may limit the distribution of fixed‐clutch taxa