Thermal tolerance of early development in tropical and temperate sea urchins: inferences for the tropicalization of eastern Australia

The thermal envelope of development to the larval stage of two echinoids from eastern Australia was characterized to determine whether they fill their potential latitudinal ranges as indicated by tolerance limits. The tropical sand dollar, Arachnoides placenta, a species that is not known to have shifted its range, was investigated in Townsville, northern Australia (19°20′S, 146°77′E), during its autumn spawning season (May 2012). The subtropical/temperate sea urchin, Centrostephanus rodgersii, a species that has undergone poleward range expansion, was investigated in Sydney, southern Australia (33°58′S, 151°14′E), during its winter spawning season (August 2012). The thermal tolerance of development was determined in embryos and larvae reared at twelve temperatures. For A. placenta, the ambient water temperature near Townsville and experimental control were 24 °C and treatments ranged from 14 to 37 °C. For C. rodgersii, ambient Sydney water temperature and experimental control were 17 °C, and the treatment range was 9–31 °C. A. placenta had a broader developmental thermal envelope (14 °C range 17–31 °C) than C. rodgersii (9 °C range 13–22 °C). Both species developed successfully at temperatures well below ambient, suggesting that cooler water is not a barrier to poleward migration for either species. Both species presently live near the upper thermal limits for larval development, and future ocean warming could lead to contractions of their northern range limits. This study provides insights into the factors influencing the realized and potential distribution of planktonic life stages and changes to adult distribution in response to global change.     

Transboundary conservation: An ecoregional approach to protect neotropical migratory birds in South America

Future conservation efforts will need to transcend geopolitical boundaries in efforts to protect entire landscapes and ecosystems. Neotropical migratory birds are as a group a useful conservation tool for linking diverse landscapes and people due to their dependence on multiple habitats, sensitivity to habitat changes, and universal public appeal. The conservation of neotropical migrants can therefore function as a powerful hemispheric umbrella for ecosystem protection. Efforts to protect neotropical migratory birds on their nonbreeding grounds have traditionally been focused on Mexico, Central America, and the Caribbean. To assess the importance of South America to neotropical migrants, an ecoregional classification system was used to determine species distributions in the Andean/Southern Cone Region (Bolivia, Colombia, Ecuador, Paraguay, Peru, and Venezuela). The occurrence of migrants in protected areas that are part of The Nature Conservancy's Parks in Peril program was also assessed. Of the 406 neotropical migrant species, nearly one third (132) occur as regular nonbreeding residents in the region and for almost half of these species (53), South America is their main nonbreeding ground. All Parks in Peril sites were found to harbor neotropical migrants. Forty-eight species (36%) have declining longterm North American Breeding Bird Survey population trends and/or high Partners in Flight concern scores and thus are of significant conservation concern. Most importantly, 29 species (22%) of conservation concern use South America as their primary nonbreeding ground, indicating a need for focused conservation action. The nature of the ecoregional approach used in this endeavor makes future prioritization of ecoregions and conservation strategies for neotropical migrants across national boundaries possible. The ability to link diverse landscapes using a common element such as migratory birds allows for unique transboundary partnerships and opportunities for habitat conservation, which support the goal of the Conservancy's new Migratory Bird Initiative.     

Prenatal diagnosis,fetal pathology and cytogenetic analysis of A 46,XX/47,XX, + 15 mosaic

Mosaic trisomy 15 was prenatally diagnosed on amniotic fluid cells from two consecutive amniocenteses and was confirmed on cells from five different fetal tissues. The proportion of normal versus trisomic cells was consistently higher in the amniotic cell cultures and-with one exception-in the fetal tissues, while serial subcultures gave different results. The slightly atypical external features and internal malformations of the affected fetus as compared to the only clinical observation from the literature are not unusual enough to allow the delineation of a specific malformation pattern.     

Prenatal analysis of the insulin receptor gene in a family with leprechaunism

Leprechaunism is an autosomal recessive disease characterized by intrauterine and postnatal growth restriction, loss of glucose homeostasis, and severe insulin resistance. This disease is caused by a failure of function of the insulin receptor and is lethal early in life. Here we report the prenatal diagnosis of leprechaunism in one consanguineous family, Atl-1, in which two homozygous-affected siblings died with leprechaunism. The mutation in their insulin receptor impaired insulin binding and altered receptor signalling. Prenatal diagnosis could not be accomplished using insulin binding to cultured amniocytes, but was possible using mutational analysis of the insulin receptor gene in DNA from amniotic cells.