Extraordinary morphological changes in valve morphology during the ontogeny of several species of the Australian ostracod genus Bennelongia (Crustacea, Ostracoda)

Ostracods belonging to the genus Bennelongia differ much in valve morphology between adults and juveniles. Adult valves are asymmetrical, characterised by a beak-like feature in the anteroventral region of the left valve, and, with some notable exceptions, mostly have smooth or weaklyornamented valves. Juvenile specimens, on the other hand, have valves that are almost symmetrical, with no beak-like feature and are often heavily ornamented. We have examined the last 3 - 4 juvenile stages of 6 Bennelongia species from 5 different lineages, in order to decipher the types of external valve ornamentation and their recurrences during ontogeny and across lineages. It is clear that ornamentation is more prevalent at the early instar stages compared to the last 2 pre-adult stages, and especially when compared to the adult stage itself. We also examined the surprising presence of a calcified inner lamella with a prominent inner list in the pre-adult stages of Bennelongia species, that is usually absent in juveniles of other ostracods, thus questioning if heterochronic processes have provided an intermediate valve morphology between the simple (normal) cypridinid juvenile state and the heavily derived and modifi ed state of adult Bennelongia. We discuss the possible (speculative) functionality of the ornamentation in juveniles

Decolonisation Processes in the South Pacific Islands: A Comparative Analysis between Metropolitan Powers

The South Pacific islands came late, by comparison with Asia and Africa, to undertake the decolonising process. France was the first colonial power in the region to start off this process in accordance with the decision taken in Paris to pave the way to independence for African colonies. The Loi-cadre Defferre in 1957, voted in Parliament, was applied to French Polynesia and New Caledonia as it was to French Africa. Territorial governments were elected in both these Pacific colonies in 1957. They were abolished in 1963 after the return to power of General de Gaulle who decided to use Moruroa for French atomic testing. The status quo ante was then to prevail in New Caledonia and French Polynesia up to today amidst statutory crises. The political evolution of the French Pacific, including Wallis and Futuna, is analysed in this article. Great Britain, New Zealand and Australia were to conform to the 1960 United Nations' recommendations to either decolonise, integrate or provide to Pacific colonies self-government in free association with the metropolitan power. Great Britain granted constitutional independence to all of its colonies in the Pacific except Pitcairn. The facts underlying this drastic move are analysed in the British context of the 1970's, culminating in the difficult independence of Vanuatu in July 1980. New Zealand and Australia followed the UN recommendations and granted independence or self-government to their colonial territories. In the meantime, they reinforced their potential to dominate the South Pacific in the difficult geopolitical context of the 1980s. American Micronesia undertook statutory evolution within a strategic framework. What is at stake today within the Pacific Islands is no longer of a political nature; it is financial

Trace-element and stable-isotope composition of the Cyprideis torosa (Crustacea, Ostracoda) shell

Shells of Cyprideis, a widespread euryhaline ostracod, have commonly been used in geochemical investigations involving determinations of trace elements (especially magnesium and strontium) and isotopes (of oxygen, carbon and strontium). In this paper, we evaluate geochemical signatures in Cyprideis based on new and previously published data. Mg/Ca and Sr/Ca determinations of fossil shells that calcified in marine-type water have potential to reconstruct palaeotemperature and past water composition using empirical relationships derived from living ostracods recovered from in vitro cultures or natural settings. For shells that calcified in non-marine waters of contrasting composition, partitioning of trace metals from water into ostracod shells may differ, meaning that relationships developed for marine waters do not apply. However, variations in Mg/Ca and Sr/Ca in Cyprideis in continental settings may still provide valuable palaeohydrological information. Determinations of oxygen isotopes in Cyprideis shells are consistent with positive offsets from equilibrium, in common with other ostracod taxa: carbon-isotope values reflect the fact that Cyprideis is a detritivore. Oxygen-isotope analyses of Cyprideis shells from continental settings provide important palaeohydrological information. Strontium-isotope analyses of Cyprideis shells provide valuable records of mixing of marine and continental water in marginal-marine settings. Geochemical analyses of different morphotypes of Cyprideis lend support to suggestions that ecophenotypic variations are controlled by factors other than, or additional to, salinity

Intraspecific variation in recent populations of Globigerinoides ruber from the eastern Indian Ocean: evidence from test morphology and geochemistry

Abstrac

Germanium incorporation into sponge spicules: Development of a proxy for reconstructing inorganic germanium and silicon concentrations in seawater

Measurements of germanium (Ge) in deep-sea sponge skeletons are presented for sponges collected by dredge and for spicules isolated from a range of deep-sea sediment cores. Germanium to silicon (Si) ratios (Ge/Sisp) for sponge silica ranged between 0.07

Airborne dust traffic from Australia in modern and Late Quaternary times

A review is provided of first-documented occurrences of dust transport within Australia for the last century, but which later on were considerably improved as a result of access to satellite observations and extensive ground observations. This was followed by the use of the HYSPLIT tracking models that enabled people to determine the major sources of dust in Australia. As a result of several important studies, the Lake Eyre Basin in central Australia is now considered to be the main source of dust entrainment, although other regions do contribute to dust production.Many of the chemical analyses of the Australian dust samples were performed during the tenure of an Australian Research Council Discovery grant DP0772180

Cyprideis torosa: a model organism for the Ostracoda?

In 1990 Danielopol et al.described the ostracod genus Cytherissa as 'the Drosophila of paleolimnology' in the sense of a model organism for their purposes at that time. In the intervening years Drosophila is no longer seen by biologists as the perfect test model and, for example, the nematode worm Caenorhabditis elegans is now viewed as preferable because 'the fly is much more complex than the worm and the anatomy of the nervous system has not reached the level of completeness achieved for the worm' (Brenner 2003, p. 278). For some years attention has focused on Cyprideis torosa (Jones, 1850), especially since the pioneering work of Rosenfeld & Vesper (1977) on sieve-pore variability in this species in relation to salinity, because torosa is a particularly widely distributed euryhaline living and fossil ostracod species. Cyprideis torosa is not only biogeographically widespread but occurs in a salinity range from freshwater to hypersaline, tolerates a wide range of temperature, oxygen and substrate conditions, and also has a large, well-calcified and easily preserved carapace. The species first occurs in sedimentary formations of early Pleistocene age but may be older. Therefore, it has the potential to be an ostracod model organism. This set of thematic papers is designed to summarize our current knowledge of one of the most important living ostracod species, its distribution, ecology, morphological response to environmental pressures, and molecular characterization, together with our understanding of its origins and value for palaeoenvironmental interpretation. The ultimate aim is to define potentially rewarding research targets using C. torosa as a model organism

Trace-element and stable-isotope composition of the Cyprideis torosa (Crustacea, Ostracoda) shell

Shells of Cyprideis, a widespread euryhaline ostracod, have commonly been used in geochemical investigations involving determinations of trace elements (especially magnesium and strontium) and isotopes (of oxygen, carbon and strontium). In this paper, we evaluate geochemical signatures in Cyprideis based on new and previously published data. Mg/Ca and Sr/Ca determinations of fossil shells that calcified in marine-type water have potential to reconstruct palaeotemperature and past water composition using empirical relationships derived from living ostracods recovered from in vitro cultures or natural settings. For shells that calcified in non-marine waters of contrasting composition, partitioning of trace metals from water into ostracod shells may differ, meaning that relationships developed for marine waters do not apply. However, variations in Mg/Ca and Sr/Ca in Cyprideis in continental settings may still provide valuable palaeohydrological information. Determinations of oxygen isotopes in Cyprideis shells are consistent with positive offsets from equilibrium, in common with other ostracod taxa: carbon-isotope values reflect the fact that Cyprideis is a detritivore. Oxygen-isotope analyses of Cyprideis shells from continental settings provide important palaeohydrological information. Strontium-isotope analyses of Cyprideis shells provide valuable records of mixing of marine and continental water in marginal-marine settings. Geochemical analyses of different morphotypes of Cyprideis lend support to suggestions that ecophenotypic variations are controlled by factors other than, or additional to, salinity