The population genetics of the ostracode Cyprinotus incongruens on the basis of esterase markers

Different digenic esterase clones of Cyprinotus incongruens reach maturity and die in their own time. Thus, when comparing populations, the presence or absence of clones rather than their frequency should be taken into account. There are no clear geographical relationships concerning the clonal composition of populations. The migration rate is in general quite high, especially to longer distances of about 200 km; the beginning of the isolation of populations by distance can be detectable in Central Europe over distances of at least 400 km. This clonal composition of populations is determined firstly by the founder effect, amplified by the “priority effect” when the founder population increases in numbers, and secondly by mutations. With regards to loci studied here (those coding for esterases), founder individuals are more likely to be doubly homozygous than singly or doubly heterozygous. Thus, the heterozygosity which arises by mutation is severely reduced at the suprapopulation level.     

Few parasites,and no evidence for Wolbachia infections,in a freshwater ostracod inhabiting temporary ponds

Biological systems with asexual reproduction have often attracted research on parasites and host immune defence, because parasites are expected to be better able to exploit genetically less diverse populations. In addition, maternally inherited parasitic microorganisms such as Wolbachia can directly alter the reproductive systems of their hosts and induce parthenogenesis. In the freshwater ostracod Eucypris virens, both sexual and asexual reproduction is known, and we speculated that parasite pressures might help to explain their co‐existence. This species complex inhabits shallow, often eutrophic temporary water bodies, conditions that should provide ample opportunities for parasite infections. We surveyed natural populations of E. virens throughout its Europe‐wide range for natural parasites, and particularly tested for the presence of intracellular Wolbachia bacteria. Surprisingly, the results indicate that very few E. virens populations support parasite infections. We also found no evidence for the presence of Wolbachia in the populations screened. The results therefore show that parasitic infections do not play a role in the maintenance of sex in this system. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 207–216.     

Austromesocypris bluffensis sp. n. (Crustacea, Ostracoda, Cypridoidea, Scottiinae) from subterranean aquatic habitats in Tasmania, with a key to world species of the subfamily

Austromesocypris bluffensissp. n. is described and we report another species, Austromesocypris sp., both collected from subterranean aquatic habitats in Tasmania. This discovery adds a major taxonomic group to the already diverse invertebrate cave fauna of Tasmania, and is of interest because, globally, obligate subterranean aquatic species (stygobites) are poorly represented within the family Cyprididae. The genus Austromesocypris Martens, De Deckker & Rossetti, 2004 is otherwise known to comprise entirely "terrestrial or semi-terrestrial" species. The second species is not described because only juvenile specimens were collected. Both species stand apart from their congeners by the carapace shape, which is rectangular in Austromesocypris bluffensis and triangular and asymmetrical in the unnamed species. Another unique feature of the new species is the almost symmetrical uropodal rami. We also identify some broader systematic issues within the Scottiinae including the position of two New Zealand species, Scottia audax (Chapman, 1961) and Scottia insularis Chapman, 1963 in the genus, and point out their closer relationship to the Gondwana genera of Scottiinae, Austromesocypris and Mesocypris Daday, 1910, than to the Palearctic genus Scottia Brady & Norman, 1889, based on the morphology of the maxillula and mandibula. The identity of the Australian records of Scottia audax (Chapman, 1961), Austromesocypris australiensis (De Deckker, 1983) and the Boreal records of Scottia pseudobrowniana Kempf, 1971 are all considered doubtful. A key to the world species of Scottiinae is provided.     

Anchialine Gyprididae (Ostracoda) from the Galapagos Islands, with a review of the subfamily Paracypridinae

The five species of Cyprididae collected from anchialine habitats of the Galapagos Islands include Paracypris crispa, previously described from marine caves and reefs on Bermuda, and the freshwater species Strandesia stocki, which is widely distributed in wells of the West Indies. Three new species, Dolerocypria ensigera, Mungava recta and Hansacypris galapagosensis, contribute to more precise understanding of these circumtropical genera. A review of known soft-anatomical characters for 68 species of Paracypridinae, five of which are transferred to different genera, reveals too many inconsistencies for a simple hypothesis. The current classification of Paracypridinae into three tribes and 18 genera may be overly subdivided, and elevation of Paracypridinae to family rank is not warranted.     

Globotalicypridea mirabilis sp. nov. – the first non-marine ostracod taxon from the Upper Cretaceous of the Haţeg Basin,Romania

A monospecific assemblage of Globotalicypridea mirabilis sp. nov. is reported from the Maastrichtian of the Ha?eg Basin, Romania. This new species is the first ostracod taxa described from the famous dinosaur-bearing continental deposits of the Ha?eg Basin. G. mirabilis sp. nov. is characterized by large, finely punctate, and posteriorly strongly inflated carapace with a few papillae on the anterior margin. This new species was restricted exclusively to freshwater (limnic-fluvial) environments. The identification in Ha?eg Basin of Globotalicypridea expands the known geographic distribution of the Talicyprideinae into Eastern Europe, creating a link between Western European and Asian occurrences.     

The origins of modern nonmarine ostracod faunas: evidence from the Late Cretaceous and Early Palaeogene of Mongolia

The Cretaceous and Tertiary development of Mongolian non-marine ostracod faunas is reviewed. During the Late Cretaceous and Early Palaeogene, representatives of the Cypridoidea were widespread and common, Cytheroidea less so and the Darwinuloidea comparatively rare. The evolutionary history of the subfamily Talicyprideinae is considered, with reference to the genera Talicypridea, Altanicypris, Khandiaand Bogdocypris. It is suggested that the extinct Talicyprideinae were related to the mid-Cretaceous to Recent subfamily Cypridinae (e.g. the genus Cypris), both belonging to the family Cyprididae. It is shown that early representatives of the Cyprididae, one of the most diverse non-marine cypridoidean families today, were present from Early Cretaceous onwards (e.g. Lycopterocypris, Mongolocypris), alongside the dominant Cretaceous cypridoideans, the Cyprideidae (e.g. Cypridea), which became extinct in the Palaeogene.     

The ontogeny of appendages of Heterocypris salina (Brady, 1868) Ostracoda (Crustacea)

The post-embryonic development of the appendages of the Cyprididae ostracod Heterocypris salina (Brady, 1868) are described in detail and compared with those of other podocope species documented in previous studies. Generally, the appearence of limbs during onotgeny of H. salina is similar to that of other species, but small differences in limb morphologies were identified between H. salina and other Cyprididae species, including other Heterocypris species. Some features appear either earlier or later in the development of H. salina compared with other species, even species of the same genus. These features may be useful characters for phylogenetic analyses at the genus and family levels.