Ostracods from freshwater and brackish environments of the Carboniferous of the Midland Valley of Scotland : the early colonization of terrestrial water bodies

The Mississippian Strathclyde Group of the Midland Valley of Scotland yields some of the earliest non-marine ostracods. The succession records shallow marine, deltaic, estuarine, lagoonal, lacustrine, fluvial and swamp environments representing a series of staging-posts between fully marine and limnetic settings. Macrofossils and ostracods are assigned to marine, marginal marine, brackish and freshwater environments based on their faunal assemblage patterns. Key brackish to freshwater ostracods are Geisina arcuata, Paraparchites circularis n. sp., Shemonaella ornata n. sp. and Silenites sp. A, associated with the bivalves Anthraconaia, Carbonicola, Cardiopteridium, Curvirimula, Naiadites, the microconchid ‘Spirorbis’, Spinicaudata and fish. Many Platycopina and Paraparchiticopina ostracods are interpreted as euryhaline, which corresponds with their occurrence in marine to coastal plain water bodies, and supports the ‘estuary effect’ hypothesis of non-marine colonization. The success of non-marine colonization by ostracods was dependent on the intrinsic adaptations of ostracod species to lower salinities, such as new reproductive strategies and the timing of extrinsic mechanisms to drive non-marine colonization, such as sea-level change. The genus Carbonita is the oldest and most common freshwater ostracod, and went on to dominate freshwater environments in the Late Palaeozoic

Hurdles in investigating UVB damage in the putative ancient asexual Darwinula stevensoni (Ostracoda, Crustacea)

Ostracoda or mussel-shrimps are small, bivalved Crustacea. Because of their excellent fossil record and their broad variety of reproductive modes, ostracods are of great interest as a model group in ecological and evolutionary research. Here, we investigated damage and repair of one of the most important biological mutagens, namely UVB radiation in the putative ancient asexual ostracod Darwinula stevensoni from Belgium. We applied three different methods: the Polymerase Inhibition (PI) assay, Enzyme-Linked Immuno Sorbent Assay (ELISA) and dot blot. All three techniques were unsuccessful in quantifying UVB damage in D. stevensoni. Previous experiments have revealed that the valves of D. stevensoni provide an average UVB protection of approximate 60%. Thus, UVB damage could be too little to make quantitative experiments work. Additional variation between individual ostracods due to season and age most likely contributed further to the failure of the three used experimental approaches. In a second experiment, we investigated the influence of temperature on survival of D. stevensoni during UVB exposure. The estimated lethal UVB dose at 4°C was with 50 kJ/m2 significantly lower than at room temperature with 130 kJ/m2. This could either indicate adaptation to low temperatures and/or the presence of metabolic processes against UVB damage in D. stevensoni. These results could also explain why the estimated lethal UVB dose of D. stevensoni is similar to that of other non-marine ostracods where valves provide around 80% protection, although the valves of D. stevensoni provide less protection. If such metabolic processes can repair UVB damage fast, they might be an alternative explanation why we could not quantify UVB damage in D. stevensoni

Ostracods (Crustacea) associated with microbialites across the Permian-Triassic boundary in Dajiang (Guizhou Province, South China)

26 samples were processed for a taxonomic study of ostracods from the Upper Permian (Changhsingian) - Lower Triassic (Griesbachian) interval of the Dajiang section, Guizhou Province, South China. 112 species belonging to 27 genera are recognized. Five new species are described: Acratia candyae sp. nov, Bairdia adelineae sp. nov., Bairdia? huberti sp. nov., Bairdia jeromei sp. nov., Orthobairdia jeanlouisi sp. nov. The unexpected survival faunas associated with microbial formations in the aftermath of the end-Permian extinction are documented for the first time. Ostracod biodiversity variations and palaeo-environmental modifications associated with microbial growth through the Permian-Triassic boundary (PTB) are discussed

Ostracods from a Marmara Sea lagoon (Turkey) as tsunami indicators

This is the post print version of the article. The official published version can be obtained from the link below - Copyright @ Elsevier Ltd.A 352 cm long sediment core from Hersek Lagoon (Gulf of İzmit) was investigated for its ostracod species composition in order to evaluate the potential of ostracods to detect tsunami deposits in coastal environments. The Gulf of İzmit is the eastern bay of the Marmara Sea which is tectonically controlled by the North Anatolian Fault. Ostracod shells are rare in the lower third of the core, which probably represents a coastal wetland environment. According to radiocarbon dating of terrestrial plant remains, this unit was deposited between AD 500 and AD 800. Above, ostracod shells are abundant and dominantly monospecific, composed almost exclusively of the widespread brackish water ostracod Cyprideis torosa. This almost monospecific occurrence indicates the establishment and maintenance of the Hersek Lagoon after AD 800. Three distinct layers of mollusc shells and fragments contain ostracod shells of marine and to a lesser extent non-marine origin in addition to those of C. torosa. The shell layers are further characterized by significant maxima in total ostracod shell numbers. The high concentration of ostracod shells, the higher species numbers and the mixture of marine, lagoonal and non-marine ostracod shells shows that shell layers were formed as high-energy deposits resulting from tsunamis or large storms in the Marmara Sea. The partial occurrence of non-marine ostracod shells in the shell layers possibly indicates that tsunamis with extensive run-ups and significant backwash flows caused the high-energy deposits rather than large storms. The investigated sediments show that lagoonal ostracods can serve as good proxies for tsunamis or large storms through significant variations in total shell numbers, species numbers and the mixing of shells of different origin.Funding was provided by the European Union in the framework of the REL.I.E.F. (RELiable Information on Earthquake Faulting) project (EVG1-CT-2002-00069)

Re-description of Strandesia sanoamuangae Savatenalinton & Martens, 2010 and description of a new species of Strandesia (Crustacea, Ostracoda) from Grande Terre, New Caledonia

The New Caledonian Archipelago is a hot spot for biodiversity and endemism. Whereas popular groups such as birds and plants are well-studied, invertebrate groups such as ostracods remain ill-known. Here, we re-describe Strandesia sanoamuangae Savatenalinton & Martens, 2010, originally described from Thailand (8000 km away from New Caledonia), and describe Strandesia mehesi sp. nov. Both species are known only from females. Material for the present study was collected from diverse aquatic non-marine habitats from Grande Terre, the main island of New Caledonia. Whereas S. sanoamuangae is seemingly easily identifiable, S. mehesi sp. nov. is part of the Strandesia vinceguerrae/vavrai species cluster in the genus, of which the 'older' species (described long ago) often have incomplete and superficial descriptions. Differentiation between the new species and the other members of this species cluster are based on small anatomical details of the valves. The current paper updates the known number of recent freshwater Ostracoda of New Caledonia from 14 to 16 species, although at least five of these species have an uncertain status

Coastal evolution in a Mediterranean microtidal zone: mid to late Holocene natural dynamics and human management of the Castelló lagoon, NE Spain

© 2016 Ejarque et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. We present a palaeoenvironmental study of the Castelló lagoon (NE Spain), an important archive for understanding long-term interactions between dynamic littoral ecosystems and human management. Combining geochemistry, mineralogy, ostracods, diatoms, pollen, non-pollen palynomorphs, charcoal and archaeo-historical datasets we reconstruct: 1) the transition of the lagoon from a marine to a marginal environment between ∼ 3150 cal BC to the 17 th century AD; 2) fluctuations in salinity; and 3) natural and anthropogenic forces contributing to these changes. From the Late Neolithic to the Medieval period the lagoon ecosystem was driven by changing marine influence and the land was mainly exploited for grazing, with little evidence for impact on the natural woodland. Land-use exploitation adapted to natural coastal dynamics, with maximum marine flooding hampering agropastoral activities between ∼ 1550 and ∼ 150 cal BC. In contrast, societies actively controlled the lagoon dynamics and become a major agent of landscape transformation after the Medieval period. The removal of littoral woodlands after the 8 th century was followed by the expansion of agrarian and industrial activities. Regional mining and smelting activities polluted the lagoon with heavy metals from the ∼ 11 th century onwards. The expansion of the milling industry and of agricultural lands led to the channelization of the river Muga into the lagoon after ∼ 1250 cal AD. This caused its transformation into a freshwater lake, increased nutrient load, and the infilling and drainage of a great part of the lagoon. By tracking the shift towards an anthropogenically-controlled system around∼ 750 yr ago, this study points out Mediterranean lagoons as ancient and heavily-modified systems, with anthropogenic impacts and controls covering multi-centennial and even millennial timescales. Finally, we contributed to the future construction of reliable seashell-based chronologies in NE Spain by calibrating the Banyuls-sur-Mer ▵ R offset with ceramic imports from the Emporiae archaeological site

Ostracoda during the early Aptian (early Cretaceous) greenhouse period on the Isle of Wight, England

The earliest Aptian marine transgression of the Lower Cretaceous across southern England resulted in the collapse of the generally freshwater Barremian environment and the initiation of marine mileux. Salinities passed from fresh-oligohaline to meso- and pliohaline, reaching fully marine conditions during the obsoletum Subzone (P. fissicostus Zone). Newly formed environmental niches were rapidly occupied by ostracod associations. In the Isle of Wight, freshwater Cypridea-rich assemblages in the lower Shepherd's Chine Member (Vectis Formation) were gradually replaced by faunas dominated by Sternbergella cornigera, Mantelliana mantelli and Theriosynoecum fittoni. Marine taxa recorded from the Atherfield Clay Formation migrated predominantly from the Paris Basin and include Asciocythere albae, Schuleridea derooi, Neocythere gottisi, N. bordeti, Cythereis geometrica, Cytheropteron stchepinskyi and Protocythere croutesensis

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