Non-marine Ostracods Research Articles

Recent non-marine ostracods (Crustacea) from New Caledonia (Melanesia, Pacific Ocean)

The New Caledonian Archipelago is a hot spot for biodiversity and endemism. Here, we report on new records of nine species from localities on the main island, Grande Terre, and illustrate these: Ilyodromus viridulus (Brady, 1886), Stenocypris hislopi Ferguson, 1969, S. macedonica Petkovski & Meisch, 1996¸ S. malayica Victor & Fernando, 1981, Bradleytriebella lineata (Victor & Fernando, 1981), Hemicypris pyxidata (Moniez, 1892), Heterocypris incongruens (Ramdohr, 1808), Cypridopis vidua (O.F. Müller, 1776) and Limnocythere stationis Vávra, 1891. We also provide redescriptions and illustrations of the valves and carapace of Stenocypris marginata Daday, 1910 sensu Méhes, 1939, Cypris granulata Daday, 1898 and Kennethia major (Méhes, 1939); for the latter species also including some soft parts. Therefore, twenty two certain species have thus far been reported from the New Caledonian Archipelago. The status of seven uncertain species is also discussed. Previous records of Stenocypris major (Baird, 1859) from Grande Terre, mainly by Méhes, are here considered to belong to S. hislopi. We propose to reject the presence of Cyprinotus cingalensis Brady, 1886 in New Caledonia and suggest to consider Cypridopsis sarasini Méhes, 1939 as an “uncertain species” (sensu Meisch et al. 2019). We also argue that Eucypris wolffhuegeli Méhes, 1914 might be a synonym of H. incongruens and suggest that Strandesia rouxi Méhes, 1939 might be considered a junior synonym of an existing species, pending further research.

Determining diagnostic characteristics of the nonmarine Ostracoda (Crustacea) and their habitat selection with unique functional traits in the Kastamonu province (Türkiye)

Nonmarine ostracods are widely distributed in a variety of aquatic habitats, from mountain lakes to underground waters, where each species tends to show species-specific habitat preferences with unique functional traits to increase their survival chances. To understand the patterns of such a relationship between habitat preferences and functional traits of the species, 101 different aquatic sites in the Kastamonu province (Türkiye) were randomly sampled during August 2023. A total of 39 ostracods (20 species, 19 unnamed taxa) were encountered from 49 sites. Seventeen species are new reports for the province. Among them, six species are the most common species with cosmopolitan (or cosmoecious) characteristics. The contribution of these species to the diversity of alpha species (p < 0.05) was more than 90 %. The species with relatively high ecological tolerances generally unveiled low-optimum estimates. Canonical correspondence analysis explained 62.5 % of the correlation between environmental variables and species in which redox potential, electrical conductivity, calcium, and pH were found to be the most related variables to the species (p < 0.05). Fundiversity analysis showed that the presence of swimming setae was correlated with high values of functional diversity, functional richness, and functional distribution of species among five elevation ranges. The results of the habitat selection index and the standardized selection index coincided with the functional traits of the most common species. The species characterized by their habitat selection can be considered as diagnostic species of those specific habitats. Among them, Neglecandona neglecta, reported primarily from dams, springs, and troughs, is considered a typical diagnostic species of these habitats, while Cypridopsis vidua found in lakes and dams can be used as an indicator species for these types of lentic habitats. Similarly, three species (Heterocypris incongruens, Ilyocypris bradyi, Psychrodromus olivaceus) can play a critical role as diagnostic species in troughs but reporting them from different habitats such as ditches and rivers / lakes (I. bradyi) and dams (P. olivaceus and H. salina) indicated their wide range of habitat preferences. Hence, the results suggest that the occurrence of diagnostic species seems to correspond to certain habitat types and their functional traits.

Multiple short-lived marine incursions into the interior of Southwest Gondwana during the Aptian

The Lower Cretaceous sediments of the Sanfranciscana Basin, southeast Brazil, are considered to have been deposited under a Gondwanan continental context. However, different authors have occasionally observed marine elements in these same deposits. This study analyzes samples from five sections of the Sanfranciscana Basin, Quiricó and Três Barras formations, to characterize the paleoenvironment around these marine incursions. We recovered continental (non-marine ostracods and palynomorphs) and marine microfossils (e.g., foraminifera, radiolarians, and ascidian spicules). The alternance of quartz-rich biogenic chert and claystone might be indicative of the occurrence of radiolarites in the studied sessions. The presence of the radiolarian genus Turbocapsula sp., the radiolarian species Holocryptocapsa fallax, and the palynomorph Tucanopollis crisopolensis enabled us to date the interval as early Aptian. Based on the lithologies and microfossils recovered, we interpreted the studied interval as a continental setting that was episodically subjected to marine incursions. We propose three successive paleoenvironmental scenarios: (1) an initial lacustrine depositional setting with a non-marine biota; (2) a second stage, characterized by the presence of episodic marine influence in the sedimentary succession (as evidenced by radiolarians, foraminifera and ascidians), and (3) the return to continental settings dominated by aeolian dune fields. These environmental scenarios characterize the initial development of the Central Segment of the South Atlantic Ocean.

New contributions to the taxonomy of non-marine ostracods from the Neogene megawetlands, western Amazonas state, Brazil

The taxonomic review of the ostracods from Solimões Formation in the western Amazonas State, Brazil, allowed the identification of eight genera and twenty-two species of the genus Cyprideis Jones, 1857. Two species are new: Cyprideis goeldiensis sp. nov and Cyprideis javariensis sp. nov.; and Cyprideis sp. 1 remains in open nomenclature. For the first time, the species Cyprideis santaelenae Sousa and Ramos 2023, originally described to the Pebas Formation, in Peru, was recorded in the Solimões Formation. A new morphotype of the species Cyprideis matorae Gross et al. 2014 is here identified. The stratigraphical distribution of the Cyprideis species in the borehole 1AS-32-AM permitted the identification of four ostracod zones: Cyprideis caraionae Zone, Cyprideis minipunctata Zone, Cyprideis cyrtoma Zone and Cyprideis paralela Zone, presenting a time range from the middle Miocene (Serravallian) to the late Miocene (Tortonian). Based on the ostracod assemblage, an environment of a semiconfined lake, with mesohaline features and sporadic marine influence is attested to the western Amazonia during the Miocene. The species turnover of Cyprideis occurred during the Tortonian.

Assessment of rarity and ecological preferences of the non-marine ostracods (Crustacea) in Çanakkale Province (Türkiye)

Rarity as a multidimensional concept has not been discussed for the ostracods along with the effects of physicochemical factors and sedimentation rates of waters on their distribution. We randomly sampled 91 aquatic sites including eight habitat types in the Çanakkale Province to study ostracod species rarity, commonness, and ecological preferences, and to test the relationships between the rarity index (average of geographic range, habitat specificity, and population size indices) and environmental factors. A total of 44 ostracod taxa (25 living) were reported from 75 sites. Among the species, Candonocypris caledonica was recorded for the first time in Türkiye. Sixty percent of 25 living species exhibited cosmopolitan characteristics, making significant contributions to the diversity of ostracods. The well-known cosmopolitan species, Heterocypris salina (rr = 0.268), Cypridopsis vidua (rr = 0.289), Limnocythere inopinata (rr = 0.330), Ilyocypris bradyi (rr = 0.370), and Psychrodromus olivaceus (rr = 0.390), were identified as common species based on the rarity index (rr) values. Of the environmental variables, only sediment grain sizes (×2000, ×500, and ×63 μm) were found to be effective on the distribution of ostracod species. The Shannon index exhibited a positively significant association with ×2000, while the population size index displayed a linear relationship with ×63 μm grain size, indicating a small population size and rarity. Associations among index values, sediment grain size, and water quality variables showed that comprehensive studies on ostracods, analyzing both water and sediment, can provide a clearer and more precise information for evaluating the rarity and ecological preferences of species.

Taxonomy, ontogeny, and ecology of Tonnacypris stewarti (Daday 1908) comb. nov. (Ostracoda: Cyprididae) from Nam Co, Tibetan Plateau

Taxonomic clarification of Tonnacypris stewarti comb. nov. (= Herpetocypris stewarti), a non-marine ostracod first described by Daday in 1908, was required due to the existence of various synonyms without detailed morphological descriptions. Our study examined specimens from Mang-tsa, Nam Co (Tibetan Plateau) and Lake Band-e Amir (Afghanistan). We identified seven definitive synonyms (Herpetocypris stewarti Daday 1908, Ilyodromus estonicus Järvekülg 1960, Eucypris afghanistanensis Hartmann 1964, E. gyirongensis Yang 1982, E. rischtanica Schneider 1963 in Mandelstam &amp; Schneider 1963, Tonnacypris estonica (Järvekülg 1960), and T. gyirongensis (Guo et al. 2016). After a detailed study of the morphology of valves and soft parts supplemented by a literature review, we propose combining the genus Tonnacypris with the specific epithet stewarti, resulting in the new name Tonnacypris stewarti. We documented the ontogenetic series of T. stewarti in surface sediment samples from Nam Co. Only female specimens were found, consistent with observations in Mongolia, where they were considered asexual populations. Sexual populations were reported from Afghanistan and the southern Tibetan Plateau, suggesting geographic parthenogenesis in the Palearctic region. Because of widely missing males, we explored the use of female genital lobes as a distinguishing feature for taxonomy. Considering current ecological knowledge, T. stewarti could serve as a (paleo)—bioindicator of cold, oligotrophic, and fresh to slightly brackish habitats, including rivers, lagoons, and lakes. This study emphasizes the importance of resolving taxonomic issues for future paleolimnological research. Moreover, our investigation highlights the potential use of sclerotized internal female genital lobes as distinctive characteristics for species differentiation, especially in asexual populations.

First record of males of &lt;i&gt;Cypridopsis vidua&lt;/i&gt; (Crustacea, Ostracoda) species complex for Europe

Until recently, only asexually reproducing populations were known in Cypridopsis vidua, a species complex with one of the widest geographical distributions among non-marine ostracods. The discovery of males, most likely functional, from the United States and China has called into question its obligate parthenogen status. Here we report the first report of males for Europe, found in a small artificial pond in northern Italy. It seems plausible that sexual populations are much more widespread than hitherto known, as the recognition of males requires the dissection of individuals. Compared with the available descriptions of males belonging to Cypridopsis vidua and related species, that of the male illustrated here show morphological differences in the antennulae and prehensile palps, which in the Cypridoidea are sexually dimorphic and often diagnostic to distinguish between related species. Adult males show significantly smaller valve sizes than adult females, while adult females in which sperm were found inside the carapace have more variable lengths than those without sperm. No differences in valve coloration or dark banding pattern were found between males and females, and differences in valve outline were mostly negligible. The limitations of an exclusively morphological approach in the case of similar morphospecies are highlighted, as well as the importance of adopting objective criteria to measure the limits of morphological variability allowing the identification of separate taxonomic entities.

Non-marine ostracods from the Cretaceous Banyaweol and Geoncheonri formations (Gyeongsang Basin, Korea) in the collections of the Geological Museum, KIGAM: Taxonomy, biostratigraphy, palaeobiogeography and palaeoenvironment

ABSTRACT The Geological Museum of the Korea Institute of Geoscience and Mineral Resources (KIGAM) houses a large collection of microfossils. From these collections, 14 species belonging to six genera of non-marine ostracods from the Banyaweol and Geoncheonri formations of the Gyeongsang Basin, South Korea are identified: Cypridea sp. 1, C. sp. 2, C. sp. 3, C. sp. 4, C. sp. 5, C? sp. 6, Lycopterocypris triangularis, L. cf. profunda, Candona declivis, C. sp. Cypria cf. elata, Djungarica sp. Ziziphocypris costata and Z. rugosa. The biostratigraphic correlation based on L. triangularis and C. declivis from the Cenomanian Banyaweol Formation suggests that these species appeared at a much earlier stage than the previous records from China. Ostracods of the Banyaweol Formation may represent a transitional fauna during the mid-Cretaceous faunal turnover in East Asia. However, L. cf. profunda and C. cf. elata suggest a Turonian – Santonian age (probably extend upwards into Campanian) for the Geoncheonri Formation. Many non-endemic species of both formations indicate that these faunas were linked with ostracod faunas of East Asia, providing evidence of active faunal exchanges and migration. The palaeoenvironments of both formations are interpreted as ephemeral waterbodies and unstable shallow-littoral zone of lakes based on faunal compositions.

Distribution of non-marine ostracods in the streams of the Ceyhan River Basin (Turkey) and assessment of their indicator properties for water quality

Distribution of non-marine ostracods in the streams of the Ceyhan River Basin (Turkey) and assessment of their indicator properties for water quality

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 from 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. Additionally, variation between individual ostracods due to season and age most likely contributed further to the failure of the three used experimental approaches to quantify damage. In a second experiment, we investigated the influence of temperature on survival of D. stevensoni during UVB exposure. The estimated relative 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 lack of adaptation to low temperatures and/or the presence of metabolic processes active at room temperature protecting against UVB damage in D. stevensoni. The latter possibility could also explain why the estimated relative lethal UVB dose of D. stevensoni is similar to that of other non-marine ostracods where valves provide around 80% protection, despite the valves of D. stevensoni providing less protection. If such metabolic processes can repair UVB damage quickly, this may provide an alternative explanation why we could not quantify UVB damage in D. stevensoni.

Non-marine Ostracoda (Crustacea) collected from pet shops and a hobbyists aquaria in Japan, including two new species.

Samples obtained from pet shops and a hobbyists aquaria in Japan have revealed a diverse non-marine ostracod fauna, consisting of 19 species, all contaminants of aquaria stocked with exotic fish, shrimps and/or aquatic plants. Of these, six are newly recorded for Japan, including two new species, belonging to the genera Pseudostrandesia and Tanycypris. Pseudostrandesia tenebrarum Smith & Ozawa, 2021, previously suspected to be an alien species in Japan, was again found in pet shops in this study. We also report living specimens of Potamocypris acuminata Fuhrmann & Goth, 2011, a species previously only known from Pleistocene deposits of Germany. The six new records for Japan reported herein are likely alien species as evidenced by previous records or congeneric species, with origins in East Asia, South East Asia, and the Americas. Thus, there are now seven ostracod species recognized as probable alien hitchhikers in the Japanese pet trade. This study highlights that the pet trade is a viable route for hitchhiking ostracod species to enter Japan, and such species have the potential to become invasive.

Functional diversity and functional traits correlate ecology of nonmarine Ostracoda (Crustacea) at different elevational ranges

Functional diversity and functional traits correlate ecology of nonmarine Ostracoda (Crustacea) at different elevational ranges

Distribution and relationships of non-marine ostracods (Crustacea, Ostracoda) with water quality variables in Amasya province (Türkiye)

Distribution and relationships of non-marine ostracods (Crustacea, Ostracoda) with water quality variables in Amasya province (Türkiye)

An updated checklist of recent non-marine Ostracoda (Crustacea) from Venezuela.

Information on the known species diversity of the non-marine ostracods in Venezuela is compiled from the available literature. The review resulted in 34 species and two varieties, belonging to the superfamilies Cypridoidea and Cytheroidea. Of these, the presence of one species should be confirmed for the country. Furthermore, eight taxonomic entities classified with open nomenclature are mentioned. As additional contributions to the annotated list, georeferences of the records are included, as well as amendments in names and information for some localities. Finally, information about the distribution of some species, which were erroneously assigned to other biogeographic areas, is clarified, which is essential to optimizing the accuracy of subsequent analyses.

Non-marine ostracod fauna from the Cretaceous Xiagou Formation (Jiuquan Basin, NW China): Taxonomy, biostratigraphy, palaeogeography and palaeoenvironment

The non-marine ostracod fauna of the Xiagou Formation of the Chijinpu Group in the Jiuquan Basin of northwestern China includes Bisulcocypridea astuta, Cypridea koskulensis, C. yumenensis, C. latiovata, C. cf. elegantula, Limnocypridea? diwopuensis, Candona sp., Lycopterocypris debilis, Mongolianella gigantea, Rhinocypris jurassica, Ziziphocypris costata, Alicenula? leguminella, Limnocythere xiagouensis and L. fragilis. Comparison of the Xiagou Formation ostracod fauna with those from Northeast China, Mongolia, Central Asia and Russia indicates that the Xiagou Formation is Aptian in age. The stratigraphic ranges of the Cypridea valdensis–parallela group, R. jurassica and L. fragilis are extended to the Aptian. The known distributions of ostracod taxa—especially the Cypridea valdensis–parallela group, Bisulcocypridea and L. fragilis—in ostracod faunas of Europe, Asia and North America provides evidence that intercontinental and continental ostracod faunal exchanges were active during the Early Cretaceous. Dispersal of these ostracods occurred alongside known dispersal events of non-marine vertebrates between Asia and Europe as well as between Asia and North America, which may imply that large animals (i.e., dinosaurs) played an important role in intercontinental invertebrate faunal interchange. In addition, Aptian palaeolakes/ponds in northwestern China were important in forming isolated environments for the explosive radiation of the superfamilies Cypridoidea and Cytheroidea, and they also provided non-marine habitats for the migration of ostracod species from other continents. The ostracod fauna indicates that the Xiagou Formation represents a fresh to slightly saline shallow to littoral-marginal lacustrine environment with a fluvial influence that may have included shallow temporary waterbodies (e.g., ponds).

Mixed marine, brackish water, non-marine, and subaerial microfaunal association in the Red Marls Formation of the Western Aurès Basin (Upper Paleocene)

In the western part of the Aurès Basin (northeastern Algeria), the Red Marls of El Kantara Formation records a mixed microfaunal association of non-marine-brackish ostracoda, marine foraminifera, lacustrine charophytes, and subaerial Microcodiums. Based on the recovered biotic component, it is considered that the Red Marls of El-Kantara Formation date from the upper Paleocene (Thanetian). Seven species of brackish water (Neocyprideis raoi) and non-marine ostracoda (Frambocythere tumiensis anjarensis, Paracypretta jonesi, Paracypretta verruculosa, Limnocythere deccanensis, Darwinula torpedo and Zonocypris spirula), have been discovered for the first time in Algeria and on the south Tethyan margin. Paleoenvironmentally, the overall biotic assemblage recovered indicates the presence of a freshwater palustrine/lacustrine depositional system connected to a low energy stream/river. This indicates that marginal marine conditions were prevalent in northeastern Algeria’s far inland regions. Paleobiogeographically, the seven known ostracod species have limited distributions that are until now common only with India. However, this disproved the theory that these species are endemic to the Indian Subcontinent, which is confirmed by their association with cosmopolitan charophytes. Keywords: limnic ostracoda, charophytes, paleobiogeography, Thanetian, western Aurès, Algeria.

A bioprovince for the Barremian–Aptian charophytes of the Central Tethyan Archipelago

A comprehensive bibliographic compilation of dozens of worldwide records of charophytes from the Barremian to early Aptian interval has been revisited aiming to gather the regional and global distribution data for the clavatoracean family. The compiled data were studied with the palaeontological statistics software PAST (PAleontological STatistics), using a cluster analysis. All analyses of the biogeographic data revealed a consistent separation of the Central Tethyan Archipelago (CTA) from other palaeogeographic areas, mainly the neighbouring Eurasian and American landmasses, based on the species richness of Family Clavatoraceae.The Central Tethyan Archipelago (CTA) is hence, proposed as a distinct bioprovince for Early Cretaceous charophytes, called the Clavatoracean Bioprovince, based on the abundance and especially the biodiversity of clavatoracean taxa (up to 26 taxa). Within the Archipelago, species distribution primarily shows a latitudinal pattern suggesting that the charophyte floras were subjected to climatic control. However, longitudinal relationships between areas in the eastern or western parts of the CTA were also found. In spite of these internal subdivisions of the Clavatoracean Bioprovince, the flux of populations between the islands must have been sufficiently strong to maintain taxonomic homogeneity within the archipelago throughout the time interval analysed. These biogeographic patterns are compared with those of non-marine ostracods for the same time interval, showing strong similarities and suggesting that they may be equivalent for other non-marine benthic organisms.

An annotated checklist of recent non-marine Ostracoda (Crustacea) from Argentina, South America.

According to an updated list of extant non-marine ostracods, there are 2,330 subjective species in 270 genera in the world, of which 333 species are known from the Neotropical region. However, the knowledge about the ostracod fauna in Argentina is scarce, fragmented and incomplete. Thus, the aim of this study was to present the first checklist of the recent non-marine ostracods from Argentina, including geographical distributions and ecological characteristics of the species. Thus far, 66 ostracod species in 33 genera and 7 families have been recorded in non-marine Argentinian environments. Of the total number of species, 29% can be considered endemic to the country. Most of the species were recorded in alkaline, freshwater to oligohaline cold waters and mainly in low to moderate altitude environments. Our results showed that most studies were mainly carried out in the Pampean and Patagonia region and, therefore, the diversity record of ostracods in Argentina is biased towards these regions.

Ostracods from the Kunming area of SW China, with description of two new species and male records of Cypridopsis vidua (O.F. Mller, 1776).

Previous studies of the Recent non-marine ostracods of Yunnan Province in southwestern China yielded 42 species, among which only 18 species were reported based on living material. Such a low number is likely to underestimate the species diversity of ostracods in Yunnan, considering the geographical disparity among its different parts. In this study, we report 11 nominal species and one species left in open nomenclature from 22 samples collected from the Kunming area in eastern-central part of Yunnan. Among these species, seven are new to the province, including Notodromas semiovata n. sp., Chrissia acuminata n. sp., and the first records of the male of Cypridopsis vidua (O.F. Mller, 1776) outside the USA. A review of previous literature indicates that, with the exception of the two new species, all the other 23 species have Palaearctic (PA) distributions, while only 14 have Oriental (OL) distributions. Such a composition contradicts previous vertebrate-based zoogeographical subdivisions of China in which Yunnan was included in the OL region, and adds to the argument that the geographical distributions of various invertebrate groups need to be investigated to map the PAOL boundary in China more appropriately.

Environmental correlates of non-marine ostracod (Crustacea: Ostracoda) assemblages of the Eastern Cape (South Africa)

Environmental correlates of non-marine ostracod (Crustacea: Ostracoda) assemblages of the Eastern Cape (South Africa)