Fossil Ostracod Research Articles

Geological Heritage of the Três Barras Farm section, Ordovician-Silurian record in the Paraná Basin, Brazil

The Três Barras Farm section is an outcrop located at the northern edge of the Paraná Basin, in Midwest Brazil. Rocks from the Ordovician-Silurian period are found in this section, represented by the Iapó and Vila Maria formations of the Rio Ivaí Group, which lie directly on the crystalline basement. Devonian rocks of the Furnas Formation are also visible at the top of the section. Although the first fieldwork was conducted there in 1985, the site has been visited by multiple generations of researchers, often for paleontological studies. The fossil record in this section includes invertebrates such as mollusks and brachiopods, mineralized microfossils like ostracods, and palynomorphs such as acritarchs and cryptospores. Analyses conducted up until the 2000s suggested a Lower Silurian age for the complete strata of the Vila Maria Formation, with no invertebrate fossils reported. However, since then, knowledge about the Rio Ivaí Group and the Três Barras Farm section has advanced. Recent studies have challenged the previously assigned Silurian age, with fossil ostracods and brachiopods indicating a Hirnantian age for the upper Iapó and lower Vila Maria formations. Recent palynological research has also reported the presence of palynomorphs in the Iapó Formation for the first time, supporting interpretations of a post-glacial paleoenvironment. Despite these advances, significant knowledge gaps remain regarding the palaeobiodiversity of the Iapó and Vila Maria formations, particularly considering recent discoveries at the Três Barras Farm. This site, located in a remote area, preserves the transition of Late Ordovician strata to Early Silurian ones, enabling studies on Lower Paleozoicspeciation and on the impact of a major glaciation on the biota. Preservation measures include sharing directions and mapping routes to the section, as well as raising awareness among the non-scientific community about its importance.

New names for homonyms in two fossil ostracod genera

New names for homonyms in two fossil ostracod genera

The response of ostracod faunal assemblages to hydrology, lake level, and carbon cycling in a Jamaican marl lake: a palaeolimnological investigation

Abstract. Ostracod taxa from shallow freshwater lakes are sensitive to a range of limnological factors including temperature, hydrological habitat, lake level, and the distribution of aquatic plants. Ostracod assemblages preserved in Quaternary lake sediments can be used to reconstruct limnological change and are therefore potentially valuable palaeoenvironmental proxies. However, lack of autecological information about some taxa may limit the validity of such reconstructions. We use fossil ostracod assemblages recovered from radiocarbon-dated late Holocene sediments from Wallywash Great Pond, a small, shallow freshwater lake in southwestern Jamaica, to reconstruct limnological change over the past ∼ 1800 years. We circumvent ongoing taxonomic and ecological uncertainties associated with the identification of fossil ostracod taxa by drawing on observations of the ecology of ostracods found living in Jamaican water bodies. By combining this information with limnological data from the extant lake, and with sedimentological and isotopic data from the lake sediments, we show that a published interpretation of ostracod assemblages for the late Quaternary of Wallywash Great Pond is simplistic, at least for the late Holocene section of the sediment record. We conclude that changes in ostracod assemblages are linked to variations in the input of undersaturated groundwater to the northern part of the lake from which the core was recovered. These variations, which were driven by changes in the precipitation / evaporation ratio (effective moisture), also controlled sedimentation, with reduced effective moisture and a decline in undersaturated groundwater input favouring marl precipitation, whereas organic sediments are linked to increased effective moisture and enhanced groundwater input. Our findings suggest that the dramatic shifts in ostracod assemblages at this site are a complex response to changes in hydrology, sedimentology, and carbonate saturation rather than being a simple indicator of lake-level change. Combining ostracod assemblage data with the results of other palaeolimnological analyses also allows more detailed reconstructions to be made for this lake, and such a multiproxy approach is recommended for similar lakes elsewhere.

Preserved appendages in a Silurian binodicope: implications for the evolutionary history of ostracod crustaceans.

Ostracod crustaceans originated at least 500 Ma ago. Their tiny bivalved shells represent the most species-abundant fossil arthropods, and ostracods are omnipresent in a wide array of freshwater and marine environments today and in the past. Derima paparme gen. et sp. nov. from the Herefordshire Silurian Lagerstätte (~430 Ma) in the Welsh Borderland, UK, is one of only a handful of exceptionally preserved ostracods (with soft parts as well as the shell) known from the Palaeozoic. A male specimen provides the first evidence of the appendages of Binodicopina, a major group of Palaeozoic ostracods comprising some 135 Ordovician to Permian genera. The appendage morphology of D. paparme, but not its shell, indicates that binodicopes belong to Podocopa. The discovery that the soft-part morphology of binodicopes allies them with podocopes affirms that using the shell alone is an unreliable basis for classifying certain fossil ostracods, and knowledge of soft-part morphology is critical for the task. Current assignment of many fossil ostracods to higher taxa, and therefore the evolutionary history of the group, may require reconsideration.

Late Quaternary ostracode stratigraphy of Mono Lake (California, USA): evidence for benthic ecosystem sensitivity to climate change

ABSTRACTThe response of aquatic ecosystems in the Sierra Nevada (California, USA) to late Quaternary hydroclimate changes remains mostly unknown. Mono Lake, a large endorheic lake just east of the Sierra Nevada, contains an expanded archive of laminated sediments that can be used to examine the response of benthos to environmental changes. Fossil ostracodes from a radiocarbon‐dated core were used to examine paleoecologic changes from ~16.6 to 4.3k cal a bp. Seven species were identified, with the co‐occurrence of Limnocythere ceriotuberosa and Limnocythere staplini indicating a large SO42−‐rich lake in the Pleistocene. The Younger Dryas was complex, with Fabaeformiscandona caudata reflecting a cold and deep lake ~13.0–12.2k cal a bp, followed by an interval of extensive littoral habitat from ~12.2–11.6k cal a bp. Ostracode diversity, valves g–1 and the ratio of adult:juvenile valves declined after ~10.7k cal a bp due to regression, altered hydrochemistry and seasonal anoxia. Strong seasonality during the Early Holocene is suggested by the presence of reworked ostracodes and macrocharcoal, delivered to Mono Lake by erosion of ancient lake beds in the basin. A depauperate ostracode fauna in the Middle Holocene suggests a strong sensitivity to drought in this ecosystem, which has implications for biodiversity in the future.

Ostracod palaeolimnology as an indicator of past human–environment interactions in Chełm Hills, south-eastern Poland

Both modern and historical data show that lake systems are undergoing profound changes because of human impacts from local to global scales. Research on this topic shows that human pressure on water systems can take various forms and is highly variable in time and space. This article presents the results of Ostracoda fauna research as an indicator of anthropogenic changes covering the time span from 7000 BP to the Mediaeval Period. The palaeoecological information (abundance and habitat preferences of Ostracoda assemblages) obtained in studies of fossil Ostracoda fauna communities amplified by palynological and archaeological data allowed to answer the following questions: (1) to what extent the impact of successive archaeological settlement cultures caused ecological changes in the lake catchment areas without directly affecting the lakes themselves, and when anthropogenic pressure caused transformations in the functioning of lake ecosystems and (2) whether the neolithization, as the first clearly legible stage of anthropopression, had a decisive influence on the functioning of lake ecosystems. Results of Ostracoda fauna studies have been compared with archaeological data available in the literature and multiproxy paleoenvironmental data previously published in a study of lake sediments in the Chełm Hills in South-Eastern Poland. Presented results of study of Ostracoda in lake sediments as a bioindicators of anthropogenic impact suggest that the pressure of prehistoric settlement in older phases (up to the early Middle Ages) was most clearly reflected in the landscape, while the functioning of lake ecosystems was disturbed only by the periodic increase in lake trophic status. A substantial change resulting from the analysis of the subfossil Ostracoda in all the studied lake ecosystems occurred in the phase of settlement related to the Early Middle Ages, which was reflected in the permanently changed species composition of the fauna.

Temperature and hydrological variations during the late-glacial in the Central Mediterranean: Application of the novel ostracod-clumped isotope thermometer

This study shows, for the first time, the absence of a vital effect in the clumped isotope carbonate (Δ47) fossil ostracod signal and confirms the ability of the novel ostracod-Δ47 thermometer to reconstruct past temperatures and hydrological conditions in complex lacustrine systems. Furthermore, the application of Δ47 analyses on the ostracod species Candona angulata and Cyprideis torosa from Lake Trasimeno record (central Italy), which today precipitate their shells during the cold and the warm season respectively provides evidence that by combining biological (i.e., ostracod shell precipitation timing), paleontological (i.e., identification of ostracod species) and geochemical (i.e., Δ47) approaches, the ostracod-Δ47 thermometer accurately reconstructs past seasonality. Despite the absence of a vital effect, not all species can be combined for Δ47 analyses in environments with seasonal temperature variations; only those that precipitate their shells during the same season should be considered. The application of the ostracod-Δ47 thermometer on the Trasimeno lacustrine record gives rise to the first continental warm season paleotemperature reconstruction of the last 43 ky in central Mediterranean area. The combination of Δ47 and oxygen isotope composition (δ18Oost) measured on ostracod shells provides the isotopic composition of the water from which the carbonate precipitated (δ18Ow) and thereby, changes in the evaporation/precipitation balance in this area. Before the Last Glacial Maximum (LGM), equivalent to the Marine Isotopic Stage 3 (MIS3, from 43 to 29ky), warm season temperatures ranged from 15 ± 1.6 °C to 22 ± 2.3 °C, equivalent to 2 to 6 °C colder than today. Hydrological conditions during this period are similar to the present-day ones, characterized by a permanent lake and a high evaporation/precipitation ratio (E/P). The drastic decrease of the warm season temperatures (ranging from 10 ± 2.9 °C to 17 ± 3.1 °C) and of the E/P ratio during LGM and Late-glacial (MIS2, from 29 to 11.6 ky) correspond to the global climate cooling and low summer insolation, suggesting an amplifying role, of the latter, in the effects of the millennial scale climatic variations. At the Pleistocene/Holocene transition, both warm season temperature (25 ± 2 °C) and the E/P ratio increased in conjunction with the summer insolation. During the early Holocene, warm season temperature (23 ± 2 °C) closely resembles present-day values. However, cold season temperature (12 ± 2 °C) is approximately 4 °CC warmer than today. Notably, no hydrological differences are identified between the warm and the cold season underlying a lower seasonality contrast compared to the present, along with enhanced warm season precipitation. The good agreement between the Δ47 temperatures reconstructed for the last 1 ky and the temperatures presently recorded at Lake Trasimeno (8 °C cold and 22 °C for warm season), confirms the accuracy of the analyses and the applicability of the ostracod-Δ47 thermometer to reconstruct seasonal temperature changes.

Evaluation of Degree of Alteration in Fossil Ostracods from Middle Callovian-Lower Oxfordian Beds of Southern Part of Kachchh Basin, Gujarat, India by Characterizing Surface Roughness of the Shell

Abstract Before proceeding with any type of analysis, the condition of preservation of microfossil shells must be determined. Preservation of the shell affects tasks, such as holotype specimen selection, distribution chart, and specimen selection for geochemical analysis. The typical way to determine the degree of alteration is to use a visual examination under the stereo microscope. The deviation of visual characteristics such as colour and smoothness of the shell surface from unaltered shells depicts the alteration status. However, our eyes are frequently misled by the roughness of the shell created by tiny crystals that form due to recrystallization during the diagenesis process and are perceived to be smooth. In turn, the shell is regarded as well-preserved. To address these limitations, we have analyzed scanning electron microscope (SEM) images of ostracod shells using ImageJ, an image processing software, to determine the roughness parameters based on the grey value of the image. In addition, we compared the values of several parameters with different types of alterations, such as recrystallization and dissolution. This study aims to characterize the surface roughness of eight selected ostracod specimens from Middle Callovian to Upper Oxfordian beds of the southern part of Mainland Kachchh. The selected eight species - Cytherella masuguluensis, Progonocythere sp. A, Progonocythere jaisalmerensis, Bythocypris rajasthanensis, Paracypris contermia, Galliaecytheridea remota, Cytherelloidea sp. A, Cytherelloidea sp. B - belong to six genera and five families.

Late Quaternary paleoceanography of Vestnesa Ridge, Fram Strait: Ostracode species as a potential indicator of cold seep activity

Abstract Past intensity of methane release from deep-ocean methane hydrates continues to be challenging to reconstruct reliably. Here, we used fossil ostracode fauna paired with foraminiferal δ13C values in a marine sediment core from Vestnesa Ridge, western Svalbard margin, to reconstruct methane seepage activity during the late Quaternary and to examine faunal response to deglacial climatic changes. Benthic foraminiferal δ13C values indicate methane seepage activity was relatively strong during marine isotope stage 2, corresponding to a high percentage of the ostracode Rosaliella svalbardensis in the assemblage. In contrast, this species was absent under conditions of no or very strong seepage of methane. Faunal changes in other taxa were more related to global climate changes regardless of the seepage activity. This result indicates that Rosaliella svalbardensis is a potential new useful proxy for past methane release.

Proposal of Christiangramia gen. nov., Neomelitea gen. nov. and Nicoliella gen. nov. as replacement names for the illegitimate prokaryotic generic names Gramella Nedashkovskaya et al. 2005, Melitea Urios et al. 2008 and Nicolia Oliphant et al. 2022, respectively.

The prokaryotic generic names Gramella Nedashkovskaya et al. 2005, Melitea Urios et al. 2008 and Nicolia Oliphant et al. 2022 are illegitimate because they are later homonyms of the names Gramella Kozur 1971, a genus of fossil ostracods, Melitea Péron and Lesueur 1810 (Scyphozoa, Cnidaria), Melitea Lamouroux 1812 (Anthozoa, Cnidaria), Nicolia Unger 1842, an extinct plant genus, and Nicolia Gibson-Smith and Gibson-Smith 1979 (Bivalvia, Mollusca), respectively (Principle 2 and Rule 51b(4) of the International Code of Nomenclature of Prokaryotes). For Gramella, we therefore propose the replacement generic name Christiangramia with type species Christiangramia echinicola comb. nov. and we propose the reclassification of 18 other species of Gramella in the genus Christiangramia as new combinations. In addition, we propose the replacement generic names Neomelitea with type species Neomelitea salexigens comb. nov. and Nicoliella with type species Nicoliella spurrieriana comb. nov.

Southward Migration of Arctic Ocean Species During the Last Glacial Period

AbstractThe East Asian winter monsoon (EAWM) is associated with northerly surface winds affecting crop and livestock productivity and social and economic activities across East Asia. However, the relationship between EAWM dynamics and marine biota remains poorly understood. In this study, we analyzed fossil ostracods from sediment cores collected in the northwestern Pacific Ocean to detect the appearance/disappearance of circumpolar species during the late Quaternary. We compared our ostracod records, including dating results, with ice‐rafted debris records from the Sea of Japan, and identified two southward migration events of Arctic ostracods at 120–100 ka (Marine Isotope Stage [MIS] 5d stadial) and 30–15 ka (MIS 3 and 2, peak Last Glacial), which corresponded to a strengthened EAWM system. Our results indicate that an intensified EAWM influenced the Yellow Sea Bottom Cold Water formation, lowered the winter water temperatures, and allowed Arctic ostracods to migrate southward into the Yellow Sea.

Latest Miocene ostracods from the Bookpurnong Formation in the Murray Basin of southeastern Australia: shallow marine migrants into an epicontinental sea

The uppermost Miocene Bookpurnong Formation within the Murray Basin of southeastern Australia overlies a regionally extensive subaerial unconformity formed by relatively low late Miocene eustatic sea levels, and the initial phase of the Kosciuszko Uplift tectonic event. A diverse marine fossil ostracod fauna has been recovered from the Bookpurnong Formation, and is associated with a marine transgression that flooded inland regions of southeastern Australia to form a shallow epicontinental sea. Many of the Bookpurnong Formation ostracods represent immigrant taxa, with species such as Puriana lubbockiana, evidencing a subtropical range expansion of thermophilic warm water forms into southern mid-latitudes. We attribute this to warm plumes from the East Australian Current, which would have impacted southeastern Australia at that time. In general, the Bookpurnong Formation ostracod assemblages indicate low to moderate energy shallow offshore palaeoenvironments subject to warm-temperate and subtropical conditions. One new genus and five new species are described: Fortistriginglymus gen. nov., Bradyleberis praecristatella sp. nov., Callistocythere bookpurnongensis sp. nov., Callistocythere mchenryi sp. nov., Callistocythere zigzaga sp. nov., and Parakeijia notoreticularis sp. nov.

Biodiversity of Non-Marine Ostracoda (Crustacea) of Botswana: An Annotated Checklist with Notes on Distribution

Botswana constitutes a major gap in our knowledge of the distribution of Ostracoda in the region of Southern Africa, restraining thorough biogeographic interpretations. We combine records from previously published surveys along with our own field collections to provide a collation of living and fossil (Late Pleistocene to Holocene) Ostracoda recorded in Botswana. Our survey yielded 17 species, of which nine species have not been recorded before in the country. Including the present update, 54 species (45 living and nine fossil or subfossil) belonging to 22 genera of five families (with 76% species belonging to the family Cyprididae) are currently reported from Botswana. Yet, 23 taxa are left in open nomenclature, indicating the urgent need for sound systematic studies on harmonizing taxonomy of Southern African ostracods, especially of those inhabiting small temporary waterbodies, considered as threatened with extinction before being properly described or discovered. This updated checklist provides detailed information about the distribution and habitat of each recorded species. Species richness, distribution patterns, and diversity of ostracod species regionally and in different freshwater ecoregions are also discussed. We found low alpha (site) diversity (mean 3.3 species per site) and a significant difference in species composition and beta diversity of the Okavango ecoregion versus the Kalahari and Zambezian Lowveld ecoregions.

Ostracod response to monsoon and OMZ variability over the past 1.2 Myr

We present the first continuous middle through late Pleistocene record of fossil ostracods from the Maldives in the northern Indian Ocean, derived from sediment cores taken at Site U1467 by Expedition 359 of the International Ocean Discovery Program (IODP). Site U1467 lies at 487 m water depth in the Inner Sea of the Maldives archipelago, an ideal place for studying the effects of the South Asian Monsoon (SAM) system on primary productivity, intermediate depth ocean circulation, and the regional oxygen minimum zone (OMZ). The Inner Sea acts as a natural sediment trap that has undergone continuous sedimentation for millions of years with minor terrestrial influence. Our record spans from Marine Isotope Stage (MIS) 35 to the present, covering the mid-Pleistocene transition (1.2–0.6 Ma) and the Mid-Brunhes Event (MBE, at ~480 ka) the time when ice age cycles transitioned from occurring every 40,000 years to 100,000 years. The ostracod data is interpreted alongside the existing datasets from the same site of sedimentological (grain-size) and XRF-elemental analyses, and new organic biomarker data also from Site U1467. These datasets support the paleoenvironmental interpretation of the ostracod assemblages. Ostracods are abundant and diverse, displaying a prominent change in faunal composition at the MBE related to the increase in the amplitude of glacial-interglacial cycles, which deeply affected the monsoon system and thereby the past oceanographic conditions of the Maldives Inner Sea. Furthermore, ostracods exhibit distinctly different assemblages across glacial-interglacial cycles, particularly after the MBE, and these changes convincingly correspond to variability of the OMZ. Glacial periods are characterized by ostracod indicators of well‑oxygenated bottom water due to the intensification of the winter monsoon and the contraction of the OMZ. Abundant psychrospheric ostracods during glacials suggests that a southern sourced water mass, such as Antarctic Intermediate Water (AAIW) and/or Subantarctic Mode water, bathed the Maldives Inner Sea during glacial periods. In contrast, interglacial stages are characterized by ostracod species and biomarker data that indicate low-oxygen conditions and sluggish bottom water circulation pointing to an expansion of the regional OMZ due to the strengthening of the summer monsoon. Our results highlight the sensitivity of ostracods to oceanographic and climate variability.

Poseidonamicus (Ostracoda) from the North Atlantic Ocean

Poseidonamicus is one of the most intensively studied genera among marine fossil ostracods due to its common occurrence in the world deep oceans and its distinctive morphological features. Many studies using Poseidonamicus have contributed to our understanding in a wide range of research topics, from evolutionary developmental biology to paleoenvironmental reconstruction. However, taxonomic confusion with Poseidonamicus species remains widespread because of subtle interspecific differences within this genus and limited taxonomic work on deep-sea faunas. The objectives of this paper are to update taxonomic information about Poseidonamicus species in the Pliocene–Quaternary North Atlantic, and to summarize paleobiogeographical distribution of all known Poseidonamicus species.We describe one new species, Poseidonamicus parasculptus n. sp., and present high-resolution scanning electron microscope images of North Atlantic Poseidonamicus major for the first time. Our distributional compilation shows that many Poseidonamicus species are confined to either the Indo-Pacific, theAtlantic, or the Southern Oceans. This information may provide identification guidance for future regional studies.

Marine and marginal marine Ostracoda as proxies in geoarchaeology

Ostracoda, minute aquatic crustaceans with calcitic shells, are highly versatile proxies in geoarchaeological contexts. Their species-specific ecological preferences and ranges allow the reconstruction of palaeoenvironments and anthropogenic impacts in detail. Environmentally driven morphological variability and shell chemistry signatures as stable isotope and trace element values can provide additional palaeoenvironmental information. Ostracods can be used for provenance analyses and stratigraphical investigations as well. Their small size and high abundance in most water bodies makes them ideal for studying sediment cores and smaller samples from trenches or outcrops, especially in coastal areas where they show a high diversity and abundance compared to other groups of meiofauna. In archaeological contexts, fossil ostracods may provide information about climate, sea level and hydrography, high energy events like storms or tsunamis, ocean currents, land use, pollution, water constructions, stratigraphy, trade connections or the origin of sediment material.We give an overview on the state of ostracod-based research in geoarchaeology today and present some European case studies to illustrate concepts and methods of such field of study.

Paleoenvironmental changes during the Pleistocene in the northern part of the Niitsu Hills, Niigata Prefecture based on fossil ostracod assemblages

Paleoenvironmental changes during the Pleistocene in the northern part of the Niitsu Hills, Niigata Prefecture based on fossil ostracod assemblages

Some theoretical aspects of the systematic study of fossil ostracods (Arthropoda, Crustacea, Ostracoda) in the context of species problems in palaeontology

Theoretical contributions into the systematics and taxonomy of fossil ostracods conducted according to unified methodological stands have resolved some key problems of paleontology. For example, this is a problem of species and its derivatives, namely the identification of species, the estimation of the taxonomic weight of morphological characters, the determination of diagnostic characters of different taxonomic ranks, and taxa diagnoses. The unification of the terminology and the formalization of morphological description of fossil shells made it possible to estimate the taxonomic weight of morphological elements. A scheme to identify the rank of taxonomic characters (pyramid principle) has been developed. A unified terminological dictionary has been prepared to describe the morphological elements of ostracod shells in detail.

Late Quaternary paleoceanographic history based on ostracode records from the Chukchi Plateau, western Arctic Ocean

Fossil ostracode assemblages were investigated in three sediment cores from the Chukchi Plateau, in the western Arctic Ocean, in order to reconstruct its late Quaternary paleoceanographic history. The cores were obtained from water depths of 435–741 m, within the range of modern Atlantic Water (AW). The ostracode abundance shows distinct glacial/interglacial fluctuations, suggesting the suppression of benthic bioproductivity during glacial periods, probably associated with the development of perennial sea ice. Based on the modern ostracode distribution in the Arctic Ocean, 11 common ostracode taxa out of a total of 33 are related to specific water mass or sea ice conditions. Analyses of key ostracode species and a benthic foraminifera species, Cassidulina teretis, reveal a pronounced faunal turnover between MIS 3 and MIS 1. A distinct assemblage dominated by Polycope spp. and accompanied by other species preferring Arctic Intermediate Water (AIW) (Microcythere medistriatum, Pseudocythere caudata, Cytheropteron sedovi, C. scoresbyi, and Pedicythere spp.) characterizes the period between late MIS 5 and MIS 3, whereas MIS 1 is characterized by a rise in Krithe spp. and two species associated with AW (Cytheropteron perlaria and Cassidulina teretis). The faunal turnover indicates an upward shift of AIW and a decline of the influence of warm AW during the period between late MIS 5 and MIS 3, presumably caused by a weakening or cessation of the westward dispersion of AW. The distributions of two sea-ice related species, Acetabulastoma arcticum and Rabilimis mirabilis, indicate minimal perennial sea-ice cover and probably summer sea-ice-free conditions throughout MIS 1 and the development of a summer sea-ice margin environment during interglacial/interstadial periods.

Life stages and morphological variations of Limnocythere inopinata (Crustacea, Ostracoda) from Lake Jiang-Co (northern Tibet): a bioculture experiment.

Limnocythere inopinata (Baird, 1843) is a Holarctic species, abundant in a number of Recent and fossil ostracod assemblages, and has many important taxonomic and (paleo)ecological applications. However, the life cycle and morphological characteristics of the living L. inopinata are still unclear. A bioculture experiment was designed to study life stages and morphological variations from stage A-8 to adult in this species. The living animals were collected from Lake Jiang-Co, in the northern Tibetan Plateau. Results reveal that this species possesses a special growth pattern with the maximum size increase occurring at the transition from the instars A-5 to A-4. The growth pattern deviates from Brooks’ rule and one population from Lake Dali, eastern Mongolian Plateau. This suggests that the life history of L. inopinata may be influenced by environmental factors. Some morphological differences between Lake Jiang-Co and European populations of L. inopinata are also uncovered. Therefore, a detailed morphological description of this population is provided, but refrain from erecting a new species at the present stage because those differences appear to be inconsistent.