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Abstract

Fossil resins and ostracods are well-known in Brazilian Cretaceous sedimentary Basins, especially in the Araripe Basin. The present work reports several ostracods encapsulated in an amber sample recovered from limestones of the Crato Formation (Araripe Basin, Northeastern Brazil). The amber was analyzed under optical microscopy revealing several ostracod specimens. Considering the general morphology, the recovered specimens were attributed to the freshwater to brackish genera Pattersoncypris Bate, 1972 and Damonella Anderson, 1966 in the superfamily Cypridoidea. Additionally, palynological analyses of the limestone rock around the amber demonstrate the predominance of pollen grains of the Classopolis genus, produced by conifers of Cheirolepidiaceae family, suggesting this family as possible botanical source of the fossil resin. The proposed interpretation for this preservation is as follow: (i) the lake level variations transported the ostracods to the margin; (ii) drops of resin exuded from the trunk fell to the margin on the dead ostracods; (iii) the exposed resin underwent polymerization preserving the ostracods; (iv) and finally, the amber was preserved in the laminated calcareous deposit. The record described here provides a detailed study of organisms fossilized in Brazilian amber as well as it reports the oldest record of ostracods enclosed in fossil resins (Aptian age).

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... In addition to the highly diverse insect taxa in amber deposits, Ostracoda (seed shrimps) and Jungermanniopsida (liverworts) are also discussed in this issue. Piovesan et al. (2022) report several ostracods encapsulated in a Brazilian Cretaceous amber sample, representing the oldest ostracods preserved in a fossil resin. Palynological analyses of amber-containing limestones of the Crato Formation (Araripe Basin, Northeastern Brazil) suggest that the extinct coniferous Family Cheirolepidiaceae was the possible botanical source of this fossil resin. ...
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Over recent decades ostracods have become established indicators of ecosystem health, biodiversity and environmental change. With applications ranging across the earth sciences (from modern pollution studies to sea-level change, basin evolution, plate tectonics, palaeoceanography) and related disciplines such as archaeology, ecology and genetics, their utility extends to almost every aquatic and semi-aquatic habitat, from the deep ocean to high mountain springs. Their temporal range is now known to cover the last 500 million years of earth history. The study of fossil ostracod assemblages follows traditional palaeontological lines of investigation, including taphonomy, morphometries and diversity, but there are a number of methodological approaches, specific to the ostracods, that render them potentially one of the most versatile organisms in the fossil record. Ostracods have been employed on a range oftemporal and spatial scales to reconstruct past environments, from world-wide, geological-scale global events in the deep-sea through to smaller-scale studies of lakes and their archives of local environmental change over recent centuries. Much information can be obtained from ostracod assemblages but it is particularly through recent advances in the chemical and physical study of single shells or carapaces that the utility of these organisms has been brought to the fore. In this paper the potential palaeoenvironmental information derived from an ostracod assemblage, a single species, or an individual shell is reviewed. The main applications for ostracods are outlined for marine and non-marine ecosystems. Finally, the role of the ostracods in detailing the recent history of the Aral Sea is outlined.
Article
Micropaleontology is crucial branch of Earth Sciences, with a pivotal role in the success of the oil and gas industry over the decades. This sector of paleontology is based on the taxonomical description of microfossils, which encompass fossils with size variation from 0.001 mm to 1 m. Normally these microorganisms have a high rate on preservation, thus they are widely accepted as reliable evidence to infer about paleodepositional settings and paleoclimate change. Furthermore, microfossils are critical to understanding the evolution through time, being many of them recognized as index fossil and providing useful biozones to correlation. Since 1950, microfossils have been taxonomically described mainly by stereomicroscopes. However, as the technology progress, traditional ways to study these organisms are challenged and improved by nondestructive three-dimensional imaging techniques, as X-ray tomographic microscopy (SRXTM), three-dimensional X-ray microscopy (3D-XRM), the X-ray computed microtomography (microCT) and X-ray computed nanotomography (nanoCT). Recently, one of the most compelling research areas in micropaleontology is the desire to automatize and enhance the details of systematic classification. Thereby, an increasing number of researches have applied the high-resolution X-ray analysis aiming to improve the morphological, taxonomic and taphonomic examination. Most of them have detailed the enhancement provided by the technique when compared with the standard microscopes, and raised questions about the traditional characters used on the microfossil systematic taxonomy. Nevertheless, even with the surpassing detail on microfossil characterization, the application of microCT has been hampered by the costs and sometimes by the needs of specific computer skill. Thus, this research has evaluated the use of microCT as the technique to classify a random bulk of microfossil (comprising foraminifers, ostracods, radiolarians, gastropods and echinoderms) with no further software treatment. No standard microscope analysis was performed. Despite chemical composition of microfossils, most of the specimens morphology, especially internal structures, have been easily acquired and analyzed. 96% of the microfossils of the dataset were identified at least on genus level. Irrespective of the deepness of detail, when considering the overall taxonomic identification, the microCT seems to be effective as the standard microscope. Nonetheless, when problematic specimens are evaluated, the microCT seems to be a more reliable and practical tool than other methods as Scanning Electron Microscopy. Thus, the technique can be used solo or as a complementary method to the stereomicroscope. Additionally, the high-resolution has the potential to lead to the expected automatized micropaleontology, since they can provide numerous images in several planes. This may create a strong database necessary to machine learning and computer identification.
Chapter
An updated taxonomic review of Ostracoda present in the Palaearctic is presented in this chapter. Dichotomous identification keys to the lowest justifiable taxonomic level based on the most recent literature are provided. These are coupled with the necessary material preparation methods, defined relevant morphological terms, and current limitations in our knowledge of the group. Additional information on the “Ecology and General Biology” of this group can be found in Volume I of this book series.
Article
The bivalved crustacean ostracods have the richest fossil record of any arthropod group and display complex reproductive strategies contributing to their evolutionary success. Sexual reproduction involving giant sperm, shared by three superfamilies of living ostracod crustaceans, is among the most fascinating behaviours. However, the origin and evolution of this reproductive mechanism has remained largely unexplored because fossil preservation of such features is extremely rare. Here, we report exceptionally preserved ostracods with soft parts (appendages and reproductive organs) in a single piece of mid-Cretaceous Kachin amber (approximately 100 Myr old). The ostracod assemblage is composed of 39 individuals. Thirty-one individuals belong to a new species and genus, Myanmarcypris hui gen. et sp. nov., exhibiting an ontogenetic sequence from juveniles to adults (male and female). Seven individuals are assigned to Thalassocypria sp. (Cypridoidea, Candonidae, Paracypridinae) and one to Sanyuania sp. (Cytheroidea, Loxoconchidae). Our micro-CT reconstruction provides direct evidence of the male clasper, sperm pumps (Zenker organs), hemipenes, eggs and female seminal receptacles with giant sperm. Our results reveal that the reproduction behavioural repertoire, which is associated with considerable morphological adaptations, has remained unchanged over at least 100 million years-a paramount example of evolutionary stasis. These results also double the age of the oldest unequivocal fossil animal sperm. This discovery highlights the capacity of amber to document invertebrate soft parts that are rarely recorded by other depositional environments.
Article
Representatives of the Class Ostracoda are widely used as tools in applied paleoecological and biostratigraphical studies in all continents. In the Araripe Basin, located in the northeastern of Brazil, the Romualdo Formation is one of the most studied, not only for the preservation but also for the abundance of its fossils. The ostracod genus Pattersoncypris Bate, 1972 is well-represented in this formation and it is the most abundant, which reinforces the importance of its taxonomic study. In this work, Pattersoncypris minima sp. nov. is described for the Romualdo Formation as a contribution to the knowledge on Brazilian Cretaceous non-marine ostracods. Taphonomic aspects are also presented, considering the complete ontogenetic stages of the material.
Article
Non-marine ostracods have been used for a long time to aid in the understanding of the Lower Cretaceous sedimentary deposits of Brazil, with various studies showing their value for biostratigraphic zonation in different basins. The northeastern region of Brazil contains several basins south of the Potiguar Basin which originated from the rifting that resulted from the opening of the Atlantic Ocean, and thus contain an important record of the Cretaceous Period. This paper has the objective of studying the ostracods recovered from two adjacent sections (Transnordestina A and Transnordestina B) belonging to the Orós Formation, Iguatu Basin, Ceará, Brazil, detailing their taxonomy and developing biostratigraphic inferences based on the observed fauna. A total of 19 species were found in the analyzed samples, distributed among 11 genera and five families: Cypridea hystricoides, Cypridea paraibensis, Cypridea cf. C. clavata, Cypridea punctacentralis sp. nov., Brasacypris ovum, Pattersoncypris sinuata, Pattersoncypris cf. P. sinuata, Pattersoncypris? sp., Ilyocypris? arca sp. nov., Ilyocypris? latanodi sp. nov., Rhinocypris? ericius sp. nov., Pythagoracypris latavectis gen. et sp. nov., Hastacypris adamantem gen. et sp. nov., Looneyellopsis mvili, Musacchiocythere plastica, Musacchiocythere? sp., Alicenula leguminella, Alicenula cf. D. oblonga, and an incertae sedis species. From the recovered species, a Hauterivian–Aptian interval can be inferred for the studied sections.
Article
The Santana Group of the Araripe Basin is a major paleontological unit in Brazil, incorporating two important Cretaceous Konservat-Lagerstätten. The lower formations are Aptian, but the age of the uppermost Romualdo Formation has been extended into the Albian. The precise chronostratigraphic position of this upper unit is of considerable significance because the Romualdo Formation records the Cretaceous marine ingression into the interior of Northeastern Brazil, thus playing a significant role in understanding the paleogeography of Gondwana. The main objective of this paper is to establish the chronostratigraphy of the Romualdo Formation based on its most complete section in the Araripe Basin, by determining the occurrence of palynomorphs, in particular establishing the vertical range of the species Sergipea variverrucata, a guide fossil of the Aptian in Brazil. Based on the presence of S. variverrucata, the Romualdo Formation is almost entirely Aptian in age. The palynological assemblage confirms the presence of at least three intervals with marine palynomorphs (dinoflagellate cysts and foraminiferal linings); and a typical regressive pattern towards the top of the Romualdo Formation, evidenced by progressive increase in inaperturate pollen grains (Araucariacites, Uesuguipollçenites and Inaperturopollenites). The palynological data presented herein indicate that the entire Santana Group is of Aptian age because of the conspicuous presence of Sergipea variverrucata and the absence of indisputably Albian forms. Precise dating of the Romualdo Formation signifies that the marine transgression into the interior of northeastern Brazil occurred in the late Aptian, thereby enabling correlation with the sedimentary events recorded in the Brazilian marginal basins.
Article
For the first time, this study describes the dynamics of white rot fungal decay in a petrified conifer branch with clear araucarian affinity from the late Aptian Crato Lagerstätte (Santana Formation, Araripe Basin, northeastern Brazil). High resolution optical microscopy was used to identify tridimensional chemical and anatomical evidence in different regions of the bark and xylem tissues of permineralized shoots, and results support the hypothesis that the host responded to disease that may have started when it was still alive. The wood decay pattern was strongly indicative of the selective decay by white rot. The general pattern of interaction is consistent with pathogenic rather than saprophytic fungal activity. Analysis of fungus–plant interactions associated with growth ring patterns imply intermittent periods of favorable temperature-moisture inputs that were crucial for fungal activity during the deposition of the Crato fossil Lagerstätte included in the Tropical Equatorial Hot arid belt.
Article
In the beginning of Gondwana's break up, small rift lakes were formed in the area that is nowadays located in Northeastern Brazil. These lakes captured the drainage systems and were subjected to hot and arid climatic conditions in a low-latitude area. These conditions are evidenced by the Lower Cretaceous fluvio-lacustrine deposits that filled the Sousa Basin, which integrates a complex of basins along the Rio do Peixe (State of Paraíba). The Sousa Formation is the most representative unit in the Sousa Basin, being predominantly composed of siltstones and shales deposited in shallow lacustrine environments with fluvial influence. The sedimentation occurred under a semi-arid climate with alternating rainy and dry seasons, indicating the presence of ephemeral lakes. This is also supported by the lithology, the sedimentary structures (mud cracks) and the evaporites (gypsum). The lacustrine environment is favorable to the proliferation of non-marine ostracods, which are microcrustaceans of great importance for the study of current and paleolake deposits. Non-marine ostracod assemblages recovered from the Sousa Formation, sampled from core 2-FC-1-PB, revealed undescribed species. In this work, these ostracods were studied taxonomically, with the new species Cypridea paraibensis sp. nov., Cypridea vianai sp. nov. and Alicenula sousaensis sp. nov., as well as the already described Alicenula leguminella (Forbes, 1855) Martens, Rossetti and Horne 2003, Brasacypris ovum Krömmelbein 1965, Cypridea ambigua Krömmelbein 1962, and Reconcavona swaini Krömmelbein 1962 being identified. Another set of taxa remained in open nomenclature, since the morphological descriptions did not fit existing species. Thus, the descriptions referring to the described groups take into consideration criteria such as similarity and variability of morphological factors (Alicenula ex gr. leguminella and Alicenula sp. 1), degree of preservation, and quantity of recovered carapaces.
Article
This work presents a detailed taxonomic study on the marine ostracods from the Paraíba Basin, northeastern Brazil, in wells from the wells Itamaracá-1IT-03-PE and Poty-1PO-01-PE, which record the Maastrichtian–Danian boundary. Besides the taxonomic data, this paper contributes to the paleoenvironmental knowledge of Cretaceous–Paleogene ostracods from the Paraíba Basin. The analysis of 98 samples of the well Itamaracá-1IT-03-PE and 59 samples of the Poty-1PO-01-PE resulted in the record of 34 ostracode species, all representative of a marine environment with normal salinity. Seven new species are proposed: Cytherella centrocompressa sp. nov.; Cytherella paraibensis sp. nov.; Neonesidea potyensis sp. nov.; Bythoceratina spinosa sp. nov.; Eucytherura ventrotuberculata sp. nov.; Langiella fauthi sp. nov. and Protobuntonia punctatum sp. nov.
Article
Source rocks from the Alagamar Formation were analysed and fifteen non-marine ostracod species and one foraminifer species were identified. Thecamoebians, gastropods, fish teeth and incertae sedis material also occurred. Among these fossils, an agglutinated foraminifer, Gaudryinella sp. aff. G. sherlocki, and occurrences of foraminiferal organic linings, indicate deposition under transitional marine (paralic) influence. Harbinia crepata is considered holoeuryhaline, Paracypria? elongata brackish stenohaline and the other ostracods are freshwater euryhaline. Limnocytheridae ostracods together with foraminifers occurred in intercalated beds, and this pattern of changes in associations is herein interpreted as a record of temporal changes, characteristic of transitional palaeoenvironments. Previous studies on biomarkers and some articles dealing with palynomorphs also suggest that at least part of this unit was deposited in lagoonal conditions.
Book
Taphonomic bias is a pervasive feature of the fossil record. A pressing concern, however, is the extent to which taphonomic processes have varied through the ages. It is one thing to work with a biased data set and quite another to work with a bias that has changed with time. This book includes work from both new and established researchers who are using laboratory, field and data-base techniques to characterise and quantify the temporal and spatial variation in taphonomic bias. It may not provide all the answers but it will at least shed light on the right questions.
Book
Paleopalynology, second edition, provides profusely illustrated treatment of fossil palynomorphs, including spores, pollen, dinoflagellate cysts, acritarchs, chitinozoans, scolecodonts, and various microscopic fungal and algal dispersal bodies. The book serves both as a student text and general reference work. Palynomorphs yield information about age, geological and biological environment, climate during deposition, and other significant factors about the enclosing rocks. Extant spores and pollen are treated first, preparing the student for more difficult work with fossil sporomorphs and other kinds of palynomorphs. Recognizing that palynomorphs occur together in rocks because of chemical robustness and stratigraphic distribution, not biological relationship, the central sections are organized stratigraphically. Among many other topics presented are the sedimentation and geothermal alteration of palynomorphs, and palynofacies analysis. An appendix describes laboratory methods. The glossary, bibliographies and index are useful tools for study of the literature.
Article
The comparison of the chemical composition of fossilized amber, copal, and resin is important for determining the botanic origin and original chemical composition of fossilized amber and copal, and for understanding the ecologic role of resin. Here we use solid phase microextraction–gas chromatography–mass spectrometry (SPME–GC–MS) to investigate the volatile and semi-volatile composition of amber, copal and resin from Africa and the Americas, produced by trees from the genus Hymenaea. We found there are four subgroups of Hymenaea resin, copal, and amber, based upon age and chemical similarity: African amber, American amber, African resin/copal (which also includes Colombian copal), and American resin/copal. This analysis allows us to narrow down the potential botanic origin of amber and copal samples, and also indicates that within this genus, resin similarity does not correspond closely with phylogenetic relationships. Therefore, resin chemistry may have been controlled by ecologic pressures, such as defence against herbivores, wood borers, humidity, and diseases and the original chemical composition of amber and copal could potentially be used to understand the role of resin in plant–insect interactions through time.
Article
Amber inclusions of fully aquatic animals are rare, most of them isolated specimens of water-bound insect larvae. In contrast, we here describe an ample, speciose fauna of 262 fully aquatic individuals of Ostracoda (Crustacea) from Mexican amber of Early Miocene age. This fauna was trapped whilst under water swimming around trunks of resin-producing trees in a brackish lagoon. Ostracod crustaceans are typically around a millimeter in length, and are known for their mostly well-calcified bivalved carapaces that account for their unparalleled fossil record in arthropods. However, in the Chiapas amber we found representatives of the tribe Thalassocypridini, which are characterised by lightly calcified carapaces and therefore lack a substantial fossil record. Embedded in amber, this ‘drawback’ becomes a clear benefit because the unobstructed view onto the appendages otherwise hidden in the carapace allowed us to identify nine ostracod species, six of them new to science. The exceptional number of individuals permitted insights into population composition, reproduction, taphonomy and into micro-environmental parameters of the amber’s place of formation. Based on ecological data available for Recent Thalassocypridini species, we posit that this tribe reached a peak radiation in open lagoonal settings during the Miocene, and shifted towards anchialine environments by the Recent. http://zoobank.org/lsid:zoobank.org:pub:3C93A06B-F86B-404F-985D-139897F97EF3
Article
A total of 113 species belonging to 54 genera are recovered from a study of the Maastrichtian and Danian deposits in the Cerro Azul section of the Neuquén Basin, west-central Argentina. Of these, 9 new genera, 38 new species and 28 species in open nomenclature are recorded. These form the basis of the present study and are listed below. Genera: Phelocyprideis gen. nov., Aleisocythereis gen. nov., Apatoleberis gen. nov., Mimicocythereis gen. nov., Castillocythereis gen. nov., Hysterocythereis gen. nov., Orthrocosta gen. nov., Petalocythereis gen. nov. and Sthenarocythereis gen. nov. Species: Cytherella saraballentae sp. nov., Cytherella semicatillus sp. nov., Paracypris bertelsae sp. nov., Paracypris imaguncula sp. nov., Argilloecia abnormalis sp. nov., Argilloecia concludus sp. nov., Argilloecia hydrodynamicus sp. nov., Bythoceratina cheleutos sp. nov., Phelocyprideis acardomesido sp. nov., Eucythere dinetos sp. nov., Krithe crepidus sp. nov., Cytheropteron hyperdictyon sp. nov., Cytheropteron bidentinos sp. nov., Cytheropteron translimitares sp. nov., Aversovalva glochinos sp. nov., Eucytherura stibaros sp. nov., Hemingwayella verrucosus sp. nov., Heinia prostratopleuricos sp. nov., Loxoconcha (s.l.) posterocosta sp. nov., Keijia circulodictyon sp. nov., Keijia kratistos sp. nov., Paramunseyella epaphroditus sp. nov., Munseyella costaevermiculatus sp. nov., Ameghinocythere archaios sp. nov., Aleisocythereis polikothonus sp. nov., Castillocythereis multicastrum sp. nov., Castillocythereis albertoriccardii sp. nov., Cythereis stratios sp. nov., Cythereis clibanarius sp. nov., Cythereis trajectiones sp. nov., Henryhowella (Wichmannella) praealtus sp. nov., Hysterocythereis paredros sp. nov., Hysterocythereis coinotes sp. nov., Hysterocythereis diversotuberculatus sp. nov., Orthrocosta decores sp. nov., Orthrocosta atopos sp. nov., Orthrocosta phantasia sp. nov. and Sthenarocythereis erymnos sp. nov. The nature of the fauna and aspects of its evolution are discussed.
Article
A well-preserved ostracod in Baltic amber has been analysed with noninvasive methods by synchrotron radiation. A micro-tomographic image stack was prepared. The appendages are visualised as images and drawings are based on photographs of different images planes provided. The result is a description of a new species, Cypria kempfi, from the Eocene of Northern Germany. The way the fossilisation of this aquatic animal may have occurred is discussed. The possible ecological preferences of the species are considered.