Ordovician Ostracods Research Articles

Changes in the morphology of Late Ordovician ostracods along the shelf-to-basin transect of the Baltic Palaeobasin

Changes in the morphology of Late Ordovician ostracods along the shelf-to-basin transect of the Baltic Palaeobasin

New Records of Ordovician Ostracodes from Two Genera of the Family Egorovellidae Schallreuter

Based on published data and material from several Ordovician sections of the Siberian Platform and northeastern Russia housed in the Paleontological Institute of the Russian Academy of Sciences, the ostracode family Egorovellidae Schallreuter, 1966 is revised. The family is of great importance for biostratigraphic correlation. The diagnosis of the genus Bodenia V. Ivanova, 1959 is clarified and two new species, B. signata sp. nov. and B. densistriata sp. nov. are described. Two species previously included in Bodenia are removed from the genus and assigned to the family Richinidae: B. aechminiformis is designated as the type species of the new genus Bodeniella gen. nov. and B. anonyma is assigned to the Siberian genus Angarallina Melnikova, 2020. Two new species of the genus Egorovella, E. porilamellata sp. nov., and E. insperata sp. nov., are also described.

Middle to Late Ordovician (late Darriwilian to early Sandbian) ostracods from the Meitan area of northern Guizhou, SW China

Well-preserved ostracods are documented for the first time from the upper Shihtzupu Formation (late Darriwilian to early Sandbian) of northern Guizhou Province, SW China. A total of 10 species are identified, including Pilla reedi (Wolfart, 2001a), Laccochilina (Prochilina) yanpingensis sp. nov., Ulrichia chekiangensis? Hou, 1956, Euprimitia compta Sun, 1987, Aechmina sp., Quadritia sp., Longiscula? sp. 1, Longiscula? sp. 2, Longiscula? sp. 3 and Silenis? sp., with the first two most common. Such an ostracod assemblage shows some similarities to ostracods documented from the Miaopo Formation of the same age in the Yichang area, Hubei Province, southern China, as well as to contemporaneous faunas found in Baltica, Australia, India, Sibumasu and the Argentine Precordillera. A global review of the temporal and spatial distribution of the biogeographically significant genus Pilla suggests that it might have originated in low-latitude areas and then migrated to other peri-Gondwana terranes like South China during the Ordovician. Yichi Zhang [zhangyc@nigpas.ac.cn], School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, PR China; State Key Laboratory of Palaeobiology and Stratigraphy, Center for Excellence in Life and Palaeoenvironment, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, PR China.

New Material on the Ordovician Ostracodes of the Siberian Platform

Twelve new species of Ordovician ostracodes are described from the sections on the Moyero, Angara and Nizhnyaya Chunku rivers. They belong to six previously described genera (Laccochilina, Kiesowia, Disulcina, Foramenella, Hallatina, and Pseudulrichia) and four new genera (Direigina, Korolyukina, Angarallina, and Tesakovites). The taxonomic assignment of Novoglanditesvarius Melnikova, 2003 and Dudinkites cavatus Abushik, 2003 has been revised.

Ordovician Ostracods from the Chunya River Basin (A Right Tributary of the Podkamennaya Tunguska River, Siberian Platform)

The ostracod assemblages of the Baksian and Dolborian horizons of the Chunya River basin (a right tributary of the Podkamennaya Tunguska River) have been studied. They add essentially the paleontological characteristics of Upper Ordovician deposits of the Siberian Platform. The age of deposits was verified and the studied sections were correlated with the Gaindinskaya 3 reference borehole. Two new genera and 9 new species were described. Images for known ostracod species are given.

Japan's earliest ostracods

AbstractMesozoic, Cenozoic and especially Holocene ostracod faunas have been documented from Japan. Not surprisingly, considering the plate tectonic factors at play, very few ostracod faunas are known from its early Paleozoic successions. Our pilot studies have recovered new ostracod assemblages from early Paleozoic terranes of Japan. Acid preparation of carbonates has yielded low diversity, poorly preserved yet significant palaeocopid and podocopid ostracod faunas from Wenlock/Ludlow Series Silurian rocks at Gionyama in the Kurosegawa Terrane, Miyazaki Prefecture, Kyushu, and Hitoegane in the Hida‐Gaien Terrane, Gifu Prefecture, Honshu. The ostracod faunas include new eurychilinoid (Pauproles supparata gen. et sp. nov.), hollinoid (Hollinella orienta sp. nov.) and beyrichioid (Clintiella antifrigga sp. nov.) palaeocopid taxa. Conodonts recovered from the same sample as the ostracods from Gionyama confirm a mid‐Silurian age for the part of the Gionyama Formation in question. The ostracod faunas recovered from Gionyama and Hitoegane are the first confirmed, well‐documented record of the group from the Silurian of Japan and are therefore the earliest known ostracods from that country (a previous record of purported Ordovician ostracods from Japan is incorrect). The ostracod taxa display links with the paleocontinents of particularly Laurentia and Baltica and demonstrate a pan‐tropical signature; it appears that climate control was stronger than geographical control in shaping this pattern of ostracod distribution. The material recovered includes adult dimorphic (assumed sexual) pairs of three palaeocopid species, which represent Japan's oldest (423–433 million years) known ‘couples’.

Radiation, diversity and environmental expansion of Early Ordovician ostracods: a view from the Southern Hemisphere

Radiation, diversity and environmental expansion of Early Ordovician ostracods: a view from the Southern Hemisphere

Upper Darriwilian (Middle Ordovician) Radiolarians and Ostracods from the Hulo Formation, Zhejiang Provicnce, South China

Considerable research has been done on the Ordovician marine fossils from South China, including macrofossils such as brachiopods, graptolites, bivalves, trilobites, some microfossils like conodonts and acritarches. However, radiolarians and ostracods that are also important constituents of the Ordovician marine ecosystem have been paid little attention in this region. In this study, ten radiolarians species belonging to four genera and sixteen ostracods species grouped into nine genera were found from the Hulo Formation at the Hengdu Section of the Jiangshan District, western Zhejiang Province, South China. The fossil-bearing strata belong to the graptolite Pterograptus elegans Zone which indicates the Late Darriwilian Age. This radiolarian fauna is the first record of the Middle Ordovician radiolarian body fossils and also the earliest Ordovician radiolarian fauna reported from South China. The occurrence of Beothuka in this fauna extends the stratigraphic range of the genus to the Upper Darriwilian. Reviews of previous literatures suggest that the diversity of Beothuka was greater during the Early Ordovician, and then declined gradually from the Early Ordovician to the Middle Ordovician before its extinction. The co-occurring ostracod fauna belongs to a shallow-water ecotype. This is contrary to the host lithofacies of the ostracod fauna which represent a deep-water environment. Therefore, these ostacods may have been transported from the shallow-water environment, most likely from the Yangtze carbonate platform. If this conjecture is the truth, then the Jiangshan District was near the shallow-water carbonate platform and received its sediments during the Darriwilian. It is still essential to do more work in the future to better understand the ecology of the Ordovician ostracod fanuas and their role in the sedimentary system of South China.

Ordovician ostracods from the Upper Kalar Graben of northern Transbaikalia, Udokan Region

Ostracods from the Middle Ordovician Nalednyi Formation of the Udokan Region are investigated in detail. A brief history of the study of these deposits and description of the new species Egorovellina (?) shuvalovae sp. nov., Cherskiella baikalica sp. nov., Gontiella mira gen. et sp. nov., Leperditella nalednaya sp. nov., Hallatina opima sp. nov., Primitia kalarensis sp. nov., Glandites planus sp. nov., and Bollia sinitsae sp. nov. are provided. The previously known ostracod species described in open nomenclature are figured.

A Hirnantian deep-water refuge for warm-water ostracods in Baltoscandia

The latest Ordovician is marked by a severe climate change, the Hirnantian glaciation. This climatic event affected many marine taxa including ostracods. Rich and abundant ostracod assemblages of the Baltic Palaeobasin were severly impoverished. Many of the typical pre-Hirnatian warm-water ostracod species died out, but also some distinct, cold-water species appeared. Two very different but likely coeval latest Ordovician ostracod assemblages are recorded in the Baltic countries and north-eastern Poland. The latest Ordovician Estonian Shelf (inner ramp) is characterized by the Medianella aequa association whilst sections in the Livonian Basin (middle to outer ramp) reveal the Harpabollia harparum association that is thought to represent a cold-water assemblage belonging to the Dalmanitina-Hirnantia Fauna sensu lato . A transitional assemblage composed of a “species mixture” of typical Hirnantian cold-water and some pre-Hirnantian warm-water ostracod species is described for the first time from the Ketrzyn IG1 borehole, north-eastern Poland. The assemblage is dominated by Cryptophyllus pius sp. n. The genus Cryptophyllus is rare in the two other well-known assemblages. The discovery suggests that marginal parts of the Baltic Palaeobasin could serve as a kind of refuge for the last representatives of the ostracod faunas of the inner shelf of Baltic Palaeobasin. The Hirnantian assemblage is replaced by the low-diversity recovery assemblage that is dated as late Hirnantian-Silurian in Estonia and other areas. This suggests that the position of the systemic boundary in the Ketrzyn borehole and elsewhere in north-eastern Poland should be re-evaluated.

Late Ordovician ostracods of the Girvan district, south-west Scotland byMohibullah Mohibullah, Mark Williams &Jan Zalasiewicz.Monograph of the Palaeontological Society, London 167 (no. 640, for 2013), 2014. No. of pages: 40 pp., 6 plates. Price: UK£25-00.

Late Ordovician ostracods of the Girvan district, south-west Scotland byMohibullah Mohibullah, Mark Williams &Jan Zalasiewicz.Monograph of the Palaeontological Society, London 167 (no. 640, for 2013), 2014. No. of pages: 40 pp., 6 plates. Price: UK£25-00.

Exceptionally Preserved 450-Million-Year-Old Ordovician Ostracods with Brood Care

Ostracod crustaceans are the most abundant fossil arthropods and are characterized by a long stratigraphic range. However, their soft parts are very rarely preserved, and the presence of ostracods in rocks older than the Silurian period [1-5] was hitherto based on the occurrence of their supposed shells. Pyritized ostracods that preserve limbs and in situ embryos, including an egg within an ovary and possible hatched individuals, are here described from rocks of the Upper Ordovician Katian Stage Lorraine Group of New York State, including examples from the famous Beecher's Trilobite Bed [6, 7]. This discovery extends our knowledge of the paleobiology of ostracods by some 25 million years and provides the first unequivocal demonstration of ostracods in the Ordovician period, including the oldest known myodocope, Luprisca incuba gen. et sp. nov. It also provides conclusive evidence of a developmental brood-care strategy conserved within Ostracoda for at least 450 million years.

The Ordovician ostracodes established by Aurel Krause, Part II

The revision of ostracodes originally established by Aurel Krause is continued and finished with the description of the following species: <i>Primitia distans, P. elongata, P. cincta, P. excavata, P. papillata, P. plicata, P. schmidtii, Strepula limbata, S. simplex, Entomis obliqua, E. plicata, E. sigma, E. sigma ornata, E. simplex, E. trilobata, Beyrichia erratica, B. erratica granulosa, B. erratica acuta, B. harpa</i>, and <i>B. marchica lata</i>. Three of these species are younger primary homonyms. For <i>Beyrichia erratica granulosa</i> Krause, 1891 a respective decision of the ICZN according to art. 23.9.5 is presently unnecessary, because it has an older synonym (<i>Beyrichia grewingkii</i> Bock, 1867), and <i>Primitia excavata</i> Krause, 1892 has a younger synonym (<i>Laccochilina paucigranosa</i> Jaanusson, 1957). The third homonym, <i>Beyrichia marchica lata</i> Krause, 1891, is considered as a nomen protectum. <i>Entomis sigma ornata</i>, and <i>E. plicata</i> are presently considered as nomina dubia. Since the type material of the three species <i>P. distans, E. sigma</i>, and <i>E. simplex</i> is apparently lost, neotypes are designated. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201300007" target="_blank">10.1002/mmng.201300007</a>

The Ordovician ostracodes established by Aurel Krause, Part II

The revision of ostracodes originally established by Aurel Krause is continued and finished with the description of the following species: Primitia distans, P. elongata, P. cincta, P. excavata, P. papillata, P. plicata, P. schmidtii, Strepula limbata, S. simplex, Entomis obliqua, E. plicata, E. sigma, E. sigma ornata, E. simplex, E. trilobata, Beyrichia erratica, B. erratica granulosa, B. erratica acuta, B. harpa, and B. marchica lata. Three of these species are younger primary homonyms. For Beyrichia erratica granulosa Krause, 1891 a respective decision of the ICZN according to art. 23.9.5 is presently unnecessary, because it has an older synonym (Beyrichia grewingkii Bock, 1867), and Primitia excavata Krause, 1892 has a younger synonym (Laccochilina paucigranosa Jaanusson, 1957). The third homonym, Beyrichia marchica lata Krause, 1891, is considered as a nomen protectum. Entomis sigma ornata, and E. plicata are presently considered as nomina dubia. Since the type material of the three species P. distans, E. sigma, and E. simplex is apparently lost, neotypes are designated. doi:10.1002/mmng.201300007

Ordovician sediments in the southeastern Siberian Platform: lithostratigraphy and ostracod zoning

The results of studying Ordovician ostracods from the southeastern Siberian Platform are presented. Ordovician sections are described in brief from outcrop and core studies. Four of the ostracod zones distinguished in the Ordovician strata of the Siberian Platform have been found in the Volgian, Kirenskian–Kudrinoan, Chertovskayan, and Baksanian Horizons. Stratigraphic correlation takes into account the available data on the distribution of other groups (e.g., conodonts and cephalopods)..

Late Ordovician Ostracods of the Girvan District, South-West Scotland

The Late Ordovician ostracod fauna recorded from the Girvan district, south-west Scotland, comprises 54 species from 26 genera and 15 families, but includes 22 species described in open nomenclature and a further 17 that are considered as nomina dubia. The ostracods include representatives of the podocope suborders Palaeocopina, Binodicopina, Leiocopina and Metacopina, and the new genera and species Danemestrinus scotus n. gen. et sp., Leperditella girvanensis n. sp. and Krausella jonesiana n. sp. are described. The fauna includes several species that allow inter-continental correlation with the Late Ordovician succession of North America, including the Sandbian species Eurychilina sunbloodensis, Balticella deckeri, Baltonotella parsispinosa and Hippula ventrospinosa. The Katian species Kinnekullea comma has correlative value between Scotland, Ireland, England and the East Baltic. Biogeographically, the Girvan ostracod fauna of Sandbian age shows strong affinities at species-level with the fauna of palaeocontinental Laurentia, but from the early Katian onwards there are species level links with the Baltic region, and some common taxa at generic and species-level with palaeocontinental Avalonia.

First Middle Ordovician ostracods from western Avalonia: paleogeographical and paleoenvironmental significance

Two new species of ostracods, Conchoprimitia cassidula n. sp. and Sorornanopsis avalonensis n. gen. n. sp., represent the first described Middle Ordovician ostracods from western Avalonia. They were recovered as phosphatized carapaces dissolved out of a late early Darriwilian (ca. 467 Ma) limestone boulder from the Triassic Lepreau Formation of New Brunswick, Canada. The ostracods form a low-diversity component of a higher energy, near-shore, shelf marine fauna dominated by the trilobites Neseuretus and Stapleyella and by the conodonts Drepanoistodus and Baltoniodus. The low diversity of this Avalonian ostracod fauna contrasts with more diverse (tens of species), coeval ostracod faunas from Laurentia and Baltica. The association of Darriwilian ostracods and trilobites from New Brunswick demonstrates continuing exchange of open marine, cool water biota between Avalonia, Baltica, and West and North Gondwana that began in the late early Cambrian.

New, early ostracods from the Ordovician (Tremadocian) of Iran: systematic, biogeographical and palaeoecological significance

New Tremadocian ostracod material from the Alborz Mountains of Iran confirms the early and widespread occurrence of the Ordovician genus Nanopsis, and the apparently simultaneous first appearance of ostracods in the fossil record at the level of the P. deltifer conodont biozone (485.5 Ma) from China to Argentina. Nanopsis pairidaeza sp. nov. adds to the pool of species diversity for the Early Ordovician, though documented Tremadocian ostracod generic diversity remains low, with only four genera. The presence of Early Ordovician ostracods in Alborz, their occurrence elsewhere in palaeocontinental Gondwana, Baltica and China coupled to their marked absence from the Tremadocian of Laurentia and Siberia, supports the notion of the earliest occurrence of ostracods centred on Gondwana/Baltica.

Early Ordovician (Floian) ostracods from the Cordillera Oriental, Northwest Argentina

The ostracod fauna from the Floian (Lower Ordovician) strata of the Cordillera Oriental, Argentina (Acoite Formation) are documented. One new genus Acoitella and four species are recognized, two of which are new (Nanopsis victoria sp. nov. and Conchoprimitia frequens sp. nov.). The diversity of the Early Ordovician ostracod faunas of the Central Andean Basin is evaluated. Compared with other regions, the ostracod diversity, at generic and specific level, of the Cordillera Oriental was comparatively high during the Tremadocian (nine species recorded) and comparatively low during the Floian (four species recorded). The taxonomic composition of the fauna is similar during the entire Early Ordovician of the Cordillera Oriental, where it displays a high percentage of soanellids. The Floian assemblages are characterized by the dominance of the eridostracan C. frequens sp. nov. with a high percentage of nondimorphic palaeocopids: Nanopsis and two genera of the Soanellidae family (Saltite and Acoitella gen nov.). An ostracod shell bed is described and interpreted to be a parautochthonous assemblage, as a result of transport within the same habitat. The composition of the fauna, with the presence of Saltite and Nanopsis, shows significant affinities with East Gondwana. Copyright © 2011 John Wiley & Sons, Ltd.

Late Ordovician (Sandbian) ostracods from the Ardwell Farm Formation, SW Scotland

Synopsis The lower part of the Late Ordovician Ardwell Farm Formation of the Girvan district in SW Scotland yields a low-diversity ostracod fauna comprising six species. Many of these ostracods are biostratigraphically short-ranging North American taxa limited to an interval equivalent to the gracilis and bicornis graptolite biozones. These species include ‘ Ctenobolbina ’ ventrospinosa and Baltonotella parsispinosa that permit inter-regional correlation with the Sandbian strata of the USA and Arctic Canada. This chain of correlation is also confirmed by chitinozoans, such as Belonechitina hirsuta , that occur with the ostracods in the Ardwell Farm Formation. Although allochthonous and transported by turbidity currents into a deep-water clastic-rich basin, the ostracod fauna of the Ardwell Farm Formation resembles other Ordovician deep-water ostracod biotopes, characterized by podocope ostracods and low species diversity. Alternatively the ostracods might simply have been transported from a carbonate ramp setting.