Journal articles: 'Paleontology Oligocene'

1

Gladenkov, Yu B. "The Oligocene of Sakhalin." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 234, no. 1-3 (December 22, 2004): 433–40. http://dx.doi.org/10.1127/njgpa/234/2004/433.

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Abdelghany, Osman, and Mahmoud Faris. "Early Oligocene calcareous nannofossils, planktonic and larger foraminifera from the United Arab Emirates, Oman Mountains." Micropaleontology 63, no. 6 (2018): 445–56. http://dx.doi.org/10.47894/mpal.63.6.06.

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The Lower Oligocene Asmari Formation occupies the western and eastern flanks of the Jabal Hafit anticline and the western limb of the Jabal Malaqet-Mundassah anticline in the southeast of the United Arab Emirates near the Oman border. In this area the Asmari Formation unconformably overlies the Upper Eocene Dammam Formation. In this study an Early Oligocene characteristic assemblage of calcareous nannofossils, foraminifera, corals, calcareous algae, bryozoa, mollusks and echinoids is described from the carbonate rocks of the Asmari Formation. The Asmari stratigraphic succession is dated by analysis of the calcareous nannofossil assemblages and planktonic and larger foraminifera. The results of this study indicate that the succession falls within the Early Oligocene Zones NP24 and P20-P21. About seventeen nannofossil species are documented for the first time in this formation, along with three planktonic and larger foraminiferal species. The Oligocene rocks in the study area provide results consistent with a shallow-water inner shelf within the photic zone.

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Freudenthal, Matias, José Ignacio Lacomba, and Maria Angeles Sacristán. "Classification of european oligocene cricetids." Spanish Journal of Palaeontology 7, no. 3 (August 10, 2022): 49. http://dx.doi.org/10.7203/sjp.25014.

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Benedetti, Andrea. "Benthic foraminiferal turnover at the Eocene-Oligocene transition in the Caltavuturo Formation cropping out near Santa Cristina Gela (Sicily)." Micropaleontology 65, no. 5 (2019): 425–34. http://dx.doi.org/10.47894/mpal.65.5.03.

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A qualitative and quantitative study was carried out on the benthic foraminiferal assemblages from the upper Eocene to lower Oligocene of a section of the Caltavuturo Formation exposed near Piana degli Albanesi (northwestern Sicily). The recognized taxa are evaluated in terms of their ecology and bathymetric interpretation. Biostratigraphic constraints are defined combining both nannofossils and planktic foraminifers biozonations. The planktic-benthic foraminiferal ratio allowed the reconstruction of water depth variations. Atotal of 48 benthic foraminiferal taxawere extracted from the samples. The benthic assemblages and the P/(P+B) ratio indicate a lower to middle bathyal depositional depth, although an abrupt drop of sea level of about 140 m is recorded across the suspected Eocene-Oligocene transition. Calcium carbonate content decreases upsection, suggesting an increase in terrigenous supply in the lowermost Oligocene.

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Kochhann, Karlos Guilherme Diemer, Simone Baecker-Fauth, and Gerson Fauth. "Systematic paleontology and biostratigraphy of Paleocene to late Oligocene Radiolaria from DSDP Site 329, Falkland Plateau, South Atlantic Ocean." Micropaleontology 59, no. 6 (2013): 529–54. http://dx.doi.org/10.47894/mpal.59.6.02.

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A systematic study was carried out on the relatively rich and abundant Paleocene to late Oligocene radiolarian fauna from DSDP Site 329 (Leg 36), located on the Falkland Plateau. Among the 78 taxa identified in the studied interval, a new species (Siphocampe ewingensis n. sp.) and a new combination (Eucyrtidium amygdala (Shilov 1995) n. comb. are proprosed. The high-latitude radiolarian interval zones Eucyrtidium antiquum, Lychnocanoma conica and Clinorhabdus robusta, Oligocene in age, were identified in the upper part of the interval. The lowermost studied sample, within core 33, was assigned to an interval of high-latitude radiolarian zones (RP2-RP5; Paleocene in age), mainly due to the co-occurrence of Amphisphaera kina and Protoxiphotractus wilsoni. These biostratigraphic results improve resolution in the early and late Oligocene, whichwas previously undifferentiated asOligocene, based on calcareous nannofossil biostratigraphy.

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Fraass, Andrew J., and R. Mark Leckie. "Oligocene Planktic Foraminiferal Taxonomy and Evolution: An Illustrated Revision of Ocean Drilling Program Site 803." Journal of Foraminiferal Research 51, no. 3 (July 31, 2021): 139–64. http://dx.doi.org/10.2113/gsjfr.51.3.139.

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ABSTRACT The Oligocene (33.9–23.0 Ma) has historically proven to be a difficult interval to examine with respect to planktic foraminifera; the tendency for many of the taxa to be basically globigerine in shape, with 4 or 5 chambers in the final whorl means differences between species are limited. Recently, an international working group has attempted to clarify the Oligocene planktic foraminiferal taxonomy, with the goal of establishing phylogenetically-consistent generic and species concepts. A relatively expanded and continuous Oligocene section recovered at Ocean Drilling Program Site 803 in the western equatorial Pacific was previously studied by Leckie et al. (1993) using fairly conservative species concepts. Since 1993, foraminiferal biostratigraphic datum age calibrations have changed, and so revised sedimentation rates for the 220-m thick Oligocene sequence are actually more constant than previously thought. As a part of the recent taxonomic revision, this site was reevaluated and numerous additional taxa are recorded at this location. Macroevolutionary rates are calculated from the occurrences, and increased extinction is found within the late Oligocene, counter to the expectations laid out in broader-scale macroevolutionary studies. An effort is made here to describe the diagnostic features, which can be used to distinguish all taxa under a standard binocular microscope. Finally, several figures of scanning electron microscope photomicrographs (from Site 803 and tropical Atlantic Ocean ODP Site 628) depict features used to describe and differentiate important, but difficult or homeomorphic taxa, with the hope that these figures can be used by other workers at the microscope attempting to do Oligocene taxonomy-based studies.

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7

Dingle, Richard V. "Review of the history of the deep-sea ostracod genera Abyssocythere Benson and Dutoitella Dingle, and their responses to Cretaceous - Cenozoic oceanic water-mass changes." Micropaleontology 68, no. 3 (2022): 243–55. http://dx.doi.org/10.47894/mpal.68.3.04.

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Abyssocythere and Dutoitella are extant benthic bathyal ostracod genera that evolved during Coniacian to Santonian/Campanian time from shallow-water progenitors around southeastern Africa. Their Late Cretaceous development was primarily in the South Atlantic, but during the Palaeogene they spread to the Indian and Pacific oceans. The establishment of the psychrosphere (late Eocene-mid-Oligocene) flushed populations of each genus from their central Atlantic cradles into the Pacific, presumably through the Panama Seaway, so that contemporaneous centres of evolution developed disjunct clades: A. trinidadensis and D. praesuhmi. The psychrospheric oceanic event defined temporal thermophyllic and cryophyllic populations of the two genera. Three Neogene ocean events appear to have affected several regionally-confined species, inter alia one of which entailed a counterflow migration of A. atlantica from the eastern Pacific back into the central Atlantic during the mid-Miocene. Modern distributions of Abyssocythere and Dutoitella are disjunct: in the Atlantic both genera occur south of approximately 40 degrees N (Dutoitella), and equatorial areas (Abyssocythere); in the Indian Ocean both are confined to the southern part; and in the Pacific, Abyssocythere is restricted to central and north-eastern areas, and Dutoitella to the west and northwest. Neither genus evolved species that were more than para-cosmopolitan: A. diagrenona (South Atlantic-Indian; Eocene-Oligocene), A. trinidadensis complex (central Atlantic-NW Pacific; Oligocene-Miocene), D. crassinodosa complex (South Atlantic-Indian; Eocene), and D. praesuhmi (north and central Atlantic-central Pacific; Oligocene-Miocene).

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8

Machalskij, D. V. "BACTERIAL PALEONTOLOGY OF THE OLIGOCENE OF THE UKRAINIAN CARPATHIANS." Collection of Scientific Works of the Institute of Geological Sciences of the NAS of Ukraine 2 (April 30, 2009): 277–81. http://dx.doi.org/10.30836/igs.2522-9753.2009.148113.

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9

Benedetti, Andrea. "Biometric study of Planorbulina (Foraminiferida) from the Late Eocene-early Oligocene of Portella Colla (Madonie Mountains, Sicily)." Micropaleontology 63, no. 6 (2018): 403–12. http://dx.doi.org/10.47894/mpal.63.6.03.

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A biometric study was carried out on planorbulinids occurring in eight samples from the upper Eocene-Lower Oligocene sediments of the Caltavuturo Formation cropping out at Portella Colla (Sicily, southern Italy). Counts and measurements on internal characters follow the methods currently employed for the similar genera Planorbulinella and Planolinderina such as the length of the initial spiral and the embryo size. The data obtained from the oriented thin sections allow to assign the late Eocene specimens to Planorbulina bronnimanni, whereas Oligocene specimens show larger embryonic apparatus, but the low amount of measured individuals prevents at present the definition of a new chronospecies. The well-known evolutionary trends of embryonic and nepionic accelerations, documented for the fossil Planorbulinella, seem not to be recognizable for Planorbulina.

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10

Verdenius, Jacob G., and Michael A. Kaminski. "Hyperammina grosserugosa, nom. nov., a replacement name for Hyperammina rugosa Verdenius and Van Hinte 1983." Micropaleontology 66, no. 6 (2020): 572. http://dx.doi.org/10.47894/mpal.66.6.07.

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In 1983 one of us (JGV) in collaboration with J. Van Hinte described the new foraminiferal species Hyperammina rugosa from the Oligocene of DSDP Hole 345 in the Norwegian Sea. It was also reported from the Eocene at Site 346, Lower Miocene at Site 348, and the Oligocene-Miocene at Site 348 (Verdenius and Van Hinte 1983). The species Hyperammina rugosa was subsequently reported throughout the North Sea, Norwegian Sea, and Barents Sea region (Kaminski and Gradstein 2005). The species has been reported more recently from the Miocene of the Fram Strait region and the Central Arctic Ocean by Kaminski et al. (2005, 2009), from the Upper Cretaceous (Santonianâ€“Campanian) of the southern Norwegian Sea by Setoyama and Kaminski (2015), and from the Upper Cretaceous to Paleogene of the Outer Carpathian region by Bindiu et al. (2019) and by Bubik (2019).

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11

Sallam, Magdy. "Benthic foraminifera from the Oligocene offshore Nile Delta, Egypt and its implications." Micropaleontology 59, no. 2-3 (2013): 167–75. http://dx.doi.org/10.47894/mpal.59.2.08.

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The detailed micropaleontological analysis carried out on four offshore Oligocene (Tineh Formation) Nile Delta successions revealed the identification of 44 foraminiferal species and subspecies. Nine benthic and two planktonic zones are identified. The established benthic zonation has been chronostratigraphically calibrated with those based on the planktonic foraminiferal ones. This sequence is assigned to the Oligocene (Chattian), and possibly extends to the upper part ofRupelian.Aremarkable feature of thisOligocene succession is the almost complete absence of planktonic foraminifera in its major lower part, a situation that caused a difficulty of subdividing it into smaller units. The environmental interpretation for theOligocene succession implies deposition under a background of persistent subsidence with remarkable paucity or complete absence of any calcareous fauna, probably related to deposition in carbon dioxide-rich marine conditions hostile to the precipitation of any calcareous material and caused by volcanic activity, lowered temperature or situation under the lysocline or carbonate-compensation depth.

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12

Barkaszi, Zoltán, and Oleksandr Kovalchuk. "New records of Oligocene selachians (Elasmobranchii) from the Outer Carpathian Basin." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 301, no. 2 (August 31, 2021): 171–82. http://dx.doi.org/10.1127/njgpa/2021/1006.

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13

Mckenzie, Kenneth G., Richard A. Reyment, and Eva R. Reyment. "ocene-Oligocene ostracoda from south Australia and Victoria, Australia." Spanish Journal of Palaeontology 6, no. 2 (August 11, 2022): 135. http://dx.doi.org/10.7203/sjp.25056.

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14

Vršanský, Peter, Markus J. Poschmann, and Ľubomír Vidlička. "Oligocene pseudophyllodromiin cockroach from the Enspel Fossillagerstätte in Germany." Palaeontographica Abteilung A 321, no. 1-6 (January 10, 2022): 149–67. http://dx.doi.org/10.1127/pala/2021/0110.

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15

Kaminski, Michael A., and Silvia Ortiz. "The Eocene-Oligocene turnover of Deep-Water Agglutinated Foraminifera at ODPSite 647, Southern Labrador Sea (North Atlantic)." Micropaleontology 60, no. 1 (2014): 53–66. http://dx.doi.org/10.47894/mpal.60.1.06.

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We present a new record of deep-water agglutinated foraminifera (DWAF) across the Eocene-Oligocene Transition (EOT) in the southern Labrador Sea (ODP Site 647). We studied 82 samples from Cores 647A-37R to -27R, and recovered over 100 species and generic groups. The EOT represents an interval of rapid climatic change connected with global cooling, Antarctic glaciation, a substantial decrease in atmospheric CO2, and concurrent changes in the composition of deep waters in the world ocean. Our high-resolution quantitative study of the DWAF faunal succession in abyssal Hole 647A confirms earlier findings that the EOT was an interval of significant faunal turnover. The faunal succession in Hole 647A is subdivided into two assemblages based on the stratigraphic ranges of characteristic benthic foraminiferal species: late Eocene Spiroplectammina trinitatensis-Reticulophragmium amplectens Zone and early Oligocene Ammodiscus latus-Turrilina alsatica Zone. The boundary between these zones, i.e., the Eocene/Oligocene (E/O) boundary, is characterized by the disappearance of 11 DWAF taxa, most of them organically-cemented taxa. The boundary interval was also characterized by a striking sharp decrease in DWAF abundance and diversity. Organically-cemented DWAF taxa increased in abundance in the early Oligocene, but their diversity and abundance never recovered to Eocene values. These data suggest a deepening of the calcite compensation depth and associated changes, such as more vigorous ocean circulation in coincidence with the E/O boundary interval. The analysis of DWAF morphogroups reveals an acme in robust suspension-feeding tubular forms previous to the extinction, suggesting increased bottom water activity. The E/O boundary interval is characterized by an increase in DWAF infaunal taxa and Spiroplectammina species, probably related to increased productivity, as already suggested by the analysis of benthic elongate-cylindrical foraminifera at the same locality. The faunal turnover across the EOT at Hole 647A suggests more vigorous deep-ocean circulation in the latest Eocene and across the E/O boundary interval in the Labrador Sea. It seems reasonable to link the disappearance of DWAF at the E/O boundary at Site 647 to more than one mechanism, including inferred higher productivity, possible competition from calcareous benthic foraminifera, changes in the CO2 content of the atmosphere and ocean, the deepening of the calcite compensation depth, and concurrent changes in taphonomic conditions caused by changes in the water masses in the North Atlantic.

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Engel, Michael S. "Halictine bees from the Eocene-Oligocene boundary of Florissant, Colorado (Hymenoptera: Halictidae)." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 225, no. 2 (August 2, 2002): 251–73. http://dx.doi.org/10.1127/njgpa/225/2002/251.

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17

Reich, Mike. "Holothurian sclerites (Echinodermata) from the Oligocene (Rupelian) of Northern Germany." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 224, no. 1 (April 25, 2002): 97–113. http://dx.doi.org/10.1127/njgpa/224/2002/97.

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18

Briguglio, Antonino, Simone Crobu, Eleni Lutaj, and Michele Piazza. "Integrated stratigraphy from a transgressive upper Oligocene section in NW Italy." Stratigraphy 18, no. 2 (June 15, 2021): 123–37. http://dx.doi.org/10.29041/strat.18.2.03.

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ABSTRACT: The Oligo-Miocene Transition (OMT) is one of the most important climatic transitions of the last 30 million years. This short period of climate warming coincides with a few biotic turnovers, which are well known in deeper marine settings where stratigraphic successions yield a detailed record; in shallowmarine environments they have been proved difficult to recognize as the occurrence and absence of certain taxa due to ecological preferences hamper the study. This study focuses on the Case CnÃ© section in the late Oligocene of the Tertiary Piedmont Basin (TPB) as it represents a gradual transgressive event, which shows the drowning of a locally developed reef complex and development of a deeper marine sedimentary setting influenced by gravity flow mechanics. Larger foraminifera biostratigraphy was used to date the section to the late Oligocene (SBZ23); preliminary strontium isotope data confirms this result. Using sedimentological, semi-quantitative microfacies and geochemical analysis the sedimentary history of the section was reconstructed and divided into four major phases: the drowning of the reef complex, a short prograding phase of the fluvial system, the onset of gravity flow mechanics and a final transgressive phase with an initial turbiditic influence which continues regionally into the Miocene.

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Muftah, Ahmed M., and Mohamed Boukhary. "New Late Eocene genus Gaziryina (Foraminifera) from the Al Bayda Formation (ShahhatMarl Member), Al Jabal al Akhdar, Northern Cyrenaica, Libya." Micropaleontology 59, no. 2-3 (2013): 103–9. http://dx.doi.org/10.47894/mpal.59.2.03.

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The foraminifers of the Shahhat Member of the Al Bayda Formation exposed in three sections (at theWadi Az Zad quarry, and the Wadi Al Kuf and Al Hamamah road cuts) in the region of Jabal Al Akhdar in Libya have been investigated. The rock unit consists of marly limestone grading intomarl in places and is assigned a Late Eocene age according to the presence of forms suggesting the Nummulites fabianii Biozone, and suggesting also the Early Oligocene age, to which the Shahhat Member has been generally assigned in most previous publications should be revised. Nummulites ruetimeyeri de la Harpe 1883 and Chapmanina gassinensis (Silvestri 1904) has been recovered in association with Nummulites fabianii (Prever in Fabiani 1905). Gaziryina pulchellus (Hantken 1883) n. gen. in de la Harpe (1883) has also been retrieved in associationwith a Nonion-Uvigerina assemblage suggesting relatively deep marine conditions in the lower intervals of the investigated Late Eocene marly sequence. Nummulites gizehensis (Forskal) is found in the underlying Darnah Formation (Middle Eocene, Lutetian), and the overlying algal limestone of the remaining of the Al Bayda Formation includes species suggesting the Nummulites fichteli Biozone of Early Oligocene age.

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20

Kvaček, Zlatko, Lilla Hably, and Steven R. Manchester. "Sloanea (Elaeocarpaceae) fruits and foliage from the Early Oligocene of Hungary and Slovenia." Palaeontographica Abteilung B 259, no. 1-6 (October 19, 2001): 113–24. http://dx.doi.org/10.1127/palb/259/2001/113.

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21

Shockey, Bruce J., Rodolfo Salas Gismondi, Phillip Gans, Annie Jeong, and John J. Flynn. "Paleontology and Geochronology of the Deseadan (late Oligocene) of Moquegua, Perú." American Museum Novitates 3668 (November 30, 2009): 1–24. http://dx.doi.org/10.1206/662.1.

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22

Hoem, Frida S., Luis Valero, Dimitris Evangelinos, Carlota Escutia, Bella Duncan, Robert M. McKay, Henk Brinkhuis, Francesca Sangiorgi, and Peter K. Bijl. "Temperate Oligocene surface ocean conditions offshore of Cape Adare, Ross Sea, Antarctica." Climate of the Past 17, no. 4 (July 2, 2021): 1423–42. http://dx.doi.org/10.5194/cp-17-1423-2021.

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Abstract. Antarctic continental ice masses fluctuated considerably during the Oligocene “coolhouse”, at elevated atmospheric CO2 concentrations of ∼600–800 ppm. To assess the role of the ocean in the Oligocene ice sheet variability, reconstruction of past ocean conditions in the proximity of the Antarctic margin is needed. While relatively warm ocean conditions have been reconstructed for the Oligocene offshore of Wilkes Land, the geographical extent of that warmth is unknown. In this study, we reconstruct past surface ocean conditions from glaciomarine sediments recovered from Deep Sea Drilling Project (DSDP) Site 274 offshore of the Ross Sea continental margin. This site, located offshore of Cape Adare is ideally situated to characterise Oligocene regional surface ocean conditions, as it is situated between the colder, higher-latitude Ross Sea continental shelf and the warm-temperate Wilkes Land margin in the Oligocene. We first improve the age model of DSDP Site 274 using integrated bio- and magnetostratigraphy. Subsequently, we analyse organic walled dinoflagellate cyst assemblages and lipid biomarkers (TEX86, TetraEther indeX of 86 carbon atoms) to reconstruct surface palaeoceanographic conditions during the Oligocene (33.7–24.4 Ma). Both TEX86-based sea surface temperature (SST) and microplankton results show temperate (10–17 ∘C ± 5.2 ∘C) surface ocean conditions at Site 274 throughout the Oligocene. Oceanographic conditions between the offshore Wilkes Land margin and Cape Adare became increasingly similar towards the late Oligocene (26.5–24.4 Ma); this is inferred to be the consequence of the widening of the Tasmanian Gateway, which resulted in more interconnected ocean basins and frontal systems. Maintaining marine terminations of terrestrial ice sheets in a proto-Ross Sea with offshore SSTs that are as warm as those suggested by our data requires a strong ice flux fed by intensive precipitation in the Antarctic hinterland during colder orbital states but with extensive surface melt of terrestrial ice during warmer orbital states.

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Kordikova, Elena G. "Remarks on the Oligocene-Miocene mammal paleontology and sequence stratigraphy of South-Western Betpakdala Steppe, South Kazakhstan." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 221, no. 1 (June 28, 2001): 35–79. http://dx.doi.org/10.1127/njgpa/221/2001/35.

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Podobina, Vera M. "The Latdorfian stage and the lower Oligocene foraminiferal zones of the West-Siberian Plain." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 234, no. 1-3 (December 22, 2004): 415–31. http://dx.doi.org/10.1127/njgpa/234/2004/415.

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Gee, Carole T., and Thomas Mörs. "Aquatic macrophytes from the Upper Oligocene fossillagerstätte of Rott (Rhineland, Germany) Part I: Seeds." Palaeontographica Abteilung B 259, no. 1-6 (October 19, 2001): 33–45. http://dx.doi.org/10.1127/palb/259/2001/33.

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Hoem, Frida S., Isabel Sauermilch, Suning Hou, Henk Brinkhuis, Francesca Sangiorgi, and Peter K. Bijl. "Late Eocene–early Miocene evolution of the southern Australian subtropical front: a marine palynological approach." Journal of Micropalaeontology 40, no. 2 (October 29, 2021): 175–93. http://dx.doi.org/10.5194/jm-40-175-2021.

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Abstract. Improvements in our capability to reconstruct ancient surface-ocean conditions based on organic-walled dinoflagellate cyst (dinocyst) assemblages from the Southern Ocean provide an opportunity to better establish past position, strength and oceanography of the subtropical front (STF). Here, we aim to reconstruct the late Eocene to early Miocene (37–20 Ma) depositional and palaeoceanographic history of the STF in the context of the evolving Tasmanian Gateway as well as the potential influence of Antarctic circumpolar flow and intense waxing and waning of ice. We approach this by combining information from seismic lines (revisiting existing data and generating new marine palynological data from Ocean Drilling Program (ODP) Hole 1168A) in the western Tasmanian continental slope. We apply improved taxonomic insights and palaeoecological models to reconstruct the sea surface palaeoenvironmental evolution. Late Eocene–early Oligocene (37–30.5 Ma) assemblages show a progressive transition from dominant terrestrial palynomorphs and inner-neritic dinocyst taxa as well as cysts produced by heterotrophic dinoflagellates to predominantly outer-neritic/oceanic autotrophic taxa. This transition reflects the progressive deepening of the western Tasmanian continental margin, an interpretation supported by our new seismic investigations. The dominance of autotrophic species like Spiniferites spp. and Operculodinium spp. reflects relatively oligotrophic conditions, like those of regions north of the modern-day STF. The increased abundance in the earliest Miocene of Nematosphaeropsis labyrinthus, typical for modern subantarctic zone (frontal) conditions, indicates a cooling and/or closer proximity of the STF to the site . The absence of major shifts in dinocyst assemblages contrasts with other records in the region and suggests that small changes in surface oceanographic conditions occurred during the Oligocene. Despite the relatively southerly (63–55∘ S) location of Site 1168, the rather stable oceanographic conditions reflect the continued influence of the proto-Leeuwin Current along the southern Australian coast as Australia continued to drift northward. The relatively “warm” dinocyst assemblages at ODP Site 1168, compared with the cold assemblages at Antarctic Integrated Ocean Drilling Program (IODP) Site U1356, testify to the establishment of a pronounced latitudinal temperature gradient in the Oligocene Southern Ocean.

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Aljahdali, Mohammed, Sherwood W. Wise, James E. Bergen, and James J. Pospichal. "A new biostratigraphically significant Late Oligocene Sphenolithus species from the equatorial region." Micropaleontology 61, no. 3 (2015): 193–97. http://dx.doi.org/10.47894/mpal.61.3.06.

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Sphenolithus avis n. sp. is a new calcareous nannofossil species described in materials recovered from Ocean Drilling Program (ODP) sites in the equatorial region. Sphenolithus avis n. sp. is small to medium size with a short tapered apical spine and a large flaring proximal cycle. Its stratigraphic range spans Martini Zones NP23 to NP25, and it is widely distributed in three different equatorial regions, ranging from marginal to deep-sea locations. Because of its relatively short range and global distribution, S. avis n. sp. is a potential secondary Sphenolithus zonal marker in the upper Oligocene.

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Takata, Hiroyuki, Jong-min Lee, Sabura Sakai, Ritsuo Nomura, Hiroshi Nishi, Akira Tsujimoto, Hyoun Soo Lim, and Boo-Keun Khim. "Impact of early Oligocene deep water circulation to the benthic foraminifera in the eastern equatorial Pacific." Micropaleontology 61, no. 3 (2015): 177–84. http://dx.doi.org/10.47894/mpal.61.3.04.

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We investigated benthic foraminifera in the eastern equatorial Pacific Ocean at the Integrated OceanDrilling Program Site U1334 (~3580 to 3650m paleo-depth) during a time interval of ~33.2–31.9Ma, which is characterized by paleoceanographic changes after the “overshoot” associated with the Antarctic glaciation across the Eocene-Oligocene transition. Correlation between MDS axis 1 (faunal composition of benthic foraminifera) and the fragmentation rate of planktonic foraminifera was positive. MDS axis 1 was also positively correlatedwith the d13C values of benthic foraminifera at Site 1218. The positive correlation between the benthic foraminiferal d13C values at Site 1218 and the fragmentation rate at Site U1334 did not correspond to the general relationship between the benthic foraminiferal d13C values and carbonate corrosivity. Transient common occurrence and subsequent gradual decrease of Astrononion echnolsi, a characteristic species of MDS axis 1 that appeared to expand temporarily from the Southern Ocean to the abyssal Pacific, occurred abundantly during ~33.2–31.9Ma. The similarities among MDS axis 1, the fragmentation rate and the benthic foraminiferal d13C values were likely explained by the heterogeneity in carbonate corrosivity changes, associated with different extent of export production in the Southern Ocean compared to other oceans after the Oi-1 Antarctic glaciation. Such heterogeneity might result from the transient expansion of the Southern Ocean deep water into the abyssal Pacific during the earliest Oligocene.

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Lima, Daniel, Orangel Aguilera, and Marcos Tavares. "The Inachoididae spider crabs (Crustacea, Brachyura) from the Neogene of the tropical Americas." Journal of Paleontology 96, no. 2 (October 11, 2021): 334–54. http://dx.doi.org/10.1017/jpa.2021.91.

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AbstractThe spider crabs Willinachoides santanai n. gen. n. sp. from the early-middle Miocene of north Brazil and Paradasygyius rodriguezi n. sp. from the late Miocene of Venezuela are described and illustrated. Additionally, Eoinachoides senni Van Straelen, 1933, from the late Oligocene–early Miocene of Venezuela, is redescribed based on photographs of the holotype, and the diagnosis of Eoinachoides latispinosus Carriol, Muizon, and Secretan, 1987, from the late Miocene of Peru, is emended also on the basis of photographs of the holotype. The past distribution points to a Tethyan background for the current amphi-American Inachoididae, with the oldest fossil species known from the early Eocene Tethyan regions (Pakistan and Italy), and from the late Eocene–late Pliocene of the Americas. The high number of monotypic genera in Inachoididae could be the result of rapid dispersion followed by diversification during the Neogene of the tropical America, facilitated by global and regional events (e.g., eustatic sea level changes, the Mi-1 Oligocene-Miocene boundary global cooling, the global warming period of the Middle Miocene Climate maximum, closure of the Panama Isthmus, and marine incursions into the Amazon Basin). The shoaling and final closure of the Central American Seaway are thought to have critically affected the evolution of the inachoidids and shaped their current distribution patterns.UUID: http://zoobank.org/6275fdc4-4bfa-4873-9320-3143d4915172.

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Přikryl, Tomáš, Jasdeep Kaur, and Alison M. Murray. "New Oligocene Pseudocrenilabrinae cichlid fishes (Teleostei, Cichlidae) from freshwater deposits of Libya." Journal of Systematic Palaeontology 19, no. 19 (October 2, 2021): 1343–66. http://dx.doi.org/10.1080/14772019.2022.2033861.

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Müller, Johannes. "Cranial osteology from Dracaenosaurus croizeti, a lacertid lizard from the Oligocene of France (Reptilia, Squamata)." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 232, no. 2-3 (July 9, 2004): 253–66. http://dx.doi.org/10.1127/njgpa/232/2004/253.

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Maus, Michael, and Michael Wuttke. "The ontogenetic development of Pelobates cf. decheni tadpoles from the Upper Oligocene of Enspel (Westerwald, Germany)." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 232, no. 2-3 (July 9, 2004): 215–30. http://dx.doi.org/10.1127/njgpa/232/2004/215.

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Toffanin, Federica, Claudia Agnini, Domenico Rio, Gary Acton, and Thomas Westerhold. "Middle Eocene to early Oligocene calcareous nannofossil biostratigraphy at IODP Site U1333 (equatorial Pacific)." Micropaleontology 59, no. 1 (2013): 69–82. http://dx.doi.org/10.47894/mpal.59.1.04.

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We present a biostratigraphic and biochronologic study of calcareous nannofossils of middle Eocene - early Oligocene age recovered during IODP Expedition 320, at Hole U1333C in the equatorial Pacific Ocean. The study succession encompasses nannofossil Zones NP16–NP21 (equivalent to CP13–CP16) and Chrons C20r–C12r (middle Eocene-early Oligocene). The distribution patterns of calcareous nannofossil taxa are studied by means of relative abundance and semiquantitative counts with the final aim to test the reliability of biohorizons used in the Paleogene standard biozonations (Martini 1971; Okada and Bukry 1980) and check alternative bioevents included in a more recent mid-latitudes biostratigraphic scheme (Fornaciari et al. 2010). Calibration ages are estimated based on the ranges of the biozones relative to a detailed magnetostratigraphy constructed for the site. Of particular biostratigraphic significance, our study shows that the Top of Sphenolithus furcatolithoides, the Base of common and continuous occurrence (Bc) of Dictyococcites bisectus and the total range of Sphenolithus obtusus can be used to better constrain the middle Eocene interval. The studied sediments cover the crucial time period that followed maximum Cenozoic warmth and led up to the initial major glaciation on Antarctica, including two important climatic events, the Middle Eocene Climatic Optimum (MECO), a transient episode of global warming during a long-term cooling trend, and the Oi-1 event. The peculiar regime in sedimentation observed in the equatorial Pacific, which roughly consists of alternating phases of Carbonate Accumulation Events (CAE) and crashes in carbonate content, are correlated with increases and decreases in calcareous nannofossil abundances. A more detailed comparison indicates that the MECO corresponds to an interval with very low carbonate in between CAE3 and CAE4. This event is correlative with the Top of S. furcatolithoides, the Bc of D. bisectus and a prominent increase in the relative abundance of heavy calcified nannofossils (e.g., discoasters).

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Cavagnetto, Carla. "Palynoflora from the As Pontes Basin, Galicia, Spain at the transition Rupelian-Chattian (Oligocene)." Palaeontographica Abteilung B 263, no. 1-6 (December 17, 2002): 161–204. http://dx.doi.org/10.1127/palb/263/2002/161.

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Brinkmann, Winand, and Michael Rauhe. "Diplocynodon ratelii Pomel, 1847 (Crocodylia, Leidyosuchidae) from the Lower Oligocene of Cereste (Southern France)." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 209, no. 3 (September 7, 1998): 295–321. http://dx.doi.org/10.1127/njgpa/209/1998/295.

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Kvaček, Zlatko, and Harald Walther. "The Oligocene of Central Europe and the development of forest vegetation in space and time based on megafossils." Palaeontographica Abteilung B 259, no. 1-6 (October 19, 2001): 125–48. http://dx.doi.org/10.1127/palb/259/2001/125.

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Hofmann, Peter, Michael Urbat, and Andreas Hensel. "Geochemical cycles recorded in Late Oligocene lake sediments of the Kärlicher Blauton (Neuwied Basin, Germany): a response to climate?" Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 235, no. 2 (March 17, 2005): 265–87. http://dx.doi.org/10.1127/njgpa/235/2005/265.

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Daneshian, Jahanbakhsh, Mahboobeh Sadat Tabatabaei, and Alireza Tahmasbi Sarvestani. "Upper Eocene and Lower Oligocene planktic foraminifera from the Bandar Abbas hinterland, southern Iran: Biostratigraphy and sea-level changes." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 305, no. 3 (September 30, 2022): 245–62. http://dx.doi.org/10.1127/njgpa/2022/1089.

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Yang, Tao, Weiyu Liang, Jiahao Cai, Haoran Gu, Lei Han, Hongyu Chen, Haojian Wang, Lin Bao, and Defei Yan. "A new cyprinid from the Oligocene of Qaidam Basin, north-eastern Tibetan plateau, and its implications." Journal of Systematic Palaeontology 19, no. 17 (September 2, 2021): 1161–82. http://dx.doi.org/10.1080/14772019.2021.2015470.

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Morlo, Michael, and Doris Nagel. "New Didymoconidae (Mammalia) from the Oligocene of Central Mongolia and first information on the tooth eruption sequence of the family." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 223, no. 1 (January 18, 2002): 123–44. http://dx.doi.org/10.1127/njgpa/223/2002/123.

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Hamdan, Abdulrahim, Mohamed Boukhary, Fayez Ahmad, Radwan Abul-Nasr, and Ahmad Samadi. "Nummulites fichteli Michelotti 1841: a new record from Jordan." Micropaleontology 59, no. 2-3 (2013): 111–18. http://dx.doi.org/10.47894/mpal.59.2.04.

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Nummulites fichteli Michelotti, is identified from a nummulitic bank atWadi Al Bisseh Section (W. Al Ghadaf), east Jordan. This species is an index species for the Rupelian. It represents a new Nummulites record for the Oligocene in Jordan. The age of the sampled stratigraphic level was previously dated bymeans of echinoids (Zachos et al. 2008). Biometrical studies on N. fichteli show that it is distinct from N. intermedius Schaub 1981. According to Schaub (1981) Nummulites fichteli is considered as the ancestral form of Nummulites sublaevigatus d’Archiac and Haime 1853. It is also a descendant species of N. fabianii retiatus Roveda 1959. According to Boukhary et al. 2010, Nummulites emiratus (of Rupelian age) is the descendant species of N. fabianii while Nummulites ptukhiani (Early Priabonian) is possibly the direct ancestor of N. retiatus since N. fabianii and N. retiatus are not phylogenetically related.

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Lu, Xiaoyu, Loïc Costeur, Marguerite Hugueney, and Olivier Maridet. "New data on early Oligocene dormice (Rodentia, Gliridae) from southern Europe: phylogeny and diversification of the family." Journal of Systematic Palaeontology 19, no. 3 (February 1, 2021): 169–89. http://dx.doi.org/10.1080/14772019.2021.1888814.

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Amoo, Michael, Ulrich Salzmann, Matthew J. Pound, Nick Thompson, and Peter K. Bijl. "Eocene to Oligocene vegetation and climate in the Tasmanian Gateway region were controlled by changes in ocean currents and <i>p</i>CO<sub>2</sub>." Climate of the Past 18, no. 3 (March 22, 2022): 525–46. http://dx.doi.org/10.5194/cp-18-525-2022.

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Abstract. Considered one of the most significant climate reorganizations of the Cenozoic period, the Eocene–Oligocene Transition (EOT; ca. 34.44–33.65) is characterized by global cooling and the first major glacial advance on Antarctica. In the southern high latitudes, the EOT cooling is primarily recorded in the marine realm, and its extent and effect on the terrestrial climate and vegetation are poorly documented. Here, we present new, well-dated, continuous, high-resolution palynological (sporomorph) data and quantitative sporomorph-based climate estimates recovered from the East Tasman Plateau (ODP Site 1172) to reconstruct climate and vegetation dynamics from the late Eocene (37.97 Ma) to the early Oligocene (33.06 Ma). Our results indicate three major climate transitions and four vegetation communities occupying Tasmania under different precipitation and temperature regimes: (i) a warm-temperate Nothofagus–Podocarpaceae-dominated rainforest with paratropical elements from 37.97 to 37.52 Ma; (ii) a cool-temperate Nothofagus-dominated rainforest with secondary Podocarpaceae rapidly expanding and taking over regions previously occupied by the warmer taxa between 37.306 and 35.60 Ma; (iii) fluctuation between warm-temperate–paratropical taxa and cool temperate forest from 35.50 to 34.49 Ma, followed by a cool phase across the EOT (34.30–33.82 Ma); and (iv) a post-EOT (earliest Oligocene) recovery characterized by a warm-temperate forest association from 33.55 to 33.06 Ma. Coincident with changes in the stratification of water masses and sequestration of carbon from surface water in the Southern Ocean, our sporomorph-based temperature estimates between 37.52 and 35.60 Ma (phase ii) showed 2–3 ∘C terrestrial cooling. The unusual fluctuation between warm and cold temperate forest between 35.50 to 34.59 Ma is suggested to be linked to the initial deepening of the Tasmanian Gateway, allowing eastern Tasmania to come under the influence of warm water associated with the proto-Leeuwin Current (PLC). Further to the above, our terrestrial data show the mean annual temperature declining by about 2 ∘C across the EOT before recovering in the earliest Oligocene. This phenomenon is synchronous with regional and global cooling during the EOT and linked to declining pCO2. However, the earliest Oligocene climate rebound along eastern Tasmania is linked to a transient recovery of atmospheric pCO2 and sustained deepening of the Tasmanian Gateway, promoting PLC throughflow. The three main climate transitional events across the studied interval (late Eocene–earliest Oligocene) in the Tasmanian Gateway region suggest that changes in ocean circulation due to accelerated deepening of the Tasmanian Gateway may not have been solely responsible for the changes in terrestrial climate and vegetation dynamics; a series of regional and global events, including a change in the stratification of water masses, sequestration of carbon from surface waters, and changes in pCO2, may have also played vital roles.

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Bose, Kanishka, Shiladri S. Das, and Subhronil Mondal. "An updated generic classification of Cenozoic pleurotomariid gastropods, with new records from the Oligocene and early Miocene of India." Journal of Paleontology 95, no. 4 (March 3, 2021): 763–76. http://dx.doi.org/10.1017/jpa.2021.4.

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AbstractAlthough taxonomically distinct, the Cenozoic pleurotomariids are the bottlenecked remnants of the Mesozoic members of the family in terms of morphology, with only conical forms surviving the end-Cretaceous mass extinction. Here, we propose an updated classification scheme for the Cenozoic representatives of this group, based on data from the entire Cenozoic pleurotomariid fossil record. We consider all conventional as well as several new characters so that this scheme can readily help to distinguish Cenozoic pleurotomariid genera. Following the new classification scheme, a revision of the generic status of Cenozoic species previously assigned to ‘Pleurotomaria’ Defrance, 1826 is presented.Only a few Cenozoic pleurotomariid gastropods have been reported from the Indian subcontinent. Here we report four species from the Oligocene of the Kutch Basin and the early Miocene (Burdigalian) of the Dwarka Basin of Gujarat, western India, of which two are described as new: Perotrochus bermotiensis n. sp., Entemnotrochus kathiawarensis n. sp., Entemnotrochus cf. E. bianconii, and Entemnotrochus? sp. 1.UUID: http://zoobank.org/89b6ff67-2834-477f-862b-67691104aca4

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Flórez, Paola, Emanuela Di Martino, and Laís V. Ramalho. "Early Miocene coral reef-associated bryozoans from Colombia. Part II: “Ascophora” Cheilostomatida." Journal of Paleontology 96, no. 2 (October 29, 2021): 274–303. http://dx.doi.org/10.1017/jpa.2021.94.

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AbstractBryozoans are common and diverse in fossil and modern coral reefs. However, studies of bryozoans in ancient reefs are generally limited, and even less is known about fossil bryozoan faunas associated with coral reefs in the Caribbean region. This is the second contribution describing the bryozoan assemblage from the early Miocene (Aquitanian) reefs of the Siamaná Formation in the La Guajira Peninsula, southern Caribbean. Here, we describe and illustrate 17 species of ascophoran-grade cheilostomes, including one new genus and three new species, Ditaxiporina colombiana n. sp., Poricella paulae n. sp., and Cycloavicularia parva n. gen. n. sp. Of the remaining fourteen taxa left in open nomenclature, one is considered confer and three affinis to species previously described, one is identified at family level, and nine at genus level. The Siamaná bryozoan fauna differs in species and colony-form composition from those associated with other paleoenvironments from Oligocene and Miocene localities of North America, the Caribbean, and Brazil.UUID: http://zoobank.org/043eadcf-0e39-4c1b-b207-f7628d6b5c84

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Kalthoff, Daniela C. "Incisor enamel microstructure and its implications to higher-level systematics of Eurasian Oligocene and Early Miocene hamsters (Rodentia)." Palaeontographica Abteilung A 277, no. 1-6 (October 30, 2006): 67–80. http://dx.doi.org/10.1127/pala/277/2006/67.

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Martínez, Gastón, María T. Dozo, Javier N. Gelfo, Martín R. Ciancio, and Rolando González-José. "A new toxodont (Mammalia, Panperissodactyla, Notoungulata) from the Oligocene of Patagonia, Argentina, and systematic considerations on the paraphyletic ‘Notohippidae’." Journal of Systematic Palaeontology 18, no. 24 (December 16, 2020): 1995–2013. http://dx.doi.org/10.1080/14772019.2021.1872723.

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Briguglio, Antonino, Grazia Vannucci, Clarissa Bruzzone, and Michele Piazza. "Stratigraphic development of a Late Oligocene Reef Complex under strong fluviatile influence in the Tertiary Piedmont Basin (Liguria, NWItaly)." Micropaleontology 67, no. 4 (2021): 315–39. http://dx.doi.org/10.47894/mpal.67.4.01.

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The modern-day decline of coral reefs due to bleaching events has been recognized as one of the major consequences of man-driven climate change. However, also eutrophication has been highlighted as an equally great danger for coral reefs and as such for biodiversity hotspots. In the latest years this phenomenon has moved to the forefront in the scientific community. Fossil reefs play a key role in studying the emergence, development and faunal/floral diversity of reef environments under eutrophic conditions. Their importance as valuable data sources for studying long-term changes of coral reef environments and their resilience cannot be disputed, especially since they may record the complete life cycle of a reef complex. In this study, nine sections nearby the town of Dego (Savona Province, NW Italy) are presented and discussed with regards to their lithostratigraphic and paleontological contents. Due to the extensive amount of data, the original morphology of a fringing reef, consisting of core, flank and fore reef, under strong fluviatile influence could be reconstructed. This study emphasizes the importance of the coralline red algae association in such biocarbonatic build-ups as major constituent and as substrate stabilizers. The sections record the original colonization event of the local basement by the builder community, the emergence of the coral reef and finally the suffocation by the fluviatile sediments. The variation of the red algae association reflects a deepening trend and is possibly correlated to enhanced fluvial input, which tends to deteriorate ecological conditions and functions as a major trigger for initial reef suffocation.

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Alvarez Sierra, María de los Angeles, Remmert Daams, and Pablo Pelaez-Campomanes. "The Late Oligocene rodent faunas of Canales (MP28) and Parrales (MP29) from the Loranca Basin, Province of Cuenca, Spain." Spanish Journal of Palaeontology 14, no. 1 (February 23, 2022): 93. http://dx.doi.org/10.7203/sjp.23691.

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Wade, Bridget S., Mohammed H. Aljahdali, Yahya A. Mufrreh, Abdullah M. Memesh, Salih A. AlSoubhi, and Iyad S. Zalmout. "Upper Eocene planktonic foraminifera from northern Saudi Arabia: implications for stratigraphic ranges." Journal of Micropalaeontology 40, no. 2 (September 28, 2021): 145–61. http://dx.doi.org/10.5194/jm-40-145-2021.

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Abstract. The Rashrashiyah Formation of the Sirhan Basin in northern Saudi Arabia contains diverse assemblages of planktonic foraminifera. We examined the biostratigraphy, stratigraphic range and preservation of upper Eocene planktonic foraminifera. Assemblages are well-preserved and diverse, with 40 species and 11 genera. All samples are assigned to the Priabonian Globigerinatheka semiinvoluta Highest Occurrence Zone (E14), consistent with calcareous nannofossil biostratigraphy indicating Zone CNE17. Well-preserved planktonic foraminifera assemblages from the lower part of the upper Eocene are rare worldwide. Our study provides new insights into the stratigraphic ranges of many species. We find older (Zone E14) stratigraphic occurrences of several species of Globoturborotalita previously thought to have evolved in the latest Eocene (Zone E15, E16) or Oligocene; these include G. barbula, G. cancellata, G. gnaucki, G. pseudopraebulloides, and G. paracancellata. Older stratigraphic occurrences for Dentoglobigerina taci and Subbotina projecta are also found, and Globigerinatheka kugleri occurs at a younger stratigraphic level than previously proposed. Our revisions to stratigraphic ranges indicate that the late Eocene had a higher tropical–subtropical diversity of planktonic foraminifera than hitherto reported.

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Journal articles on the topic 'Paleontology Oligocene'

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